New Study Shows Humans Pushing Global Warming at Catastrophic Pace Not Seen in at Least 11,300 Years

Carbon-Final

(Image provided by Climate Progress)

A New Study published in Science by researchers at Oregon State University (OSU) and Harvard University shows that the pace of warming over the past century is faster than at any time in the past 11,300 years.

The research team used ice cores to identify the pace of warming and cooling during a period since the end of the last ice age called the Holocene. Researchers found that the 1.3 degree Fahrenheit temperature rise since the 1880s was about 30-50 times faster than any comparable period of temperature change during any time in the last 11,300 years.

Temperatures gradually rose from the end of the last ice age to a plateau that occurred from 8,000 to 3,000 BCE. Then, temperatures began to fall, dropping about 1 degree Fahrenheit over the course of 3,000 years. A long cooling trend that ended abruptly with the rise of industry about 130 years ago. Since that time, temperatures have risen sharply by over 1.3 degrees Fahrenheit and are set to rise again, in the event of ongoing fossil fuel use, by between 5 and 11 degrees Fahrenheit by the end of this century.

The above graph, provided by Science and Climate Progress shows the extreme difference between current and projected temperature increases and the comparative stable base-line of the last 11,300 years. If the shape of the graph looks familiar to you, it should. It is yet another validation of Michael Mann’s original temperature work dubbed “The Hockey Stick” due to its characteristic shape. The OSU/Harvard study simply provides further validation to Mann’s Hockey Stick study by extending temperature measurements outward to 11,300 years.

Pace of Change is Catastrophic

What the study also shows is that the current pace of warming is far, far outside the geological norm. Michael Mann, in response to the recent paper notes:

The real issue, from a climate change impacts point of view, is the rate of change—because that’s what challenges our adaptive capacity. And this paper suggests that the current rate has no precedent as far back as we can go w/ any confidence—11 kyr arguably, based on this study.

Lead author Shaun Marcott of OSU told NPR and AP that paleoclimate data show how unprecedented current warming really is:

It’s really the rates of change here that’s amazing and atypical. Even in the ice age the global temperature never changed this quickly.

Even in the ice age, temperature never changed so quickly… This statement is worth repeating because it gives us a degree of corollary to the troubles we are causing. Among other things, the slower pace of change at the end of the last ice age melted the entire Laurentide ice sheet. The catastrophic melt that followed broke an ice damn and unleashed a flood of water across the North American continent that was, in some cases, over a thousand feet tall. There is no Laurentide ice sheet left. But a vast expanse of ice rests over Greenland. And the vast Antarctic ice sheets smother an entire continent.

If the pace of temperature change is now faster than that during the ice age and if that pace of change is, under current human fossil fuel emissions, set to accelerate by another factor of 5 or more, then we can expect catastrophic impacts that are even greater than those seen at the end of the last ice age and occurring with far greater frequency.

We have no guarantee that pace of sea level rise will not exceed the maximum of ten feet per century seen during the last ice age. We have no guarantee that an unbalanced weather system won’t spawn storms never seen before. And we have no guarantee that the powerful human forcings won’t set into play feedbacks unprecedented to the Earth-climate system.

The OSU/Harvard Study is yet one more warning that we need to reduce and eliminate fossil fuel use as rapidly as possible. The human forcing on the climate system is massive and unprecedented in the geological record. The response from nature is likely to be equally massive and unprecedented. Yet we still have a small window of time in which to prevent the very worst impacts. Let us hope that a large, coordinated policy response develops soon.

“I certainly hope we can pull ourselves out of it,” Shaun Marcott said at the end of his CNN interview.

Links:

http://www.cnn.com/2013/03/08/world/world-climate-change/index.html

http://thinkprogress.org/climate/2013/03/08/1691411/bombshell-recent-warming-is-amazing-and-atypical-and-poised-to-destroy-stable-climate-that-made-civilization-possible/

http://summitcountyvoice.com/2013/03/07/global-warming-new-study-sharpens-hockey-stick/

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