Reality check: UN climate change report drives home need for urgent action
According to a new report issued by the United Nations' Intergovernmental Panel on Climate Change (IPCC), human-caused climate change will have dire consequences over the next 20 years. And while some of the damage could be mitigated, it will take a lot of work.
Released this Monday (Aug. 9), the "Climate Change 2021: the Physical Science Basis" report was compiled by a total of 234 authors from 66 countries, all members of the IPCC's Working Group I. The report is the first installment of the IPCC's larger Sixth Assessment Report (AR6), which is due for completion next year.
Citing over 14,000 references from studies conducted by member scientists, the report states that since 1850-1900, emissions of greenhouse gases from human activities caused an average global temperature rise of 1.1 ºC (1.98 °F). That trend is predicted to continue over the next 20 years, resulting in a total increase of at least 1.5 ºC (2.7 °F) since the pre-industrial era.
While temperatures will rise all over the planet, the change will be more pronounced over land areas. It will be particularly acute in the Arctic, where the average temperature increase is predicted to be more than twice the global average.
As a result, the present thawing of the Arctic permafrost will be amplified, glaciers and ice sheets will melt, plus sea ice may completely disappear during the summer months. The problems won't just be confined to the Arctic, however.
It is predicted that rainfall will increase at higher latitudes – causing floods, mudslides and other natural disasters – while some regions will experience more severe droughts. The ocean will likewise experience an increase in marine heatwaves – along with the associated acidification and reduced oxygen levels – while low-lying coastal areas will be subject to more flooding and erosion. The report states, "Extreme sea level events that previously occurred once in 100 years could happen every year by the end of this century."
There is some hope, however. If human-caused emissions of carbon dioxide and other greenhouse gases are drastically reduced, the effect on air quality should be quickly apparent. That said, even if significant measures are taken now, it could still take 20 to 30 years for global temperatures to stabilize. In fact, it may take hundreds or even thousands of years for sea levels to cease rising.
"This report is a reality check," says IPCC Working Group I Co-Chair Valérie Masson-Delmotte. "We now have a much clearer picture of the past, present and future climate, which is essential for understanding where we are headed, what can be done, and how we can prepare."