We have never clearly understood the causes of these changes and despite what some environmentalists say there is no scientific consensus around the causes. Some claim that recent climate change is due to CO2 production from industrialisation, our energy use, our love affair with the car and foreign holidays by jet airplane. The difficulty with this explanation is that climate change occurred even when we did not have the increase on CO2 emissions experience in the last 200 years. Another difficulty they have is that the increase in CO2 occurs after the increase in temperatures.