text: Ecological measurements Measuring economic output and progress is done through the use of economic index indicators. Green indices emerged from the need to measure human ecological impact, efficiency sectors like transport, energy, buildings and tourism, as well as the investment flows targeted to areas like renewable energy and cleantech innovation.
  2016 - 2022 Green Score City Index is an ongoing study measuring the anthropogenic impact human activity has on nature.
  2010 - 2018 Global Green Economy Index™ (GGEI), published by consultancy Dual Citizen LLC is in its 6th edition. It measures the green economic performance and perceptions of it in 130 countries along four main dimensions of leadership & climate change, efficiency sectors, markets & investment and the environment.
  2009 - 2013 Circles of Sustainability project scored 5 cities in 5 separate countries.
  2009 - 2012 Green City Index  A global study commissioned by Siemens
  Ecological footprint measurements are a way to gauge anthropogenic impact and are another standard used by municipal governments.
  Green energy issues
  Green economies require a transition to green energy generation based on renewable energy to replace  fossil fuels as well as energy conservation and efficient energy use. Renewables, like solar energy and wind energy, may eliminate the use of fossil fuels for electricity by 2035 and replace fossil fuel usage altogether by 2050.