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Posted at 10:00 AM ET, 01/ 4/2011

Record warmth in 2010, despite cooling influences

By Andrew Freedman

Countries that set all-time heat records in 2010. Graphic by Climate Central. Data from Jeff Masters/Weather Underground.

No matter how you crunch the data, 2010 is certain to go down in history as one of the warmest - if not the warmest - years since the beginning of instrumental records in the late 19th century. This is despite the recent cold and snowy weather in much of the U.S. and across Europe.

All three widely cited surface temperature datasets show that 2010 will most likely rank near the very top of the list - a remarkable feat considering that two factors that tend to cause cooler-than-average conditions were present for all or part of the year - a La Nina event and a "quiet" sun. Both of these sources of natural climate variability make it more difficult to set monthly and annual global average temperature records than during a period of high solar activity or an El Nino year.

The fact that 2010 turned out to be so warm despite these factors begs the question as to what role rising concentrations of greenhouse gases, especially carbon dioxide, had in this outcome. We know that they are playing an increasingly dominant role in many aspects of our changing climate system. However, the "signal" of manmade climate change is most evident when viewed over longer time periods, such as decades, as I discussed in a recent post. Detecting their influence in short-term events requires a much more complex approach that, as of now, lies at the cutting edge of climate science.

Both the National Oceanic and Atmospheric Administration (NOAA) and NASA have reported that January to November 2010 was the warmest such period on record. While their data closely matches one another, the two agencies use slightly different methods to calculate changes in global average surface temperatures. Data from a third group, based in the U.K., also depicts record warmth in 2010.

Furthermore, temperature readings from satellites also indicate that 2010 was an extremely warm year. The University of Alabama reported yesterday that, according to their satellite records, 2010 was just 0.1 degree Celsius cooler than 1998, which makes it the second-warmest year.

Remote Sensing Systems, which is another group that tracks temperatures via satellite, also ranked 2010 as the second-warmest year behind 1998.

NOAA reported that for the January to November period, the combined global land and ocean surface temperature was 1.15°F above the 20th century average, making this the warmest such period since records began in 1880.

Interestingly, according to NOAA, the warmth in the Northern Hemisphere was more noteworthy compared to that in the Southern Hemisphere. Northern Hemisphere land areas had the warmest November on record, whereas land areas in the Southern Hemisphere ranked as the 21st warmest. However, since more than two-thirds of the planet's land area is located in the Northern Hemisphere, the warmth in the north outweighed the relatively cool temperatures in the south.

Temperature departures from average for November 2010. Credit: NOAA

This year saw some stunning all-time heat records fall worldwide - including 19 national extreme heat records (see graphic at top of post). These records, some of which are still awaiting official confirmation from the World Meteorological Organization, included a sizzling 128.3°F in Pakistan. This now stands as the new record high temperature for the entire sprawling continent of Asia.

According to meteorologist Jeff Masters of Weather Underground, as of Nov. 23, no country had set an all-time record cold temperature during 2010, although that may have changed in December given the extreme cold in parts of Europe.

There were several noteworthy heat waves during the summer in the U.S. and abroad. It was the hottest summer on record in Washington, D.C., Baltimore, New York City and 10 states - including Maryland, Virginia, Delaware and New Jersey. D.C. set a new record for most 90°F plus days in a year, with 67.

July in Washington became the hottest month of any month on record. Similar all-time records were established in July in Trenton and Atlantic City, N.J.

Warm temperature records outpaced cold ones

For a broader perspective on 2010 temperatures, it's helpful to examine the ratio of record high temperatures to record low temperatures. In a climate that is neither warming nor cooling, when the ratio is considered over a large region over several consecutive years, there should be on average about as many record highs as record lows, for close to a 1:1 ratio. However, a study published in 2009 showed that in recent years, over the U.S. as a whole, warm temperature records have been outpacing cold ones by a ratio of two to one - further evidence of an overall warming climate.

Ratio of record daily highs (red) to record daily lows (blue) observed at about 1,800 weather stations in the 48 contiguous United States from January 1950 through September 2009. Record highs have increasingly predominated in the last 30 years, with the ratio now about two-to-one. Credit: NCAR.

That trend has continued with the start of a new decade. According to figures compiled by Guy Walton of The Weather Channel using data from the National Climatic Data Center, there were 19,213 record daily high temperatures set in the U.S. during 2010, compared to 8,374 record daily lows. There were also 596 monthly record highs, compared to 156 monthly record lows, and 59 all-time record highs, compared to just two all-time record lows.

The domestic heat last summer was overshadowed by events in Western Russia, where Muscovites experienced an unprecedented heat wave, both in terms of the actual air temperatures (above 100°F) and the duration of the event (more than one month). Add to that toxic smoke from nearby wildfires, and the result was a story that dominated world headlines, as at least 15,000 people are believed to have perished in the event.

Scientists are investigating how human-caused climate changes affect the odds of events like the Russian heat wave, and the related heat and deadly flooding in Pakistan.

Probability of June, July and August average temperature anomalies in Moscow, Russia since 1950. This image shows that the average temperature in Moscow for summer 2010 was significantly hotter than in any year since 1950. Credit: Climate Central.

Cooling influences not so cool after all?

The record or near-record warm global average surface temperatures last year were rather surprising, given the coincidence of La Nina conditions and relatively low solar activity. La Nina is a phase of the El Nino-Southern Oscillation (ENSO), a natural cycle that affects sea surface temperatures and air pressure across the equatorial Pacific Ocean. During a La Nina, winds enhance upwelling along the west coast of South America, bringing cold ocean waters to the surface and cooling the overlying air. La Nina events, particularly moderate to strong ones such as the one currently underway, can dampen global average surface temperatures (in contrast to its sibling, El Nino, which is characterized by warmer-than-average sea surface temperatures and helps boost global temperatures).

In fact, according to NASA, November 2010 was the only "warmest month on record" to occur when La Nina conditions were present (h/t Jeff Masters).

Time will tell how natural climate variability, such as solar fluctuations and El Nino/La Nina events, will interact with the extra greenhouse gases in the air due to human activities. No one should expect global climate change to be monotonic, with each year warmer than the last. But 2010 should raise some eyebrows for its record warmth in the face of two influential cooling forces.

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  | January 4, 2011; 10:00 AM ET
Categories:  Climate Change, Freedman, Latest, Local Climate, Science, Temperature Extremes  
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Record warmth?

Doesn't it really depend upon the date range of your record? Why don't you expand your date range a little and see how 2010 compares in the big picture.

--begin quote--
So where do the 1934/1998/2010 warm years rank in the long-term list of warm years?

Of the past 10,500 years, 9,100 were warmer than 1934/1998/2010.

Thus, regardless of which year ( 1934, 1998, or 2010) turns out to be the warmest of the past century, that year will rank number 9,099 in the long-term list.
--end quote--

source of the above quote

An interesting graphic to put it all in perspective.

Happy New Year!!

Mr. Q.

Posted by: Mr_Q | January 4, 2011 11:29 AM | Report abuse

We really need threaded comments so we can point out to people with poor reading comprehension that the post is discussing temperatures "since the beginning of instrumental records in the late 19th century."

Posted by: wiredog | January 4, 2011 11:36 AM | Report abuse

Record warmth is foreplay discussion. What I want to note is that after a brief scare with the 06z gfs, we are now back in line for a huge snowstorm jan 11-12. Although I refuse to get excited still, I must admit I'm quite...excited.

Posted by: bbirnbau | January 4, 2011 11:42 AM | Report abuse

The ever changing

instrumental record.

I will stick with the ice core.

They haven't found a way of "adjusting" that one. At least not yet. But I am sure they are working on it. ;)

Mr. Q.

Posted by: Mr_Q | January 4, 2011 12:08 PM | Report abuse

We still seem to be getting normal cooling when the sun is shining directly over the Southern Hemisphere.

Is there any credible evidence that springs are beginning earlier, summers are lasting longer and winters aren't so harsh?

Extreme weather events such as the current flooding in Queensland, Australia might be related to global warming, but they might also be due to random variations or long term cycles. Seems there was a lot of extreme weather around the world when I was growing up during the 1960's.

Posted by: Bombo47jea | January 4, 2011 12:50 PM | Report abuse

heating degree days (days median temp is below 65*amount below 65) since July 1 at DCA are 1572, right near the historical avg of 1569, so the fall and winter have seen average temps in total, and are likely to drop below average with the cold forecasts of the next couple weeks

can we have a colder/warmer than average season now without someone in the global warming cult panicking?

Posted by: TGT11 | January 4, 2011 2:47 PM | Report abuse

"Is there any credible evidence that springs are beginning earlier?"

There's a long record of Japanese cherry blossom bloom dates and they've been getting earlier, e.g.

Posted by: imback | January 4, 2011 10:12 PM | Report abuse

Solomon Islands set a new temperature record? Heat records exceed cold records? See previous article, and note that while care is taken to adjust average temperature for heat island effects so the global average is accurate, no adjustments are made for records. So that graphic is biased. Likewise, imback, the arnold arboretum that I used to live next to is not adjusted for the crowded urban setting that it is in. Blossoms are earlier because that spot is urban.

Other than that, just another new year, with nothing new from Andrew.

Posted by: eric654 | January 5, 2011 10:59 AM | Report abuse

From the press release accompanying the temperature records study I cited:

The study team analyzed several million daily high and low temperature readings taken over the span of six decades at about 1,800 weather stations across the country, thereby ensuring ample data for statistically significant results. The readings, collected at the National Oceanic and Atmospheric Administration's National Climatic Data Center, undergo a quality control process at the data center that looks for such potential problems as missing data as well as inconsistent readings caused by changes in thermometers, station locations, or other factors.

Posted by: afreedma | January 5, 2011 12:18 PM | Report abuse

Andrew, there's are flaws in that paper. The full text is here: where they say

"We use a subset of quality controlled NCDC US COOP network station observations of daily maximum and minimum temperatures, retaining only those stations with less than 10% missing data"

In fact they used 1800 stations out of about 11,000. Because of that "quality" of data criteria, they did in fact select urban stations with a great potential for urban bias. There are previous papers that talk about the urban bias on record temperatures e.g. but there was no mention by Meehl et al about that issue, nor apparently no awareness of the selection bias introduced by the quality criteria (they would have had an unbiased result by a random sample of the 11,000 regardless of quality).

Posted by: eric654 | January 5, 2011 3:10 PM | Report abuse

Also you might want to let readers know that "Climate Central" was one of the funders of that study.

Posted by: eric654 | January 5, 2011 3:35 PM | Report abuse

As usual, eric654, you're all bluster and no honesty. The cherry blossom study was for Japan as I said, not for some US arboretum. Japanese scholars have retrieved about 1000 years of bloom dates and have shown how climate change affects the onset of spring. The article does take into account the effects of urbanization as well as global warming. Furthermore, eric654, linking to a pseudoscience site doesn't really help your denialist cause.

P.S. Capital Weather Gang did cover the cherry blossom bloom time topic a couple of years ago:

Posted by: imback | January 5, 2011 8:56 PM | Report abuse

imback, I am very honest, and I honestly only looked at your URL but didn't click it. So I assumed that it was Arnold Arboretum run by Harvard. I apologize to everyone else for not reading your link. Next time I will be more careful.

Posted by: eric654 | January 5, 2011 9:28 PM | Report abuse

Poor Mr Q throws around data without understanding the first thing about the subject!

No Mr Q, the debate is not about the warmest US temperature on record (1934), it is about the warmest global average temperature on record. Sorry to inform you that US represents less than 2% of the global surface area. I am very sorry that people like you and Don Easterbrook make such deceptive pronouncements without understanding the first thing about the subject. Please read up a little on the theory rather than continuing to spread your misinformation (or perhaps disinformation).

Posted by: Jake_D | January 6, 2011 12:27 AM | Report abuse

Poor Mr Q throws around data without understanding the first thing about the subject!

No Mr Q, the debate is not about the warmest US temperature on record (1934), it is about the warmest global average temperature on record. Sorry to inform you that US represents less than 2% of the global surface area. I am very sorry that people like you and Don Easterbrook make such deceptive pronouncements without understanding the first thing about the subject. Please read up a little on the theory rather than continuing to spread your misinformation (or perhaps disinformation).

Posted by: Jake_D | January 6, 2011 12:29 AM | Report abuse


What are you talking about? The Don Easterbrook graphic was from Greenland ice core data. The graphic is very clearly labeled. It didn't have anything at all to do with the U.S.

That is a cool graphic though, isn't it? ;)

Using Greenland ice core data, and plotting the last 10,500 years, the year 2010 ranks at the bottom. Out of the last 10,500 years, over 9,000 years were HOTTER than 2010. Looking at the big picture, very few years were COLDER than 2010.

Using that graphic, if you had to guess what the future temperature might be, what would you guess?

Mr. Q.

Posted by: Mr_Q | January 6, 2011 1:00 AM | Report abuse

Mr. Q,

The graphic is nice enough but since it is labeled as defining the present as 2000 AD and the most recent data point from the ice core is shown as 95 years before present (therefore 1905, though that's actually a mistake since the ice core data uses a convention in which the "present" is 1950) it doesn't show how 2010 compares to the past 10,500 years since it doesn't show 2010 at all.

Perhaps you ought to rely on someone more competent than Don Easterbrook for analysis of past temperatures. This sample of his work clearly shows he either doesn't understand the data he's analyzing or does understand it and is being intentionally deceptive.

Posted by: jontorrance | January 7, 2011 11:32 AM | Report abuse

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