2018-01-03. Why So Cold? Climate Change May Be Part of the Answer.

posted Jan 9, 2018, 9:13 AM by Alan Gould   [ updated Jan 16, 2018, 1:51 PM ]
By Henry Fountain, The New York Times. For GSS Climate Change chapter 8. Excerpt: As bitter cold continues to grip much of North America and helps spawn the fierce storm along the East Coast, the question arises: What’s the influence of climate change? Some scientists studying the connection between climate change and cold spells, which occur when cold Arctic air dips south, say that they may be related. But the importance of the relationship is not fully clear yet. The Arctic is not as cold as it used to be — the region is warming faster than any other — and studies suggest that this warming is weakening the jet stream, which ordinarily acts like a giant lasso, corralling cold air around the pole. ...And as with any single weather event, it’s difficult to directly attribute the influence of climate change to a particular cold spell. But scientists have been puzzled by data that at first seems counterintuitive: Despite an undeniable overall year-round warming trend, winters in North America and Europe have trended cooler over the past quarter-century. ...the jet stream — usually referred to as the polar vortex this time of year — is weakening more frequently and staying weaker for longer periods of time. That allows cold air to escape the Arctic and move to lower latitudes. ...the study focused on Europe and Russia.... https://www.nytimes.com/2018/01/03/climate/cold-climate-change.html