http://science.nbcnews.com/_news/2013/03/07/17225440-warming-fastest-since-dawn-of-civilization-study-shows?lite
Not satisfied with mapping the past 1500 years of planetary climate, scientists have now been able to go back 11,000 years. they did it by using ice cores and layers of "foraminifera"- deposits of tiny shelled creatures on the ocean floor. how did they know to do this? hey fool, they are scientists, that is what they do. :)
results? after the end of the last ice age, the temperature of our planet inched upward with amazing slowness, around one degree over 5000 years. then it peaked, and inched downwards by the same amount over another 5 or 6 thousand years. then in the last 150 years, it jerked higher so that the temperature averages today are higher than they were at 75% of that past 11,000 years. and are poised to leave that chart behind and start a new one that goes almost straight UP.
if humans had never done that industrial revolution thing, our planet probably would have eventually ended up in another ice age in another 5000 years. But since we DID invent that fossil fuel burning thing, not really worth mentioning ice ages because they ain't gonna happen.
yeah I know you are really tired of hearing about the global warming hockey stick chart. But it is what it is. if you don't like hearing about it, don't read my stuff.
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The full abstract:
Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time. Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling through the middle to late Holocene (<5000 years ago), culminating in the coolest temperatures of the Holocene during the Little Ice Age, about 200 years ago. This cooling is largely associated with ~2°C change in the North Atlantic. Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history. Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.
Q: What do paleotemperature reconstructions show about the temperature of the last 100 years?
A: Our global paleotemperature reconstruction includes a so-called “uptick” in temperatures during the 20th-century. However, in the paper we make the point that this particular feature is of shorter duration than the inherent smoothing in our statistical averaging procedure, and that it is based on only a few available paleo-reconstructions of the type we used. Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions.
Is the rate of global temperature rise over the last 100 years faster than at any time during the past 11,300 years?
A.
Our study did not directly address this question because the paleotemperature records used in our study have a temporal resolution of ~120 years on average, which precludes us from examining variations in rates of change occurring within a century.
"There’s much more at RealClimate, although there’s also room for more questions — one being how the authors square the caveats they express here with some of the more definitive statements they made about their findings in news accounts."