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Posted at 10:45 AM ET, 10/ 5/2010

Hansen projects hottest year on record... in 2012

By Andrew Freedman

Were extreme events caused by global warming?

* Slowly warmer: Full Forecast | Warmest Sept. since 1980 *


Global surface temperature departures (in degrees Celsius) from the 1951-1980 average for June-July-August 2010. Credit: NASA-GISS.

According to James Hansen, the director of NASA's Goddard Institute for Space Studies (GISS), 2010 may not wind up being the hottest year in the modern temperature record after all. In an analysis posted last week, Hansen said the onset and intensification of La Nina conditions in the Pacific Ocean have cooled global average surface temperatures, and despite the record heat in the first eight months of the year, 2010 may wind up either tied with or behind 2005, currently the warmest year in the GISS analysis.

Other climate research institutions, including the U.S. National Oceanic and Atmospheric Administration (NOAA) also keep such records and typically rank years slightly differently. For example, in the GISS analysis, June-July-August 2010 was the fourth warmest on record, but according to NOAA's methods it was the second warmest.

"It is likely that the 2005 and 2010 calendar year means will turn out to be sufficiently close that it will be difficult to say which year was warmer, and results of our analysis may differ from those of other groups," Hansen wrote. "What is clear, though, is that the warmest 12-month period in the GISS analysis was reached in mid-2010."


Global surface temperature departures (in degrees Celsius) from the 1951-1980 average for January-Augusts 2010 (top left), 2005 (top right) and 1998 (bottom left). Image on bottom right is a monthly plot of the globally averaged surface temperature anomalies in those years. Credit: NASA-GISS.

The news here isn't just that Hansen is no longer calling for an all-time record warm calendar year this year. Rather, it's that next year -- due to the lag between ocean and air temperatures -- likely won't be a record hot year in the NASA GISS record, at least the way it looks right now, but that 2012 currently looks like a prime opportunity for the atmosphere to go for the title.

"It is likely that 2012 will reach a record high global temperature," Hansen wrote. "The principal caveat is that the duration of the current La Nina could stretch an extra year, as some prior La Ninas have."

However, according to Hansen, the calendar year temperature ranking is not as relevant to monitoring long-term global climate change as the 12-month running mean -- which did hit a record high this year.

FAQ: Did climate change cause...?

A deep dive through Hansen's analysis provides yet more compelling evidence that despite shorter-term ups and downs, the overall climate is warming, due largely to increasing concentrations of greenhouse gases in the atmosphere. It also provides interesting advice to Hansen's fellow scientists about how to address the relationship between extreme events and climate change, a topic of great interest on this blog.

His comments are worth quoting in full, since it's unique to see a scientist considering both the message and how the public receives that message, since the two are often quite different:

"...A comment on frequently asked questions of the sort: Was global warming the cause of the 2010 heat wave in Moscow, the 2003 heat wave in Europe, the all-time record high temperatures reached in many Asian nations in 2010, the incredible Pakistan flood in 2010? The standard scientist answer is 'you cannot blame a specific weather/climate event on global warming.' That answer, to the public, translates as 'no'."
"However, if the question were posed as 'would these events have occurred if atmospheric carbon dioxide had remained at its pre-industrial level of 280 ppm?", an appropriate answer in that case is 'almost certainly not.' That answer, to the public, translates as 'yes', i.e., humans probably bear a responsibility for the extreme event."
"In either case, the scientist usually goes on to say something about probabilities and how those are changing because of global warming. But the extended discussion, to much of the public, is chatter. The initial answer is all important."
"Although either answer can be defended as 'correct', we suggest that leading with the standard caveat 'you cannot blame...' is misleading and allows a misinterpretation about the danger of increasing extreme events. Extreme events, by definition, are on the tail of the probability distribution. Events in the tail of the distribution are the ones that change most in frequency of occurrence as the distribution shifts due to global warming."
"For example, the 'hundred year flood' was once something that you had better be aware of, but it was not very likely soon and you could get reasonably priced insurance. But the probability distribution function does not need to shift very far for the 100-year event to be occurring several times a century, along with a good chance of at least one 500-year event."

I should note that Hansen is both a highly regarded scientist and an increasingly outspoken advocate for reducing greenhouse gas emissions. Just last week, for example, he was arrested in front of the White House with around 100 others while protesting mountaintop removal mining -- not exactly your typical activity for a late-career researcher.

I have criticized Hansen in the past for simultaneously working as the head of NASA-GISS while also carving out a role for himself at protest rallies, but such is his right as a free citizen of this country, provided he does not use taxpayer dollars for his advocacy activities.

The views expressed here are the author's alone and do not represent any position of the Washington Post, its news staff or the Capital Weather Gang.

By Andrew Freedman  | October 5, 2010; 10:45 AM ET
Categories:  Climate Change, Freedman, News & Notes  
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Comments

Readers should know that those graphics are SERIOUSLY misleading. The vast majority of the areas depicted in red and dark red are areas with no actual thermometer readings. None at all. The depicted anomaly is a computer generated guess. Not an actual measurement of temperature.

And Mr. Freedman knows this. Why he keeps using that graphic without disclosing the facts is something only he knows. I suspect it is because the graphic looks scary and he wants to scare people. But, that's pure supposition on my part.

I will post a link in a few minutes verifying what I wrote. I don't expect anyone to take it on faith. I will back it up.

Mr. Q.

Posted by: Mr_Q | October 5, 2010 11:40 AM | Report abuse

What is the Earth's temperature? I cannot tell from this chart.

Posted by: win_harrington | October 5, 2010 11:46 AM | Report abuse

OK--so what sort of winter are we supposed to get?

Posted by: chunche | October 5, 2010 12:00 PM | Report abuse

Mr Q: Are you saying that we can't look at the temperatures where we do have measurements and reasonably assume that nearby areas are in the same range?

If it's 90 degrees on my front porch and 90 degrees on my next-door-neighbor's front porch and 90 degrees on the front porch of my neighbor across the street, is it reasonable to assume that the neighbor behind my house might be at only 75? Or to say that because that neighbor has no thermometer we can't assume it's also about 90 degrees at his house?

Posted by: mhardy1 | October 5, 2010 12:04 PM | Report abuse

Try this for yourself.

We are going to open a new window/tab, so that you can leave this window/tab open and go back and forth between the new window/tab and these instructions.

Right click on this link and open it in a new window or new tab.

Don't change a single thing. Notice that the default "Smoothing radius" is 1,200 km. Click on the button labeled "Make Map".

Take a long look at that map. Read the note at the top of the page - "Note: Gray areas signify missing data."

If you read that note, and look at the map, you will most likely think to yourself, "Not too much missing data."

Now try this. Click the back arrow for your browser. You should now be back at the original page.

We are only going to change one setting. Click the drop down arrow next to 1200 km under the "Smoothing Radius:" option. Change the 1200 km to "250 km". Now click on the "Make Map" button.

The map looks a little different now, doesn't it? Where did all of that red, orange, and yellow go? A whole bunch more gray, isn't there? The gray represents missing data. Where is the gray on Andrew's graphic above? Notice all of the missing data for Greenland, Canada, China, Africa, and South America. But you wouldn't know that from looking at Andrew's NASA/GISS map, would you?

Take a long look at the gray area. Pay particular attention to where the gray area is located. Now take another look at Andrew's NASA/GISS graphic above. Notice anything?

It is really hot in the areas with the "missing data".

Mr. Q.

Posted by: Mr_Q | October 5, 2010 12:13 PM | Report abuse

mhardy1 wrote, "If it's 90 degrees on my front porch and 90 degrees on my next-door-neighbor's front porch and 90 degrees on the front porch of my neighbor across the street, is it reasonable to assume that the neighbor behind my house might be at only 75? Or to say that because that neighbor has no thermometer we can't assume it's also about 90 degrees at his house?"

What if the neighbor with no thermometer lives over 700 miles away?

If you lived in Washington D.C. and the thermometer on your porch said 90 degrees, can you accurately tell me the temperature in Grand Rapids, Michigan? That is the equivalent to what NASA/GISS is doing - reading the temperature in Washington, D.C. and guessing what the temperature is in Grand Rapids, Michigan.

Mr. Q.

Posted by: Mr_Q | October 5, 2010 12:22 PM | Report abuse

I see the inimitable Mr. Q is back. In Mr. Q's world, the entire field of signal processing, interpolation and statistics simply doesn't exist. Oh to be a climate denier. Life is so simple. Nothing to worry about until the Atlantic ocean actually comes knocking at your door in person.

As for the real subject of the blog post, this is such an irritating human characteristic. People really really really want simple, binary answers to everything in life. That things might have multiple causes, each with weights attached to them - with error bars around those weights to boot, because we don't have an exact read on them(!) - is just too straining for their minds.

TELL ME YES OR NO, WHAT CAUSED THE TRAFFIC JAM I WAS STUCK IN SATURDAY? WAS IT THE SOLD-OUT GAME AT THE STADIUM, THE LIGHT RAIN THAT WAS FALLING, THE HEAVILY-ADVERTISED SALES AT THE MALL NEARBY OR THE FACT THAT IT WAS A WEEKEND AFTERNOON?? IT HAS TO BE JUST ONE THING!!! DON'T MAKE ME THINK COMPLEX THOUGHTS!! EITHER THE STORM WAS CAUSED BY GLOBAL WARMING OR IT WASN'T! MAKE UP YOUR MINDS, SCIENTISTS! OW, IT HURTS! PLEASE DUMB IT DOWN FOR ME.

Sorry, pet peeve of mine. I now return you to calmer posters.

Posted by: B2O2 | October 5, 2010 12:48 PM | Report abuse

B2O2,

You have no clue what you are talking about. How you came up with your wild accusations, I do not know. You pulled them out of thin air. You want to create some imaginary caricature of me and then belittle the caricature that you created.

You want to make it about me, rather than the facts. Why is that?

I would absolutely LOVE to see error bars and disclaimers attached to everything NASA/GISS puts out! I would pay money if they would start providing that. Can you provide the error bars to go with their graphics? Can you, Mr. Freedman? That would be awesome!

Oh, that reminds me of something! I can help a little with that. I can't provide the error bars, but I do have a nice quote of what Dr. Hansen thinks of the U.S. temperature record. Give me a little while and I will provide it for you.

Mr. Q.

Posted by: Mr_Q | October 5, 2010 12:59 PM | Report abuse

Mr Q.... I believe that current geophysical and meteorological satellites now have remote-sensing equipment which can gauge temperatures over remote terrain with a high degree of accuracy. This pertains to remote oceanic areas between weather buoys as well as remote desert and mountainous areas with few or no weather stations...

On the other hand Eastern U.S. Wx Forums has a post regarding Joe D'Aleo's prediction that we could be entering a global "negative Dalton" or cooling cycle. Such an event coupled with anthropogenic intervention could result in some wildly extreme climatic swings. Additional volcanic activity could also contribute to global cooling, or counteract anthropogenic warming.

Current data on melting montane glaciers and shrinking ice at high latitudes appears to support global warming at present. If we are entering a global cooling cycle as D'Aleo thinks, we should see an increase in both high-latitude and high-altitude ice, and mean sea level should begin to decrease as more water gets locked up in glaciers or ice caps.

Posted by: Bombo47jea | October 5, 2010 1:45 PM | Report abuse

"If we are entering a global cooling cycle as D'Aleo thinks..."

Ah yes. Very appropriate to fix our attention on what one person speculates may happen, rather than the 97% of climatologists believe IS happening. Selective focus and faith will get us through this crisis.

(Sorry, I know you are a frequent serious and valued contributor to this comment area, Bombo47jea. I just find it a bit grating, the disproportionate attention that the rare dissenter gets at the expense of the armies of experts saying the opposite. I guess I'm on a pet peeve roll today.)

And Mr. Q, all I can suggest is that you get a good textbook on linear and higher-order 2-D signal interpolation methods. Best of luck to you.

Posted by: B2O2 | October 5, 2010 2:32 PM | Report abuse

Mr Q: Correlation coefficient between annual average temp in Grand Rapids and Washington/Na between 1894 and present: 0.66. Not bad, huh?

Using data from GISS (links below), after subtracting the mean temperature for the period from each data set, and using Excel's "correl" function.

http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=425726350001&data_set=2&num_neighbors=1

http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=425724050001&data_set=2&num_neighbors=1

Posted by: marcusmarcus | October 5, 2010 2:37 PM | Report abuse

After looking at the two figures Mr. Q suggests, the only big differences I see are in the polar regions, which this type of plot exaggerates in size. I totally disagree with Mr. Q's conclusion.

As to the forecast for 2012, well ....

Someone at the Met Office has said it's easier to forecast decades ahead, where we can be fairly confident it will be consideably warmer, than to forecast a few years ahead.

Posted by: Dadmeister | October 5, 2010 4:04 PM | Report abuse

Here is my conspiracy theory:

Since Mr. Q only likes to post on climate change topics (i have rarely seen him post on other topics on capital weather) he is probably funded by the Koch bros or some other high profile anti-environment organization.

He has been hired to patrol websites such as this, giving his worthless 2-cents backed up by other skeptic blogs to make him look somewhat credible to those that don't want to bother clicking on his links.


Posted by: jfva | October 5, 2010 5:36 PM | Report abuse

Dear Mr. Q, riddle me this - if the temperature data from GISS showing heating is so unreliable, why does the satellite temperature data administered by Dr. Roy Spencer at the University of Alabama-Huntsville show the global average lower tropospheric temperature anomaly stubbornly remaining extraordinarily high, at a whopping +0.60 deg. C for September, 2010. But maybe this is not reliable information since it comes from that eco-fascist warmist-alarmist site, Watts Up With That
http://wattsupwiththat.com/2010/10/05/september-2010-uah-global-temperature-update-0-60-deg-c/#more-25905

Posted by: lgcarey | October 5, 2010 6:49 PM | Report abuse

you guys are such noobs! Mr. Q. is obviously trolling. Noone could be that stupid. Just ignore him. He has too much free time on his hands.

Posted by: samdman95 | October 5, 2010 9:59 PM | Report abuse

That's the problem. Too many people ARE discounting and ignoring Mr. Q. Fortunately, I'm not one of them. I worked for NOAA for many years.....enough to see that Mr. Q is correct in many of the things he says (though not necessarily all.)

Posted by: MMCarhelp | October 6, 2010 12:37 AM | Report abuse

Andrew, does Hansen feel comfortable with the rate of warming too? What I mean is this- looks at this chart again: http://voices.washingtonpost.com/capitalweathergang/images/2010vs2005+1998.jpg The 2010 Jan-Aug is 0.04C warmer than the 1998 Jan-Aug. Both were significant El Nino events. 2010 is 12 years later with lots more CO2 added to our atmosphere: http://www.esrl.noaa.gov/gmd/ccgg/trends/

So even being generous and saying we are warming .04C/decade from peak-to-peak right now, isn't there a realization that the more aggressive IPCC forecasts for warming rates are failing?

Perhaps we shouldn't look peak-to-peak, but perhaps a great posting from you in the future is to see if the rate of warming is keeping pace with the aggressive IPCC projections.

Posted by: MattRogers1 | October 6, 2010 5:15 AM | Report abuse

@samdman95

While you're welcome to express your opinion about the validity of arguments, please do so without name calling. Our policy to suspend posting privileges if this happens on multiple occasions. Thanks.

Posted by: Jason-CapitalWeatherGang | October 6, 2010 7:16 AM | Report abuse

"Both were significant El Nino events"

Look at:
http://www.esrl.noaa.gov/psd/people/klaus.wolter/MEI/table.html
http://www.esrl.noaa.gov/psd/people/klaus.wolter/MEI/rank.html

The past el Nino was not comparable to the 1998 one.

Solar TSI is also lower (the current Solar minimum is significant on the scale of the past century)

Posted by: marcusmarcus | October 6, 2010 8:17 AM | Report abuse

Thanks Marcusmarcus, so the weaker El Nino and lower solar activity may have affected the situation, resulting in less warming.

Posted by: MattRogers1 | October 6, 2010 8:47 AM | Report abuse

Thanks Marcusmarcus, both El Nino events were classified as strong, but I believe your point is that the weaker El Nino and reduced solar contributed to a weaker response than would otherwise be expected per the 1998 example. Makes sense to me.

Posted by: MattRogers1 | October 6, 2010 8:52 AM | Report abuse

It's easy to prove the IPCC's projections of AGW from CO2 are grossly exaggerated. This is because there has been a fundamental mistake in the optical physics of clouds.

The mathematical formulation in the models is from an equation based solely on computed optical depth arising from multiple optical scattering in the body of clouds. Since the effect of aerosol pollution is to reduce droplet size/increase optical depth, you always get an increase of albedo, therefore cooling.

In AR4 it's called the 'cloud albedo effect', the least well known part of the science having a range of a factor of 6. But this optics cannot give an albedo >0.5 yet measured albedo can range up to 0.9 for some clouds. Interestingly, an entirely false physical explanation for such high albedos is put out in NASA literature, e.g.: http://earthobservatory.nasa.gov/Features/Aerosols/ - greater 'reflection' because smaller droplets have higher surface area.

The reality is that there are two optical effects in clouds, internal optical scattering and a boundary effect which shields the interior. Pollute the cloud and its albedo decreases, a heating effect - another form of AGW. Decrease albedo from 0.7 to 0.55 and this heating effect increases by nearly half, very substantial.

The questions that must be asked are: how much relative heating has been from CO2 and the cloud effect [which may have resulted from Asian industrialisation]; did NASA deliberately create a false scientific explanation?

So, AR4's predictions are meaningless. It could all be a dreadful mistake but Hansen has worked on such physics in the past, so must know it inside out.

Posted by: apdavidson | October 6, 2010 9:35 AM | Report abuse

Marcusmarcus says "Mr Q: Correlation coefficient between annual average temp in Grand Rapids and Washington/Na between 1894 and present: 0.66. Not bad, huh?"

It was interesting to correlate the monthly mean temperatures for which Grand Rapid and Wash/Nat data were available (1894-2009). In Dec, Jan, Feb and Mar the correlation was 0.83 to 0.84. In April, July and Aug, there was no correlation (-0.01, -0.1, 0.1). Other months were about 0.6 to 0.7 Since Andrew is displaying June - August in the top drawing, substituting Grand Rapids for DC or v.v. would not work so well.

Posted by: eric654 | October 6, 2010 10:51 AM | Report abuse

Marcus also says "Solar TSI is also lower". Can you explain why CO2 warming has an alleged 40 year lag, but TSI is supposed to be instant?

Posted by: eric654 | October 6, 2010 10:54 AM | Report abuse

MattRogers: I admit that I would be interested in seeing for the research studies that investigated climate sensitivity based on the past 100 years what the difference would be based on 1900-2000 versus the 1900-2010 time frame. My guess is that the output pdf wouldn't be that different: 10 years just isn't long enough. Additionally, past century studies don't really constrain climate sensitivity fully: they usually use expert elicitations or pdfs from paleoclimate work as Bayesian inputs.

http://rankexploits.com/musings/wp-content/uploads/2010/10/UAH.jpg compares UAH and models, though I'd put many caveats on such a comparison.

eric654: it isn't really a 40 year lag, it is more like asymptotically approaching the equilibrium temperature, and it takes 40 years to get 90% of the effect.

Posted by: marcusmarcus | October 6, 2010 3:23 PM | Report abuse

ENSO and other cycles are not perfect sinusoidal patterns that can be easily averaged out over a single cycle. So I don't think a 12-month running mean is any better guide than an annual mean to measure climate change. For the same reason, Matt's suggestion of differencing peak to peak is not very useful. The reliable measure of global warming remains averages of at least 10 years and preferably longer.

And as Dadmeister says, there's a reason operational prediction centers do not put out two year forecasts. I hope Hansen's call for 2012 warming is a bust, for all our sake.

Posted by: imback | October 6, 2010 11:34 PM | Report abuse

The attribution of extreme events from the tail end of skewed probability density functions is a very interesting subject. Consider the PDF http://www.resourceinvestor.com/News/2008/11/PublishingImages/VOX%20EU%2011-22-08%20two.png for the climate sensitivity parameter. This parameter is the amount of surface air temperature warming for a doubling of CO2 concentration. The most likely value is 3 degrees C. But the PDF has a long tail to the right. There is a significant chance the sensitivity is 5 degrees or more. The uncertainty makes the climate situation even more worrisome.

The PDF for weather events such as heat waves would be even more skewed to the right. Under global warming, the whole PDF would move to the right. The extreme events out on the tail would increase their frequency manyfold. Anyway, Hansen explains extreme event attribution much better than me.

Posted by: imback | October 6, 2010 11:45 PM | Report abuse

imback, marcusmarcus,
i've heard a skeptic theory that storms/hurricanes cool the atmosphere by "transporting" (my interpretive word) heat from the lower atmosphere to the upper atmosphere where it can more easily escape to space.

so, this (hopeful) theory proposes essentially a self-regulating system wherein global warming causes more storms but the more storms cause global cooling.

what say you? is it possible that storms cool the globe?

(apologies if i've explained this theory incorrectly.)

Posted by: walter-in-fallschurch | October 7, 2010 7:49 AM | Report abuse

imback, you said,
"I hope Hansen's call for 2012 warming is a bust, for all our sake."

i know what you mean, but can you imagine the skeptic glee hansen's being wrong would spark? and it wouldn't be glee over that healthy state of the planet - it would be more like "see, those 'alarmists' were wrong again." i mean, seriously, it could be the third warmest year ever, and "skeptics" would gloat over their "victory".

it totally infuriates me how scientists are losing the PR war. i believe the problem is psychological - with analogies in budget deficits and overeating.

it's difficult because if global warming is happening, we'll have to go on an low-carbon diet - and people hate diets. (we'd all rather just buy bigger pants....)

if on the other hand, global warming is not happening, we can go on "eating" whatever we want. see? since the result is so much nicer (no change in lifestyle) if global warming is not happening, people are choosing to believe that - like it's a matter of "personal preference".

Posted by: walter-in-fallschurch | October 7, 2010 9:15 AM | Report abuse

Hi Walter, a single storm won't do much of anything to the planet. Having more storms in general might or might not cool the planet. What it mostly depends on is the distribution of water vapor. If water vapor becomes more unevenly distributed on a worldwide basis whether due to more or stronger storms or some combination of factors, then the world will cool (or slow its warming).

The models show that concentrated convection can cool the planet by drying the upper troposphere (if it increases worldwide). There are other warming/cooling factors besides UTWV but that is a big one. And there are plenty of other weather situations that will alter UTWV.

So the slightly shorter answer is if there are more hurricanes AND more concentrated convection in general AND those are greater than other factors that work in the opposite direction, then the planet will cool. The really short answer is that there is no short answer.

Posted by: eric654 | October 7, 2010 9:37 AM | Report abuse

walter: I haven't read any studies discussing the storm/cooling link (eric's answer sounds plausible). Work I've seen has discussed the possibility of hurricanes and tropical storms being a contributor to heat mixing at depth in the ocean, which would mean that increased storms would at least slow warming (but not change the final equilibrium).

Of course, the other question is whether we really know how storms will change: while it seems that research still points towards an increasing number of the largest tropical storms in the future (due to increased ocean surface heat), research also seems to indicate that total frequency may stay unchanged or even drop (due to all other sorts of confounding factors like wind shear and dustiness and such). Increased water vapor means more potential energy for non-tropical storm formation, but decreased latitudinal gradient means less driving force. So, um, while I am certain that various aspects of storm frequency and strength and location will change due to human influence, I don't think it is clear exactly how they will do so (this all falls into the intersection between weather modeling and climate modeling, which is hard). This is not my area of specialization, though, so take anything I say with a nice chunk of sea salt.

Posted by: marcusmarcus | October 7, 2010 10:08 AM | Report abuse

thanks eric and marcus.

eric,
sorry, bear w/me here.

what is "concentrated convection"? is that a storm....where lower atmosphere heat rises to the upper atmosphere?

how does it dry the upper troposphere? (rain? or does it have to do with the ability of warm air to hold water? something else?)

how does drying our the upper troposphere cool the planet? (rain?)

Posted by: walter-in-fallschurch | October 7, 2010 10:24 AM | Report abuse

Walter, one explanation is buried in this link http://www.cesm.ucar.edu/publications/PhD%20and%20Masters%20Theses.htm at 3088067. Their idea is pretty simple, that diffuse convection leaves more WV in the UT than concentrated convection. The more general idea is that convection is balanced by subsidence (air that goes up must come down) and those subsidence regions actually remove more heat than a less strong subsidence region.

Think about the IR satellite presentation of a hurricane. There are cold cloud tops with the storm so less heat sent to space (the opposite of what one might think). But above the storm is a warm high pressure and that warm air spreads outward and then cools and sinks in a large subsidence area around the storm. On IR satellite it looks like warm ocean water sending IR out to space with no clouds getting in the way, hence the overall cooling.

Posted by: eric654 | October 7, 2010 1:43 PM | Report abuse

thanks eric. i'm digesting...

Posted by: walter-in-fallschurch | October 7, 2010 4:59 PM | Report abuse

Walter,

Compare:
-- glee from the flat-Earth fringe
-- deadly heat waves, fires, droughts, crop loss, extreme weather
It's an easy choice what to wish for.

Your analogy to overeating is especially apt. The rational part of me knows I should lose a few pounds. The irrational part of me loves me some fries. My waistline is losing the war, unfortunately, and buying bigger pants is not a long-term solution.

Posted by: imback | October 7, 2010 8:02 PM | Report abuse

About stronger storms causing cooling. This idea makes little sense to me. The heuristic argument behind global warming actually *requires* convection. Convection maintains the tropospheric lapse rate so that the upper troposphere is cold and thus radiates less to space, and so when greenhouse gases increase, the surface must warm to maintain radiative equilibrium.

Also, there is no evidence for global warming causing a major change in water vapor distribution. If anything, a warmer planet means more convection, causing a stronger Hadley circulation, implying a more well-mixed upper troposphere. Eric is engaging in wishful thinking on this topic (like I am about those fries).

Posted by: imback | October 7, 2010 8:07 PM | Report abuse

imback, the average convection doesn't really matter just like the average lapse rate, just like average WV. What matters is weather and the areal and temporal distribution of those values. How the weather will change in a world warmed by CO2 is the great mystery. Your notion that the Hadley will increase and expand is correct but that is not going to mix the troposphere by very much compared to the diurnal and seasonal variations and spatial variations from weather.

The evidence for a change in WV distribution from GW is trumpeted from the hilltops any time there is a weather events. Floods in Pakistan: global warming? Maybe, maybe not, but certainly they represent an increase in the variability of water vapor. If that is true on a global scale (i.e. if floods are becoming more common), then climate sensitivity is reduced accordingly.

Posted by: eric654 | October 7, 2010 9:16 PM | Report abuse

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