There is an opinion in the New York Times by Judah Cohen titled

Bundle Up, It’s Global Warming

The op-ed starts with the text

“The earth continues to get warmer, yet it’s feeling a lot colder outside. Over the past few weeks, subzero temperatures in Poland claimed 66 lives; snow arrived in Seattle well before the winter solstice, and fell heavily enough in Minneapolis to make the roof of the Metrodome collapse; and last week blizzards closed Europe’s busiest airports in London and Frankfurt for days, stranding holiday travelers. The snow and record cold have invaded the Eastern United States, with more bad weather predicted. All of this cold was met with perfect comic timing by the release of a World Meteorological Organization report showing that 2010 will probably be among the three warmest years on record, and 2001 through 2010 the warmest decade on record.”

This article is yet another one that spins the recent cold extremes and winter storms (e.g. in Europe, the United States), to be consistent with annual global average warming.

I have several comments on this op-ed.

First, the author of this op-ed writes

“Annual cycles like El Niño/Southern Oscillation, solar variability and global ocean currents cannot account for recent winter cooling. And though it is well documented that the earth’s frozen areas are in retreat, evidence of thinning Arctic sea ice does not explain why the world’s major cities are having colder winters.”

This is incorrect. The El Niño/Southern Oscillation and other circulation features (such as the PDO, NAO etc) are NOT “annual cycles”. Moreover, as shown by Roy Spencer (e.g. see) these features can result in changes in the global average heat content ( by altering cloudiness). Also, the recently relatively quiet Sun (with its alteration of its shorter wavelengths of radiation -e. g. see at Watts Up With That) may be playing a role.

The author further writes

“But one phenomenon that may be significant is the way in which seasonal snow cover has continued to increase even as other frozen areas are shrinking. In the past two decades, snow cover has expanded across the high latitudes of the Northern Hemisphere, especially in Siberia, just north of a series of exceptionally high mountain ranges, including the Himalayas, the Tien Shan and the Altai.”

First, the statement that while the statement “other frozen areas are shrinking” is correct for Arctic sea ice, it is incorrect for Antarctic sea ice (e.g. see). Moreover, the statement that seasonal snow cover has increased conflicts with the 2007 IPCC WG1 Statement for Policymakers (SPM) where they write

“Observed decreases in snow and ice extent are also consistent with warming……snow cover on average have declined in both hemispheres.”

Figure SPM.1c in the 2007 IPCC WG1 SPM illustrates this decline. Thus, the author of the op-ed reports on a major disagreement with the IPCC report, yet neglects to alert the reader to this difference.

The author continues

“As global temperatures have warmed and as Arctic sea ice has melted over the past two and a half decades, more moisture has become available to fall as snow over the continents. So the snow cover across Siberia in the fall has steadily increased. The sun’s energy reflects off the bright white snow and escapes back out to space. As a result, the temperature cools.”

Even if we ignore whether atmospheric water vapor has really increased over this region during the last two and a half decades, the op-ed writer does not report that, if this effect of added snow cover in a warming world were real, it is a negative radiative feedback which the 2007 IPCC WG1 report (and multi-decadal global model projections) did not recognize.

Finally, he writes

“Most forecasts have failed to predict these colder winters, however, because the primary drivers in their models are the oceans, which have been warming even as winters have grown chillier. They have ignored the snow in Siberia. “

However, the oceans have not been warming in recent years (e.g. see the 2010 paper by Know and Douglas ). However, I agree that “[m]ost forecasts have failed”. Indeed, I would go further to state that ALL seasonal and longer time scale model predictions have failed to skillfully predict these extreme cold events. One of the reasons, of course, is that these models are unable to skillfully predict the development of large amplitude atmospheric circulations (such as blocking high and low pressure systems, called “Omega Blocks” and ‘Rex Blocks”).

Until, and unless, the multi-decadal global models can show skill in predicting these atmospheric features AND their change in frequency and patterning in the coming decades, they are misleading policymakers and others on their skill. This op-ed, despite seeking to support the 2007 WG1 IPCC perspective, actually raises further substantive issues with the robustness and accuracy of that report.