Climate positive activities are aimed at not only achieving but surpassing net zero emission goals through eradicating additional carbon dioxide (CO2) and/or greenhouse gases (GHG) from the atmosphere. In short, it’s about saving more GHG emissions than your actions produce, in order to create an environmental benefit.
When developing a climate positive strategy, the first stage is to apply a carbon accounting framework. For instance, if a building product manufacturer wants to develop a climate neutral or positive product, they must determine the total carbon footprint of that product. The carbon footprint covers everything — from the energy needed to source the original material/s as well as to produce, supply, use and dispose of the product — to the emissions related to product original material/s sourcing as well as product production, usage and disposal.
Once the total carbon footprint is calculated, as well as what needs to be counteracted to become carbon neutral, then an additional measurement number, such as an extra 10% for example, can then be tagged on to estimate what is needed to go climate positive.
How enterprises actually achieve climate positivity can differ. Usually, however, they meet the requirements via a mixture of reducing carbon emissions, shifting to renewable energy, producing locally, investing into offsetting, and purchasing carbon credits.
Transforming Your Real Estate
Buildings can realize climate-positive results in a number of ways, and simply put, the steps to climate positive are the steps to net zero plus that extra mile, whatever takes the building to remove more greenhouse gas (GHG) than it is producing. The building’s strategy should include a mixture of the following steps:
CHOOSE: the optimal building location, design, energy modelling, eco-friendly materials, renewable energy and intelligent energy management systems
MAXIMISE: the structural efficiency, insulation and greenhouse gas reduction systems
MINIMISE: the material and operational wastage and water usage
MAINTAIN: the hardware and software
RE-USE: upon current-use obsolescence


Visit the forum if you have a language query!
- (Britain, Australia) tô(r)-nā'dō, /tɔː(ɹ)ˈneɪdəʊ/, /tO:(r)"neId@U/
- WEAE /toɹˈnaɪ.do/
From Spanish tronada (thunderstorm) < tronar (to thunder) < Latin tonare (to thunder) < Proto-Indo-European *(s)tene- (to thunder). The 'o' and 'r' were reversed in English (metathesis) under influence of Spanish tornar (to twist, to turn) < Latin tornare (to turn).
- (meteorology) A violently rotating column of air, pendant from a cumulonimbus cloud, and nearly always observable as a funnel cloud or tuba. On a local scale, it is the most destructive of all atmospheric phenomena. Its vortex, commonly several hundred yards in diameter, rotates counterclockwise in the northern hemisphere and clockwise in the southern hemisphere with wind speeds of 100 to more than 300 miles per hour (161 to 483 kmph). Its general direction of travel is governed by the motion of its parent cloud.
- tornado watch, tornado warning (A tornado watch means that conditions are favorable for producing a tornado. A tornado warning means that a tornado has been sighted in the area or has been detected on radar.)
- tornado shelter
- A rolled pork roast.
Nountornado m. (plural tornados)
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January 30, 2019 - Cold!
Coldest day in Winnipeg in almost 12 years. February 5, 2007 we hit -41.7C. This morning we got down to -39.9C (or -40.0C) depending on the weather station at the airport. My sensor saw -37.6C. The 'warm spells' are the heat from the HRV unit - which is exhausting warm air from the house about 3m away from the temperature sensor.


As most of our hunting areas are placed in the middle region of Anatolia; You can feel a typical anatolian climate in the year. In winter you can see low snow and mostly the temperature is not below 0 celcius in both wildboar and Bezoar hunting areas. In the summer period the weather is sunny but not very hot like at the Mediterranean Coast.
In Summer of Anatolian region the average temperature is running
between + 20 till +26 celcius.
The Blacksea Region has a climate where rainfall averages more than the other regions of Turkey and winters are mild. Also East hunting areas has very low temperatures below 0 celcius in hunting periods.


penpals from Bahamas - Students of the World. Magician, Mailman, Mannequin, Top model, Mechanic, Meteorologist, Midwife, Museum director, Musician
by TC Peterson - 2002 - Cited by 70 - Related articles15 Nov 2002 Freeport Weather Department, Grand Bahama Airport Co., Ltd., Bahamas. Selvin Burton. Caribbean Institute of Meteorology and Hydrology,
File Format: PDF/Adobe Acrobat - Quick ViewOctober. 49 hurricanes passed near The Bahamas between 1886 and 1990. An analysis of hurricane activity by the Meteorological Department revealed that the
Chief Meteorologist Jason Kelley In The Bahamas For The Bahamian Weather Conference Fri, 17 Apr 2009 20:41:00 EST.
This pre-hurricane season event is an important forum for Bahamian and U.S. meteorologists, raising awareness of the particular concerns and geographical
24 Mar 2010 Akinyede, however, admitted that Nigeria lacked meteorological facilities to capture and Australia Dollar (AUD), Bahamian Dollar (BSD)
File Format: PDF/Adobe Acrobat - Quick Viewwanted to be a meteorologist. And then we moved to the East coast to Norfolk, Virginia, Bahamas, the Grand Bahama Bank and also the Caribbean.
Nassau , The Bahamas -- The 31st session of the World Meteorological Organization's Hurricane Committee opened on Monday with a reminder of the impact
25 Aug 2008 Grand Bahama, Chief Meteorologist Donna Duncombe is encouraging residents to Home " National " GB Residents Advised Prepare for
Meantime, meteorologist Arnold King said Bahamians should continue to prepare for hurricane-like situations as the season is already proving to be a very
9 Jul 2009 Thursday 24th September, meteorologist Wayne Neely author of “The Major Hurricanes to affect the Bahamas” and “The 1929 Hurricane” will
Hurricane season 2008: Meteorologist Dr. William Gray Grand Bahama Island - An exclusive interview by The Bahamas Weekly News Team with famed hurricane
bahamian meteorologist bill evans meteorologist certified broadcast meteorologist carey coleman meteorologist what meteorologist predict about weather
This book provides a rare glimpse of three significant meteorological events that affected every part the Bahamian Society in 1926. Through vivid and unique
File Format: PDF/Adobe Acrobat - Quick Viewby FF Whitakera - Cited by 10 - Related articles1 A. Distribution of rainfall in the Bahamian Archipelago [from data supplied by the Bahamas Meteorological Office and from Mather


Most Americans today believe that the burning of fossil fuels is causing global warming, but not everybody agrees. Climate contrarians proclaim that global warming is not occurring at all, or that it is occurring but is entirely natural, i.e., that the anthropogenic (human) contribution to global warming is negligible. The contrarian ranks include the well-known radical journalist Alexander Cockburn, who forcefully proclaimed anthropogenic global warming to be a myth in three articles published in 2007 on the CounterPunch Web site and in The Nation.1
I have been reading Cockburn’s political writings with pleasure, and usually with agreement, for three decades, dating back to his career at The Village Voice. However, as a physics professor who has lectured on global warming since 2001, I emphatically disagree with Cockburn’s perspective on global warming.2 I am also dissatisfied with the quality of much of the response that Cockburn’s articles have evoked, as judged by the letters columns in The Nation.3
Most climate scientists believe that the human contribution to today’s global warming is important, and cannot by any means be dismissed as negligible. The consequences of global warming are potentially very dangerous. In view of the importance of the issue, and in view of Cockburn’s prominent (and well-deserved) role as a left intellectual and his formidable powers of persuasion, it is worthwhile restating the scientific case for modern anthropogenic global warming.
The present article consists of (1) a summary of the scientific case for modern anthropogenic global warming, (2) a summary of the contrarian case advanced by Cockburn, (3) an assessment of global warming in greater depth, and (4) my detailed critique of the contrarian arguments advanced by Cockburn.
The scientific case is not dependent on citation of authority, no matter how distinguished the authority may be. The case is dependent upon experimental evidence, logic, and reason. The present article does not touch on the impact of global warming, or on policy questions: what to do about global warming, whether the Kyoto treaty is a good idea or not, etc.
Part 1: Summary of the Case for Modern Anthropogenic Global Warming
When sunlight strikes the earth, infrared radiation is emitted by the earth. Greenhouse gases in the atmosphere absorb this radiation, which results in a warming of the earth. The greenhouse effect is a very large effect: without greenhouse gases in the atmosphere, the earth’s surface would likely be below the freezing point of water. Carbon dioxide (CO2) in the atmosphere has been increasing since the Industrial Revolution began, due primarily to the burning of fossil fuels and to deforestation. This increase in greenhouse gases causes an enhanced greenhouse effect, which warms the earth.
A straightforward calculation reveals that when the CO2 in the atmosphere reaches twice the pre-industrial level, the enhanced greenhouse effect alone (i.e., neglecting any response by the earth to the enhanced greenhouse effect) will warm the earth by 1.2 to 1.3˚C. There is no significant controversy among scientists about this part of global warming.
The earth will in fact respond to the increased temperature. This is called “feedback.” There is controversy about the magnitude of the feedback. Analysis that takes feedback into account predicts global warming in the range of 1.5 to 4.5˚C (as indicated by the Intergovernmental Panel on Climate Change [IPCC]). Controversies among climate scientists concern the magnitude of the warming, not whether or not it is occurring.
Climate is controlled by a number of factors, including changes in the earth’s orbit, possibly solar variability, possibly volcanoes, and the greenhouse effect. All but the last factor are entirely natural. Human activities are not the only contribution to the greenhouse effect. Until the last two centuries, humanity had a negligible effect on climate, and all climate change was naturally occurring. Some climate changes in the distant past have been very large (e.g., ice ages) and were not caused by humans. None of these statements refute the proposition that human activities (particularly burning fossil fuels) are an important contribution to the global warming that is occurring right now.
Part 2: Summary of Alexander Cockburn’s Contrarian Arguments
In his articles in The Nation and on the CounterPunch Web site, Alexander Cockburn makes six arguments against anthropogenic global warming:
- During the Great Depression of the 1930s, the burning of fossil fuels plunged by 30 percent, but the concentration of CO2 in the atmosphere did not decrease. Therefore, he contends, increased atmospheric CO2 does not come from the burning of fossil fuels.
- Water vapor, not CO2, is the main greenhouse gas, and the portion of global warming attributable to CO2 is therefore tiny.
- When the earth emerged from the most recent ice age some 10,000 years ago, the global temperature and the concentration of atmospheric CO2 both rose, but the temperature rise preceded a rise in atmospheric CO2. Therefore it was the warming that caused the rise in CO2 and not vice-versa. The warming was caused by a Milankovitch cycle, a small change in the earth’s motion.
- The increasing concentration of CO2 in the atmosphere is caused by CO2 coming out of the oceans, not by the burning of fossil fuels. Hence the increase in atmospheric CO2 is natural, not anthropogenic.
- The residence time of CO2 in the atmosphere is only a year or two before it dissolves in the ocean. This turns out to be important in supporting point 4 above.
- The forecasts of anthropogenic global warming are entirely dependent on the results of large-scale computer models, which can be easily manipulated by the computer modelers to get any result they want by tweaking the variables in the computer models.
Based on these scientific arguments, Cockburn goes on to argue that the computer modelers proclaim their unjustified doomsday forecasts in order to keep their grant funds flowing. He also argues that the nuclear power industry is supporting global warming hysteria in order to promote nuclear power.
Part 3: Global Warming in More Depth
The greenhouse effect warms the earth. The warming power of the sun is mostly in the visible and ultraviolet region of the spectrum. The surface of the earth re-radiates solar energy back toward space in the form of infrared light. Because of greenhouse gases in it, the atmosphere is transparent to the visible light coming from the sun, but opaque at many wavelengths in the infrared band, resulting in the trapping of thermal energy and the warming of the earth. This is the so-called greenhouse effect, which has been known for two centuries.4 The first scientist to realize that the atmosphere warms the earth may have been the French mathematician and physicist Joseph Fourier in the 1820s (who should not be confused with the journalist and utopian socialist Charles Fourier). The primary greenhouse gases are water vapor, CO2, and methane (natural gas, CH4). I don’t know any scientist who doubts that the greenhouse effect is a real effect.
Too many people fail to appreciate how large the greenhouse effect really is. A simple calculation based on the Stefan-Boltzmann law shows that if there were no greenhouse gases in the atmosphere (and if nothing else about the earth changed as a result of removing the greenhouse gases), the average surface temperature of the earth would be –18˚C (–1˚F), which is below the freezing point of water.5
The actual observed average surface temperature of the earth is 15˚C (59˚F). Thus the greenhouse effect raises the earth’s surface temperature by 33˚C (60˚F). In this sense, global warming has already happened! Not only is the greenhouse effect a real effect, it is a large effect.
The greenhouse effect is intensifying as a result of the greenhouse gases building up in the atmosphere due primarily to CO2 from the burning of fossil fuels (coal, oil, and natural gas) and deforestation. Accurate data by direct experimental measurement was not available until 1959, when the geochemist C. D. Keeling started taking data at Mauna Loa, Hawaii. That measurement program has continued up to the present.6 Chart 1 shows the data from 1959 to the present.
The data show a seasonal cycle that matches the growing season in the Northern Hemisphere, with a maximum in May and a minimum in October.7 Most significant is a long-term upward trend: from 315 ppm in 1958 to 387 ppm in 2008. While other aspects of global warming have been controversial, nobody has ever doubted the data from this measurement program. The data are rock solid. Several research teams have measured the atmospheric CO2 concentrations and the data from the different researchers are in agreement.
Although the earliest data from direct measurement of CO2 in the atmosphere are from 1958, it is possible to extend the data earlier by examining air bubbles trapped in ice in Antarctica and Greenland. Data on the long-term CO2 trend show that the CO2 level remained stable around 280 ppm during the last 10,000 years.8 Then CO2 began to rise around the time of the Industrial Revolution, and is now 38 percent higher than pre-industrial levels. Climate scientists attribute the pre-industrial level of CO2 (280 ppm) to natural causes, and the rise since then to human activity, primarily due to the aforementioned causes.
Chart 1. Concentration of atmospheric CO2, measured at the Mauna Loa observatory, showing the increase in atmospheric CO2 (ppm)
The question naturally arises, what will be the effect of increased greenhouse gases? Since the greenhouse effect is a real effect, it is hard to avoid the conclusion that the buildup of greenhouse gases will result in an intensified greenhouse effect, resulting in increased global warming to some extent. In other words, the argument is over the amount of increased global warming, not over whether or not it is occurring. The amount of increased global warming might be small or large, but it is a real effect. The important scientific question is whether or not increased global warming will be large enough to cause a problem.
To answer this question, we need to understand in more detail how greenhouse gases absorb light in the infrared band. Different gases absorb light of different wavelengths. Measurements from outside the earth’s atmosphere by a satellite show that CO2 has a particularly strong absorption of light around wavelengths of 15 micrometers.9 Gavin Schmidt in 2005, following work done by Ramanathan and Coakley in 1978, calculated the effect of greenhouse gases in the following way: If you remove one gas from the atmosphere, while keeping all the other gases constant, what is the resulting percentage change in the infrared power that is absorbed by the atmosphere?10 Schmidt obtained the following numbers, shown in table 1.
Table 1. Contributions to the greenhouse effect by different greenhouse gases
Source: Gavin Schmidt, (http://www.realclimate.org/index.php?p=142).
The data in table 1 were computed by assuming that one gas is removed from the atmosphere, leaving everything else unchanged. But since there is overlapping infrared absorption, the absorption from one species will interact with the absorption from another species. Some wavelengths of infrared light are absorbed by both water vapor and CO2. At these overlapping regions, if you remove water vapor alone (leaving the CO2), the CO2 will absorb the infrared light, while if you remove CO2 from the atmosphere (leaving the water vapor), the water vapor will absorb the infrared light. Thus the absorption by one species depends on what other species are present in the atmosphere. This accounts for the otherwise puzzling fact that the numbers do not add up linearly: If you remove all water vapor from the atmosphere, the infrared absorption will decrease by 36 percent. If you remove all greenhouse gases (and clouds) and leave only water vapor, the infrared absorption will decrease by 34 percent. The two do not add up to 100 percent, because of overlaps.
All this is valuable background for the crucial question: How important is CO2 in the greenhouse effect? If you remove all the CO2 from the atmosphere, the infrared absorption decreases by 9 percent. If you remove all the greenhouse gases (including clouds) from the atmosphere except CO2, the absorption decreases by 74 percent, meaning that 26 percent (= 100 percent – 74 percent) of the absorption is still present if CO2 were the only greenhouse gas in the atmosphere. So the effect of CO2 can be either 9 percent or 26 percent of the greenhouse effect, depending on how it is defined. Undoubtedly the different definitions account, in part, for the different values cited in the literature for the importance of CO2 in the greenhouse effect. But whether it is 9 percent or 26 percent, the effect of CO2 is not a negligible effect.
For water vapor, the table above gives two numbers: 36 percent and 66 percent (= 100 – 34), depending on the definition. From the table above, the water vapor contribution to the greenhouse effect is 36 to 66 percent, while the contribution of CO2 is 9 to 26 percent, depending on the definition. Taking the first numbers, water vapor is more important by a factor of 36/9 = 4.0, and taking the second numbers, water vapor is more important by a factor of 66/26 = 2.5. Note that water vapor is somewhat more important than CO2, but CO2 is by no means negligible.
How Much Warming? A Naïve and Frightening Miscalculation
Let’s ask what the result would be if the greenhouse gases in the atmosphere were to double? A naïve (and incorrect) calculation would be the following: Since the existing level of greenhouse gases resulted in a temperature increase of 33˚C (60˚F) compared to a hypothetical earth without greenhouse gases, then doubling of all the greenhouse gases would result in an additional increase of 33˚C (60˚F), giving an average surface temperature of the earth of 48˚C (119˚F). Fortunately, this frightening result stems from a misunderstanding of how greenhouse gases retain heat. The prediction of the IPCC is that doubling the level of CO2 will result in a temperature increase of a few degrees Celsius. It is at first glance surprising and welcome that the forecasted effects of global warming are smaller than this naïve calculation would expect.
This naïve calculation is incorrect for two reasons. First, the effect of saturation. The atmosphere is already opaque in parts of the infrared spectrum. Increasing the level of greenhouse gases will not make any difference at those parts of the spectrum. If the absorption at a certain wavelength is close to 100 percent, doubling the CO2 level will not double the greenhouse effect. For example, suppose that at a certain wavelength, 90 percent of the infrared light from the earth is absorbed by CO2 in today’s atmosphere. If the concentration of CO2 in the atmosphere were doubled, the absorption cannot go to 180 percent, which is an impossibility, but will go instead to nearly 100 percent.
Second, the effect of spectral overlap. The absorption of infrared light by water vapor has areas of overlap with the absorption by CO2. In regions where infrared light is already strongly absorbed by water vapor, changing the concentration of CO2 will make little or no difference. These two effects (saturation and spectral overlap) explain why naïvely adding the effects of greenhouse gases is not correct, and overestimates the effect of increased greenhouse gases on the transmission of the atmosphere.
An increasing concentration of CO2 will have little effect at the center of a strong absorption peak, because the atmosphere is opaque there already. Instead, an increasing concentration of CO2 will have its largest effect on the wings of a strong peak. The atmosphere is opaque in some parts of the infrared, with “windows” where the atmosphere is transparent or partially transparent. The effect of increasing concentrations of CO2 is to close the windows.
Although this naïve calculation is mistaken, it illustrates an important point. People are often surprised at the thought that CO2, present in the atmosphere at only a few hundred parts per million, can result in a large enough change in the earth’s average temperature to make a difference. Instead, the real surprise is that global warming is as small as it is.
How Much Warming?
Climate scientists separate the climate problem into two parts: climate forcing and climate response. The forcing includes possible changes in the brightness of the sun, or changes in the greenhouse effect.11 The climate response is a resulting change in the equilibrium temperature. The climate sensitivity is the change in temperature divided by the climate forcing. A very simple calculation from a standard textbook shows that (if you make the assumption that nothing else in the system changes) a doubling of CO2 from the pre-industrial levels is estimated12 to produce a temperature rise of about 1.2 to 1.3˚C (2.2 to 2.3˚F). The calculation is straightforward enough that there is little controversy in the scientific community about it. The logic is hard to dispute: the greenhouse effect is a real effect, the burning of fossil fuels leads to increasing concentrations of CO2, producing an enhanced greenhouse effect. The resulting temperature rise, if you assume that nothing else changes in the meantime, is only 1.2 to 1.3˚C.
It’s All About the Feedback
The real challenge in climate science comes with the assumption that when the greenhouse effect is intensified by increasing CO2 concentration, nothing else changes. This increase of 1.2 to 1.3˚C only takes into account the direct atmospheric warming associated with the enhanced greenhouse effect. It does not take into account any changes in the system. These changes are “feedback.”
If the feedback is positive, then changes in the earth will enhance the change in temperature, and global warming arising from a doubling of pre-industrial CO2 will be more than 1.2 to 1.3˚C. If the feedback is negative, then changes in the earth will counteract the change in temperature, and global warming from a doubling of pre-industrial CO2 will be less than that. If the feedback is positive, then temperature change feeds on itself. If the feedback is negative, then temperature change will be self-limiting.
If the feedback is positive, it does not imply that temperature changes would feed upon themselves forever. An enhanced greenhouse effect causes a rise in the average temperature of the earth, which in turn will increase the power radiated by the earth, as given by the Stefan-Boltzmann law. The average temperature of the earth will rise from the present value to a new, higher average temperature, “glowing” more brightly and re-radiating more energy into space until a new equilibrium is reached. Global warming is about the shift in the equilibrium temperature, arising from the enhanced greenhouse effect.
The estimate of the IPCC is that doubling the concentration of CO2 in the atmosphere will lead to an increase of 1.5 to 4.5˚C (2.7 to 8.1˚F). The predicted temperatures consist of 1.2 to 1.3˚C from the enhanced greenhouse effect that is multiplied by an “amplification factor” arising from positive feedback. The calculated amplification factor is in the range from 1.2 to 3.75. If the amplification factor is 1.2, then the temperature will be 20 percent higher than it would be in the absence of feedback, while if the amplification factor is 3.75, the temperature rise will be nearly quadruple what it would be in the absence of feedback. The controversy is all about the feedback. That’s what the climate scientists are arguing about: How much is the feedback?
Two important examples of positive feedback are the ice-albedo effect and water vapor.
The ice-albedo effect: If the temperature increases, ice and snow melt near the poles, replacing white snow with dark earth. Since snow reflects sunlight while earth absorbs sunlight, this decreases the reflectance (“albedo”) of the earth. Decreased reflectance means that a larger fraction of the sunlight falling on the earth is absorbed. This in turn leads to further warming. Thus a small warming leads to larger warming.
The ice-albedo effect can also work in reverse: A small decrease in temperature will lead to increased snow cover, resulting in higher albedo, meaning that more of the sunlight falling on the earth is reflected and less is absorbed. Thus a small cooling leads to a larger cooling.
Water vapor: Warmer air can hold more water vapor than cooler air. The so-called saturation vapor pressure of water rises with temperature. Thus, a small temperature rise can lead to an increased water vapor concentration, which in turn results in an enhanced greenhouse effect, and more warming.
If the temperature decreases from 15˚C by 1˚C, the equilibrium vapor pressure of water decreases by 6 percent, while if the temperature increases by 1˚C, the equilibrium vapor pressure increases by 7 percent. This is quite significant given the importance of water vapor as a greenhouse gas.
It is helpful to clarify an important point: Climate scientists believe that water vapor is a feedback, not a forcing. If you somehow removed all the water vapor from the atmosphere, it would restore itself in a matter of weeks. After all, most of the surface of the earth is covered by water. Change in the water vapor in the air is one of the ways that the earth reacts to external forcings. And it’s a positive feedback.
Possible Negative Feedback Mechanisms
In addition to positive feedback mechanisms, there are possible negative feedback mechanisms. For example, if increased temperatures cause more clouds, and if clouds have a net cooling effect (this is uncertain), then this would constitute a negative feedback mechanism.
Another suggested negative feedback mechanism was the “adaptive iris” proposed by MIT professor Richard Lindzen in the early 1980s. Lindzen proposed that increased sea-surface temperatures in the tropics lead to decreased cirrus cloud formation, leading in turn to increased “leakage” of infrared radiation, which amounts to a decreased greenhouse effect. The upshot is negative feedback. Lindzen, a global warming skeptic, agrees that increased atmospheric CO2 leads to an enhanced greenhouse effect, but does not believe that feedback is positive.
The full complexity of modern climate science arises in attempting to grapple with the feedback. The number of possible feedbacks is quite complex.13 The crucial question is the sign and magnitude of the feedback. In view of the complexity of the system, it may very well not be possible to determine from first principles whether the feedback is positive or negative. However, there are other pieces of evidence that support positive feedback. In analyzing the past temperature record, the temperature changes are larger than would be expected if there were no feedback. This will be pointed out in several sections below.
Climate Change in the Past
If you look at the temperature record for a long span of time, you find that there have been changes in the temperature in the past, including big changes. During the Cretaceous Period 100 million years ago, the global mean surface temperature may have been as much as 6–8˚C (11–14˚F) higher than today. Obviously these temperature changes in the distant past had nothing to do with human activities, because there were no humans back then. Climate scientists do not contend that climate changes in the past were due to humans. They do maintain that the global warming we are experiencing now is at least partially due to human activities.
The Ice Ages
In the past million years, the earth has undergone ten major and forty minor episodes of glaciation. The triggers for these events are believed to be changes in the motion of the earth, first investigated by Milutin Milanković in the 1920s. Specifically, the tilt of the axis goes from 22 degrees to 24.5 degrees and back again every 41,000 years. The month when the earth is closest to the sun varies in cycles of 19,000 years and 24,000 years. The shape of the orbit is observed to vary from elliptical to nearly circular, with a period of 100,000 years. These slow variations arise from the gravitational forces and torques exerted on the earth by the other planets (especially Jupiter and Saturn), the sun, and the moon.
The climate science community almost unanimously believes that the Milankovitch cycles are the triggers for the beginning and ending of ice ages, because the timing of the climate changes agrees so well with the observed orbital changes of the earth and planets. (Nevertheless there are some unresolved problems in the frequencies of changes: the orbital changes predict a 400,000-year cycle, but no such cycle is observed in the climate record of the last million years.)
Although the Milankovitch cycles get the period of the cycles (mostly) right, problems arise when attempting to calculate the intensity of the cooling that results from the changing sunlight. The “effect” (temperature change) is bigger than the “cause” (changing sunlight). A standard textbook remarks that “orbital changes alone appear not to have caused the vast climate shifts associated with glaciation and deglaciation.”14 This means that the response of the earth to changing sunlight may increase the effect; i.e., this is evidence for positive feedback.15
In addition to Milankovitch cycles and the enhanced greenhouse effect, another possible cause of climate change is solar variability. Since 1979, spacecraft-borne instruments have recorded variations in the sun’s output, on time scales ranging from minutes to decades. The largest short-term dips of 0.3 percent last about a month, and are associated with sunspots that are carried across the face of the sun. (The sun’s rotation rate has a period of twenty-seven days.) The eleven-year sunspot cycle is associated with changes in the sun’s output of about 0.1 percent.
There are no precise measurements of the solar output before 1979, and no direct measurements at all before about 1900. Instead, climate scientists rely on proxy indicators of solar activity, isotopes in cosmic rays, carbon-14 (14C) and beryllium-10 (10Be), which are found in tree rings and ice deposits, respectively. This record stretches back thousands of years.
The sun may make a contribution to climate change, at least in the period before 1800. Lean and Rind believe that in the period 1600–1800, the reconstructed solar radiation (from proxy indicators 14C and 10Be) correlates well with the surface temperature of the Northern Hemisphere. If you use that period to compute a climate sensitivity, you get an increase in solar radiation of 0.14 percent, which is too small by a factor of two to account for the observed temperature rise of 0.28˚C, in the absence of positive feedback. If the modest climate changes in the period 1600–1800 are attributed to solar variations, then this is another argument in favor of positive feedback.
The climate fluctuations in the period 1600–1800 can perhaps be attributed to solar forcing, if you assume positive feedback. However, the warming in the twentieth century is a different story. In the last quarter of the twentieth century, solar changes can account for less than one third of the observed warming.16
Part 4: Scientific Rebuttal to Contrarian Arguments
Contrarian Claim 1: The Great Depression Argument.
Alexander Cockburn argues that during the Great Depression of the 1930s, worldwide anthropogenic production of CO2 fell by 30 percent, but the concentration of atmospheric CO2 didn’t fall by even one part per million, at a time when the atmospheric concentration was just over 300 ppm. Cockburn’s data indicate that worldwide annual CO2 production from fossil fuel plunged 30 percent, from 1.17 gigatons (Gt [1 Gt = 1012 kilograms, i.e., a billion metric tons]) in 1929 to 0.88 Gt in 1932, but the CO2 concentration did not fall by even 1 ppm. Cockburn cites the following figures: 306 ppm in 1928 and 1929, and 307 in 1932.
Cockburn proclaimed that “a whopping 30 percent cut in man-made CO2 emissions didn’t even cause a 1 ppm drop in the atmosphere’s CO2. Thus it is impossible to assert that the increase in atmospheric CO2 stems from human burning of fossil fuels.”17 Cockburn does not specify how large an effect on the CO2 mixing ratio he expects to see, but clearly, in his mind, there ought to be a drop of at least 1 ppm, if anthropogenic CO2 were a significant contributor to the atmospheric CO2.
Let’s calculate how large an effect should be expected, using Cockburn’s numbers. First, let’s distinguish between a reservoir of carbon and a flux of carbon. The atmosphere is a reservoir holding a certain amount of carbon, while the annual production of CO2 is a flux, transferring a certain amount of carbon to the atmosphere every year. The reservoir of carbon (as CO2) in the atmosphere is proportional to the concentration (expressed as parts per million), measured by the Mauna Loa observatory. The flux from burning fossil fuel (and other anthropogenic sources) is a certain amount of CO2 injected into the atmosphere every year.
The pre-industrial level of CO2 in the atmosphere was about 280 ppm. As a result of the industrial revolution, the level crept up to just over 300 ppm by the onset of the Great Depression. The increase of 20 ppm (= 300 – 280) was primarily due to the accumulated emissions from fossil fuels since the beginning of the Industrial Revolution. If the Great Depression had cut the burning of fossil fuels to zero, the result would have been the gradual decrease (over a long period) from 300 ppm back down to the pre-industrial level of 280 ppm.
Nobody should expect a 30 percent decrease in the 300 ppm level of atmospheric CO2, because 280 ppm is natural. Instead you expect a 30 percent decrease in the rate at which CO2 is increasing in the atmosphere.
In more detail: Even after cutting back the burning of fossil fuels in the Great Depression, the fluxes were still unbalanced, and atmospheric CO2 continued to increase. In the 1995 IPCC report, which covers the 1980s, the following numbers reveal the reservoir and fluxes to and from the atmosphere.
The reservoir of carbon in the atmosphere was 750 Gt in the 1980s—this is the total mass of all carbon in the atmosphere. The atmospheric concentration was about 340 ppm. From these numbers, we can calculate that back in the early 1930s, when the atmospheric concentration was 300 ppm—i.e., 88 percent (300/340 x 100) of the value in the 1980s—the atmospheric reservoir was about 662 Gt., i.e., 88 percent of the value in the 1980s (662 = 750 x 300/340), since the concentration is proportional to the total amount (reservoir) of carbon.
Cockburn’s estimate of the pre-Depression (1929) rate of carbon emissions (the flux) is 1.17 Gt/year. To simplify, let’s assume that all of the CO2 emitted were retained in the atmosphere and all other fluxes were balanced. This would be associated with an annual increase of 0.18 percent (1.17/662 x 100) in the atmospheric CO2 concentration. That’s an expected increase of 0.54 ppm (0.18 percent of 300 ppm) in the CO2 concentration.
By 1932 the fossil fuel consumption rate had fallen from 1.17 Gt/year to 0.88 Gt/year. This is a 30 percent drop in the rate at which the CO2 level increases. But it just means that you expect the annual increase in atmospheric CO2 to be 0.13 percent (0.88/662 x 100) instead of 0.18 percent, or 0.39 ppm (0.13 percent of 300 ppm) instead of 0.54 ppm. It is the rate of increase that has fallen, from 0.18 to 0.13 percent or from 0.54 ppm to 0.39 ppm. Thus, the rate of increase has fallen by 0.15 ppm (= 0.54 – 0.39).
To recap: If the Depression hadn’t happened, you would expect an annual increase of 0.54 ppm. But since the Depression did happen, you expect an increase of 0.39 ppm. The difference is 0.15 ppm.
Is it realistic to expect to be able to detect a change in the concentration of CO2 in the atmosphere from such a small change in the rate of flux over just a few years? The signal of 0.15 ppm should be compared with the year-to-year noise in the data. Looking at the data in the 1980s, where the high-quality post-1958 data from Mauna Loa is available, I examined the year-to-year fluctuations. There are ten years in the series 1980–1989. For each year, I obtained the CO2 concentration in ppm. By subtracting one year from the previous year I obtained the increase from the previous year. These ranged from 1.2 ppm to 2.55 ppm. Then I calculated the change from one year to the next of that increase. I had nine data points (= 10 – 1). Six of the nine data points had year-to-year fluctuations of more than 0.15 ppm, and three data points had less than 0.15 ppm year-to-year fluctuations. So, even in this favorable case, where the Mauna Loa has more reliable data than that which Cockburn cited from the air bubbles in the ice records, you would not expect to detect a change of 0.15 ppm.
Furthermore, I simplified the calculation by assuming that all the CO2 from fossil fuel burning was retained in the atmosphere. Today’s climate scientists believe that roughly half of the CO2 injected into the atmosphere by burning fossil fuel is retained in the atmosphere, with the other half dissolving in the ocean (over a period of decades to a century or two). My simplified calculation is, thus, an overestimate, by roughly a factor of two, of the increase expected in the CO2 mixing ratio.
In conclusion, the Great Depression argument is not valid. The expected impact of the cutback of CO2 emissions that occurred between 1929 and 1932 is too small relative to the historical buildup of CO2 in the atmosphere to show up in Cockburn’s numbers.
Contrarian Claim 2: Water Vapor Is Vastly More Important than CO2 as a Greenhouse Gas.
Cockburn thinks18 water vapor is more important than CO2 as a greenhouse gas by a factor of 20. Cockburn did not cite any source for this number. It’s true that CO2 has a smaller greenhouse effect than water vapor, but only by a factor of 2.5 to 4.0 (as shown above), and it is the concentration of CO2 in the atmosphere that has been changing rapidly due to anthropogenic forces. The effect of CO2 is appreciable. The numbers advanced by Cockburn, claiming that CO2 is negligible, are wrong. These numbers circulate among the contrarians. The large absorption in the infrared band caused by CO2 is in and of itself clear evidence of the importance of CO2.
Contrarian Claim 3: The rise in CO2 around 10,000 years ago happened after the beginning of the end of the last ice age, not before. Therefore the rise in atmospheric CO2 is a consequence of global warming, not a cause of global warming.
Cockburn is entirely correct when he says that when the last ice age started to end about 10–12 thousand years ago, the triggering cause was not CO2. Instead, the trigger is believed to be a Milankovitch cycle. This topic is found in standard textbook treatments.19
Cockburn thinks this is a crushing blow against the claim of anthropogenic global warming. He thinks that there is one factor determining the climate, so if he can prove that increasing temperature caused increased CO2 and not vice-versa at any one time (10,000 years ago), then he has proven it for all times.
Many decades ago, numerous scientists also thought that there was one overriding factor determining climate. They no longer think so. Instead, the current scientific thinking is that there are a number of factors that influence climate, including: greenhouse gases in the atmosphere, the reflection of light from the earth’s surface, the exact shape of the earth’s orbit (which varies according to the Milankovitch cycle), and changes in the sun’s intensity.
Which factor is more important? That varies from one era to another. (a) The event that initiated the ending of the last ice age was a Milankovitch cycle. Once the process started, increasing CO2 levels caused further warming. (b) During the period 1600–1800, a plausible argument can be made that solar variations caused appreciable temperature changes. (c) The temperature rise during the last half of the twentieth century is caused by the enhanced greenhouse effect, resulting from the burning of fossil fuels.
Cockburn lays great stress on the timing issue: 10,000 years ago, the rise in temperature preceded the rise in CO2 levels. This proves (and I agree) that CO2 didn’t cause the beginning of deglaciation (the end of the ice age).
But in the last two centuries, the rise in CO2 preceded the rise in temperature. This strongly suggests that the rise in CO2 caused the rise in temperature. The CO2 in the atmosphere has risen since 1800 and especially since 1950, while it was steady for centuries until about 1800. In the modern era, the rise in CO2 came first, then the rise in temperature.
Contrarian Claim 4: The rise in atmospheric CO2 comes from the ocean, not from burning fossil fuel. Thus the rise is natural and not anthropogenic.
Climate scientists believe that CO2 from the burning of fossil fuels and deforestation enriches the CO2 in the atmosphere. Cockburn believes that most of the increased CO2 in the atmosphere comes from the ocean instead. So where does the CO2 in the atmosphere come from, the burning of fossil fuels, or the ocean?
Nature has performed an experiment to decide this question, by putting a label on CO2 molecules, and using one kind of label on CO2 from fossil fuels and deforestation, while putting another kind of label on CO2 from the ocean. We can examine the CO2 molecules in the atmosphere, and the labels will tell us whether the CO2 is coming from burning fossil fuels or from the oceans.
The labels are carbon isotopes. Most carbon atoms have an atomic mass of 12, but about one percent have an atomic mass of 13. Carbon-12 atoms can be distinguished from carbon-13 atoms in the laboratory, and both kinds of carbon atoms can form CO2 molecules. So about 1 percent of the CO2 we exhale is 13CO2.
The two types of CO2, 13CO2 and 12CO2, behave pretty much the same during most chemical reactions. However, some biological processes show “isotopic fractionation,” in which one isotope is more readily used than the other. For example, in photosynthesis, plants take in CO2 from the air to build up their biomass. Terrestrial plants have a preference to take in 12CO2 instead of 13CO2, so the CO2 in plants is richer in 12C and poorer in 13C than the surrounding atmosphere.
In other words, while the abundance of 13C is about one percent of the abundance of 12C, it’s not exactly one percent. The ratio of abundances of 13C to 12C can be slightly higher or slightly lower than one percent depending on the source.
Scientists compare the abundance of 13C relative to 12C using the so-called d13C scale. The 13C/12C ratio in a sample is compared to the ratio in a standard material. If the 13C/12C ratio in the sample is exactly the same as the ratio in the standard, then d13C = 0. If the sample is enriched in 13C relative to the standard, the sample is assigned a positive d13C value, while if the sample is depleted in 13C relative to the standard, the sample is assigned a negative d13C value. If the 13C/12C ratio in the sample is higher than the standard by 0.1 percent, then the d13C for that sample is +1. If the 13C/12C ratio in a sample is lower than the standard by 0.2 percent, the d13C for that sample is –2.
The d13C values for fossil fuels/biomass, the atmosphere, and the oceans are shown in table 2. Notice that the value of d13C in the atmosphere is in between the level for fossil fuel/biomass and the value for the surface waters of the oceans.
If the CO2 in the atmosphere (whose d13C is –8) comes from the surface of the oceans (whose d13C is positive) then the d13C of the atmosphere will increase with time. However, if CO2 in the atmosphere comes from burning fossil fuel (whose d13C is –27), then the d13C of the atmosphere will decrease.
The result, from the Mauna Loa observatory, shows the 13C/12C ratio in atmospheric CO2 is decreasing with time.20 These data conclusively demonstrate that the increasing CO2 in the atmosphere comes from burning fossil fuels and deforestation, and not from CO2 released by the oceans to the atmosphere. This conclusion does not depend on the validity of computer models.
In a response to critics who raised exactly the issue of isotopic abundance ratios in CO2, Cockburn replied that burning fossil fuel is not the only way of introducing 13C-poor material into the atmosphere. Cockburn believed that “cold ocean waters absorb lightweight 12C preferentially, resulting in lots of 13C-deﬁcient carbon in the oceans. This low-13C carbon most certainly would have been released massively into the atmosphere over the course of the world’s warming trend since 1850….”21
Cockburn would have a valid point if the ocean surface waters were in fact depleted in 13C. Unfortunately for his argument, the ocean surface waters are enhanced in 13C, while the deep ocean is depleted in 13C. Clearly, Cockburn is wrong on this point.
Contrarian Claim 5: A short atmospheric residence time for CO2.
How long does CO2 stay in the atmosphere before permanently dissolving in the ocean? This may seem like an unimportant detail, but it turns out to be an important question. If atmospheric CO2 dissolved in the ocean in a short time (a year or two), then cutting back on emissions would promptly lower the atmospheric concentration of CO2. However, if the residence time is long (decades to centuries), then the human race will be stuck with the consequences of global warming for a long time.
This was once the subject of an enormous amount of controversy. As recently as the 1950s, many scientists thought that atmospheric CO2 would dissolve almost immediately in the oceans. This was one important reason why many scientists paid little attention to global warming—they thought it was impossible. Estimates of the atmospheric residence time for CO2 ranged from 6 months to 10,000 years.
Shortly after C. D. Keeling began his measurement of atmospheric CO2 in 1958, it became clear that atmospheric CO2 was accumulating. This ruled out the short lifetimes: If atmospheric CO2 could dissolve in the ocean in a year or two, it would not be accumulating in the atmosphere.
Modern scientists understand that the dissolving of atmospheric CO2 into the oceans is a three-step process: (1) transfer of CO2 across the air-sea interface, (2) chemical interaction of dissolved CO2 with seawater constituents, and (3) transport of CO2 to the deep ocean by vertical mixing.
Steps 2 and 3 are the rate-limiting steps—i.e., these are the processes that happen fairly slowly, making the absorption of atmospheric CO2 by the oceans take decades or centuries, rather than years. The chemistry of seawater is complicated. A thorough treatment of CO2 in seawater involves the bicarbonate ion (HCO3–), boric acid (B[OH]3) and the borate ion (B[OH]4–). The inclusion of the last two species is surprising to many scientists without a background in ocean chemistry. The subject is complicated enough to merit a 356-page monograph.22
For a long time, many scientists misunderstood the problem. They looked up the solubility of CO2 in water, and there seemed to be nothing to prevent CO2 from dissolving rapidly in the ocean. However, these scientists misconceived the problem. The solubility tells you whether all the atmospheric CO2 can dissolve eventually in the ocean. And all the CO2 can dissolve, but it takes a long time to reach equilibrium.
This is the wrong approach. It’s not an equilibrium problem. Instead, it’s a transient problem. The real question is: How long does the system take to reach equilibrium? This was not understood by scientists until the mid-1950s.
It has been estimated that of 100 molecules of CO2 injected into the atmosphere, 6 molecules will dissolve in the ocean in 1 year; 29 molecules will dissolve in 10 years; 59 molecules will dissolve in 60 years; 84 molecules will dissolve in 360 years; and the last 16 molecules will take over 1,000 years.23
This is the result of a number of different processes taking place on different time scales. There is not a single time scale for dissolving CO2 in the ocean, but it takes a long time. Because it was once a very contentious area, there were lots of naïve ideas circulating, that are now known to be wrong. Those ideas don’t ever totally die away. Since 1960, many new people have entered the field of climatology, and people with technical backgrounds but little experience in climatology have investigated this issue. People who are new to the field are prone to repeat the same mistakes that climate scientists were making in the 1950s and earlier.
Cockburn found one PhD, a retired aerospace engineer, Dr. Jeffrey Glassman, who calculated a lifetime of 1.5 to 2.0 years.24 Judged by his Web site, Glassman’s thinking is based on solubility. As just mentioned, this is a transient problem, not a solubility problem. And, of course, if the lifetime were that short, then the CO2 would not be accumulating in the atmosphere, which it clearly is.
Contrarian Claim 6: Believers in anthropogenic global warming are entirely dependent upon large-scale computer modeling, whose validity is suspect.
If the only evidence for global warming were computer models, then skepticism or at least agnosticism would be entirely justified. In fact there is a great deal of evidence besides computer models that supports global warming. Some of the evidence has been discussed in this essay.25
The greenhouse effect is after all a real effect, and a large one. Increasing CO2 in the atmosphere leads to an enhanced greenhouse effect, which will be a little over 1˚C when the CO2 level reaches twice the pre-industrial levels.
There is more controversy over the feedback, but an estimate of the feedback based on the recovery from the last ice age (see the section “The Ice Age” above, including endnote 15) yields a prediction that doubling the amount of CO2 over pre-industrial levels will result in a temperature rise of 3˚C, in good agreement with the IPCC estimates of 1.5 to 4.5˚C.
Thus the estimates by the IPCC seem quite reasonable. Their results, although based on computer models, are supported by arguments that are independent of computer models. This, of course, should enhance confidence in the validity of the computer models.
Anthropogenic global warming is based on very solid science. The discussion in the scientific climate change community is about how much anthropogenic global warming is occurring, but not about whether or not anthropogenic global warming is happening at all. The contrarian arguments raised by Alexander Cockburn lack scientific validity.
This is not to say that Cockburn and other skeptics should not have raised some of the questions they have. Science demands constant scrutiny and the misuse of science, when it occurs, is everyone’s concern. But it is also important to recognize a truth when it has been established. The verdict is in. Modern global warming stemming to a considerable extent from anthropogenic causes is real and constitutes a serious threat to life on the planet as we know it. It is time to stop debating its reality and to do something about it, while there is still time.
- ↩ Alexander Cockburn, “Is Global Warming A Sin?” CounterPunch Web site, April 28/29, 2007. http://www.counterpunch.org/cockburn04282007.html. Print edition of The Nation, May 14, 2007. http://www.thenation.com/doc/20070514/cockburn; Alexander Cockburn, “Who Are the Merchants of Fear?” CounterPunch Web site, May 12, 2007. http://www.counterpunch.org/cockburn05122007.html. Print edition of The Nation, May 28, 2007. http://www.thenation.com/doc/20070528/cockburn; Alexander Cockburn, “Dissidents Against Dogma: Sources and Authorities,” Counterpunch Web site, June 9, 2007. http://www.counterpunch.org/cockburn06092007.html. Published in The Nation, June 25, 2007. http://www.thenation.com/doc/20070625/cockburn.
- ↩ John Farley, “The Ozone Hole, the Greenhouse Effect, and Global Warming,” University Forum Lecture, University of Nevada, Las Vegas, January 26, 2001.
- ↩ Alexander Cockburn, “The Greenhousers Strike Back, and Strike Out,” Readers’ letters to The Nation; Cockburn responds. Print edition of The Nation, June 11, 2007. http://www.thenation.com/doc/20070611/cockburn. See also the Web letters to The Nation, http://www.thenation.com/bletters/20070514/cockburn, http://www.thenation.com/bletters/20070528/cockburn, http://www.thenation.com/bletters/20070625/cockburn, http://www.thenation.com/bletters/20070611/cockburn.
- ↩ This effect was originally called the greenhouse effect because it was believed that this explained the higher temperature of the interior of a greenhouse, compared with the temperature outside a greenhouse. The windows of a greenhouse are transparent in the visible spectrum, and opaque in parts of the infrared. In fact, the main effect that warms real greenhouses is that the windows stop the exchange of air between outside and inside the greenhouse.
- ↩ The Stefan-Boltzmann law shows the connection of the power radiated by a body with area and temperature and is expressed by the equation P/A = s e T4, where P is the power in Watts, s is the Stefan-Boltzmann constant (5.67 x 10-8 W/(m*K2)2), e is the emissivity (e is about 1 for the earth), A is the area in m2, and T is the temperature in degrees Kelvin. The Stefan-Boltzmann law, found experimentally by Stefan in 1879 and derived theoretically by Boltzmann in 1884, is found in every introductory college physics textbook that covers thermodynamics. This calculation of the temperature that the earth would have in the absence of the greenhouse effect can be found in physics textbooks. The intensity of incoming solar radiation is the so-called solar constant S0 = 1370 W/m2, which gives the maximum solar power falling on a square meter of area when the sun is directly overhead. Averaging over the entire earth, taking into account that half of the earth is in darkness, and the sun is not always directly overhead, it turns out that the average solar power per square meter of the earth’s surface is S0/4, or 343 W/m2, of which a fraction Rp is reflected and a fraction (1–Rp) is absorbed. For the earth Rp is about 0.3. From this we obtain an expression for the average net incoming solar power, 343 (1.0–0.3) = 240 W/m2. The earth radiates heat at long wavelengths, with a power per square meter given by the Stefan-Boltzmann law. Equating the incoming solar power to the earth’s radiating power yields an equilibrium temperature of 255 K, or –18˚C (–1˚F).
- ↩ www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.html.
- ↩ Since the majority of the landmass on earth is in the Northern Hemisphere, the bulk of vegetation and, thus, photosynthesis and carbon absorption occurs in the Northern Hemisphere during its spring and summer months.
- ↩ D. A. Peel, “Antarctic Ice,” New Scientist 98 (1983), 477, cited in Richard P. Wayne, Chemistry of Atmospheres (Oxford: Clarendon Press, 1985), 342.
- ↩ R. E. Dickinson, in W. C. Clark (ed.) Carbon Dioxide Review (Oxford: Oxford University Press, 1982). Cited in Wayne, Chemistry of Atmospheres, 39.
- ↩ V. Ramanathan and J. A. Coakley Jr., “Climate Modeling through Radiative-Convective Models,” Reviews of Geophysics and Space Physics 16, no. 4 (1978): 465; Gavin Schmidt (http://www.realclimate.org/index.php?p=142). Gavin Schmidt is a climate modeler at NASA Goddard Space Studies in New York. Schmidt lists the infrared absorption, while this paper lists the change in the infrared absorption, upon removal of the indicated species.
- ↩ Forcing is expressed as W/m2.
- ↩ An approximate expression for the climate sensitivity is 1/(4 sT3), where s is the Stefan-Boltzmann constant and T is the equilibrium temperature in degrees K. See John Seinfeld and Spyros Pandis, Atmospheric Chemistry and Physics (New York: Wiley, 1998), 35–36. Numerically, this climate sensitivity is 0.3 K(W/m2)–1, meaning that if the forcing increases by 1 W/m2, the global equilibrium temperature will increase by 0.3˚C. A doubling of CO2 from the pre-industrial levels is estimated to produce a forcing of about 4 W/m2. Multipying 0.3 x 4 yields a temperature rise of about 1.2 to 1.3°C.
- ↩ See A. Robock, “An Updated Climate Feedback Diagram,” Bulletin American Meterological Society 66 (1985): 786–87, cited in Seinfeld and Pandis, Atmospheric Chemistry and Physics, 1095.
- ↩ Seinfeld and Pandis, Atmospheric Chemistry and Physics, 37.
- ↩ Someone who distrusts all models can examine the change in temperature and solar forcing between glaciation (ice age) and interglacial (no ice age) periods. The change in temperature, revealed in ice core samples, is 5˚C, while the change in solar forcing is 7.1 W/m2. The computed climate sensitivity is therefore 5/7.1 = 0.7 K(W/m2)-1. We can use this empirically derived climate sensitivity to predict the temperature rise from a forcing of 4 W/m2, arising from a doubling of the atmospheric CO2 from pre-industrial levels. The result is a predicted temperature increase of 3˚C, which is perfectly consistent with the IPCC predictions of 1.5 to 4.5˚C (Seinfeld and Pandis, Atmospheric Chemistry and Physics, 1102).
- ↩ J. Lean and D. Rind, “The Sun and Climate,” Consequences 2, no. 1 (1996): 27–36, cited in Seinfeld and Pandis, Atmospheric Chemistry and Physics, 1085.
- ↩ Cockburn, “Is Global Warming A Sin?”
- ↩ Cockburn, “Dissidents Against Dogma.”
- ↩ Wayne, Chemistry of Atmospheres; Seinfeld and Pandis, Atmospheric Chemistry and Physics.
- ↩ IPCC 2004 report, chapter 2, 138.
- ↩ Cockburn, “The Greenhousers Strike Back.”
- ↩ Richard E. Zeebe and Dieter Wolf-Gladrow, CO2 in Seawater: Equilibrium, Kinetics, Isotopes (Elsevier, 2001).
- ↩ Seinfeld and Pandis, Atmospheric Chemistry and Physics, 1089–90.
- ↩ Cockburn, “Dissidents Against Dogma” Jeffrey Glassman, “The Acquittal of Carbon Dioxide,” http://www.rocketscientistsjournal.com/. Dr. Glassman has a background in electronics, satellites and missiles, but not in ocean chemistry.
- ↩ Anyone interested in the history of the science behind global warming will benefit from reading Spencer Weart, The Discovery of Global Warming (Cambridge: Harvard University Press, 2003) and his extended essay available at http://www.aip.org/history/climate/index.html.


Do we have a say when it comes to the air we breathe? Well, that depends on who you ask. Where we live, work, and play can have a large impact on the level of air pollution in our air. Lauren intends to study air quality and the health impacts associated with inhaling harmful air pollutants. Lauren also plans to investigate the effectiveness of current policy and learn how future policy can address air pollution. Ultimately, Lauren seeks to use her knowledge and research to educate the public about the relationship between air quality, health, and policy. Her research interests include air pollution trends and predictions, citizen science, and values-based decision making.
MORE ABOUT LAUREN
Lauren enjoys transdisciplinary collaboration and believes that it brings about innovative and effective solutions. Most recently, Lauren has contributed to a project about democratizing access to social determinants of health data. Lauren has a background in atmospheric science and systems engineering, which provide her with a diverse skill set.


The webcast and presentations from the BIPM Workshop on Global to Urban Scale Carbon Measurements are now available.
The workshop held on 30 June to 1 July 2015, focused on identifying requirements for advanced measurements, standards, reference data, and instrument comparisons for carbon measurement and other related climate variables to enable complete monitoring systems for greenhouse gases to be operational both at global and regional levels and useful for validating greenhouse gas flux and emission calculations and for the verification of emission inventories.
The workshop was organized around three topic areas:
- Carbon measurement and other related climate variables: Global systems, principles and traceability
- Megacities and Metrology Needs for Supporting Greenhouse Gas Mitigation - Urban Greenhouse Gas Domes
- Standards for greenhouse gas emission inventories.
Evolution of background carbon dioxide concentrations measured at the Mauna Loa Observatory over the last 60 years, presented by Dr James Butler (NOAA) as part of his presentation on 'Tracking the World's Carbon' and the challenges in developing a measurement system to measure CO2 emissions and fluxes at a regional and local level around the globe.


In March, we arrived in the rain. Sunday evening, Canberra airport, and a thick clingy drizzle. Being Wellingtonians this wasn’t anything particularly new. We just adopted our weather posture (a hunch, shrinking back into one’s clothes like a tortoise into its shell) and hurried to the rent-a-car, trying to keep our bags dry.
Rain in Wellington is so common it doesn’t even warrant comment. This isn’t the case in Canberra though. Over the next few days people advised us that the drizzle which had welcomed us to the city was really quite something.
“Several days of it.”
“Most rain we’ve had in 4 years, mate.”
Over time, and with the occasional intermittent deluge, that number increased.
“Dams haven’t been this high in 7 years.”
“Hasn’t been this much rain for 14 years.”
Finally the TV weatherman gave the official verdict.
“Canberra has had its wettest month in 20 years. The drought is over.”
That last comment made me chuckle. The drought breaking weather we’ve been experiencing – the most rain in 20 years! – equates to one, maybe two, days of rain a fortnight. Small bursts of wetness punctuating otherwise blue skies.
I’m pretty sure Canberra’s recent wet-spell would qualify as a plant destroying drought in Wellington.
Anyhow, I’m not complaining. Although, today, the weather is actually really, really bad. Even by New Zealand standards. A low, grey, damp, blanket of clouds across the sky. Windy, wet and cold.
Safe to say, I’m feeling more or less at home.


NEW MEXICO (KRQE) — A dry and warmer-than-average winter is likely again for New Mexico this winter as we move toward a third straight La Niña.
We know all too well what La Niña means for the New Mexico winter, having looked at it for the past two years in a row. Now we’re on our way to experiencing another La Niña this winter. There is currently a 75% chance that La Niña will last into winter.
La Niña is caused by strong trade winds along the equatorial Pacific, resulting in colder-than-average sea surface temperatures in the eastern Pacific. This may seem a long way from New Mexico, but these below-average sea surface temperatures help drive the jet stream north. This usually brings drier weather in the southern US and heavier rain in the Pacific Northwest and Canada. Also, winter temperatures during La Niña years are typically warmer than average in the south and cooler than average in the north.
There might be some hope on the horizon. Sea surface temperatures in the eastern Pacific are expected to return closer to average by April and May. There is a 54 percent chance of neutral conditions by spring. This bodes well that we may be nearing the end of this historic triple dip La Niña.
There’s no doubt that La Niña will play a part again in our winter here in New Mexico. This brings with it a subsequent prognosis similar to the typical effects of La Niña during the winter and how the last two winters have played out. However, signs that La Niña may be weakening towards spring are good news for the state.
Above-average temperatures are likely throughout New Mexico this winter, with the greatest reliance on warmer temperatures in the southeastern portion of the state. Intermittent winter storms bring colder weather to the state, but overall winter temperatures remain above average.
Precipitation is below average in much of New Mexico this winter. There is hope that a nose of wetter weather will creep into Colorado and even far northern New Mexico this winter. This would bring better snowfall amounts to the headwaters of the Rio Grande. With La Niña currently still strong, drier conditions are expected across most of the state. December and early January will probably be the driest time of winter, with intermittent winter storms. As La Niña weakens late in winter, we will likely see a more active pattern bringing more snow and rain to the areas in February and March.


Nature and impact of global warming nature is the ultimate spring of everything man requires therefore, concern over nature is natural to him we are concerned of nature as it is the eventual source of all we need the food we eat the water we drink, the air we breathe. Global warming is the greatest challenge facing our planet it is, in fact, the increase in the temperature of the earth’s neon- surface air it is one of the most current and widely discussed factors. How to write a essay about global warming gcse german on violent crimes in america ucla college essay in english research paper with reference gattinara.
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Vredenburg normally receives about 239mm of rain per year and because it receives most of its rainfall during winter it has a Mediterranean climate. The chart below (lower left) shows the average rainfall values for Vredenburg per month. It receives the lowest rainfall (1mm) in February and the highest (45mm) in June. The monthly distribution of average daily maximum temperatures (centre chart below) shows that the average midday temperatures for Vredenburg range from 16.5°C in July to 25.6°C in February. The region is the coldest during July when the mercury drops to 8°C on average during the night. Consult the chart below (lower right) for an indication of the monthly variation of average minimum daily temperatures.


choosing the weather
With this year's summer festival season just about to start, I'm betting there's lots of festival organisers and festival goers wondering when it'll stop.
For some they're now in the two-week range, when the more reputable weather forecasters are prepared to give general-ish forecasts for that long into the future. So up pops one of the festival season's more ridiculous happenings.
Everyone of course wants great weather for their festival, and there's nothing that will stop them finding it - in theory at least. People will trawl around the various weather forecasting websites looking for the best one, and will then try and convince everyone that the weather they'll get will be what is forecast by the best forecast and not by the worst forecast.
Perhaps there's a place for a new weather forecasting service, where only good forecasts are ever given? It'd certainly get a lot of traffic from festival goers.
PS: cheer up folks, this summer IS going to give us some great weather.


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Detailed Boston forecast
This AfternoonPartly sunny with a chance of showers and thunderstorms. Near steady temperature in the upper 80s. Southwest winds around 10 mph with gusts up to 20 mph. Chance of rain 30 percent.
TonightMostly cloudy. A chance of showers and thunderstorms in the evening. Lows in the upper 60s. Southwest winds 5 to 10 mph...becoming northwest after midnight. Chance of rain 30 percent.
Labor DayMostly cloudy with a chance of showers. Highs in the upper 70s. Chance of rain 40 percent.
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08/27National High Today (through 3 pm) 100 at Enid, Oklahoma
08/27National Low Today (through 3 pm) 32 at West Yellowstone, Montana
08/27Global High Yesterday 121 at Baghdad, Iraq
08/27Global Low -18 at Summit Station, Greenland


Lightning: Strange gamma ray flashes from storms may have explanation
Flashes of gamma radiation that seem to be produced by lightning storms have puzzled researchers for some time, but now there may be an explanation
26 May 2022
Lightning storms produce powerful flashes of gamma rays, and now we may know why, after researchers captured one using cameras across multiple wavelengths.
Gamma rays are normally seen coming from objects in space, such as neutron stars or pulsars, but they can also be produced by lightning storms on Earth. These terrestrial gamma ray flashes (TGFs) can damage nearby electronics, such as those in aircraft, but we still don’t know exactly why they occur – only a very small fraction of lightning events seem to produce them. …


Project Scientist II and Willis Research Fellow, NCAR Earth System Laboratory
Dr. James Done is a scientist at the National Center for Atmospheric Research (NCAR) and he is research lead for NCAR’s Capacity Center for Climate and Weather Extremes. In this role Dr. Done works with stakeholders from the energy, water and insurance sectors to understand future weather and climate impacts. Central to this effort is the development of the Global Risk, Resilience and Impacts Toolbox (GRRIT) – a suite a public domain tools based in the latest science to support societal planning and management of weather and climate extremes.The foundation of GRRIT is massive environmental databases that GRRIT taps into and mines for the appropriate details, and feeds information back up to decision-making tools.


England is part of the United Kingdom (along with Northern Ireland, Wales and Scotland). It is situated to the west of Eurasia and has an extensive coastline. Such a positioning is responsible for its fairly complex climate, which demonstrates the meeting of the dry continental air and the moist maritime air. This creates rather large differences in temperature ranges and also leads to the occurrence of several .seasons. over the course of one day.
English cathedral on a perfect summers day.
Generally speaking, the parts of England closest to the Atlantic Ocean experience the mildest temperatures, although these are also the wettest and experience the most wind. The areas in the east, on the other hand, are drier and less windy, but also display cooler temperatures.
England is warmer and sunnier than any of the other countries making up the United Kingdom. The month with the most sunshine is July, which is also England.s driest month.
On average, the sun shines for about 1340 hours every year in England. The south coast has the clearest skies (i.e. the least cloud cover) due to the prevailing winds in that area. This means that counties like Kent and Sussex benefit from significantly more sunshine, attracting local and international visitors to their shores. The cloudiest areas are in the northern and western parts of England as well as in the mountainous areas.
England.s climate is expected to change over the course of a few decades due to pollution and global warming. Annual temperatures are expected to rise by two degrees Celsius and summer highs are expected to soar by three degrees by the year 2050. Rainfall will decrease in general but winter rainfall will increase.
Spring is from March to May and is cool and dry. Noonday highs can become quite warm, particularly as summer approaches. However, snow is still possible, right up until the middle of April. Temperatures range between about 0 and 10 degrees Celsius during the English spring time.
Between June and August, England experiences its highest temperatures. While this is the driest season, localised thunderstorms (usually in the southern, eastern and central parts of the country) ensure that the gardens are kept lush and green. The south eastern parts of England generally experience higher noonday temperatures, which reach around 30 degrees Celsius at the hottest, while most days average around 17 to 20 degrees.
Autumn occurs between September and November and produces unstable weather conditions throughout England. Different pressure systems and cold air creates an increased amount of precipitation. Autumn temperatures range between about 1 and 13 degrees Celsius.
The cold winter lasts from December until February. This is a very wet and windy season and snowfall is common in many parts of England. Temperatures can range from as low as 0 degrees Celsius to about 10 degrees Celsius, with very chilly winds. During late winter, when the Atlantic Ocean has cooled down, the climate stabilises, particularly along the coastal regions.
Snowfall is an annual event, with only the quantities differing over regions and time. Over the past few centuries, decades and years, snowfall has decreased due to the ever-changing effects of global warming.
For more information, please view: http://www.metoffice.gov.uk/


Randolph nearly back to normal after enduring Hermine's wrath
By Robert Goetz
| 502nd Air Base Wing OL-B Public Affairs | Sept. 13, 2010
Tropical Storm Hermine blew through Randolph Air Force Base with wind gusts of more than 70 miles per hour causing trees to be uprooted damage to base and personal property. (U.S. Air Force photo/Steve Thurow)
Mark Rangel and Andy Montemayor, 902nd Civil Engineering Squadron, coordinate their efforts to replace a the broken pipe of a water main caused by ground shifting as a result of Tropical Storm Hermine. (U.S. Air Force photo/Steve Thurow)
High wind gusts from Tropical Storm Hermine blew a tree onto a pickup truck at Randolph Air Force Base, Texas. Wind gusts of up to 70 mph were reported in the San Antonio area, with rainfall averaging about six inches in the area. (U.S. Air Force photo/David Terry)
RANDOLPH AIR FORCE BASE, Texas —
Most of the cleanup effort at Randolph is complete after the remnants of Tropical Storm Hermine cut a wide swath of destruction from Texas to Oklahoma last week.
Like many areas in the storm's path, Randolph suffered substantial wind damage, with several trees blown down and numerous limbs scattered throughout the base, while nearly 8 inches of rain taxed the drainage system. At least one vehicle was damaged by a fallen tree.
"All of the rain was more than our system could handle, resulting in a couple of items," said Zakary Payne, 902nd Civil Engineer Squadron project management chief. "Some facilities required sand bags around the doors to prevent flooding."
Limbs and leaves that were caught in storm drain inlets compounded the problem, resulting in "inefficiencies due to decreased drainage areas," Mr. Payne said.
"As a result, a lot of these inlets drained slower than normal and were backing up," he said. "Our shops were out following the rain event, cleaning these inlets to improve flow."
The storm caused power outages at a few houses and at Bldgs. 902 and 907 in the Headquarters Air Education and Training Command complex, Mr. Payne said.
"This happened during the rain event and required our shops to work in the storm to replace a high-voltage switch," he said. "Power was restored within three hours of the outage."
Mr. Payne called site management "a big issue."
"Contractors spent most of the next days following the storm replacing fences that were knocked over and reinstalling erosion-control devices as needed," he said. "Replacing fencing is the primary item remaining and it is ongoing."
Mr. Payne also said eight roof leaks and two basement leaks were reported following the storm.
The storm shut down the base's flying training mission Sept. 7, said Alvin Hill, 12th Operations Support Squadron Weather Operations Flight chief.
"However, some transient aircraft arrived and departed after the storm moved out of the area," he said. "Training missions resumed the following day."
Mr. King said Randolph recorded 7.72 inches of rain due to Tropical Storm Hermine, including 6.58 inches Sept. 7. Sustained winds in the San Antonio area were estimated at more than 40 miles per hour with gusts close to 60 mph.
He said the last comparable event was Tropical Storm Erin in August 2007, which also drenched the San Antonio area with more than 7 inches of rain.


Background: 2014 BASELInE
- What processes, interactions, and feedbacks control the lifecycle of biomass-burning aerosols from source to receptor regions in boreal spring Southeast Asia?
- How do droplet nucleation and the resulting products (e.g., cloud albedo, water content, precipitation efficiency, etc.) of warm rain processes in the cloud-resolving model simulations respond with respect to key aerosol physicochemical observables (e.g., number/mass concentration, size/shape distribution, and chemical composition) over a regional scale?
- How do changes to aerosol-cloud interactions in boreal spring Southeast Asia provide feedbacks to regional climate through exchanges of energy, water, gases, and particulate matter between the surface and troposphere?


Climate Change & Fire
While wildfires seem to be burning over larger landscapes and more acres than we can remember in our lifetimes, overall fewer acres are burning today compared to that estimated to have burned in the late 1800s and early 1900s. Yet the impact that drought and climatic changes are having in lengthening the wildfire season in the West is undeniable. The West has moved from an average fire season of five to seven months, and the number of large wildfires over 1,000 acres has nearly doubled. Average annual temperatures have risen by nearly 2 degrees Fahrenheit since 1970s and winter snow pack has declined. Increases in acres burning is attributed, in part, to climate change and the increase is expected to continue in many areas with additional warming, leading to even greater suppression costs and loss of life.
Fire is an emotional issue with deeply rooted cultural beliefs that hamper our ability to challenge conventional wisdom and chart a rational course. Will applying more money to fire suppression make us more or less safe? Given that many of our biggest fires burn through grasslands and shrublands is it possible to alter fire behavior by removing trees? Or are there simpler and more effective ways to protect the tens of millions of homes that are currently in fire prone areas?
When we see huge clouds of smoke billowing up from the woods, we worry that wildfires release lots of carbon dioxide and other greenhouse gases. But scientists have determined that the plumes are mostly harmless water vapor. Forest fires only release an average of an average of 5% of the carbon in a forest, and rapidly uptake that carbon after a fire. The larger the tree, the lower the % of wood lost from combustion. To face the challenges ahead, scientists recommend we increase efforts to restore our forests ability to store carbon as a buffer against climate change and fire.


Department of Applied Environmental Science
Dr. Fernandez is currently working with researchers from NASA Ames who are looking to use the data from the collectors to ground truth satellite images from Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, which have the ability to extract information on the presence or absence of fog. The NASA researchers are hoping to establish long time series of fog to look at its effects on regional ecosystems and to evaluate whether the patterns of fog presence are shifting as a result of climate change.
UC Santa Cruz
Dr. Fernandez is also working with research groups at UC Santa Cruz. One group is looking at fog as an indicator of lizard extinctions throughout the world. That is, some lizards are dependent upon the moisture and cooler temperatures that the fog brings. As these fog regimes shift their spatial and temporal extent, various lizard species are shown to go extinct. Another group at UC Santa Cruz is looking at some of the chemicals present in fog and has identified monomethyl mercury, a biologically “fixed” compound of mercury,as having a concentration several times greater in fog than in rain.


The softest? You’re a real genius if you answer that!
I used it on some of my favorite drawings I did in the past year or so and it has given me an edge in the drawing process.
I really hope I can do a bunch more drawings like that in the future 🙂
In a previous article in The Nation, I argued that in addition to reducing the “social cost” of carbon emissions, a more direct approach is needed to address climate change. It is clear from the scientific evidence that we are getting dangerously close to 2°C climate change over pre-industrial temperatures. A combination of emissions reductions and adaptation measures that would allow ecosystems and societies of the future to adapt. But how might it be done?
The “carbon floor” of the atmosphere – above which atmospheric concentrations of greenhouse gases don’t rise – is believed to be around 800 parts per million (ppm). But for a long time it has been assumed that no changes in these concentrations can be sustained for more than 800 years. Because of this, when the world warms (at least 1.5°C above pre-industrial temperatures) there is virtually a constant rise above which a level of CO2 above this concentration cannot be sustained – known as the “carbon floor.”
This “carbon floor” has also come to be known as “the climate ” floor. It has been the focus of some of the most important policy discussions of recent history: the Copenhagen Conference of 2007, the Paris Climate Accord of 2015, the 2016 Paris Agreement, and so on. Yet, despite this fact, many have been puzzled as to whether it is even possible to get such a floor. The answer is yes, but only because the Paris Agreement does not contain any ” carbon-floor” at all.
This paper gives the first estimates of precisely how much CO2 can be released into the atmosphere by 2100 before it depletes it’s capacity to store large amounts of energy. As the authors point out, the “carbon floor” has now become the “climate floor” – the point at which the emissions of both greenhouse gases and infrared (heat) radiation exceeds the climate “floor” and becomes a net negative feedback. Therefore, in order to avoid potentially irreversible changes to temperature and ice-coverage, it is also necessary to take action now to limit those two emissions sources. The key elements of such action are:
A global cap-and-trade system. A carbon tax. A carbon dividend. In combination
pencil drawings step by step, pencil rendering pros and cons, pencil drawingseasy, easy pencil drawings of love, amazing pencil drawings


Exploring technologies with real life use-cases is always more fun. When experimenting with machine learning, I try to avoid made-up datasets because they are usually biased and built to yield good results. Instead, I prefer to use real data to evaluate ML algorithms and hopefully create useful predictions.
I live in Hong Kong where air quality is an ongoing concern. The Environmental Protection Department is monitoring air quality in a number of locations to publish an air pollution index ranging from 1 to 10+ and makes this data available publicly on an hourly basis. So I saw an opportunity to apply some machine learning and predict air quality for the coming hours and days!
I'm no weather or environment specialist, but my intuition was that the weather has some influence on air pollution; hot days usually brings lower air quality and the wind obviously moves pollutants around. So my initial goal was to see if I could predict the air quality (AQ) index based on past AQ and weather, or more precisely predict tomorrow's AQ based on the AQ and weather of the past 3 days.
Getting the data
Next, I had to select the data sources. For such an experiment, it's important to remember that you need both:
- historical data to train your model
- current / real-time data to feed your model and produce the prediction
Some datasets provide historical data and an API to retrive current data, some don't, so this has to be carefully planned beforehand.
Air quality data
The Hong Kong government has launched an open data initiative some years ago and there's now a portal that registers all public data sources. There's quite a lot of stuff available there with varying degrees of quality (in both usefulness and convenience of access) but we should recognize that there's some good will shown by the authorities and I hope it will expand and improve.
When it comes to environment and air quality, things are pretty good as we have access to an "API" returning the current AQ reading from 16 stations, updated every hour. I put "API" between quotes because what the endpoint actually returns is in XML format - which is fine - with all the relevant data (the AQ readings) in plain text within a
CDATA section! So close yet so far... So I ended up extracting the AQ values through regular expressions.
Historical data is also available in CSV format through monthly digests since December 2013.
Now that I had the AQ data sorted out, it was time to do the same thing for the weather data. Obviously, the first thing I checked was the very same open data portal and I did find a current weather "API" (here again, some XML with all the data in a
CDATA section!). But two things bothered me with this data source. First, access to historical data wasn't straightforward and required to first use the open data portal to generate URLs for each past day. But most importantly, this API didn't return any data about winds, which made it less interesting for my experiment.
I spend quite some time looking around all available online services to see which one would provide the best data. I ended up using OpenWeatherMap which has a current weather API that's free to use. I also purchased a "history bulk" set for 10 USD so I could download 5 years of hourly data, which is a good deal. I was a bit worried that the readings from OpenWeatherMap seemed a bit off when compared to those of the Hong Kong Observatory (like a couple of degrees warmer for example) but I thought that they were probably using a single station located in some urban area.
Preparing the data
So I had my raw data, consisting of air quality and weather readings for every hour since January 2014. Next, I had to somehow merge them to generate a clean dataset that could be used as training data for my machine learning experiment.
The approach I took was to inject everything in a lightweight database, from which I could then query, extract and clean-up the data. I choose LiteDB, which is a NoSQL datastore that's very easy to embed in a .NET application. The schemaless nature of LiteDB made the ingestion process very straightforward and once all the data got into LiteDB, I just had to query it back using LINQ queries.
As explained above, my goal was to predict the AQ for day d from the AQ and weather data from days d-1, d-2 and d-3. As the weather data was composed of temperature, humidity, pressure, wind speed and wind direction, I had to generate some CSV with the following "schema":
aq, aq_1, t_1, h_1, p_1, ws_1, wd_1, aq_2, t_2, h_2, p_2, ws_2, wd_2, aq_3, t_3, h_3, p_3, ws_3, wd_3. My data sources provided hourly data so I computed average daily values... which was easier said than done for the wind! A basic average wouldn't work here so I had to convert wind speed and direction into a vector, average those vectors and convert the result back into speed and direction. And yes, I had to look up the good old trigonometry on Google... I also added extra rows for the weekday (ranging from
6) and month as I expected these to help in the prediction.
Running the first experiment
With my data ready, I could finally prepare the actual experiment. I decided to use Azure ML Studio as it provides an excellent user experience, a good choice of learning algorithms to play with and the convenience of publishing your model as an API in just a couple of clicks.
This is not the place to explain fundamental machine learning concepts; if you're interested in learning more about the different flavors of ML and their respective algorithms, the ML Studio documentation has a nice section about that and also this handy cheat sheet that can help with deciding which algorithm to choose. Let's just cut to the chase: we're dealing with a regression problem because we want to predict the air quality index, which is a non discrete value. So among all the algorithms available on ML Studio, I had to experiment with the ones from the "Regression" section.
I built a pretty classic pipeline, consisting of:
- the input dataset
- a data splitter that routes 70% of the data to the training and the remaining 30% to the scoring
- a model trainer, applying the chosen algorithm to the training data
- a model scorer, testing the resulting model against the scoring data
- an evaluation module to output the performance of the model
So, what results did this experiment produce? Head to part 2 to find out!


The winter storm hit the northeastern New England snow wind – Beijing by Beijing in February 9 Xinhua comprehensive report, snow, from the lunar new year, is the beginning of 8, affected by the two kinds of storm systems, including the new England area of the east coast of the United States and the Midwest have ushered in the heavy snow. Reported that a Mars winter storm at local time 8, arrived in the northeastern United States, encountered strong winds and heavy snow in the new England area attack, dangerous coastal areas and flood. The National Weather Service says the Mars will affect 2 million people on the east coast, with the worst disaster in the new England region. At 8 local time, the highest snowfall in Cape Cod (Cape Cod) in Massachusetts will reach about 46 centimeters, and many areas of Massachusetts also have seawater intrusion. The weather forecast shows, Massachusetts and most area of Connecticut for 8 days in the winter storm warning range, the highest will these areas about 25 centimeters of snow in Boston will have the same thickness of snow. But in the northern part of new England and downtown New York, the snowfall will be much smaller. New York, Philadelphia and Northern New Jersey will continue to snow from 8 to 9 nights. According to the weather forecast, from the beginning of 8, the first few days of the week there will be two streams come to New York, will bring a small snow and windy weather, to 11 days will turn cloudy weather, but by 12 and 13, and there will be a big wave hit cooling.
冬季风暴袭击美东北部 新英格兰地区遭大雪强风-中新网 中新网2月9日电 综合报道，瑞雪兆丰年，从农历大年初一，也就是8日开始，受到两股不同的暴风雪系统影响，包括新英格兰地区的美国东部海岸以及中西部都迎来了大雪。 报道称，一场名为Mars的冬季风暴于当地时间8日抵达美国东北部，新英格兰地区遭遇强风和大雪的袭击，沿海地区还有洪水的危险。 美国国家气象局表示，Mars将影响东海岸的200万人，其中新英格兰地区的灾情将最为严重。当地时间8日，马萨诸塞州鳕鱼角(Cape Cod)的降雪最高将达约46厘米，而麻州的多个地区也出现了海水倒灌。 天气预报显示，麻州和大多数康涅狄格州地区8日都处于冬季风暴的警告范围内，这些地区最高将会有约25厘米的降雪，波士顿地区也会有同样厚度的降雪。不过在新英格兰的北部和纽约市区，降雪将会小得多。纽约市，费城和新泽西北部地区的降雪将从8日持续到9日晚。 据气象预报，从8日开始，一周的头几天将有两股气流降临纽约，将带来小规模降雪和大风天气，至11日将转为多云天气，但到了12和13日又将有一大波降温袭来。相关的主题文章：


Remember how mountains were often depicted in paintings by early visitors to New Zealand? That’s how Mt Taranaki appeared to some of us at Labour Weekend, from the ridge above Waiopehu Hut, on a very still clear morning. It seemed to tower much higher above the horizon than usual. Paul Bruce, weather forecaster, was on the trip and his explanation was as follows:
A mirage is an optical illusion that is the result of refraction of light by air with unusual density patterns. The desert mirage makes you think that you have found water when you are actually seeing blue sky (Fig. 1). It occurs on the sunniest of days when the ground becomes so hot that it superheats the air lying just above it. Several meters above the ground the air is colder and heavier. Therefore, light waves travel faster near the ground than several meters up, and so they bend away from the ground.
Our view from the Tararua Ranges was through a relatively warm, dry layer above a shallow cool layer left over following a period of southerlies. When the surface of the earth or bottom layer is very cold and the air touching the surface is colder than the air above, light rays will bend in the opposite way. Small objects may then appear as “castles” in the air. This is sometimes called the fata morgana after the magician-sister of King Arthur. (Fig 2).
''Depending on the precise temperature structure of the air, the images of objects in the distance may appear either right side up or upside down, and may appear either magnified or compressed. Several images of the same object may be visible. Some distortion is to be expected in these unusual situations, and this tends to reinforce feelings that something supernatural is happening...
(Edited extracts from The Science and Wonders of the Atmosphere by Stanley David Gedzelman.)