By Seth Borenstein
The Seattle Times/Associated Press
WASHINGTON — A key element of the second major report on climate change is a chart that maps out effects of global warming with every degree of temperature rise, most of them bad.
There’s one bright spot: A minimal heat rise means more food production in northern regions of the world.
However, the number of species going extinct rises with the heat, as does the number of people who may starve, or face water shortages, or floods, according to the most recent draft obtained by The Associated Press.
Some scientists are calling this degree-by-degree projection a “highway to extinction.”
The Intergovernmental Panel on Climate Change 20-chapter draft report, to be released Friday, likely will be the source of sharp closed-door debate, some scientists say. While wording in the draft is almost certain to change, several scientists say the focus won’t.
An earlier draft obtained by The Associated Press was published March 11 in The Seattle Times.
The final document will be the product of a U.N. network of 2,000 scientists as authors and reviewers, along with representatives of more than 120 governments. It will be the second of a four-volume assessment of Earth’s climate.
The first report, released in early February, concluded that scientists are 90 percent certain that people are the cause of global warming and that its effects are being felt and will continue for centuries.
University of Victoria climate scientist Andrew Weaver said the chart of results from various temperature levels in the upcoming report is “a highway to extinction, but on this highway there are many turnoffs. This is showing you where the road is heading.”
The report says global warming already has degraded conditions for many species, coastal areas and poor people.
But as the world’s average temperature warms from 1990 levels, projections become more dire. Add 1.8 degrees Fahrenheit and between 400 million and 1.7 billion extra people can’t get enough water, some infectious diseases and allergenic pollens rise, and some amphibians go extinct. The food supply, especially in northern areas, also could increase. That’s the likely outcome around 2020, according to the draft.
Add another 1.8 degrees and as many as 2 billion people could be without water and about 20 percent to 30 percent of species near extinction. Also, more people start dying because of malnutrition, disease, heat waves, floods and droughts. That would happen around 2050, depending on the level of greenhouse gases from the burning of fossil fuels.
At the extreme end of projections, a seven- to nine-degree average temperature increase, the chart predicts: “Up to one-fifth of the world population affected by increased flood events … “1.1 to 3.2 billion people with increased water scarcity” … “major extinctions around the globe.”
Several scientists involved in the process say they are optimistic that such a drastic temperature rise won’t occur because carbon-dioxide emissions that cause global warming will be reduced.
“The worst stuff is not going to happen because we can’t be that stupid,” Harvard University oceanographer James McCarthy said. “Not that I think the projections aren’t that good, but because we can’t be that stupid.”
Details on the group’s first report were provided by Seattle Times archives.