Human activity is changing the Earth’s climate in ways “unprecedented” in thousands or hundreds of thousands of years, with some of the changes now inevitable and “irreversible”, climate scientists have warned. Within the next two decades, temperatures are likely to rise by more than 1.5C (34.7 F) above pre-industrial levels, breaching the ambition of the 2015 Paris climate agreement, and bringing widespread devastation and extreme weather such as increasing heatwaves, more intense storms, and more serious droughts and floods.
Only rapid and drastic reductions in greenhouse gases in this decade can prevent such climate breakdown, with every fraction of a degree of further heating likely to compound the accelerating effects, according to the International Panel on Climate Change (IPCC), the world’s leading authority on climate science.
The comprehensive assessment of climate science published on Monday, the sixth such report from the IPCC since 1988, has been eight years in the making, comprised of the work of hundreds of experts and peer-review studies. It represents the world’s full knowledge to date of the physical basis of climate change, and found that human activity was “unequivocally” the cause of rapid changes to the climate, including sea level rises, melting polar ice and glaciers, heatwaves, floods, and droughts.
— Greta Thunberg (@GretaThunberg) August 9, 2021
World leaders said the stark findings must force new policy measures as a matter of urgency, to shift the global economy to a low-carbon footing. Governments from 197 countries will meet this November in Glasgow for vital UN climate talks, called Cop26. Each nation is asked to come to Cop26 with new and viable plans to reduce greenhouse gas emissions to a level that will limit global heating to no more than 1.5C above pre-industrial levels, which was the ambition of the Paris climate agreement and a goal the IPCC emphasized was still possible, but barely.
One of the most important lessons from the COVID-19 pandemic is that when scientists are warning about a looming threat, we all ought to listen.
Today, the @IPCC_CH is once again sounding the alarm on the climate crisis and their warning is clearer than ever.
— Al Gore (@algore) August 9, 2021
Even if the world manages to limit warming, some long-term impacts of rising global temperatures are already likely to be inevitable and irreversible. These include sea level rises, the melting of Arctic ice, and the warming and acidification of the oceans. Drastic reductions in emissions can stave off worse climate change, according to IPCC scientists, but will not return the world to the more moderate weather patterns of the past.
ClimateChange 2021: the Physical Science Basis – provides the most updated physical understanding of the climate system and #climatechange, combining the latest advances in climate science, and multiple lines of evidence.
— IPCC (@IPCC_CH) August 9, 2021