Climate change

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.

An existential threat – Part 1

This 4 part post explains the myriad of changes we are forcing Earth to undergo pose a threat to the existence of civilisation. Part 1 describes sea level rise due to ice sheet loss.

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.

An existential threat – Part 3

Climate change impacts on human health and wellbeing.

An existential threat – Part 4

Climate change impacts on biodiversity.

Responsibilities

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.

The UNFCCC

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.

1.5˚C

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 our civilisation, and we have been slow to act.

350 ppm

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

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.

Greenhouse gas emissions

Rapidly increasing CO₂ emissions, mainly from our energy systems, almost solely determine Earth’s long term warming commitment. These emissions continue to grow with no peak in sight, at a rate unprecedented in the past 66 million years.

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 often overlooked consequential changes to seasonal extremes.