I don’t put much merit in this study especially when we see statements like “statistically significant, though minor, increase in extreme Arctic cyclone frequency” because we really haven’t had good observational capability until the satellite era to check their model output against back to 1850. Recent improved observation would have more effect than anything, but that isn’t even a factor in this case, it’s a model simulation. I wonder if they factored in this paper, which said that Arctic Cyclones are more common than previously thought, even in the satellite era? I reckon if we don’t even have a good handle on Arctic Cyclones in our current satellite observations, what possible hope could anyone have of determining an accurate historical trend back to 1850? Guesswork GIGO IMHO.

Increase in Arctic Cyclones is Linked to Climate Change, New Study Shows

Winter in the Arctic is not only cold and dark, it is also storm season when hurricane-like cyclones traverse the northern waters from Iceland to Alaska. These cyclones are characterized by strong localized drops in sea level pressure, and as Arctic-wide decreases in sea level pressure are one of the expected results of climate change, this could increase extreme Arctic cyclone activity, including powerful storms in the spring and fall.

A new study in Geophysical Research Letters uses historical climate model simulations to demonstrate that there has been an Arctic-wide decrease in sea level pressure since the 1800’s.

“This research shows that the Arctic appears to be expressing symptoms expected from ongoing climate change,” said Dr. Stephen Vavrus from the University of Wisconsin-Madison. “The long-term decline in atmospheric pressure over most of the Arctic is consistent with the response typically simulated by climate models to greenhouse warming, and this study finds a general corresponding increase in the frequency of extreme Arctic cyclones since the middle 19th century.”

Tracking changes in Arctic cyclone activity through time, Vavrus calculated a statistically significant, though minor, increase in extreme Arctic cyclone frequency over the study period, with increases strongest near the Aleutian Islands and Iceland. Dr. Vavrus suggests that, as of yet, the effect of climate change on Arctic cyclone activity has been minimal, but that future changes in polar climate will drive stronger shifts.

“One societally relevant implication is that more storminess probably means more erosion of Arctic coastlines, especially in tandem with declines in buffering sea ice cover and increases in thawing coastal permafrost,” concluded Dr. Varnus. “Erosion of Arctic coastlines has already been growing more severe during recent decades, and this study points to a contributing factor that will likely become an even more recognizable culprit in the future.”

Source: GRL press release

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Extreme Arctic cyclones in CMIP5 historical simulations

Abstract [1] Increasing attention is being paid to extreme weather, including recent high-profile events involving very destructive cyclones. In summer 2012, a historically powerful cyclone traversed the Arctic, a region experiencing rapid warming and dramatic loss of ice and snow cover. This study addresses whether such powerful storms are an emerging expression of anthropogenic climate change by investigating simulated extreme Arctic cyclones during the historical period (1850–2005) among global climate models in the Coupled Model Intercomparison Project 5 (CMIP5) archive. These general circulation models are able to simulate extreme pressures associated with strong polar storms without a significant dependence on model resolution. The models display realism by generating extreme Arctic storms primarily around subpolar cyclone regions (Aleutian and Icelandic) and preferentially during winter. Simulated secular trends in Arctic mean sea level pressure and extreme cyclones are equivocal; both indicate increasing storminess in some regions, but the magnitude of changes to date are modest compared with future projections. http://onlinelibrary.wiley.com/doi/10.1002/2013GL058161/abstract

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