On the February 2 edition of MSBNC's 1600 Pennsylvania Avenue, anchor David Shuster let syndicated columnist Deroy Murdock tout climate change skeptic Martin Hertzberg's assertion that global warming is not occurring because, in Murdock's words, “the Earth temperature has gone down 1.8 degrees Fahrenheit since 1997.” Murdock was referencing the following quote from Hertzberg that Murdock included in a February 1 column: "[T]he average temperature of Earth's atmosphere has declined over the last 10 years. From the El Nino Year of 1998 until Jan. 2007, it dropped a quarter of a degree Celsius (0.45 degrees Fahrenheit). From Jan 2007 to the spring of 2008, it dropped a whopping three-quarters of a degree Celsius (1.35 degrees Fahrenheit)." Rather than challenge this use of data, Shuster named Murdock “our Muckraker of the Day” and “congratulat[ed]” Murdock for “stirring the pot.”

However, climate scientists warn against cherry-picking yearly temperature averages as purported evidence that global warming is not occurring, as Hertzberg -- and Murdock -- did by comparing the average temperature in 1998 to the average temperature in 2007 and 2008. For instance, Gavin Schmidt, a climate modeler at the NASA Goddard Institute for Space Studies, recently stated that while 2008 was the coolest year since 2000, “such variability is ... predicted by climate models” and is not evidence that global warming has “stopped.” Scientists such as Schmidt and Climatic Research Unit (CRU) professor Phil Jones have also pointed out that warming caused by an El Niño event and cooling caused by a La Niña event can have a drastic impact on year-to-year variability in global average temperatures, making Hertzberg's comparison of “the El Nino Year of 1998” -- the hottest year on record according to CRU and the Met Office Hadley Centre -- to the period spanning from January 2007 to “the spring of 2008” -- when a significant La Niña was occurring -- especially misleading.

In a December 16, 2008, post on RealClimate.org, Schmidt wrote of the release of 2008 global temperature data: “The great thing about complex data is that one can basically come up with any number of headlines describing it -- all of which can be literally true -- but that give very different impressions. Thus we are sure that you will soon read that 2008 was warmer than any year in the 20th Century (with the exception of 1998), that is was the coolest year this century (starting from 2001), and that 7 or 8 of the 9 warmest years have occurred since 2000. There will undoubtedly also be a number of claims made that aren't true; 2008 is not the coolest year this decade (that was 2000), global warming hasn't 'stopped', CO₂ continues to be a greenhouse gas, and such variability is indeed predicted by climate models.” He also wrote of “the release of the 'meteorological year' averages for the surface temperature records (GISTEMP, HadCRU, NCDC)":

This puts 2008 at #9 (or #8) in the yearly rankings, but given the uncertainty in the estimates, the real ranking could be anywhere between #6 or #15. More robustly, the most recent 5-year averages are all significantly higher than any in the last century. The last decade is by far the warmest decade globally in the record. These big picture conclusions are the same if you look at any of the data sets, though the actual numbers are slightly different (relating principally to the data extrapolation - particularly in the Arctic).

So what to make of the latest year's data? First off, we expect that there will be oscillations in the global mean temperature. No climate model has ever shown a year-on-year increase in temperatures because of the currently expected amount of global warming. A big factor in those oscillations is ENSO - whether there is a warm El Niño event, or a cool La Niña event makes an appreciable difference in the global mean anomalies - about 0.1 to 0.2ºC for significant events. There was a significant La Niña at the beginning of this year (and that is fully included in the D-N annual mean), and that undoubtedly played a role in this year's relative coolness. It's worth pointing out that 2000 also had a similarly sized La Niña but was notably cooler than this last year.

Schmidt added that "[p]icking any single year as a starting point is somewhat subjective and causes the visual aspect to vary - looking at the trends is more robust."

In a December 16, 2008, press release, the United Kingdom Met (Meteorological) Office Hadley Centre and the Climatic Research Unit at the University of East Anglia -- which produce the HadCRU data -- also attributed the “slightly down” global average temperature for 2008, in part, to La Niña, and quoted Jones as saying: “The most important component of year-to-year variability in global average temperatures is the phase and amplitude of equatorial sea-surface temperatures in the Pacific that lead to La Niña and El Niño events.” From the press release:

Climate scientists at the Met Office Hadley Centre and the Climatic Research Unit (CRU) at University of East Anglia maintain the global climate record for the WMO. They say this figure is slightly down on earlier years this century partly because of the La Niña that developed in the Pacific Ocean during 2007.

La Niña events typically coincide with cooler global temperatures, and 2008 is slightly cooler than the norm under current climate conditions. Professor Phil Jones at the CRU said: “The most important component of year-to-year variability in global average temperatures is the phase and amplitude of equatorial sea-surface temperatures in the Pacific that lead to La Niña and El Niño events”.

The ten warmest years on record have occurred since 1997. Global temperatures for 2000-2008 now stand almost 0.2 °C warmer than the average for the decade 1990-1999.

Dr Peter Stott of the Met Office says our actions are making the difference: “Human influence, particularly emission of greenhouse gases, has greatly increased the chance of having such warm years. Comparing observations with the expected response to man-made and natural drivers of climate change it is shown that global temperature is now over 0.7 °C warmer than if humans were not altering the climate.”

According to the Goddard Institute, “a strong La Niña ... existed in the first half of the year [2008].” According to a November 21, 2008, "WMO El Niño/La Niña Update" by the World Meteorological Organization (WMO), “Historically, the normal period for development of El Niño or La Niña is March-May.”

Schmidt and the Hadley Centre/CRU each also pointed to the broader warming trend when comparing the past decade to previous decades. Michel Jarraud, secretary general of the WMO, was similarly quoted in a January 7 Agence France-Presse article as saying that despite cooler temperatures in recent months, “The major trend is unmistakably one of warming.”

Indeed, according to the annual mean global temperature data jointly produced by the Met Office Hadley Centre and CRU, while no recent year has surpassed the average global temperature in 1998, the next 11 warmest years on record have all also occurred since 1995, demonstrating a broader warming trend:

Similarly, another widely used data set, the 2008 GISS Surface Temperature Analysis issued by NASA's Goddard Institute, estimates that “2008 is the ninth warmest year in the period of instrumental measurements, which extends back to 1880 (left panel of Fig. 1). The ten warmest years all occur within the 12-year period 1997-2008. The two-standard-deviation (95% confidence) uncertainty in comparing recent years is estimated as 0.05°C [ref. 2], so we can only conclude with confidence that 2008 was somewhere within the range from 7th to 10th warmest year in the record.”

Shuster also allowed Murdock to cite unusual snowfall as evidence that the “Earth is not cooperating with people on the left who push this stuff.” As Media Matters for America has repeatedly documented, climate scientists -- including at least one who has disputed aspects of the scientific consensus on global warming -- completely reject the notion that short-term changes in weather, let alone individual storms, bear any relevance to the global warming debate.

From the February 2 edition of MSNBC's 1600 Pennsylvania Avenue:

SHUSTER: Welcome back to 1600. Here in the Northeast, we're experiencing a beautiful 50-degree February day, but across the pond, Londoners are under four inches of snow -- the heaviest snowfall in almost two decades. To the south, Paris, Spain, and even Morocco are getting unusual amounts of the white stuff. So where's the global warming? That question's now being asked in unusual circles, progressive and scientific ones.

In an op-ed published across the country last week, columnist Deroy Murdock writes: “So-called global warming has shrunk from problem to punch line. And now Leftists are laughing, too. ... As Earth faces global cooling, both troglodyte Right-wingers and lachrymose Left-wingers find Albert Gore's simmering-planet hypothesis increasingly hilarious.”

Deroy Murdock is a columnist with the Scripps Howard News Service and a media fellow with the Hoover Institution at Stanford University. He's definitely stirring the pot with this piece, and he is our Muckraker of the Day. Deroy, who are the lefties who don't agree with global warming anymore?

MURDOCK: David, there have been a number of people, both scientists and commentators, who have come out and denounced this notion. And they're very clear in saying that they are not people on the right, but people on the left. For example, you have a man named Harold Ambler who writes for HuffingtonPost.com, and he said he voted for Barack Obama for a thousand times a thousand reasons. And, nonetheless, he says that he believes that Al Gore should apologize for what he's done on global warming. He also believes that Al Gore's comment that the science is in, that the debate is over -- he describes that as the biggest whopper ever sold to the public in the history of mankind.

Then you have another man named Martin Hertzberg -- he's a professor, a former Navy meteorologist, he has a Ph.D. -- a very serious scientist. He calls himself a lifelong liberal Democrat. He does not believe in global warming, and he says that this is -- that the Earth's temperature has gone down 1.8 degrees Fahrenheit since 1997. He says that we're cooling at the moment; we're not warming. And there are number of others, including a former Socialist minister in France -- former minister of education, member of the Socialist Party. He's a geophysicist, and he says the Earth is not warming, and the only warming is going on is really in the bank accounts of people on the left who push this, and he believes this is being done essentially as a way --

SHUSTER: Deroy, what about --

MURDOCK: -- of making money.

SHUSTER: What about the argument, though, that global warming -- it's going to be -- the signs are not that the entire planet is going to get warmer, but that weather patterns are going to change. Some places will get cooler, some will get warmer -- particularly like the polar icecaps, where the evidence is clear that the icecaps are melting, right?

MURDOCK: Well, actually, the polar icecap in the north grew last year by approximately the size of Texas. So, what you're seeing is -- despite the claims that the poles are melting -- you're actually seeing that the evidence is that the North Pole is actually bigger than it was back in August 2007 -- grew, again, about the size of Texas. So, the slogans of global warming are fascinating.

It's interesting to hear Al Gore's speeches. Unfortunately, the weather is not cooperating; the climate is not cooperating. You're seeing snow in the United Arab Emirates, you saw snow in Malibu, snow in Las Vegas, snow in New Orleans, for God's sake. You actually had snow falling on the street cars on Canal Street in New Orleans. So, unfortunately, the Earth is not cooperating with people on the left who push this stuff.

SHUSTER: Well, Deroy, it's a great --

MURDOCK: And now people on the left are disagreeing with it and pointing out that there is no evidence to this theory.

SHUSTER: It's a great piece, Deroy. And even though a lot of people disagree with you, you've done enough reporting on this and stirring the pot to be our Muckraker of the Day. Congratulations, we appreciate you coming on tonight.