Code red for humanity
Rakesh Roul / Shutterstock
The most recent IPCC report brings together evidence of the impact of human activity on global temperatures, and the effect this is having on every region on Earth. Catriona Toms looks at the lessons to be learned ahead of COP26.
Indian coastal city Puri, in the aftermath of Cyclone Fani, May 2019.
A
ugust’s Intergovernmental Panel on Climate Change (IPCC) report was unequivocal: we are seeing widespread, rapid and intensifying changes in the Earth’s climate in every region and across the whole climate system. Many of these changes are unprecedented in thousands, if not hundreds of thousands of years. Some are ‘irreversible over hundreds to thousands of years’. No wonder, then, that UN SecretaryGeneral António Guterres called the report ‘a code red for humanity’, saying: “The alarm bells are deafening, and the evidence is irrefutable: greenhouse gas emissions from fossil fuel burning and deforestation are choking our planet and putting billions of people at immediate risk.”
Compiled by 234 authors from 66 countries and drawing on more than 14,000 cited references, ‘Climate Change 2021: The Physical Science Basis’ brings together the latest information from climate science to provide the most upto-date physical understanding of the climate system and climate change. Whilst the basic thrust of the report comes as no surprise, the unrelenting detail of the profound changes being wrought by human activity still has the power to shock.
Impacts on every region on Earth
The report outlines the evidence for multiple different changes already taking place across different regions, and their attribution to human influence – evidence which the authors are clear is now ‘unequivocal’.
Some of the headline observed changes include: • I n 2019, atmospheric carbon dioxide concentrations were higher than at any time in at least 2 million years. • I n the same year, concentrations of methane were higher than at any time in at least 800,000 years. • Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2000 years. • Global surface temperature was 1.09°C higher in 2011-2020 than in 1850-1900. • Warming over land is larger than the global average, and it is more than twice as high in the Arctic. • Global mean sea level has risen faster since 1900 than over any preceding century in at least the last 3000 years.
Clean Slate 15
