The 5 facts of global warming

Here are the 5 facts you need to know about global warming

1 The atmospheric CO2 concentration has risen strongly
since about 1850, from 280 ppm (a value typical for
warm periods during at least the past 400,000 years) to
380 ppm.

2 This rise is caused by humans and is primarily due to
the burning of fossil fuels, with a smaller contribution
due to deforestation.

3 CO2 is a gas that affects climate by changing the earth’s
radiative budget: an increase in its concentration leads
to a rise in near-surface temperature. If the concentration
doubles, the resulting global mean warming will
very likely be between 1.5 and 4.5°C.

4 In the 20th century, global climate warmed by ~0.6°C).
Temperatures in the past ten years have been the highest
since instrumental records started in the 19th century and
for at least several centuries before that.

5 Most of this warming is due to the rising concentration
of CO2 and other anthropogenic gases; a smaller part is
due to natural causes, like fluctuations in solar activity.