Global Warming backdown

[Keepitsimple]

The warming that occurred in the first part of the 20th century has always contributed to me scepticim about CO2 being the major driver behind the warming that occurred in the 80's and 90's. This article provides an apt comparison of the two periods. Interesting......here's the text of the article - click on the link for the graphs and video.

As you can see in Phil Jones’ HadCRUT graph above, the 25 year period from about 1975 to 2000 did warm about half a degree C.

You can also see that the 30 year period from 1910 to 1940 similarly warmed about half a degree C. At that time, atmospheric CO2 averaged about 305 ppm, well below Dr. Hansen’s suggested “safe level” of 350 ppm. See the graph below for that period:

Global CO2 - click to enlarge

Here’s an annotated HadCRUT graph to help you see the relevant periods and the changes of temperature versus changes in global CO2 concentration during the same period:

The video below superimposes the 1975 warming (blue line) on the 1910 warming (black line.) Note the similarity in slope, duration and patterns. It would be difficult to explain the 1910 warming as being due to CO2, because CO2 was barely above pre-industrial levels and rose only 10 ppm during that period.

Given the similarity between the 1975 warming and the 1910 warming, it is irrational to blame the 1975 warming entirely on CO2. The practice of good science tells us to look for a hypothesis which can explain both similar warming periods.

If there is an influence of CO2 in the recent warming, it appears small. And the warming stopped ten years ago, as shown in the HadCRUT graph, despite rapid increases in CO2.

Or perhaps one might conclude that climate sensitivity has decreased as CO2 levels have risen. In 1910, with CO2 at 300 ppm, it only took ten additional ppm to raise temperatures by 0.5°C. By contrast, in 1975 it took about fifty ppm more to produce the same 0.5°C warming by the year 2000.

There were also periods of time with rising CO2, and little or no rise in temperature. From 1940 to 1980, there was no net warming while CO2 rose by 30 ppm. Since 1998, there has been no warming – as CO2 levels have risen 30 ppm.

I feel a chill of La Niña coming on.

Link: http://wattsupwiththat.com/2010/08/22/picking-carbonated-cherries-in-1975/#more-23774

[waldo]

The warming that occurred in the first part of the 20th century has always contributed to me scepticim about CO2 being the major driver behind the warming that occurred in the 80's and 90's. This article provides an apt comparison of the two periods. Interesting......here's the text of the article - click on the link for the graphs and video.

as always, Simple... you are most encouraged to step-up and attribute the latter warming to something... to anything... other than CO2. As for the earlier 1915-1940 warming => attributed to a lull in cooling volcanic activity, to a solar output increase and to a GHG increase.

Steve Goddard... from the #1 science blog WTFIUWT!

[waldo]

don't worry Simple... be happy!

Disaster at the Top of the World

Aboard the Louis S. St-Laurent

STANDING on the deck of this floating laboratory for Arctic science, which is part of Canada’s Coast Guard fleet and one of the world’s most powerful icebreakers, I can see vivid evidence of climate change. Channels through the Canadian Arctic archipelago that were choked with ice at this time of year two decades ago are now expanses of open water or vast patchworks of tiny islands of melting ice.

In 1994, the “Louie,” as the crew calls the ship, and a United States Coast Guard icebreaker, the Polar Sea, smashed their way to the North Pole through thousands of miles of pack ice six- to nine-feet thick. “The sea conditions in the Arctic Ocean were rarely an issue for us in those days, because the thick continuous ice kept waves from forming,” Marc Rothwell, the Louie’s captain, told me. “Now, there’s so much open water that we have to account for heavy swells that undulate through the sea ice. It’s almost like a dream: the swells move in slow motion, like nothing I’ve seen elsewhere.”

The Arctic is warming twice as fast as the rest of the planet, and this summer its sea ice is melting at a near-record pace. The sun is heating the newly open water, so it will take longer to refreeze this winter, and the resulting thinner ice will melt more easily next summer.

At the same time, warm Pacific Ocean water is pulsing through the Bering Strait into the Arctic basin, helping melt a large area of sea ice between Alaska and eastern Siberia. Scientists are just beginning to learn how this exposed water has changed the movement of heat energy and major air currents across the Arctic basin, in turn producing winds that push remaining sea ice down the coasts of Greenland into the Atlantic.

[Pliny]

The New York Times....Bwaahhahaha.