Letter from Earth: We’re Getting Warmer

by Bill Chameides | May 18th, 2010
posted by Erica Rowell (Editor)

Permalink | 12 comments

2010 is shaping up to be the warmest year on record.

The U.S. National Climatic Data Center (NCDC) has released its preliminary analysis of global temperatures for the month of April: it was a hot one.

NCDC reports that April’s globally averaged surface temperature is the warmest on record. Also the warmest on record are the first four months of 2010 (January through April).

Temperature measurements for the first four months of 2010 show record-breakingwarmth. (Source: NCDC/NOAA)

This April’s temperatures beat out 1998’s, the previous record-holder for the warmest April. Global temperatures during April 2010, according to NCDC, averaged 58.1 degrees Fahrenheit, which is some 1.37 degrees above the 20th century average, NCDC’s baseline. In April 1998, global temperatures averaged about 1.28 degrees Fahrenheit above the baseline.

The comparison between 2010 and 1998 is interesting. NCDC ranks 1998 as the second warmest year on record, right behind 2005. Two things probably contributed to 1998’s record warmth — a strong El Niño in the South Pacific, which favors the transfer of heat from the ocean to the atmosphere, and a so-called solar maximum, in which a little extra energy in the form of solar radiation hits Earth.

Interestingly, after a long period of either La Niña (i.e., anti-El Niño) or neutral conditions, the South Pacific returned to El Niño in mid-2009 and there it has stayed at least through last month.

However, the current El Niño is not nearly as strong as the one in 1998, and the current Sun, much less active than it was in 1998 when it was just shy of its peak, has just recently started to dig out of a very deep and long solar minimum.

So, with this year’s weaker El Niño and much weaker solar activity, another explanation for 2010’s warmth is needed. What could that possibly be? Gee, hey, gee … it’s a gas to try to solve such a conundrum.

United States Playing It Cool, but Mark My Words, Elsewhere It’s Been Hot

While most of the rest of the world is heating up, U.S. temperatures have remained fairly unremarkable, even on the cool side for the most part (see graphic below). This continues a trend seen last winter, when much of theUnited States shivered while most other parts of the globe saw record warmth.

(Source: NCDC/NOAA)

The discouraging part of this temperature pattern is that while conditions remain stable over the contiguous United States, temperatures in Alaska and north of the border in Canada and over Greenland — some of the world’s most climate-sensitive regions — are way up. At the very least those warmer conditions will mean more melting permafrost and more melting of the Greenland ice sheet.

So what’s at the bottom of the recent absence of a U.S. warming trend? Some would point to changes in the jet stream and the polar front. But more visionary folks might see this as validation of that New Age philosophy that if you just believe something hard enough, it will happen. Under this scenario, as long as Americans remain in denial about global warming, they will be able to stay “cool” so to speak? This kind of takes to an extreme Mark Twain’s quip that “it’s your human environment that makes your climate.” But, with all due respect to Mr. Twain, I just can’t accept that much human-induced climate change. You might say I am a skeptic. And speaking of skeptics …

(Source: NCDC/NOAA)

If You’re Skeptical — When in Doubt, Tell the Truth

It has been my experience that there are folks out there who are skeptical of these temperature records.

A frequent complaint from such skeptics: You can’t believe temperature records from surface networks, because the data are skewed by effects such as urban heat islands and station creep and questionable statistical manipulations to remove such artifacts. It’s all “lies, damned lies, and statistics,” I guess.

Well, I don’t agree, but OK, let’s throw out all the land data and just look at the data from the ocean.Average Temperatures Over the Ocean Surface

  • During the month of April ocean temperatures were the warmest on record; and
  • Over the first four months of 2010 they were the second warmest.

The last time I checked: urban heat islands weren’t really a factor over the ocean.

Satellite-based Temperature Record from University of Alabama

Some skeptics go even further, claiming you can’t believe any of those surface measurements or the government scientists who analyze them. They prefer mid-atmospheric temperatures analyzed by scientists from the University of Alabama (UAH) using satellite data.

Again I don’t agree, but take a gander at the temperature trends from UAH. Not quite at the 1998 level but clearly warmer than any other year on the UAH record.

The bottom line: anyway you cut it, 2010 is shaping up to be a very warm year.

(Source: UAH)

The Bigger Picture

The 21st century’s opening decade, although the warmest on record, saw little rise in global temperatures from year to year. That stasis in global temperatures prompted some to declare that global warming was over, even that an ice age was coming. Using such a short temperature record to prognosticate might make good PR, but scientifically it’s silly. Likewise, we shouldn’t make too much of the recent jump in global temperatures. Let’s wait and see. But harking back to an earlier quotation: reports of global warming’s death are exaggerated.

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  1. MattN
    Jun 7, 2010

    You do know 2003 was when the ARGO bouy system went on-line, right? Murphy and Solomon are only speculating. They have zero evidence that occured. A much more likely explaination is poor data gathering before ARGO went active. What atmospheric signal are you talking about? The land-based temp measurements that are full of errors? That signal?

    • Bill Chameides
      Jun 15, 2010

      MattN: Again, take a look at the Lyman paper.

  2. MattN
    May 21, 2010

    Everyone from Hansen to McIntyre agree that upper ocean heat content is THE measure of global warming. So you might be surprised at the latest data, showing the largest decrease in ocean heat content ever recorded: Put the party hats away, Doc…

    • Bill Chameides
      Jun 7, 2010

      MattN: Not. Check out a recent issue of SCIENCE and the paper by Lyman entitled “Robust Warming of the Global Upper Ocean.” They find a “robust” increase in ocean heat content from 1993 to 2008. They do see a flattening of OHC since 2003 (for reasons not fully understood but possibly due to heat transport to the deep ocean – see the paper by Murphy and Solomon) but not a decrease. I find it interesting that the evidence that there was no global warming was the lack of an atmospheric signal. Now that the atmospheric signal has reappeared, it is suddenly not relevant.

  3. MattN
    May 20, 2010

    La Nina conditions are forming MUCH faster than thought/predicted: I was so dang right, I should start taking calls. This is what happens when the PDO is in the negative phase. El Ninos are mild/moderate and short lived. They are the exception instead of the rule. At this point, I give the probability of a major La Nina at 50%.

    • Bill Chameides
      Jun 7, 2010


  4. MattN
    May 20, 2010

    You really should read this, Doc: THAT’S the problem with the surface record…

    • Bill Chameides
      Jun 7, 2010

      MattN: Try reading the post. It does refer to satellite data.

  5. MattN
    May 19, 2010

    Kudos for using UAH data. I fully believe their data is far superior to any ground based temperature measurements and is sigificantly better than RSS satellite measurements due to the fact that the RSS satellite is in a decaying orbit and must be continually adjusted. UAH uses the newer orbit-stable AQUA satellite.

  6. MattN
    May 19, 2010

    Ignoring the “21st century opening decade being the warmest on record” comment (which I have provided data to the contrary in the other thread), I do not think 2010 will be the warmest year on record. Here’s why: 2010 *was* indeed warmer Jan-March vs. 1998, but the 2010 El Nino has vanished and SSTs have dropped much sooner than they did in 1998. April was cool enough to drop 2010 behind 1998, wrt Jan-April data. The 1998 super El Nino held on for several more months that year with continued VERY warm SSTs in the Nino 3.4 region in May and June of that year. We’re already on the downward slide in ’10, and in fact, are currently at neutral conditions: El Nino is gone, much sooner than anticipated. But this is what happens when the PDO is in its negative phase (as opposed to the positive phase in 1998). El Ninos are shorter lived. In the end, I think 2010 will be +/-.1 on either side of 2009. But I think 1998 will still remain the warmest year on record. UAH data: There are already several forecasts for La Nina conditions arriving later this fall: So, if I were a betting man, I would put my money on 2010 NOT being the warmest year on record, and crowning 2010 the champ is WAY premature…

    • Bill Chameides
      May 19, 2010

      MattN: Bet away. I did not say, predict, or imply that 2010 will end up being warmer than 1998. Let’s see what happens.

      • MattN
        May 20, 2010

        This is the first sentence of this entry: “2010 is shaping up to be the warmest year on record.” How can you then say “I did not say, predict, or imply that 2010 will end up being warmer than 1998.” You most certainly did.

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