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Study: Earth Is At Its Warmest In 120,000 Years (washingtonpost.com)
An anonymous reader quotes a report from Washington Post: As part of her doctoral dissertation at Stanford University, Carolyn Snyder, now a climate policy official at the U.S. Environmental Protection Agency, created a continuous 2 million year temperature record, much longer than a previous 22,000 year record. Snyder's temperature reconstruction, published Monday in the journal Nature, doesn't estimate temperature for a single year, but averages 5,000-year time periods going back a couple million years. Snyder based her reconstruction on 61 different sea surface temperature proxies from across the globe, such as ratios between magnesium and calcium, species makeup and acidity. But the further the study goes back in time, especially after half a million years, the fewer of those proxies are available, making the estimates less certain, she said. These are rough estimates with large margins of errors, she said. But she also found that the temperature changes correlated well to carbon dioxide levels. Temperatures averaged out over the most recent 5,000 years -- which includes the last 125 years or so of industrial emissions of heat-trapping gases -- are generally warmer than they have been since about 120,000 years ago or so, Snyder found. And two interglacial time periods, the one 120,000 years ago and another just about 2 million years ago, were the warmest Snyder tracked. They were about 3.6 degrees (2 degrees Celsius) warmer than the current 5,000-year average. Snyder said if climate factors are the same as in the past -- and that's a big if -- Earth is already committed to another 7 degrees or so (about 4 degrees Celsius) of warming over the next few thousand years. "This is based on what happened in the past, Snyder noted. "In the past it wasn't humans messing with the atmosphere."
Recently posted perspective here.
Politics; n. : A religion whereby man is god.
According to Gavin Schmidt, the director of NASA Goddard Institute for Space Studies: "The paper claims that ESS is ~9C and that this implies that the long term committed warming from today’s CO2 levels is a further 3-7C. This is simply wrong." He goes on to show why: http://www.realclimate.org/ind...
Here is another perspective based on non smoothed data.
Star Trek, there maybe hope.
James Hanson, the previous director of NASA GISS and Gavin's former boss, weighs in with his own perspective. In a comment to the post he says in part: There are various technical issues with both Schmittner and Snyder approaches that lead them toward their low and high values. Suffice it to say that I expect the true answer lie between the two, but closer to Snyder’s. The evidence favors a temperature change in the range ~4-5C for LGM-Holocene, and thus a fast-feedback climate sensitivity close to 3C or a bit larger. This then leads to an ESS sensitivity ~6C or somewhat higher as discussed in our 2013 paper. http://www.realclimate.org/ind...
I think the XKCD comic is rather more clever as he uses peer reviewed science. Your other perspective presumes that temperatures in Greenland represent temperatures around the world. That's not going to work. It looks like he snipped only certain parts though as using the whole core wouldn't fool "even the dimmest denier at WUWT" as Sue explains here: http://blog.hotwhopper.com/201...
The data it's based on is also not global. It's from a single ice core in Greenland - the very definition of cherry-picked data, and hardly comparable to global temperature reconstructions.
Why would anyone engrave "Elbereth"?
There have been several glacial/interglacial periods over the last 120,000 years. The peak of the current interglacial occurred about 8000 years ago. Since then temperatures have been slowly falling... up until about 150 years ago when something happened and temperatures dramatically reversed course.. Here's just the last 20,000 years by XKCD: http://xkcd.com/1732/
I think you have that backwards. Snyder is saying that the historical record shows that the sensitivity of temperature to carbon dioxide is much HIGHER than the GISS estimates.
Gavin Schmidt's comment is, basically, that her data shows correlation, not causation.
http://www.geoffreylandis.com
https://stream.org/xkcds-global-warming-time-series-mistakes/
Is this the same idiot?
Ezekiel 23:20