A strong, credible body of scientific evidence shows that climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems….
Some scientific conclusions or theories have been so thoroughly examined and tested, and supported by so many independent observations and results, that their likelihood of subsequently being found to be wrong is vanishingly small. Such conclusions and theories are then regarded as settled facts. This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities.
The National Academy released three reports today on “America’s Climate Choices.”
Today I’ll focus on their review of climate science, Advancing the Science of Climate Change (news release here, Report in Brief here, Read/purchase full report here).
The report is a typical NAS product, which means it is uber-conservative from a scientific perspective, much like the IPCC. So that means whenever it actual makes a strong assertion, like the ones above, it is doubly impressive. Those who continue to attack what are essentially ’settled facts’ deserve the label that I and others have been using — ‘anti-scientific’.
The report has same fatal failing as the IPCC report: It fails to spell out clearly to policymakers, the public, and the media what the likely impacts are if we stay anywhere near our current emissions path, including both business-as-usual and plausible worst-case scenarios.
The report does note, “A separate NRC report, expected in summer 2010, provides an analysis of impacts at different magnitudes of future climate change.” So that presumably will be the report to watch for. It also notes:
Some of the greatest risks posed by climate change are associated with these abrupt changes and other climate “surprises” (unexpected changes or impacts), yet the likelihood of such events is not well known. Moreover, there has been comparatively little research on the impacts that might be associated with “extreme” climate change—for example, the impacts that could be expected if global temperatures rise by 10 °F (6 °C) or more over the next century.
Well, 10F might be “extreme” climate change to scientists who can’t imagine why the world basically keeps ignoring their calls to action — but right now, it isn’t close to the plausible, “extreme,” worst case:
No, 10F warming is merely the high end of business-as-usual emissions projects (and I think we are getting a better understanding of what this Hell and High Water means):
- M.I.T. doubles its 2095 warming projection to 10°F — with 866 ppm and Arctic warming of 20°F
- U.S. media largely ignores latest warning from climate scientists: “Recent observations confirm … the worst-case IPCC scenario trajectories (or even worse) are being realised” — 1000 ppm
- Our hellish future: Definitive NOAA-led report on U.S. climate impacts warns of scorching 9 to 11°F warming over most of inland U.S. by 2090 with Kansas above 90°F some 120 days a year — and that isn’t the worst case, it’s business as usual!”
- “The Copenhagen Diagnosis” warns “Without significant mitigation, the report says global mean warming could reach as high as 7 degrees Celsius by 2100.”
- Hadley Center: “Catastrophic” 9-13°F warming by 2100 on current emissions path
- An introduction to global warming impacts: Hell and High Water
The chapter on sea level rise does do a pretty good job summarizing the post-IPCC science (click here). And it reproduces this figure (see “Sea levels may rise 3 times faster than IPCC estimated, could hit 6 feet by 2100“):
But it refuses to draw any conclusions or even present its own range of SLR by 2100. I’m hopeful the summer report will be clearer on this.
The best thing about the report is the unequivocal defense of our basic scientific understanding that the climate is changing and that humans are a primary cause. Here is the discussion of how we know humans are responsible for most of the observed warming in the last century and especially the last several decades (from page 29):
The climate is changing, humans are causing it, and the time to act is now.
Note: I’m in meeting the rest of the day, so I welcome readers identifying any choice nuggets in the report good or bad.