Past the tipping point

Smokey, if two typo’s is all you found to critique in my post, that’s a very good thing indeed. It was late at night afterall.
And whoever said that absorbed solar is not cummulative over the summer, perhaps you don’t understand what I meant by that and what the figure in the ppt shows. The figure focused on the months of May-August. Solar radiation is absorbed at the surface during all those months as the surface albedo decreases: cummulative simply refers to the total absorbed during that time-period (i.e. sum of May + June + July + August multiplied by the number of seconds during that time-period to get the units discussed). If you go to NSIDC’s web site, you can see images of sea ice concentration trends. Negative trends in sea ice concentration during summer imply a corresponding decrease in albedo. This together with incoming solar energy (which you can get from CERES data or from radiative transfer modeling) will give you the total absorbed energy. It does not appear to be as trivial as some on here would have you believe.

stevengoddard says:
May 25, 2010 at 5:22 pm
R Gates,
It is extremely clear from the maps that sea ice concentration is greater now than it was 20 years ago.
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And I would say that it is extremely UNCLEAR that anything of the sort is the case. Looking at the data as displayed on this chart:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg
All one has to do is zoom into 1990, and look at it close, and you’ll see that the sea ice extent never even came close to a negative anomaly of 1,000,000 sq. miles, yet we are over that here in May of 2010. So, again, in your orginal post, you said:
“Sea ice concentration is considerably higher now than it was on this date 20 years ago.”
So I must completely disagree with your assessment and I’m not sure what data you’re using. If you want to post an actually data set for sea ice in May 1990, I’d be glad to compare it to 2010’s actual data. Perhaps different data sets we’re looking at?

Gail Combs says:
May 26, 2010 at 4:33 am
“At the pole you are talking abouthigh angles of incident light. since the sun is close to the horizon most of the time.”
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This might be true if the open ocean in the arctic was completely flat and horizontal and smooth like but the open ocean at the poles also has waves, and the incident light that falls on the sides of the waves actually strikes it much more directly than some realize. This is the same reason that solar panels are raised up off the level ground so that the sun might stike them more directly. Think of the sides of the waves in the open arctic waters as being like the inclined solar panels…they absorb a lot more radiation than you’d think, even with the sun lower on the horizon.

Ken Hall says:
May 26, 2010 at 1:21 am
Anu,
Are you aware that the temperature increase associated with an increase in CO2 concentration is logarithmic? This means that the greater the increase in CO2, the less temperature rises, until adding more CO2 will not make any difference as the entire heat absorption frequency available is saturated.
Yes, the temperature increase is logarithmic.
2^1 = 2
2^2 = 4
2^3 = 8
2^4 = 16
logarithm – the exponent required to produce a given number
So, the temperature increase goes as 1, 2, 3 and 4 as the CO2 amount goes up by a factor of 2, 4, 8 and 16.
The equilibrium temperature increase from a sustained doubling of CO2 in the atmosphere is proportional to the exponent of the increase, not the increase itself.

http://en.wikipedia.org/wiki/Climate_sensitivity
equilibrium climate sensitivity refers to the equilibrium change in global mean near-surface air temperature that would result from a sustained doubling of the atmospheric (equivalent) CO2 concentration (ΔTx2). This value is estimated, by the IPCC Fourth Assessment Report (AR4) as likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values. This is a slight change from the IPCC Third Assessment Report (TAR), which said it was “likely to be in the range of 1.5 to 4.5°C”. More recent work continues to support a best-guess value around 3 °C.

Increasing CO2 by a factor of 3 will NOT create 3 x 3 (+/-1.5) Celsius degrees of warming.
True, but the example was:
280 –> 2,470 would be a factor of 8.8. More than 3 doublings.
Each CO2 doubling causes 3 +/- 1.5 °C change in planetary temperature.
This was not a “factor of 3”, it was a factor of 8.8. More than 3 doublings.
Doubling of CO2 from pre-industrial levels should produce 2 Celsius degrees of warming.
Well, the best-guess value is 3 degrees of warming, but 2 is within the error bars, so OK.
A further doubling would produce a further 1 Celsius degree of warming, and a further doubling would produce a further 0.5 Celsius degree of warming.
No, each further doubling would produce another 3 °C of warming. That’s pretty much the definition of climate sensitivity. You’re thinking of “a further 280 ppm” would produce less warming, and another 280 ppm would produce even less additional warming, etc.
The near doubling of CO2 from pre-industrial levels
280 –> 390 is a 39.3% increase, not a “near doubling”
has resulted in approximately 0.7 degrees in reality, so there are some negative feedbacks mitigating the warming.
The Industrial Revolution started about 1780, say. The temperature records are a bit spotty back in 1850 to 1880.
I’d say about 0.9 °C so far, with 39.3% CO2 increase.
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
And climate sensitivity is not instantaneous – it takes awhile for all the effects of the new forcings to show up in the “global mean near-surface air temperature” (that’s the ‘equilibrium’ part).
(and that is accepting the official temperature record, which is now open to serious doubt due to the methodology involved in constructing [manipulating] the official record through removing temperature stations in colder locations and extrapolating and homogenising data from warmer stations subject to UHI effect).
There are only a few organizations that bothered to try to figure out the planetary temperature back to 1850 or 1880. If someone else does it “better”, I’ll certainly take a look. Remote Sensing Systems (RSS) redid all the satellite data processing that Univ. of Alabama, Huntsville (UAH) had done for decades, and did it better, correcting some crucial errors. I’m all for progress.

pat says:
May 25, 2010 at 6:33 pm
O/T but wondering if these figures are accurate:
24 May: Politico: EPA can’t regulate climate change
by SEN. JOHN BARRASSO (R-Wyo.), member of the Environment and Public Works Committee.
Regulating carbon dioxide as a pollutant, for example, would require all stationary sources that emit more than 250 tons of carbon dioxide — a threshold that catches even small emitters — to apply for “prevention of significant deterioration” permits for new construction or modifications. The typical PSD permit costs an applicant approximately $125,000, according to the EPA’s own estimate, and takes roughly 866 hours to obtain. If America’s small businesses are forced to operate under these sorts of conditions, it will crush them.
By June 7, the Senate has a chance to pass a resolution that would stop the EPA from regulating climate change through the Clean Air Act.
http://www.politico.com/news/stories/0510/37660.html
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I wonder what THAT regulation will do to the new house market. As a chemist working in industry for thirty years, I have watched as the “thresholds” for various chemical have been driven lower and lower. The new threshold of 15 ppm of sulfur in diesel that caused the price of diesel to skyrocket in the last few years comes to mind.
Does anyone remember when the change to unleaded fuel happened and we were told the major jump to a higher price was to offset the cost of new pumps but the price would go back down in a year? (Of course it just kept going up)
But then again individually owned homes are considered”unsustainable” by the Agenda 21 crowd. The Wildlands Project and UN Convention on Biological Diversity Plan to Restore Biodiversity in the United States MAP shows the ultimate goal of all this Global Warming and Environmental Extremism nonsense. Humans get to live in the green areas, no humans allowed in the red areas except for “green scientists” A bill to make this map law was almost passed here in the USA about ten years ago. Talk about a real close call!

tonyb says:
May 26, 2010 at 12:23 am
It melted abnormally in the period 1915 to 1940
It melted abnormally in the period 1820 to 1860 (see my article here)
It melted abnormally in the period 1700-1740
It melted abnormally in the 1400′s.
It melted extremely abnormally around 1000 AD (the Vikings) and 1000 years before that (The Ipiatuk).
Did it ever disappear entirely in the summer melt during these times ?
No?
Then if it does this century, that would be “extremely abnormal”, would you agree ?
Melting ‘abnormally’ is what the arctic does. Our satellite records in 1979 caught it at a historically high point and it would be expected melt back from those levels.
The satellite data for the Arctic ice in the early 1970’s shows that it was even “historically higher”, then.
The Nimbus 5 ESMR data started from 1972.
Here’s a paper that discusses the Arctic sea ice extent in the 70′s:
http://www.tos.org/oceanography/issues/issue_archive/issue_pdfs/6_1/6.1_barry_et_al.pdf
See Figure 3 for 1972, 1973, 1974, 1975 and 1976 summer Arctic sea ice minimums – “about 8 * 10^6 km^2″ for each of these years.
Compare with:
http://nsidc.org/images/arcticseaicenews/20091005_Figure3.png
I think the “alarmists” should add in those early 1970’s September sea ice extents, it makes the melting trend more impressive.
Of course, hitting 0 one summer soon will be the most impressive data.
We must invite James Hansen (and others) to look at a much broader historic perspective in order to put the modern age into its proper context.
Dr. Hansen models the Earth’s climate. GCM models don’t really care about anecdotal evidence for Arctic ice in the 1400’s, or even 1700-1740.
Paleoclimatologists are the ones interested in climate centuries and millennia ago. Maybe you should invite Dr. Mann.

Thanks for another stimulating and enjoyable post Steve.
One of the problems in understanding the polar radiative balance is that the average albedo at any moment in time changes, depending on the amount of snow, surface water on top of the ice, age of ice (older = dirtier), wind conditions, e.t.c.
Differences in the wavelength of solar radiation also have a big effect on the balance, with the proportion of UV being the most important. So no simplistic way to get a good fix on what will happen at max./min. each year and linear trends have little or no meaning regarding the sea ice cover.
@ur momisugly Anu: May 25, 2010 at 8:44 pm
…Science is not the same as Business or Military – if it were, you couldn’t demand to see their data and get to make graphs and videos like you do.
It’s a shame not all climate scientists are confident enough in their work to let others see their data. For example, Jones et al refused to supply information and either lost of hid the raw data to stop others checking their results.

There is an old yardstick for ice cover in the Arctic: the spring’s first boat from Norway to Svalbard.
In 2007 there was no such thing. Longyearbyen remained ice free through the year.
In 2010 the first boat reached Longyearbyen on May 4.

Here is the Goddard Arctic sea ice extent and area data through this April:
April
year extent area
1979 15.46 12.43
1980 15.49 12.45
1981 15.12 12.16
1982 15.57 12.55
1983 15.30 12.12
1984 15.15 12.1
1985 15.34 12.46
1986 15.15 11.95
1987 15.33 12.27
1988 15.21 13.11
1989 14.44 12.26
1990 14.68 12.16
1991 14.93 12.79
1992 14.70 12.76
1993 15.18 12.95
1994 14.95 12.84
1995 14.59 12.32
1996 14.22 12.23
1997 14.59 12.48
1998 14.89 12.76
1999 15.13 13.08
2000 14.63 12.51
2001 14.86 12.99
2002 14.37 12.35
2003 14.57 12.38
2004 14.11 12.08
2005 14.07 12.16
2006 13.97 11.97
2007 13.87 11.75
2008 14.47 12.42
2009 14.59 12.54
2010 14.69 12.43
I know that fits and trend lines don’t prove anything, but they do help us see the data more clearly, and polynomial fits above second or third degree all trend up at the current end. Also, linear regression lines through cyclical data is an almost useless practice.

“…..So much for Dr. Hansen’s tipping points.
Are you aware that the Sun has been getting 1% brighter every 100 million years ?
And that people here argue about how powerful an effect 0.1% fluctuations in TSI (Total Solar Irradiance) caused by sunspots can be…
As for 2,470 ppm of CO2 – this is compared to the pre-industrial level of 280 ppm, not the current level – the warming in the pipeline from increasing from 280 ppm to 390 ppm is not realized yet (large inertia in planet-scale climate changes). The 280 ppm level lasted many centuries.
280 –> 2,470 would be a factor of 8.8. More than 3 doublings.
Each CO2 doubling causes 3 +/- 1.5 °C change in planetary temperature.
About 9 °C warming. On average. Some regions much higher.”
So much for Charles S. Opalek, PE teacher of climatology nonsense.
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I am sure you are referring to Page 446 of the IPCC 4AR which has the following text, “ Ice core records show that atmospheric CO2 varied in the range 180 to 300 ppm over the glacial-interglacial cycles of the last 650kyr…”
The problem is 280 ppm CO2 is not a solid number. Basically plants stop growing at 200 ppm. When CO2 drops to 220 ppm grasses become the dominant plant species since they can still grow at these levels while most bushy plants and trees can’t. Stomata data by Wagner, Aaby and Visscher prove conclusively that the ice core data is seriously in error. The ice core data can be corrected using J.J.Drake’s correlation, the profile does not change but the ppm values do so the analysis is still valid.
Researchers find carbon dioxide,is not well mixed in the troposphere, but is rather “lumpy” – NASA
Atmospheric CO2 1826 to 1960 WITH ERROR BARS!
Abstract
“The atmospheric CO2 mixing ratio has fluctuated widely over the Phanerozoic, according to the estimates from available proxy records. Because atmospheric CO2 is a major greenhouse gas, these fluctuations should have led to significant climatic variations. The “classical” view is indeed that atmospheric CO2 has been the main driver of the Earth’s climate history. On long-term time scales, the atmospheric CO2 level is the result of the balance between CO2 inputs from volcanoes or oxidation of old organic carbon (kerogen) in exposed rocks and outputs through silicate weathering or organic carbon deposition. Existing model reconstructions of the Phanerozoic history of atmospheric CO2 are based on such budgets. Recent data and model experiments currently challenge these models. First, the carbon cycle may be more complex than represented in the earliest models. In particular, silicate weathering depends on numerous factors, which are not obvious to model or are poorly known over the Phanerozoic. Mountain uplift is one such factor, which has been much debated in the last decade. Lithology is another example: basalts weather much more rapidly than other silicate rocks and the emplacement of large basaltic areas on the continents may trigger glaciations. Continental configuration is also more important than previously thought, as indicated by recent model experiments on super-continent fragmentation coupling geochemical and climate models. Problems of “classical” Phanerozoic CO2 models are also well illustrated by the fact that the most recent estimates of CO2 degassing show very little variation between the Cretaceous and the present, a period when large changes in CO2 have occurred, whereas degassing is the most important forcing of CO2 evolution in long-term carbon cycle models. Second, CO2 is not the only driver of climate evolution. This obvious fact has largely been forgotten in Phanerozoic studies. What the proxies tell us on paleo-atmospheric CO2 is not always in line with what we know about paleoclimatic records. For instance, the proxies suggest relatively high CO2 levels during the Late Ordovician glaciations. Similarly, the Late Jurassic now appears to be colder than earlier thought, while again proxies suggest high atmospheric CO2 at that time. The mid-Miocene climate warming, which occurs simultaneously with a drop in CO2, provides another example. This latter change in CO2 is unanimously reflected in all proxies and, so, this decoupling between CO2 and climate cannot arise from uncertainties on the reconstructed CO2 levels or from dating problems, as might be the case of the former two examples. Other climatic drivers than CO2 clearly need to be considered. In this respect, vegetation- climate feedbacks have been completely disregarded in long-term climatic studies. Cenozoic cooling is, however, accompanied by a progressive transition from closed forests to more widespread grasslands and deserts on the continental areas, a change which must have had major impacts on the surface albedo and the water cycle. “ http://adsabs.harvard.edu/abs/2006AGUFMPP23E..01F
And then there is the usual problem. Can you trust the data. NASA says CO2 distribution is surprisingly “lumpy” yet the data we have been getting for ages has been surprisingly “smooth” Perhaps this may contribute to the problem: Greenhouse Gas Observatories Downwind from Erupting Volcanoes
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Steve Keohane says: May 26, 2010 at 7:17 am
As one approaches an object from a distance, it gets larger, not smaller.
Agreed. Here are the links again. Right click “open in new tab” for each so you can flip back and forth, and pay attention to the stars surrounding the Earth. This makes it very evident that the observation point is closer to the Earth in 2010.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/19900525.png
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20100525.jpg
Please explain how the Arctic area shrinks from a closer observation point.
By “Arctic area” do you mean the boundary of ice? I agree, if there was no change in boundary, a closer observation point would make it appear larger. Since it does not appear larger, I would conclude the the 2010 ice is not spread out as far as the 1990 ice. However, the % concentration shown by color over the two images shows 2010 to be more concentrated. So we’re talking about ice chunks being packed more tightly in 2010 and not being as spread out as in 1990.
Here is a scale drawing of the earth and the two points of observation. The satellite is obviously too close to capture the full diameter of the earth, so it is within the area where the relative size of the features can vary in area wrt the diameter of the earth, but not in the way you describe.
Good point. The diagram indeed explains that >50% of the surface is blocked by the horizon. In order to see the full diameter of the planet, the observation point would need to be at infinity distance, or the planet would need to be cut in half by divine intervention (preferably with me riding in a comfy cockpit of the satellite). As for the relative size of features, as an object gets closer, the nearest features should appear to enlarge at a faster rate than the farthest ones, unless the features themselves were changing in shape/size during the trip. So although it is obvious that the ice is not as spread out in 2010 as in 1990, it would be hard to quantify the statement without normalizing the data by 3 dimensional projection/scaling operations (as opposed to simple 2D scale/crop operations).