Understanding the Warming Arctic

While the representation of physical processes in climate models has become more sophisticated over the last 30+ years, the vertical and seasonal fingerprints of Arctic greenhouse warming have not changed. Are the models right? Observations in recent decades show the same fingerprints: surface amplified warming especially in late fall and winter. Recent observations show no summer cloud response to Arctic sea ice loss, but increased cloud cover and a deepening atmospheric boundary layer in fall. Taken together, clouds appear to not affect the fingerprints of Arctic warming. The interconnected positive surface albedo feedback and positive lapse rate feedback rule. Can we check the models? Having observations alone does not enable robust model evaluation and model improvement. Comparing models and observations is hard enough but to improve models, one must make credible comparisons, understand why models and observations differ, and improve the physics. It’s all a tall order, but recent progress is summarized here.

Jen Kay is an Assistant Professor in the Department of Atmospheric and Oceanic Sciences and a Fellow of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado at Boulder (CU).

Originally presented May 13, 2019, at NASA's Jet Propulsion Laboratory, Pasadena, California as a JPL Center for Climate Sciences Distinguished Climate Lecture

[a.randomjack]

Thank you for all your hard work, and overtime ;-)
This has improved my understanding of what's happening in the Arctic quite a bit.
Say hi to a polar bear for me :)

[anglosaxonmike]

This winter is colder than last year and last year was colder
than the previous. It has snowed in Japan down to Athens. Even Corsica
where winter highs are typically in the mid-50s, lows around 40, saw
snow. We need to pay attention to Climate Change but stop blaming man.