The North Atlantic is cooling because the Greenland ice sheet is melting

By | September 23, 2009

There is a flurry of wrong information in the news about a German meteorologist and oceanographer named Mojib Latif.  I’d say the North Atlantic Ocean is cooling because the Greenland ice sheet is melting…  The ice sheet is melting due to global warming.  Look at what he actually said, and you will see that this is a non-story. He didn’t predict 20 years of cooling, he gave an example that there *may* be cooling over the course of even 17  years due to natural variability, but we are not off the hook.  Have a look at Greenland. That much ice does not melt for no reason. The Earth is a dynamic system, heat up one area and you melt ice. Ice water  in the ocean changes currents and that changes wind patterns causing new weather patterns.  You may get snow in places you’ve never had snow… but you have to look at the big picture.

Fred Pearce wrote a recent column for New Scientist claiming climate modeler Mojib Latif predicted that up to two decades of cooling were coming: “We could be about to enter one or even two decades of cooler temperatures, according to one of the world’s top climate modellers.” Pearce’s claim was promptly picked up by the denialosphere and has been cited by “skeptics” as well as those who believe climate science is undergoing some sort of shake up, like Mr. Berger. Pearce’s story is greatly misleading both in terms of what Latif actually said and the role climate scientists believe natural variability plays in the climate system. …

This does not represent a “shake up” of the climate science community’s understanding of the system, or a blow to “settled science”. This is acknowledged in the IPCC’s most recent Assessment Report (AR4 WG1 8.3 and 9.4) as well as in the relevant primary literature. For example, the AR4 Synthesis Report states:

On scales [smaller than 50 years], natural climate variability is relatively larger [than human influences], making it harder to distinguish changes expected due to external [] forcings.

Latif begins the section of his presentation misrepresented by Pearce by confirming that the media incorrectly believes that global warming is monotonic- something that we know the warming is decidedly not; something not claimed by “climate science” or “climate scientists”. Significant natural variability is superimposed on the long term man-made warming trend. Although the press might expect for us to set a new temperature record every year, the existence of natural variability means that we could in theory wait a long time (~17 years) before setting a new temperature record. ..

This was not an explicit prediction by Latif- it was a hypothetical scenario that is a real, if  not necessarily likely, possibility. Latif is saying that because people don’t understand that global warming isn’t supposed to be monotonic, and that there could be periods where temperatures pause or even dip below the present, the media and/or public will incorrectly believe that global warming has stopped/was wrong/etc. even though such “pauses” in warming are decidedly not contrary to our understanding of the climate system and how we anticipate it will respond to emissions driven warming. – thingsbreak

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