September 06, 2009
Natural Arctic Cooling Reversed Starting 1900

A long term climate trend in the Arctic has reversed course.

Warming from greenhouse gases has trumped the Arctic's millennia-long natural cooling cycle, suggests new research. Although the Arctic has been receiving less energy from the summer sun for the past 8,000 years, Arctic summer temperatures began climbing in 1900 and accelerated after 1950.

The decade from 1999 to 2008 was the warmest in the Arctic in two millennia, scientists report in the journal Science. Arctic temperatures are now 2.2 F (1.2 C) warmer than in 1900.

To track Arctic temperatures 2,000 years into the past, the research team analyzed natural signals recorded in lake sediments, tree rings and ice cores. The natural archives are so detailed the team was able to reconstruct past Arctic temperatures decade by decade.

As part of a 21,000-year cycle, the Arctic has been getting progressively less summertime energy from the sun for the last 8,000 years. That decline won't reverse for another 4,000 years.

The new research shows the Arctic was cooling from A.D. 1 until 1900, as expected. However, the Arctic began warming around 1900, according to both the natural archives and the instrumental records.

What I want to know: If we wanted to select a temperature at which to stabilize the world's climate (since, after all, it naturally warms and cools) at what temperature would we need to stabilize it at to stop average global ice melting? My guess is that temperature is cooler than it is today. Is that temperature also cooler than it was in 1900?

If I understand this correctly the 1.2 C warming since 1900 reverses the last 6 thousand years of cooling (1.2 C divided by 0.2 C per thousand years).

The analysis shows that summer temperatures in the Arctic, in step with reduced energy from the sun, cooled at an average rate of about 0.36 F (0.2 C) per thousand years -- until the 20th century.

Naturally we should be cooling as we head back into the next ice age. But do you want the natural cycle to continue? Or do you want whatever climate we get as a side effect of continued industrialization? Or do you want to select a climate target and manipulate climate policy to achieve that target?

Share |      Randall Parker, 2009 September 06 09:41 AM  Climate Trends


Comments
not anon or anonymous said at September 6, 2009 9:55 AM:
What I want to know: If we wanted to select a temperature at which to stabilize the world's climate (since, after all, it naturally warms and cools) at what temperature would we need to stabilize it at to stop average global ice melting?

I hope you realize where this reasoning leads.

To sketch a parallel: freezing economic and social and geographical conditions in law is exactly what government should not be doing (and what the US federal government is prohibited from doing, but does anyway).

Ok, you didn't explicitly mention government doing anything. It's just a thought experiment, and it's definitely something that boffins don't discuss (enough) and that pols are dangerously ignorant of or deliberately hiding. Still, "there ought to be a law" are individuals' solution to societal ills, since government is the natural tool for such things, being so wonderfully efficient at killing people and such.

Girm said at September 6, 2009 11:54 AM:

Avoiding an ice age would be a prudent goal. Doing so without really understanding the effects of what we are doing is not.

Synchro Ryo KoKo said at September 6, 2009 2:55 PM:

Only a moron really believes that the climate is stable for long periods of time. It is exactly the up and down movements of temperatures seen in the 20th century which are typical of longer term climate. Of course you have extremely rapid and violent shifts as well, which occur for natural reasons over periods of years to decades.

Far from being an example of a radical reversal of trends, the 20th century was mild and typical for the intervening periods.

Not having thousands of years of satellite and ocean buoy readings, we are forced to use proxies of extremely low resolution. These proxies are very tricky and subject to distortion and artifact. Unfortunately, the foundations and agencies give more grants to the people who claim the more sensationalist findings. A built in bias of the system.

John Moore said at September 6, 2009 11:58 PM:

As I mentioned on the other post, the ice gain in the antarctic exceeds the loss in the arctic.

Also, the Pacific Decadal Oscillation may be a culprit in the recent northern warming. Another candidate is particulate pollution from china.

But do you want the natural cycle to continue? Or do you want whatever climate we get as a side effect of continued industrialization? Or do you want to select a climate target and manipulate climate policy to achieve that target?

Continued industrialization? It may very well be totally dwarfed by the natural cycle. For example, global temperature trends for the last ten years have been counter to the CO2 concentration increase.

Furthermore, we really have no significant control over CO2 emissions, since China and India aren't going to cut CO2 emissions anyway.

Engineer-Poet said at September 7, 2009 6:28 AM:

This antarctic "ice gain"—do you mean area of sea ice, or total mass of ice?  I'm wondering what could compensate for the loss of the various ice shelves and acceleration of the glacial flows; the NASA GRACE experiment found mass loss of several percent, IIRC.

Bruce said at September 7, 2009 10:25 AM:

The Arctic warmed up considerably in the 20's/30's/40s and then cooled again.

The "warmest in 2000 years" is just the hockey stick liars at it again.

"Despite all the changes in Greenland, this is not the first time temperatures have risen on the world's largest island. During the 1920s and 1930s, there was a significant warming trend that occurred without the level of man-made greenhouse gases recorded in our atmosphere today. The majority of scientists say greenhouse gases are the chief cause of global warming.

The fact Greenland has warmed before leads some scientists to question how worried we should be about the current warming trend."

http://www.cnn.com/2007/TECH/science/10/23/greenland.melting/index.html

http://www.agu.org/pubs/crossref/2005/2005GL024254.shtml

http://forces.si.edu/arctic/02_01_02.html

wes george said at September 8, 2009 3:13 AM:

Kaufman, et al, note that the temperature history of the Arctic is “sparsely documented” and thus requires a “proxy reconstruction.” Paradoxically, Kaufman ignores the most obvious proxy data of all: Written historical records from a multitude of sources! I wonder why?

Too bad Kaufman, et al, didn’t begin with the Isendigabok or Eiriks Saga Rauoa as a climatological proxy, if he had he would have discovered what has been a well-known and undisputed historical fact for centuries:

Graenland was once green. It had forests and valleys full of grasses and herbs now buried under glaciers. The Norse created an economy based on dairy exports to Europe where now only permafrost exists. Even Jared Diamond examined the Norse dairy farm colonies in Greenland in his 2005 masterpiece of millenarian alarmism, “Collapse: How Societies Choose to Fail or Survive” and concluded the poor bastards all froze to death because they wouldn’t adopt the Inuit lifestyle over that of butter, bread, mead and dandelion salads.

Kaufman’s claim that the Arctic is now warmer than at any time in the last 2,000 years is demonstrably false. “The science really is settled.” Or as Americans like to say BullSh#t.

Say, how's that Greenland dairy farming industry going today?

Kralizec said at September 8, 2009 11:06 AM:
As part of a 21,000-year cycle, the Arctic has been getting progressively less summertime energy from the sun for the last 8,000 years. That decline won't reverse for another 4,000 years.
Then it seems our ancestors experienced temperatures similar to those of the present day, and now (ex hypothesi) we're mitigating an estimated 8,000 years of past, northern-hemispheric cooling and an expected 4,000 years of additional cooling. It seems it would be reasonable for everyone on both sides of the issue of global warming to make the simple admission that this may not be a problem.
Trent Telenko said at September 8, 2009 11:32 AM:

FP,

We may be looking at politically correct -- AKA fudged -- data.

Any scientist who refuses to show his data to ensure validity & repeatability of his published theory results by other scientific experts cannot be trusted:

"Since we can’t really look at the Hadley CRU data since it is held under lock and key despite the repeated FOI requests so that analysis and verification can be performed, we can’t really analyze it pertaining to NOAA’s claim of warming. Since NOAA and HadleyCRU use many of the same stations above 60N (they’d have to since there are so few) it seems reasonable to assume they share similar data in the Kaufman et al paper."

See these links:

http://wattsupwiththat.com/2009/09/04/dmi-arctic-temperature-data-animation-doesnt-support-claims-of-recent-arctic-warming/#more-10531

http://blogs.nature.com/climatefeedback/2009/08/mcintyre_versus_jones_climate_1.html

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