World Must Adapt To Unknown Climate Future, Says IPCC
There is still great uncertainty about the impacts of climate change, according to the latest report from the Intergovernmental Panel on Climate Change, released today.
So if we are to survive and prosper, rather than trying to fend off specific threats like cyclones, we must build flexible and resilient societies.
Today’s report is the second of three instalments of the IPCC’s fifth assessment of climate change. The first instalment, released last year, covered the physical science of climate change. It stated with increased certainty that climate change is happening, and that it is the result of humanity’s greenhouse gas emissions. The new report focuses on the impacts of climate change and how to adapt to them. The third instalment, on how to cut greenhouse gas emissions, comes out in April.
The latest report backs off from some of the predictions made in the previous IPCC report, in 2007. During the final editing process, the authors also retreated from many of the more confident projections from the final draft, leaked last year. The IPCC now says it often cannot predict which specific impacts of climate change – such as droughts, storms or floods – will hit particular places.
Instead, the IPCC focuses on how people can adapt in the face of uncertainty, arguing that we must become resilient against diverse changes in the climate.
“The natural human tendency is to want things to be clear and simple,” says the report’s co-chair Chris Field of the Carnegie Institution for Science in Stanford, California. “And one of the messages that doesn’t just come from the IPCC, it comes from history, is that the future doesn’t ever turn out the way you think it will be.” That means, Field adds, that “being prepared for a wide range of possible futures is just always smart”.
Here New Scientist breaks down what is new in the report, and what it means for humanity’s efforts to cope with a changing climate. A companion article, “How climate change will affect where you live“, highlights some of the key impacts that different regions are facing.
What has changed in the new IPCC report?
In essence, the predictions are intentionally more vague. Much of the firmer language from the 2007 report about exactly what kind of weather to expect, and how changes will affect people, has been replaced with more cautious statements. The scale and timing of many regional impacts, and even the form of some, now appear uncertain.
For example, the 2007 report predicted that the intensity of cyclones over Asia would increase by 10 to 20 per cent. The new report makes no such claim. Similarly, the last report estimated that climate change would force up to a quarter of a billion Africans into water shortage by the end of this decade. The new report avoids using such firm numbers.
The report has even watered down many of the more confident predictions that appeared in the leaked drafts. References to “hundreds of millions” of people being affected by rising sea levels have been removed from the summary, as have statements about the impact of warmer temperatures on crops.
“I think it’s gone back a bit,” says Jean Palutikof of Griffith University in Brisbane, Queensland, Australia, who worked on the 2007 report. “That may be a good thing. In the fourth [climate assessment] we tried to do things that weren’t really possible and the fifth has sort of rebalanced the whole thing.”