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Posted at 10:45 AM ET, 12/13/2010

With climate change, long-term trends are key

By Andrew Freedman

GISS 2010 met year anomalies.gif
December 2009-November 2010 surface temperature anomalies (or departures relative to a 1951-80 average) in the preliminary Goddard Institute for Space Studies analysis from NASA. Yellow, orange, and red regions all recorded warmer than average temperatures.

As the start of the New Year rapidly approaches, you're going to hear conflicting news about whether 2010 was the warmest year in the instrumental record. The first salvo has already been fired.

On Friday, NASA reported that the "meteorological year" spanning from December 2009 to November 2010 was the warmest in that agency's 131 years of record keeping. Never mind that the meteorological year is relevant only to meteorologists - the news still made headlines.

The two other groups that maintain official global surface temperature data - the U.S. National Oceanic and Atmospheric Administration (NOAA) and the UK Met Office Hadley Centre, which works in conjunction with the University of East Anglia Climatic Research Unit - will soon release data that may conflict with NASA somewhat, by ranking 2010 differently. NOAA, for example, currently ranks 1998 as the warmest year on record, rather than 2005, which is in NASA's top spot.

So, what should you, dear readers, make of the varying rankings? And does it really matter if 2010, compared to 2005 or 1998, was officially number one?

The bottom line is that all of the data as measured by land, sea, air, and even from space, shows 2010 has been an unusually warm year globally. This can be partially linked to El Nino conditions that were present up until last spring, but also to increasing concentrations of greenhouse gases in the atmosphere, which scientists say are very likely responsible for a large portion of the long-term warming trend.

This year's warmth is especially noteworthy because 2010 fell in a period of lower solar irradiance, which can help cool the climate. "The new record temperature in 2010 is particularly meaningful because it occurs when the recent minimum of solar irradiance is having its maximum cooling effect," wrote James Hansen, longtime director of NASA's Goddard Institute for Space Studies, along with three colleagues.

Some climate skeptics often point to the sun as the overriding driver of recent climate fluctuations, rather than greenhouse gases, but most published studies have refuted this argument.

The warm year is also interesting because a strong La Nina event got underway late last summer, and has helped to dampen global average temperatures since then.

Another key point to remember is that the temperature differences from one year to the next are not very meaningful, and even in this year's case can turn out to be very small. In NASA's release last week, scientists noted that the December 2009 to November 2010 period stands just a few hundredths of a degree warmer than the same period in 2005.

As Hansen and others explain in a research paper that is pending publication in a scientific journal, each climate monitoring center uses their own methods to track and rank global temperatures, which can lead to discrepancies between them. The NASA group uses techniques that infer temperatures across the Arctic, where available data indicates the most dramatic warming is occurring, but temperature-recording stations are sparse. (The paper in press describes NASA's methods in much greater detail).

The three time series show annual values (January through December means) of globally averaged temperature anomalies from 1880 to 2009. The black line shows values from NOAA/NCDC's data; the red line shows NASA/GISS data; the green line shows the UK Hadley Center/CRU data. All three datasets have been constructed including both land and sea surface observations. The three time series have been centered around the common reference period 1961-1990, i.e., each value is the difference between that year's temperature and the average temperature from the corresponding dataset over the 30-year period 1961-1990. Dashed vertical lines indicate the two warmest calendar years on record to-date, 1998 and 2005. In order to measure the agreement among the three data sources, the difference between the corresponding values of each dataset has been computed for each year. On average over the 130 years shown, the absolute error is 0.043 degrees Celsius. The smallest error is 0.0004 C. The largest error is 0.176 C. CREDIT: Claudia Tebaldi/Climate Central.]

The analysis in this graphic, which was prepared by research scientist Claudia Tebaldi, a colleague of mine at Climate Central, shows the differences between the three datasets over time.

It drives home the point that over the long-term, NASA, NOAA, and the UK's records are all consistent in showing a sharp uptick in global temperatures beginning during the latter half of the 20th century, and continuing on through the present day. Furthermore, NASA, NOAA, and the UK data all show the 2000s were the warmest decade since instrumental records began.

In fact, the NASA analysis released last week rebuts the argument that warming has slowed or ceased in the past decade. "Contrary to frequent assertions that global warming slowed in the past decade... global warming has proceeded in the current decade just as fast as in the prior two decades," Hansen and his colleagues wrote.

It's that long-term trend that is most important, given the numerous factors that can influence year-to-year weather and climate. So when you hear conflicting stories about whether this year was really the warmest, remember the overall context in which this first, second, or perhaps third-ranking warmth is occurring.

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  | December 13, 2010; 10:45 AM ET
Categories:  Climate Change, Freedman, Latest  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Forecast: Wicked cold winds & snow showers
Next: Analyzing pre-Christmas snow odds


Interesting - west Antarctica is becoming colder? Any idea why or is it a data anomaly?

Posted by: vnangia | December 13, 2010 11:02 AM | Report abuse


That graphic is just indicating that portion of West Antarctica was cooler than average over the past year. That graphic does not speak to the long-term trend. For more on temperature trends in Antarctica, see this post:

Posted by: Jason-CapitalWeatherGang | December 13, 2010 11:10 AM | Report abuse


Sorry, I misread the caption. I thought that was the overall delta from 1951 to 1980.

Thanks really helpful.

Posted by: vnangia | December 13, 2010 11:17 AM | Report abuse

I'm anxious to see who will be the first to claim that the extreme cold and snow over the past week in much of the central U.S., Canada, and Europe undermines the case for global warming and reinforces the conclusion global warming is a conspiratorial hoax.

Posted by: SteveT-CapitalWeatherGang | December 13, 2010 11:29 AM | Report abuse

Posted by: Jason-CapitalWeatherGang | December 13, 2010 11:53 AM | Report abuse

is the standard explanation for the "dip" after the 1940s that man-made aerosols kept temps artificially low during those years? then after the 70s/80s when we cleaned up the air a bit temps went back up?

Posted by: walter-in-fallschurch | December 13, 2010 11:58 AM | Report abuse

There's apparently evidence that, ironically, more open water in the Arctic leads to COLDER temperatures over the European and North American continents during the winter [possibly due to warmer ocean water contributing to blocking patterns near areas such as Greenland].

Thus our colder winter weather may actually be evidence SUPPORTING global warming, the views of skeptics to the contrary!

Posted by: Bombo47jea | December 13, 2010 12:02 PM | Report abuse


Aerosols are part of it...and solar intensity are thought to have dropped off 1930s peak.

Posted by: Jason-CapitalWeatherGang | December 13, 2010 12:04 PM | Report abuse

"Contrary to frequent assertions that global warming slowed in the past decade... global warming has proceeded in the current decade just as fast as in the prior two decades," Hansen and his colleagues wrote.

The satellite data is has accurate measurements than his thermometer network but has issues with long term trends due to changes in satellites, drift, etc. But the slope is adequate to see that warming slows down and speeds up month to month, year to year and decade to decade. The reason in all cases is weather, it rules the short run and modulates the amplification of the CO2 warming in the long run.

Posted by: eric654 | December 13, 2010 12:06 PM | Report abuse

Looks as though that storm hit my old stomping grounds...Menomonie/Eau Claire, WI pretty hard...18+ inches.

In that area, this is a big storm, but not really unprecedented. Often the "State Basketball Tournament Snowstorm" in mid to late March drops totals equal to or exceeding twenty amount rivaling the big Mid-Atlantic coastal storms around here.

This is the region which gave birth to the legends of Paul Bunyan, the "Winter of the Blue Snow" and Babe the Blue Ox. There have been times when the deep newly fallen snow has actually acquired a bluish tint [due to refracted or transmitted light], particularly when I had to shovel sidewalks on a corner lot at Farwell and Jefferson Streets in Eau Claire. December, 1968 and the winter of 1968/69 stand out prominently in my memory, as does the early winter of 1972 just before I relocated to Washington in December of that year.

Posted by: Bombo47jea | December 13, 2010 12:21 PM | Report abuse

good "pull". figures watts could be counted on for telling one side of the story...

from that page he summarized national records set during the past week"

Here’s a summary of the weather records:
Record Events for Mon Dec 6, 2010 through Sun Dec 12, 2010

Total Records: 2002
Rainfall: 319
Snowfall: 320
High Temperatures: 71
Low Temperatures: 426
Lowest Max Temperatures: 767
Highest Min Temperatures: 99

wow... about 6 TIMES more cold records than warm records.... any idea what a chart like this would look like if it covered the entire year? or more correspondingly, if you picked a certain "heat wave" week?

to be fair, watts does not actually tout this as evidence against global warming, though i would be curious to know if he did similar posts about recent heat waves?

i know you guys mentioned earlier that you'd be doing a summary of all the records set during this crazy weather year. i hope you can have something comparing the number of record cold events and the number of record warm events.

Posted by: walter-in-fallschurch | December 13, 2010 12:42 PM | Report abuse

"The new record temperature in 2010 is particularly meaningful because it occurs when the recent minimum of solar irradiance is having its maximum cooling effect," wrote James Hansen,

That leaves out a chunk of their own story which is that warming from CO2 plus postulated sensitivity is higher than what has been observed. Therefore, their theory is that the extra warming has been stored in the ocean. But there is no reason that the extra heat that was stored in the ocean can't exit into the atmosphere at the same time the solar TSI has dropped. In any case, the TSI hasn't dropped very much so that argument is mostly a red herring.

Posted by: eric654 | December 13, 2010 12:47 PM | Report abuse


CapitalClimate answers your question directly on records. It's not even close. Watts, characteristically, doesn't provide context.

Posted by: Jason-CapitalWeatherGang | December 13, 2010 12:49 PM | Report abuse

jason, thanks.

that link didn't work (i think it was the "." at the end), but i found the info you referenced on CapitalClimate's page.

indeed, record highs have FAR exceeded record lows this year. surely watts is planning on posting something about this soon... hahahaha ...for balance and context....hahahaha (or maybe he already did? haahaha

Posted by: walter-in-fallschurch | December 13, 2010 1:07 PM | Report abuse

For WUWT, here is a greatly summarized list of postings in the "records" category (most recent first): cold and snow (above), Gore effect (Cancun), UK cold, Gore effect, Norway cold, hurricanes (lack of US), GISS warmth (a fairly neutral report), NZ snow, hot and cold (US summer, US winter), SH cold, 1923/4 heat, SF cold, blizzards, snowfall, SH cold, miscategorized CO2, NOAA heat (critique), and two articles on bad station placement.

So over those 5 months we have 8.5 articles on cold records, 1.5 articles on record heat, and the rest N/A. So unless there were 8.5/1.5 cold to hot records, WUWT is biased, which we kind knew already.

Posted by: eric654 | December 13, 2010 2:57 PM | Report abuse

thanks for that research eric.

Posted by: walter-in-fallschurch | December 13, 2010 3:45 PM | Report abuse

Nothing significant really changes with time regarding this issue. We will eventually grow weary and focus on a perceived greater threat.

Probably about as many will attempt a correlation between recent cold and snow undermining AGW as the misguided folks in the MSM who attempt an at least subliminal correlation between heat waves
and AGW.

Yes, there has been a smoothed uptick in global temperatures during the past 40 years but there was also a smoothed global uptick in temperatures from 1000-1300 AD, 50-300 AD, 800-1100 BC, etc. etc.

The question is, how much is human induced this time around and how much is natural cyclical climate change that has been occuring for millions of years......and what if anything can we do about it???

Probably, we have a mix of variables regarding causes of the present uptick. We were certainly due an uptick beginning 40 years ago because of the average 300-500 year interval between warm periods historically. And, probably in conflict with the wishes of some who dream of the ideal world, there is very little we can or perhaps should attempt in mitigation.

It is interesting to note that in spite of all the best from the staunchest of the AGW proponents, fewer Americans believe in AGW today than two years ago

Posted by: AugustaJim | December 13, 2010 3:58 PM | Report abuse

According to IPCC AR4 Section 9.2.2 figure 9.1.f, the theory of AGW, caused by greenhouse gas release, has a particular signature in the atmospheric temperature profile.

One important aspect of this temperature profile is commonly called the "Tropical Tropospheric Hotspot".

According to the IPCC, if the currently warming is caused by greenhouse gas release, there must be evidence of it through the "Tropical Tropospheric Hotspot".

The difficulty for the true believers is that the "Tropical Tropospheric Hotspot" cannot be found.

Radiosonde data does not show it. Satellite data does not reveal it, even when tortured by the Hockey Team.

An attempt to "prove" that it is really there, but hidden using some hocus, pocus about wind shear has been recently debunked and falsified.

Since the signature that the IPCC claims their theory says must be there, there are only a few alternatives-

1. IPCC climate theory is fundamentally wrong.
2. To the extent that IPCC climate theory is correct in predicting a hotspot due to extra carbon dioxide, we know that carbon emissions did not cause the recent global warming.

More information-

Posted by: orkneygal | December 13, 2010 11:06 PM | Report abuse

Look at the map you showed us.

Where is the biggest warming of all, the reddest of all red?


According to NASA-GISS





Too bad it's drifty ice,
Else you could buy your summer home there ahead of the crowds,

Except that


NOT WITH THERMOMETERS - There are no ships around.

NOT WITH SATELLITES - A fluke makes the Arctic off the orbits of both satellites.



(I didn't make any of this up.

Hansen says that the difference between all other measured global temperatures and his NASA-GISS is that he estimates temperatures in the Arctic Ocean - he doesn't detail how. In his own words
The first one there in line to congratulate Hansen for his "great work" is our own Mike Roddy

And Hansen mentions he is more of an activist these days)


Press, TV, Internet, Cancún. Even the World Meteorological Organization uses Hansen's Arctic estimates.


Here are - completely unembellished other than shifted for same average - the evolutions of global temperatures.

In green, the satellite RSS measures global cooling for more than a decade.
In red, NASA-GISS "estimates" go up and up and UP AND UP…

Posted by: adrianoc | December 14, 2010 12:14 AM | Report abuse

NOT WITH SATELLITES - A fluke makes the Arctic off the orbits of both satellites.


Polar orbit, as it's name might suggest, passes over the poles. NOAA operates several weather observation satellites in polar orbit.
(Scroll down past the GOES section.)

Posted by: mason08 | December 14, 2010 1:31 AM | Report abuse

are you really making the "it's cooled since '98" argument?

see false arguments #4 and #7, with a bit of #67 and #120 tossed in.

Posted by: walter-in-fallschurch | December 14, 2010 7:58 AM | Report abuse

mason08, others,
do those polar satellites measure temperature?

Posted by: walter-in-fallschurch | December 14, 2010 8:16 AM | Report abuse

What Walter says is also evident in my link above (by Roy Spencer). The 1998 El Nino had a peak almost exactly the height of the current one. But the 1998 El Nino was much stronger than the current one, see So that means there has been warming since 1998. A better test will be to see how low we go in the current La Nina. If it stays about as strong as the 1999 La Nina, then we should eventually dip to 0.0 on Roy's chart. If we dip to 0.1 instead, then that is 1C warming per century, or very roughly, a "sensitivity" of 2C. If we only dip to 0.2, then sensitivity is 3C using the trend for the past decade. Of course the trend may go up or down so it is a very crude sensitivity estimate, but at least it should settle the no warming argument.

Posted by: eric654 | December 14, 2010 8:36 AM | Report abuse

It would be a badly designed weather satellite that couldn't measure land and sea surface temperature, don't you think?

But here is your answer:

That's the primary instrument on the polar orbiting satellites. You'll note the note indicating that the three channels within the infrared band are used to measure sea and land temperature. The data represented in the OP's graph are land and sea surface temperature.

Posted by: mason08 | December 14, 2010 4:45 PM | Report abuse

Walter asks "do those polar satellites measure temperature?"

Yes, and much better than the geostationary satellites do. The main reason the measurement is better from the polar orbiters is because they are much closer, about 900 km out rather than 36000 km out. The polar orbiters have a cluster of precision instruments, and the primary ones used for temperature and moisture sense a suite of microwave and infrared channels.

Posted by: imback | December 14, 2010 5:03 PM | Report abuse

right, of course they measure temps. one of people like mr.q's, and my relatives' (whom i love dearly), favorite little things to nitpick about global warming is "lack of weather stations" and how we're "extrapolating" on vast areas w/ no thermometers and just ideologically conspiratorially filling in high numbers or something....

i guess the real rub is that satellite data only goes back a few to tens of years.

on the broader issue of AGW, could i characterize your opinion as:
it's warming because of human activity but it's not worth it to worry about it"?

Posted by: walter-in-fallschurch | December 14, 2010 5:40 PM | Report abuse

According to the IPCC AR4, tropical upper tropospheric warming is *not* a signature of global warming specifically due to increasing greenhouse gases. Any surface warming would also warm the tropical upper troposphere, where convection maintains the lapse rate. On the other hand, according the the IPCC AR4, stratospheric cooling *is* a signature of AGW. And stratospheric cooling is definitely observed. It seems that posting stuff that is both off-topic and dead wrong is a signature of denialism.

Posted by: imback | December 14, 2010 8:52 PM | Report abuse

I didn't think Jim Hansen was deemed credible anymore. Too political.

Posted by: silencedogoodreturns | December 18, 2010 11:04 AM | Report abuse

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