It’s no surprise that as much of the U.S. hit was with an unusual January cold spell, hyperbolic warnings of an impending ice age would be close behind.

The British tabloid The Daily Mail recently misrepresented the work of a prominent German climate scientist, Mojib Latif, to suggest that “The bitter winter afflicting much of the Northern Hemisphere is only the start of a global trend towards cooler weather that is likely to last for 20 or 30 years.”

The article has been picked up and distributed widely by Fox News, and others. But a closer look at both the temperature data and the work of Latif and his colleagues reveals that the world was not and is not unusually cold this January, and Latif’s work does not support the suggestion of an imminent multidecadal global cooling trend.

The cold weather that gripped much of the U.S. the last few weeks brought dramatic images of snow in Florida and large minus-temperatures in parts of the Midwest. While the weather in North America and parts of Northern Russia was exceptionally cold (albeit not unprecedentedly so), the world as a whole (and even the Northern Hemisphere) was not particularly cold.

The NASA image below shows that “the Arctic was exceptionally warm,” as was northern Africa and the Middle East.

View larger image
Image via NASA.

The dramatic patterns of cold and warm temperatures appear to be the result of a natural mechanism called the Arctic Oscillation … AO. When the AO is strongly negative, as it was over the past month, cold Arctic air slides southward and warmer air flows north, warming the Arctic while cooling adjacent areas.

NASA explains it this way:

A low-pressure air mass usually dominates the Arctic, and while higher pressure air sits over the mid-latitudes. This pressure difference generates winds that confine extremely cold air to the Arctic. Sometimes, the pressure systems weaken, decreasing the pressure difference between the Arctic and mid-latitudes and allowing chilly Arctic air to slide south while warmer air creeps north. A weaker-than-normal Arctic Oscillation is said to be negative. When the pressure systems are strong, the Arctic Oscillation is positive.

Throughout December 2009, the North Atlantic Oscillation was strongly negative, said the National Weather Service … Cold Arctic air chilled the land surface at mid-latitudes, while Arctic land, such as Greenland and Alaska, was much warmer than usual.

This unusual Arctic warmth has helped reduce Arctic sea ice levels to close to the lowest extent on record for this time of year, as shown by the National Snow and Ice Data Center:

View larger image
Daily Sea Ice Excent for January 12th, 2010 from the National Snow and Ice Data Center.

Furthermore, a review of global temperature readings from satellites (via AMSU channel 5), shows almost all January daily temperatures exceeding the 20-year high. Although AMSU channel 5 readings are not the same as the end-of-month temperatures produced by the University of Alabama, Huntsville (UAH) group, they tend to be strongly indicative.

View larger image
AMSU Channel 5 Data comparing the 20-year mean (in yellow), 20 year highs (in pink), and 2010 temperatures to-date (in green).

Reviewing the data for 2009, one can see that the past year was an exceptionally warm one, ranking as the 5th hottest in the past 150 years in HadCRUt and 2nd hottest in NASA’s GIStemp. Correcting for the effects of the cyclical El NiƱo Southern Oscillation, 2009 may have been the hottest year on record in NASA’s GIStemp.

View larger image
Global Monthly Temperature Records relative to the 1979-1998 baseline temperature for each series. Updated through December 2009 when available.

Based on available temperature records, there seems little reason to conclude that the planet is witnessing “the start of a global trend towards cooler weather” as The Daily Mail opined. But to further examine that position, one should refer directly to the work of Mojib Latif.

Lafit gave a presentation in Geneva in the fall of 2009, presenting work he had done in Keenlyside et al (2008) suggesting that the 2005-2015 mean temperature might be cooler than the 1994-2004 mean temperature.

In doing so, Latif was not suggesting that the next decade (2010 to 2020) will be cooler, and certainly not the next two decades (2010 to 2030), just that the decadal average surrounding 2010. The Keenlyside et al model is shown below:

View larger image
Figure from Keelyside et al 2008. Obtained via RealClimate.

Latif’s presentation in Geneva contained a slide that showed a hypothetical example of the type of cyclical variability described in Keenlyside et al imposed on a long-term warming trend.

View larger image
Slide from Latif’s Geneva Presentation. Via DeepClimate.

It’s worth noting that Keenlyside et al is just one of many climate models, and other groups do not necessarily agree with their projections. Keenlyside et al’s model also does not reveal anything new about the climate’s sensitivity to anthropogenic greenhouse gases, or contradict anything in the recent IPCC report, notwithstanding the claims of The Daily Mail. Rather, they emphasize the scale and importance of cyclical decadal oscillations in influencing short-term variability in the context of the long-term GHG-driven trend.

As Latif has remarked, “It comes as a surprise to me that people would try to use my statements to try to dispute the nature of global warming.” He also objected to tying the recent U.S. cold spell to his work, saying that “[t]hey are not related at all … what we are experiencing now is a weather phenomenon, while we talked about the mean temperature over the next 10 years. You can’t compare the two.”

In a response to earlier misrepresentations of his work, Latif attempted to put things in perspective:

[W]hat I said is that the cooling in the Atlantic and Pacific may offset global warming for a decade so that there may be not much of an additional warming. I showed a prediction that was published last year in the science magazine Nature. I also pointed out that the British group issued a competing forecast for the next decade. They predict that global warming will continue at the rate of the last decades. Thus, and I made this very clear, there is quite some uncertainty about the short-term evolution. Yet we all agree that in the long run, say by 2050 and thereafter, the earth will considerably warm, if we do not considerably reduce global greenhouse gas emissions.

Finally The Daily Mail reported that decadal oscillations could account for a significant part of late 20th Century warming, quoting Latif as suggesting that “it could be anything between ten and 50 per cent.” However, Latif argues that this misrepresents his statements, that he was referring to the warming over the entire 20th Century, and that his remarks were completely consistent with the analysis of climate forcings over the past century presented in the most recent IPCC report. He points out that “No climate specialist would ever say that 100 percent of the warming we have seen is down to greenhouse gas emissions.”

As shown in the figure from Meehl et al (2004) below, much of the warming in the early part of the 20th Century is indeed attributable to natural factors, and anthropogenic effects predominate only after 1960.

View larger image

Perhaps Latif’s closing remarks to the Guardian newspaper best describe the dangers of the media’s overplaying particular remarks and conflating climate and weather given the enormous complexity of the climate system:

There are numerous newspapers, radio stations and television channels all trying to get our attention. Some overstate and some want to downplay the problem as a way to get that attention … We are trying to discuss in the media a highly complex issue. Nobody would discuss the problem of [Einstein’s theory of] relativity in the media. But because we all experience the weather, we all believe that we can assess the global warming problem.

Topics: Climate Science