Determining how warm this summer really was

Oct 01, 2010 By Adam Voiland
This map, based on land surface temperatures observed by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, shows temperature anomalies for the Russian Federation from July 20-27, 2010, compared to temperatures for the same dates from 2000 to 2008

An unparalleled heat wave in eastern Europe, coupled with intense droughts and fires around Moscow, put Earth's temperatures in the headlines this summer. Likewise, a string of exceptionally warm days in July in the eastern United States strained power grids, forced nursing home evacuations, and slowed transit systems. Both high-profile events reinvigorated questions about humanity's role in climate change.

But, from a global perspective, how warm was the summer exactly? How did the summer's temperatures compare with previous years? And was global warming the "cause" of the unusual heat waves? Scientists at NASA's Goddard Institute for Space Studies (GISS) in New York City, led by GISS's director, James Hansen, have analyzed and released an update on the GISS website that addresses all of these questions.

Globally, June through August, according to the GISS analysis, was the fourth-warmest summer period in GISS’s 131-year-temperature record. The same months during 2009, in contrast, were the second warmest on record. The slightly cooler 2010 summer temperatures were primarily the result of a moderate La Niña (cooler than normal temperatures in the equatorial Pacific Ocean) replacing a moderate El Niño (warmer than normal temperatures in the equatorial Pacific Ocean).

As part of their analysis, Hansen and colleagues released a series of graphs that help explain why perceptions of vary -- often erroneously -- from season to season and year to year. For example, unusually warm summer temperatures in the United States and eastern Europe created the impression of global warming run amuck in those regions this summer, while last winter's unusually cool temperatures created the opposite impression. A more global view, as shown below for 2009 and 2010, makes clear that extrapolating global trends based on the experience of one or two regions can be misleading.

The four graphs show seasonal-mean temperature anomalies relative to 1951-1980 for the most recent two summers and winters; that is, they show how temperatures during the various seasons differ from the mean temperatures from 1951-1980, which serves as a reference period. Unusually warm summers in eastern Europe and much of the United States created the impression of record global temperatures this summer (lower right), while unseasonably cool winters in the same regions had the opposite effect during winter of 2010 (lower left).

"Unfortunately, it is common for the public to take the most recent local seasonal temperature anomaly as indicative of long-term climate trends," Hansen notes. "[We hope] these global temperature anomaly maps may help people understand that the temperature anomaly in one place in one season has limited relevance to global trends."

Last winter, for example, unusually cool temperatures in much of the United States caused many Americans to wonder why temperatures seemed to be plummeting, and whether the Earth could actually be experiencing global warming in the face of such frigid temperatures. A more global view, seen in the lower left of the four graphs above, shows that global warming trends had hardly abated. In fact, despite the cool temperatures in the United States, last winter was the second-warmest on record.

Though calendar year 2010 may or may not turn out to be the warmest on record, the warmest 12-month period in the GISS analysis was reached in mid-2010. The lower portion of the graph shows when major volcanic eruptions have occurred with green triangles. The lowest part shows El Niño (red) and La Niña (blue) trends. For more information about this graph, please visit the GISS website Credit: NASA/Goddard Institute for Space Studies/Hansen

Meanwhile, the global seasonal temperatures for the spring of 2010 -- March, April, and May -- was the warmest on GISS's record. Does that mean that 2010 will shape up to be the warmest on record? Since the warmest year on GISS’s record -- 2005 -- experienced especially high temperatures during the last four calendar months of the year, it’s not yet clear how 2010 will stack up.

"It is likely that the 2005 or 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 notes. "What is clear, though, is that the warmest 12-month period in the GISS analysis was reached in mid-2010."

The Russian was highly unusual. Its intensity exceeded anything scientists have seen in the since widespread global temperature measurements became available in the 1880s. Indeed, a leading Russian meteorologist asserted that the country had not experienced such an intense heat wave in the last 1,000 years. And a prominent meteorologist with Weather Underground estimated such an event may occur as infrequently as once every 15,000 years.

In the face of such a rare event, there’s much debate and discussion about whether can "cause" such extreme weather events. The answer -- both no and yes -- is not a simple one.

Weather in a given region occurs in such a complex and unstable environment, driven by such a multitude of factors, that no single weather event can be pinned solely on climate change. In that sense, it's correct to say that the Moscow heat wave was not caused by .

This map shows temperature anomalies relative to 1951-1980 for the summer of 2010; that is, how temperatures in June through August 2010 differed from the mean temperatures from 1951-1980. A NASA visualizer created it based on data from the Goddard Institute for Space Studies. Credit: NASA/Goddard/Earth Observatory

However, if one frames the question slightly differently: "Would an event like the Moscow heat wave have occurred if carbon dioxide levels had remained at pre-industrial levels," the answer, Hansen asserts, is clear: "Almost certainly not."

The frequency of extreme warm anomalies increases disproportionately as global temperature rises. "Were global temperature not increasing, the chance of an extreme heat wave such as the one Moscow experienced, though not impossible, would be small," Hansen says.

Explore further: NASA begins hurricane mission with Global Hawk flight to Cristobal

More information: For GISS's full analysis, please visit: data.giss.nasa.gov/gistemp/

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User comments : 24

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marjon
1.6 / 5 (23) Oct 01, 2010
""Unfortunately, it is common for the public to take the most recent local seasonal temperature anomaly as indicative of long-term climate trends," Hansen notes."
The 'consensus' is guilty of this as well.
Parsec
4.3 / 5 (11) Oct 01, 2010
I am wondering how the deniers will explain away the temperature graph in this article. Ignore it (like marjon did), or wave their arms?

In fact, climate scientists do NOT take local temperature abnormalities and extrapolate them into global warming trends. Any scientist would be laughed out of the field if they did that, and they certainly wouldn't be able to get published.

This is a trait of the uneducated public.
mikiwud
1.2 / 5 (18) Oct 02, 2010
I am wondering how the deniers will explain away the temperature graph in this article. Ignore it (like marjon did), or wave their arms?


Where does it mention things like the record lows in places like Bolivia (tropical) where rivers froze and millions of fish (and not a few crocs etc) died? Cherry picking again?
marjon
1.4 / 5 (20) Oct 02, 2010
I am wondering how the deniers will explain away the temperature graph in this article. Ignore it (like marjon did), or wave their arms?

When will AGWites explain the MWP? Until they can understand what happened in the past, how can they explain today's observations?
Caliban
4.2 / 5 (10) Oct 02, 2010
Here we see, again, the denier sophistry of ignoring the TREND of increasing temperatures GLOBALLY- as indicated by the graphs of annual temperature. Local temperature anomalies do not equal climate, and the MWP has been shown to have been a localised, rather than global, trend in temperature increase.
marjon
1.6 / 5 (19) Oct 02, 2010
Here we see, again, the denier sophistry of ignoring the TREND of increasing temperatures GLOBALLY- as indicated by the graphs of annual temperature. Local temperature anomalies do not equal climate, and the MWP has been shown to have been a localised, rather than global, trend in temperature increase.

The MWP cause is still not explained.
The chart show 60 years. That is a climate trend?
The MWP lasted centuries as did the cooling period and the warming the melted the glaciers has lasted thousands of years.
NSF states the uncertainty of the record past 400 years is highly uncertain. Can even 400 years signify a climate trend?
Caliban
3.3 / 5 (7) Oct 02, 2010
The MWP cause is still not explained.
The chart show 60 years. That is a climate trend?
The MWP lasted centuries as did the cooling period and the warming the melted the glaciers has lasted thousands of years.
NSF states the uncertainty of the record past 400 years is highly uncertain. Can even 400 years signify a climate trend?


So, mangy would have it that, even though the record is highly uncertain, we should pay special attention to the MWP, since we are so much better able to quantify that anomaly than climate in general over the last few hundreds of thousands of years? Hogwash.

One thing we do know is that it cannot be attributed to Industrialization and an explosive increase in human population. Maybe it was all the European peasantry, huddled around their cottage fires, waiting to die from the Plague?

The chart shows GLOBAL MEAN TEMPERATURE increasing over the last 60 years. Yes, a TREND.
marjon
1.4 / 5 (18) Oct 02, 2010
Data for 60 out of 400 years signify a trend?
Quantum_Conundrum
1.5 / 5 (17) Oct 02, 2010
Data for 60 out of 400 years signify a trend?


Nobody really even has data for 60 years. Infrared weather satellites were first used in 1992, and those only had 12km resolution, so they were horrible compared to those most recently launched.

The algorithms used by NOAA and NHC for ESTIMATING ocean heat content based on satellite and buoy data were changed after 2005.

So pretty much everything before 1992 is unreliable at best, and even since 1992 the instruments and algorithms have been changed several times. So how the heck can any consistent basis be made for GW?
marjon
1.4 / 5 (18) Oct 02, 2010
"Very little confidence can be assigned to statements concerning the hemispheric
mean or global mean surface temperature prior to about A.D. 900 because of sparse
data coverage and because the uncertainties associated with proxy data and the methods
used to analyze and combine them are larger than during more recent time periods."
http://www.nap.ed...id=11676

Climate: "it is the weather of a locality averaged over some period (usually 30 years) plus statistics of weather extremes."
http://nsidc.org/...ate.html
Two climate periods are sufficient to establish a trend?
40 years ago the 'trend' was claimed to be an ice age.
thermodynamics
4.6 / 5 (9) Oct 03, 2010
marjon: I don't know why I keep wasting my posts on you. You just come back with the same baseless claims. For instance, you stated: "40 years ago the 'trend' was claimed to be an ice age." I have shown that it is not true before but that doesn't seem to matter to you. So, I just went out to search hacks claiming cooling and an ice age now. You use unresearched popular press articles from 40 years ago. Here is an example from 2009.

http://www.redorb...ice_age/

Here is another one that says we are going to freeze to death in 2013 (luckily that will be after the end of the Earth in 2012).

The point is that you can find any kind of unsubstantiated claims during any time period. Show me some credible papers published on cooling 40 years ago - other than newspaper articles based on sound bites or goofballs like the two I cited that haven't done their math correctly. Quit using FOXnews as your science source
marjon
1.5 / 5 (15) Oct 03, 2010
"However widely the weather varies from place to place and time to time, when meteorologists take an average of temperatures around the globe they find that the atmosphere has been growing gradually cooler for the past three decades. The trend shows no indication of reversing. Climatological Cassandras are becoming increasingly apprehensive, for the weather aberrations they are studying may be the harbinger of another ice age.
"When Climatologist George J. Kukla of Columbia University's Lamont-Doherty Geological Observatory and his wife Helena analyzed satellite weather data for the Northern Hemisphere, they found that the area of the ice and snow cover had suddenly increased by 12% in 1971 and the increase has persisted ever since.

Read more: http://www.time.c...l"

BTW, your link does not function.
marjon
1.3 / 5 (13) Oct 03, 2010
""The climatic trend changed once again around the mid-19th century. The northern temperate zone grew markedly warmer; indeed, the century from 1875 to 1975 is now regarded by some as one of the warmest in 4000 years. In this time the industrial age boomed, and world population more than doubled. Farming and fishing expanded to keep up with food needs; Canada’s wheat line inched a hundred miles north. But this period of climate, which our grandfathers and fathers came to regard as normal, is now recognized by scientists to have been abnormally warm and beneficent. What will happen to our food output if there is a return to the more truly normal, cooler climate? Are we now at the end of a cycle?"

Read more: http://newsbuster...q"
In the mid 70s a warming climate was considered to be a good thing.
Caliban
5 / 5 (5) Oct 03, 2010
BTW, your link does not function.


Accounting for the fact of your semiliteracy, I've decided to make it easy on you, mongo--stop blowing for a while and suck on this:

http://www.stthom...abraham/

which dissects and dispenses with each and every one of your specious claims. But make sure that you are seated squarely upon your datapoint armchair before starting, as the shock may prove too much for your trollsenses, and you wouldn't want to risk a collapse that might cause you to abruptly land upon that spotty, inflamed backside, now, would you?
marjon
1.3 / 5 (14) Oct 03, 2010
He didn't comment on all those who have published, like Lindzen.
Slide 71 is funny. Slide 70 is correct as is 71.
Abraham's objectivity is questionable.
If publications are important, Abraham is not well published in climate research: http://courseweb....abraham/
thermodynamics
4.2 / 5 (5) Oct 03, 2010
Caliban:

That is an outstanding presentation at the URL you listed. As usual, marjon completely misses the point. Abraham did not present his own work (where marjon is bringing up the lack of climate research publications by Abraham as a red herring). Abraham just checked Mockton's work and found it seriously lacking by studiously checking against publications Mockton used. marjon just raised that point to try to cover up the great site.

I do agree with marjon though. There does seem to be a conspiracy of AGW deniers and marjon is clearly one of them since he continues to put forward misinformation that he has been shown is wrong multiple times. It is of no use to even try to reason with marjon because he is part of the conspiracy to prevent action on GHG reduction. It appears, from other conversations, that reducing CO2 scares him because he believes it will cost him money and he cares nothing for the others it will help.
GSwift7
1.2 / 5 (11) Oct 04, 2010
Are there records of previous heat waves of this magnitude? What is the frequency? Has that frequency increased? If this is something that happens once every 1000 years, and it's been 1000 years since the last one, then is this a sign of global warming? If it happens again in 500 years, is that enough to show a trend of increasing frequency of heat waves? How many data points do you need in order to show a trend? If this is a 15000 year event, then what? Without some kind of reference that shows paleoclimate trends of heat waves, it's impossible to interpret this. Does anyone have a link to data like that? I can't find anything on it.

If we eliminate CO2 and replace it with H2O from burning hydrogen, would that be an improvement?
thermodynamics
5 / 5 (3) Oct 04, 2010
GSwift7: I was not going to get into this because I figured marjon would just put his fingers in his ears and hum. However, I have seen that you are actually interested in the science so I will go into the physics a little here. The answer to your question about replacing CO2 with H2O is straight forward. CO2 is not condensable at conditions found on Earth. H2O is. When the atmosphere is at a given temperature and pressure the H2O will condense. With all of the open sources of water on the planet the addition of additional water vapor will be transient (it will condense). The addition of CO2 is not transient in that it will have to be taken up by plants or react or dissolve. It stays as a gas in the air as opposed to condensing. So, the bottom line is that there is a marked improvement going to H2O. However, you will not find me as a supporter of the hydrogen economy because H2 is an energy storage solution not an energy production solution. (out of characters or would...
marjon
1 / 5 (10) Oct 04, 2010
Who is Mockton? Why should anyone care? Again, I point out slides 71ish where Abraham twists the statistics on CO2. Both were correct. The amount of CO2 as a percentage of the atm is very small. Start with a small number double it, and is is STILL a small number.
I still don't buy that CO2 is that significant. The qty of CO2 is small, its absorption bands are few, and the modelers can't think of anything better to put into their model. CO2 is easy to measure and quantify on a global scale.
Another reason I don't trust the 'experts' is their first remedy is to destroy the world economy. Had they promoted nuclear power they may have had more credibility. You 'experts' decided to play politics and in doing so destroyed any credibility.
And, if CO2 is such a significant heat trapping gas, the delta between daily high-low temperatures over dry deserts should be decreasing as the increasing CO2 'traps' more of the desert heat radiating into space at night.
marjon
1 / 5 (9) Oct 04, 2010
Are there records of previous heat waves of this magnitude? What is the frequency?

Of course there are records which correlate with solar cycles.
There was peak warming period which aided the rise of Rome, and a decline which hastened its demise. There are all sorts of historical observations from the Thames freezing to the explosion of the Vikings on to the world. How did those Vikings obtain the numbers and the crops to support their raids?
Of course this does not fit the current claims based upon scant decades of instrument records.
marjon
1 / 5 (7) Oct 04, 2010
"The warming in Central America that was disastrous for the Mayans was, on the other hand, fortunate for the Vikings. Warmer temperatures in the north meant their land was more hospitable to live on. Complex push-and-pull factors allowed the Vikings to expand their settlements from Scandinavia to Iceland, Greenland, and later Newfoundland. It was in Newfoundland that they encountered Native Americans. The Native Americans, too, perceived the warmer climate as a new opportunity and fought to control the increasingly abundant land. The Vikings and Native Americans would alternately trade and fight with each other throughout the Vikings' time in Newfoundland."
"The year without summer illustrates two different stories--one in Europe and another in North America. In Europe, the cold forced people to migrate."
http://www.thebul...conflict
GSwift7
1 / 5 (7) Oct 05, 2010
That's a good point Thermo, about CO2 being far less reactive than H2O. Official sources estimate, however, that the huge amounts of ground water we pump to the surface are responsible for around 25% of sea level rise we're seeing right now. The other two sources are thermal expansion of the oceans and of course, ice melt. I can't remember which was which but one was 50% and the other was 25%. They say that the ground water we use evaporates from the land where we use it (mainly talking about industrial cooling and agricultural irrigation), and then rains back down to add to sea level rise. That would seem to me like a significant amount of additional water in the air. That has to have some effect. Many of the alternative energy schemes being proposed now will result in increased water use. Bio-fuel, hydrogen of course, and even nuclear power all result in more water in the air. Since CO2 maps don't match up exactly with thermal maps, there must be some other major factor, like water.
GSwift7
1 / 5 (7) Oct 05, 2010
I see your point about water being transitory, but as long as we don't have 100% relative humidity, there is the potential for human activity to increase the water content of the air. I don't think there has been adequate study about how much effect we have in that regard. Some experts seem to think that it could be bigger than most people would expect, especially considering the potency of water as a GHG; a little goes a long way in that regard. The higher than average daily nighttime lows of the past 6 months on the US East Coast are a good example of water having a major impact on daily average temperature. I'm not making any claims here, just to be clear, I'm just pondering the current situation as evidenced by the above thermal maps. Notice the high temperatures centered around areas of high water use. Those same areas are also CO2 sources, to be sure, but CO2 spreads more than water does, as you correctly pointed out. I'm just think out loud about it, and welcome your thoughts.
Skeptic_Heretic
3.7 / 5 (3) Oct 05, 2010
He didn't comment on all those who have published, like Lindzen.
Just an FYI: Lindzen hasn't published anything within a scientific journal in regards to agcc or agw. He passed a non-peer reviewed essay to a non-peer review journal and cited it as peer reviewed. He's been called out on this and his essay was retracted.

But, you know, don't let facts dissuade you from your story.