New study traces historic changes in North American weather patterns
By Bob Berwyn
FRISCO — A new University of Utah-led study suggests that this past winter’s persistent weather pattern across North America is linked with changes in the jet stream that may become even more pronounced as the Earth’s climate warms.
Changes in the Arctic likely to have widespread hemispheric impacts
By Summit Voice
FRISCO — A new climate study by scientists at the University of Exeter (UK) adds to the growing body of research looking at the hemispheric impacts of dwinding Arctic sea ice.
The findings suggest that that the loss of ice shifts the jet stream farther south, bringing increased summer rainfall to northwestern Europe, but drier conditions to the Mediterranean region. The study could offer an explanation for the extraordinary run of wet summers experienced by Britain and northwest Europe between 2007 and 2012.
After reciting a list of temperature statistics, downplaying wildfires and making critiques of other blog posts, the author ends with this assertion: “Moderation, it would seem, is the key to accurately representing data and making an informed decision on climate change.”
It’s not even remotely clear what is meant by moderation, but the reference to data is even more puzzling, considering that every credible temperature record from the past 50 years shows an inexorable rise in global temperatures — that’s why it’s called GLOBAL warming, regardless of what year-to-year, or decade-to-decade cycles may have been observed in Alaska. Continue reading “Op-ed: Did global warming cause Alaska heat wave?”→
German researchers cite ‘frozen’ jet stream waves as possible sign of climate change
By Summit Voice
FRISCO — Ten days of weather that included the largest tornado ever measured and some of the worst flooding Europe has ever seen are sure to rekindle the heated debate about possible links between global warming and extreme weather.
And despite the countless statistical arguments suggesting there has been no overall increase in extreme weather events, some scientists are becoming more willing to make the link, including researchers with the Potsdam Institute for Climate Impact Research.
In one recent study, scientists with the Cooperative Institute for Research in Environmental Science found that as sea ice disappeared, the areas of relatively warm open water began to strongly influence the atmosphere, increasing surface temperatures in the region, and shifting low- and high-pressure zones around most markedly in the fall and winter.
FRISCO — Increasing global temperatures are “freezing” atmospheric waves, resulting in more frequent weather extremes, including the 2011 U.S. heat wave and a 2010 heat wave in Russia that coincided with unprecedented flooding in Pakistan.
Scientists have surprised by how far outside past experience some of the recent extremes have been. The new data show that the emergence of extraordinary weather is not just a linear response to the mean warming trend.
“What we found is that during several recent extreme weather events these planetary waves almost freeze in their tracks for weeks,” said Vladimir Petoukhov, lead author of a study to be published this week in the US Proceedings of the National Academy of Sciences. “So instead of bringing in cool air after having brought warm air in before, the heat just stays. In fact, we observe a strong amplification of the usually weak, slowly moving component of these waves,” Petoukhov said. Continue reading “Are ‘frozen’ atmospheric waves causing extreme weather?”→
SUMMIT COUNTY — If it feels like the weather has been stuck in a rut, that may not be too far from the truth. The jet stream is slowing down and meandering farther north and south, with more blocking patterns setting up across the northern hemisphere.
Francis has been studying the connection between vanishing Arctic sea ice and weather in the mid-latitudes of the northern hemisphere, and evidence is piling up that the intense warming at high latitudes has serious implications for North America, Europe and Asia. Continue reading “Climate: The jet stream blues”→