December 21, 2011

Winter 2011-12: Global Warming to Blame?

No matter what this winter holds in store, someone, somewhere, will blame it on global warming.

Recall that the last two snowy and cold winters in the eastern U.S. were blamed, by some, on greater than normal snowfall amounts across Eurasia during the preceding fall season. And the snowy Eurasian autumns were blamed on the low levels of Arctic sea ice during September—which of course was blamed on anthropogenic global warming. Forecaster Judah Cohen explained how this works in a Christmas day op-ed in the New York Times last year—published the day before a nearly 2 foot snowstorm buried the city:

“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. … It’s all a snow job by nature. The reality is, we’re freezing not in spite of climate change but because of it.”

And back in January of 2000, during a particularly mild winter in New York City, the Times ran an article which blamed the mild, snowless weather on global warming:

“I bought a sled in ’96 for my daughter,” said Dr. Michael Oppenheimer, a scientist at the nonprofit Environmental Defense Fund. ”It’s been sitting in the stairwell, and hasn’t been used. I used to go sledding all the time. It’s one of my most vivid and pleasant memories as a kid, hauling the sled out to Cunningham Park in Queens.”

…Dr. Oppenheimer, among other ecologists, points to global warming as perhaps the most significant long-term factor.

But such is the cycle of the daily news. Anything unusual has to have a cause, and global warming has gone from being the cause du jour, to being the cause de rigueur. So you don’t have usually to look very far to find someone fingering global warming for anything meteorological—especially when it can be spun in a negative context.

So, what kind of global warming linkages should we expect from this year’s winter?


December 16, 2011

“Methane Time Bomb in Arctic Seas – Apocalypse Not”

Our headline is taken from New York Times blogger Andy Revkin’s recent DotEarth post covering the results of a new paper which investigates the relationship between higher temperatures in recent decades and methane release from the Arctic seabed off the Siberian coast. As you can probably tell from the headline, the research team, led by Igor Dmitrenko, did not find that global warming, current and future, was going to have much of a dramatic impact on the release of methane from the Arctic seas. This is a fairly significant finding because methane—which has about 20 times the impact on the greenhouse effect that carbon dioxide does on a molecule by molecule basis—has the potential to act as a large amplifier (positive feedback) to a warming climate. Consequently the specter of a large Arctic methane release plays a prominent role in many of the more alarming future climate change storylines.


December 14, 2011

Big Picture Items

Oftentimes, World Climate Report focuses on how elevated atmospheric levels of CO2 benefits various organisms or how observed changes in elements of climate in specific regions are not consistent with expectations from numerical climate model experiments. We could almost feature an article on climate change and hurricanes every week—these kinds of articles are found throughout the peer-reviewed scientific journals. But we don’t want to lose sight of the big picture—the term “global warming” implies that the world is indeed warming, humans are somehow responsible, and we better change our evil ways or we could inadvertently destroy of climate system. So here, we’ll review a couple of “Big Picture” articles from the recent scientific literature to see if things really are as cut and dry as they are implied.


December 5, 2011

Huh? A Reply to Nathan Urban

Filed under: Climate Forcings

A few weeks ago, we ran a story about a paper which was (then) soon to be published in Science magazine which generally concluded that the earth’s climate sensitivity (how much the earth’s average temperature will rise from a doubling of the atmospheric carbon dioxide concentration) was likely lower than the IPCC’s best guess (which is 3°C) and known with far less uncertainty—especially at the high end. While the IPCC’s vision of the uncertainty as to the true value of the climate sensitivity included a “fat tail” at the high end (that is, a non-negligible possibility that the true climate sensitivity was greater than 6°C), the new Science paper put the kibosh on that notion, concluding “In summary, using a spatially extensive network of paleoclimate observations in combination with a climate model we find that climate sensitivities larger than 6 K are implausible.” And adding “Assuming paleoclimatic constraints apply to the future as predicted by our model, these results imply lower probability of imminent extreme climatic change than previously thought.”

A pretty provocative finding to say the least!


Powered by WordPress