In a landmark report for the future of our planet, the Intergovernmental Panel on Climate Change on Monday issued a ‘code red for humanity’. Observing changes across every region of the planet on a scale unprecedented in many cases for thousands of years, the report states that humans are ‘unequivocally’ to blame for rising greenhouse gas emissions, which are responsible for 1.1°C of warming since 1850-1900 and are expected to result in 1.5°C of warming averaged over the next 20 years.
Such an outcome would exceed one of the goals set by the Paris climate agreement, which vowed to limit global warming to ‘well below’ 2°C above pre-industrial levels while pledging to ‘pursue efforts’ to limit the rise to 1.5°C. In its report, the Intergovernmental Panel on Climate Change warns that some of the changes wrought to our planet are already impossible to reverse. Current levels of warming are twice as high in the Arctic, the Greenland ice sheet is likely to continue melting, while the oceans are heating at a rate not witnessed since the last ice age 11,000 years ago. Sea levels are therefore almost certain to rise for centuries to come.
At higher levels of warming, extreme temperature events of the type which once occurred every 50 years on land will become commonplace, producing complex heatwaves and lasting droughts. Extreme sea level events which previously occurred once in 100 years could happen every year by the end of the century, resulting in coastal erosion and more frequent and severe floods.
Many of the effects of climate change are already being felt, as Eastern Europe and the Pacific Northwest endure sustained heatwaves, record-breaking wildfires rage across California and Siberia, and floods wreak havoc across India, China, and Central Europe. Drought imperils southwest Africa, the Mediterranean, and parts of the American West. Global warming poses fresh challenges for food production, while ocean acidification and habitat destruction is reducing the diversity of life on Earth.
But the Intergovernmental Panel on Climate Change also strikes a note of optimism, indicating that an immediate and sustained reduction in carbon dioxide emissions could still limit global warming to 1.5°C over the long haul. Strong action by local governments would swiftly improve the air quality, though global temperatures would take several decades to stabilise as pollutants dissipate from the atmosphere and temporarily lead to added warming from the sun.
This is the sixth report from the Intergovernmental Panel on Climate Change since 1990, with the last arriving in 2013. 234 authors from 66 countries drew from the evidence compiled in more than 14,000 scientific studies, before the report received approval at the end of a two-week virtual summit from all 195 members of the IPCC. The environment will be on the agenda in a major way in Glasgow in November, as the COP26 climate conference seeks to wring from national governments more ambitious targets and funding promises.
