Question

Explain the evidence that shows that climate change is caused by human use of fossil fuels.

Answer 1

The climate change is mainly caused by the human beings. The use of fossil fuels are a reason. The increase of carbon dioxide in the atmosphere from about 280 ppm to 400 ppm is an evidence. Carbon dioxide is the heat trapping gas. More the carbon dioxide in the atmosphere, more heat would be trapped as the gas forms a layer above, that doesn't let the Earth to radiate back the heat.

The extraction as well as burning of fossil fuels are leading to an increase in the carbon dioxide level. Scientists can distinguish between the carbon dioxide coming from natural sources and the ones from the combustion by determining the proportion of the lighter and the heavier atoms of $\delta$ 13C. $\delta$ 13C has decreased and carbon dioxide has increased to a level from where we can't return. From this the scientists could comclude that the climate change is caused by the human use of fossil fuels.