Emissions linked to the combustion of fossil fuels: climate change
The natural greenhouse effect is what makes life on Earth possible: without it, the average temperature would be about 30 °C lower!
Most greenhouse gases occur naturally in the atmosphere. But a whole series of human activities has caused a significant increase in emissions of some of these gases, as well as the appearance of new greenhouse gases in the atmosphere.This is what is behind "climate change", the effects of which are already visible in some places (e.g. the way glaciers have become smaller).
