Changing temperature extremes

Global warming is often described and summarised as a change of global mean surface temperature (e.g. the ‘1.5˚C’ temperature limit that formed part of the ‘Paris Agreement’). This page describes the consequential changes to seasonal extremes.


CO2 emissions from fossil fuels and industry in 2020 increased 90% since 1980, when the first joint scientific meeting about CO2 was held, and 57% since the first ‘international climate summit’ (COP1) in 1995.

Our current path

Every year energy use increases, and most of the increases come from fossil fuels. Current policies presently in place around the world are projected to result in about 3.3°C warming above pre-industrial levels.


Future emission pathways that temporarily overshoot 1.5˚C prescribe global CO2 emission reductions of a rate similar to that in Russia following the collapse of the Soviet Union, and in France and Sweden after the commissioning of large shares of nuclear energy. In addition to this, these pathways also prescribe a new carbon sink on the scale of the global ocean carbon sink, because we don’t expect to be able to fully decarbonise and have been too slow to act.

350 ppm

Dr Hansen prescribes changes needed to reduce atmospheric CO2 to less than 350 ppm, in order to limit global temperature close to the Holocene range.

Climate change summary

We have warmed our climate to the temperature range of the Eemian, a period when seas were metres higher. Such impact is beyond adaptation for an organised global civilisation, yet we continue to carbonise.


Those countries most to blame for climate change, and therefore should be leading wth radical emission reductions, are those that have the highest cumulative-per-capita emissions: the U.S., U.K., Germany, Canada, Russia, Australia and Japan.

An existential threat – Part 4

Climate change impacts on biodiversity.

An existential threat – Part 3

Climate change impacts on human health and wellbeing.

An existential threat – Part 2

Rapidly melting Arctic sea ice is triggering a fast amplifying feedback that drives further warming.
A striking consequence is the global trend of glacier retreat.