By Steve Goddard
In 2007, Dr. Hansen boldly declared
“…defying government gag orders. Hansen told Reuters, quote, “The reason so much (of the Arctic ice) went suddenly is that it is hitting a tipping point that we have been warning about for the past few years.”
and Mark Serreze placed the blame squarely on CO2.
“…the effects of greenhouse warming are now coming through loud and clear.”
So let’s see how the greenhouse gas induced tipping point is working out. By this date in 1990, there was already a large hole in the ice in the Laptev Sea (upper right, near Siberia.) Watch the video:
Generated from UIUC maps.
Solar radiation in the Arctic is very close to it’s peak by May 25, so there was a lot of solar energy being absorbed through the ice in the Arctic ocean by this date in 1990.
http://earthobservatory.nasa.gov/Features/EnergyBalance/images/annual_solar_insolation.png
Sea ice concentration is considerably higher now than it was on this date 20 years ago.
Generated from UIUC maps.
This means higher albedo (reflectance) and less absorption of solar energy. Note in the insolation graph above, that by the end of July the amount of sunshine in the Arctic begins to drop off very quickly.
You can see in the JAXA graph above that the 2007 divergence occurred in late July after Arctic insolation was already shutting down, essentially nullifying the Arctic albedo feedback argument. The Arctic minimum comes too late in the summer to have a significant impact on the radiation budget, due to the very low angle sun at that time. In fact, CERES has measured that during September 2008, the Arctic net radiation balance was strongly negative. The open water loses heat to the atmosphere (because it is not insulated by ice) meaning that declining ice cover is probably a negative feedback, not a positive one. NASA’s Earth Observatory explains:
This map (below) of net radiation (incoming sunlight minus reflected light and outgoing heat) shows global energy imbalances in September 2008, the month of an equinox. Areas around the equator absorbed about 200 watts per square meter more on average (orange and red) than they reflected or radiated. Areas near the poles reflected and/or radiated about 200 more watts per square meter (green and blue) than they absorbed. Mid-latitudes were roughly in balance. (NASA map by Robert Simmon, based on CERES data.)
http://earthobservatory.nasa.gov/Features/EnergyBalance/images/ceres_net_radiation_200809.jpg
Looks like the Arctic is less tipped than it was 20 years ago. It is a shame that Dr. Hansen feels like he is gagged, when he has such important information needed to save the planet.
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kwik says:
May 26, 2010 at 10:46 pm
Anu, if you are as worried as it looks like here, I think you owe it to yourselves to read Dr. Spencers latest book.
I admire Roy’s tenacity in the face of overwhelming disagreement from most of his colleagues, but I really can’t forgive him mis-processing the NASA satellite data for decades at UAH. Not only did he and Dr. Christy get it so wrong for so long, but they ignored repeated calls by their colleagues to check again if they had overlooked something, since their work disagreed with most other work. Not only did they not find their errors (found by outside researchers in 2005), but trumpeted their erroneous results for many, many years as “proving” Global Warming was “wrong”.
This is scientific malpractice, and taxpayers should be screaming for their heads.
I’m not that interested in his “Intelligent Cloud Design” ideas on Earth’s climate, but I find it interesting that he is also “skeptical” about Evolution and a proponent of the other “Intelligent Design”.
Vincent says:
May 26, 2010 at 8:17 am
Anu,
“No, each further doubling would produce another 3 °C of warming. That’s pretty much the definition of climate sensitivity.”
To argue what the future climate will be as the result of modelled outputs of a poorly understood non linear system is not even funny. It’s just dumb.
That’s why they use paleoclimate data from the Ice Ages to estimate climate sensitivity. Lot’s of people spent many man-centuries on the work.
But you’re right, I’m sure Science is hopeless.
Gail Combs says:
May 26, 2010 at 2:36 pm
Did it ever disappear entirely in the summer melt during these times ?
…
Yes it probably melted around 1000 AD – the Vikings
Here are the Greenland temperatures: Greenland Ice Core Data
Please note, during the time when the vikings (Norse) were in Greenland, Greenland was a full 2C warmer than today.
What do you mean by “today” – 1898 ?
Because the Greenland Ice Sheet Project Two (GISP2) drilled that ice core in 1993:
http://www.ncdc.noaa.gov/paleo/icecore/greenland/summit/document/gispinfo.htm
and the most recent data in that core was 0.095 thousand years ago:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt
I hear Greenland is much warmer these days than in 1898, even at the surface of an ice sheet hundreds of miles from the warming effect of the nearest ocean.
Yes it probably melted around 1000 AD – the Vikings
Oh, that’s nice.
People scream that Dr. Hansen shouldn’t be allowed to extrapolate from 3 different stations all within 1200 km of an Arctic “data point”, but here you are, asserting that a single data point in the center of Greenland’s vast ice sheet is just fine for estimating the entire Arctic temperature. Not even “temperature anomaly”, but “temperature”.
“Skeptics” sure are forgiving of sloppy methods when they like the results.
BTW, the Arctic Circle is 5,209.127 km wide, measuring across the North Pole.
Extending this single data point “temperature estimate” to sub-Arctic globe positions, such as the Bering Sea, is even more of a stretch.
If everyone is bleating “It’s Melting” today then during the period 986 to 1121, when we know the Norse were sailing in that area to hunt whale, seal and polar bears, it would have to have been ice free during the summer.
“that area” ?
Even journeys like Amundsen travelling the Northwest Passage took many years – 1903 to 1906. All that means is every summer, the ice shifts, and if you’re lucky, you can sail a bit farther before you have to stop again because of winter ice.
Look at three different summer ice extents (not even the 2007 minimum):
http://nsidc.org/news/press/2006_seaiceminimum/images_SJR/20060927_extent.png
http://nsidc.org/news/images/20081002_Figure1.png
http://nsidc.org/images/arcticseaicenews/20091005_Figure1.png
Every summer, a different path is opened up. Over years, people back in 1000 AD could get to almost any land in the Arctic.
Wtihout satellite data, you will have a difficult time proving that the Arctic was ever “ice free” in the summer back in 1000 AD or 1300 BC.
One data point is not going to cut it. That’s why the current Arctic climate research is not limited to a single data station on Greenland.