The Science in a Nutshell

We know greenhouse gases such as CO2 warm the air by trapping heat radiating from the Earth’s surface.

That is 100-year-old science.

The first calculations that doubling CO2 in the atmosphere would raise temperatures by 2-6ºC were done over a century ago by Swedish chemist Svante Arrhenius.

Today’s climate models broadly agree.

We know the world is warming, on average by 0.74ºC during the past century, with most of that since 1970. Human-made CO2 is responsible for the vast majority of the warming.

Concentrations of CO2 in the atmosphere are now almost 40% above those of 200 years ago and emissions to the atmosphere have been rising by more than 2% a year since 2000.

This extra greenhouse gas stems overwhelmingly from humans burning fossil fuels and destroying forests, both of which are made of carbon.

It would contradict 100 years of physics if this CO2 were not warming the planet.

Moreover, there is no alternative explanation for the observed warming.

Solar cycles have contributed on average less than 10% in the past decades whereas volcanic eruptions and other known natural influences on global climate have been having a cooling influence since 1970 – the period of greatest overall warming and of the largest increase in atmospheric CO2 and other greenhouse gas levels.
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Historic carbon emissions from fossil fuel burning 1900-1999
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