8.4.2012 Leave a comment
We conclude that Earth in the warmest interglacial periods of the past million years was less than 1°C warmer than in the Holocene. Polar warmth in these interglacials and in the Pliocene does not imply that a substantial cushion remains between today’s climate and dangerous warming, but rather that Earth is poised to experience strong amplifying polar feedbacks in response to moderate global warming. Thus goals to limit human-made warming to 2°C are not sufficient — they are prescriptions for disaster. Ice sheet disintegration is nonlinear, spurred by amplifying feedbacks. We suggest that ice sheet mass loss, if warming continues unabated, will be characterized better by a doubling time for mass loss rate than by a linear trend. Satellite gravity data, though too brief to be conclusive, are consistent with a doubling time of 10 years or less, implying the possibility of multi-meter sea level rise this century. Observed accelerating ice sheet mass loss supports our conclusion that Earth’s temperature now exceeds the mean Holocene value. Rapid reduction of fossil fuel emissions is required for humanity to succeed in preserving a planet resembling the one on which civilization developed [citations added].
Hansen and Sato support their conclusion with statistical data, not the products of a climate model. I want to point this out although no one should infer from my remark a rejection of climate modeling (as if I or most critics were competent to make that judgment). The point I want to make is a simple one which an outsider like me can make without fear: The critics of the anthropocentric thesis cannot rely upon their reservations about climate modeling which criticizing the defenders of the anthropocentric cause thesis. The climate change controversy is, of course, is an effect of a red herring strategy. Eventually, we may expect this strategy to give way to a use of the idiot defense: “We did and could not have known that we were causing the apocalypse.”
But we do know.
- Paleoclimate implications for human-made climate change (pubs.giss.nasa.gov)
- Study Links Events to Climate Change (abcnews.go.com)
- New study links current events to climate change (cnsnews.com)
- New study links current events to climate change (kansascity.com)
- Global warming: A new study from Denmark suggests the Greenland ice sheet may not be doomed quite yet (summitcountyvoice.com)
- Loss of Antarctic ice could trigger super-interglacial (newscientist.com)
- New study links current events to climate change (news.terra.com)
- Must-Read Hansen: ‘Climate Change Is Here – And Worse Than We Thought’ (thinkprogress.org)