Venue: AGU Fall Meeting 2012
Judah L. Cohen; Jason C. Furtado; Mathew A. Barlow; Jessica E. Cherry; Vladimir A. Alexeev (2012) Has Anthropogenic Global Warming in the Arctic Contributed to Colder Winter Weather in the Northern Hemisphere Mid-latitudes?. AGU Fall Meeting, San Francisco, CA. (Invited)
The global climate models predict that temperatures will warm the greatest in winter due to a positive feedback of increased greenhouse gases and a diminished and darker cryosphere. Furthermore, current consensus on global climate change predicts warming trends over the NH continents during boreal winter. However, recent trends in Northern Hemisphere (NH) seasonal surface temperatures diverge from these projections. For the last two decades or so, NH landmasses have experienced significant warming trends for all seasons except winter, when large-scale cooling trends exist instead. We propose a mechanism linking Arctic warming and winter continental cooling. Evidence suggests that summer and autumn Arctic warming trends are concurrent with increases in high-latitude moisture and an increase in autumnal Eurasian snow cover, which dynamically induces large-scale wintertime cooling. Understanding this counterintuitive response to radiative warming of the climate system has the potential to improve climate predictions at seasonal and longer timescales.