More ‘adjustments’: US Cold Winters Mysteriously Disappear

By: - Climate DepotJanuary 16, 2018 3:08 PM

US Cold Winters Mysteriously Disappear!

By Paul Homewood Bob Ward has taken exception with Booker’s column last week on the severe cold weather this month in the US, with this letter in today’s Telegraph: SIR – Christopher Booker, discussing climate change, is wrong to claim that this year “is the latest in a succession of recent record cold winters” in North America. According to the United States National Oceanic and Atmospheric Administration, the coldest winter on record for the contiguous United States was in 1978-79, followed by 1935-36, 1898-99, 1909-10 and 1904-5. Seven of the 10 past winters have been warmer than average, including the warmest winter on record in 2015-16. The winters of 2007-08 and 2013-14, which Mr Booker highlights as particularly cold, were respectively only the 68th and 33rd coldest since records began in 1901. The mean temperature for the US in December 2017 was above average. Bob Ward Policy and Communications Director Grantham Research Institute on Climate Change and the Environment London School of Economics As I pointed out a couple of weeks ago, NOAA’s official record, which Ward quotes from shows no sign of any unusually cold winter weather in recent years, even in the Northeast. What Ward omits to tell you though is that this NOAA record has been heavily adjusted, to cool the past. Furthermore the record seems to bear little resemblance to what scientists have been saying about how severe several recent winters have been in the US. For instance, in 2014 we had that notorious video from John Holdren, during which he clearly stated: But a growing body of evidence suggests that the kind of extreme cold being experienced by much of the United States as we speak is a pattern that we can expect to see with increasing frequency as global warming continues. In the same month, New Scientist reported: DON’T blame the polar vortex. The real reason for the cold snap that paralysed North America this week was a slow jet stream. The cold was extreme, and deadly. In Minnesota, the wind chill was down to -51 °C. Weather channels warned that frostbite could set in after just 5 minutes of exposure, planes were grounded after fuel froze, schools closed and Indianapolis banned driving. Key crops like wheat were also at risk. It is 20 years since the entire mainland US was affected like this, says forecaster Brian Korty of the NOAA Weather Prediction Center in College Park, Maryland. As temperatures fell, some blamed a mysterious polar vortex, but this is a system of winds in the stratosphere that spins around the Arctic and Antarctic during their respective winters, many kilometres above the weather. There was nothing unusual about the polar vortex, according to the UK Met Office. Instead, cold Arctic air reached North America thanks to a weakened jet stream. Dr Jennifer Francis has frequently claimed that extreme cold weather is being caused by Arctic sea ice reduction. For instance, at a conference in September 2014, she stated: The rapid retreat of Arctic sea ice caused by climate change may be to blame for more frequent prolonged spells of extreme weather in Europe, Asia and North America, such as heat waves, freezing temperatures or storms. These are relatively short-term periods of bizarre weather, like the cold snap that paralysed North America earlier this year, rather than longer-term rises in temperature. Also in 2014, a paper by Kim et al found: Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea-ice, the mechanism that links sea-ice loss to cold winters remains a subject of debate. Over the past two decades, the Arctic Ocean has warmed significantly in conjunction with conspicuous increase in global surface air temperature (SAT) and rapid decline of Arctic sea-ice1,2. A growing number of studies have found pronounced changes in atmospheric circulation due to Arctic sea-ice loss, including changes in the tropospheric jet stream that may lead to cold extremes over Eurasia and North America Jennifer Francis was in the news again last year: Residents of Anchorage, Alaska, found themselves enjoying a stretch of relatively balmy weather this past December, with temperatures at times climbing above freezing. More southerly cities near the Canada-U.S. border, meanwhile, sat in the grip of a deep freeze, with some double-digit temperature drops triggering extreme cold weather alerts. You can blame the dreaded “polar vortex,” a term popularized in early 2014, when record low temperatures descended across Canada and the United States. What’s less clear is whether the polar vortex is changing because of a warming Arctic – and whether North Americans are going to have to get used to those frigid winter temperatures. “There’s a lot of things we’re realizing now have never happened before,” said Jennifer Francis, a research professor in the Department of Marine and Coastal Sciences at Rutgers University. And just this month, we have another scientist, Marlene Kretschmer, saying that winters in North America have been trending cooler over the last quarter century, again with a warmer Arctic the supposed culprit: Much of the Northern Hemisphere is cold this time of year (it’s winter, after all). Cold snaps have occurred throughout history — certainly long before industrialization resulted in large emissions of greenhouse gases. 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. “We’re trying to understand these dynamic processes that lead to cold winters,” Ms. Kretschmer said. And Kretschmer’s paper specifically confirms that recent winters in the US Northeast have been “anomalously cold”: Yet none of these extreme cold events or cooling trends appear in the NOAA record. So, who is right? Is it all these scientists who have spent years researching ways to blame cold weather on melting Arctic ice? Or is it NOAA’s temperature record? Perhaps Bob Ward might like to tell us!

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