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Stories · 9
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Extreme Winter Weather In the US Linked To a Warming Arctic (theverge.com)
A new study shows how global climate change can have ripple effects at the local level. According to the research, extreme winter weather is two to four times more likely in the eastern U.S. when the Arctic is unusually warm. The Verge reports: Researchers analyzed a variety of atmospheric data in the Arctic, as well as how severe winter weather was in 12 cities across the U.S. from 1950 to 2016. Since 1990, as the Arctic has been warming up and losing ice, extreme cold snaps and heavy snow in the winter have been two to four times more frequent in the eastern U.S. and the Midwest, while in the western U.S., their frequency has decreased, according to a study published today in Nature Communications. The study, however, only shows there might be a correlation -- not a direct causal link -- between the warming Arctic and severe winters in the U.S. And it doesn't show how exactly the two are connected, so it doesn't really add much to what scientists already knew, according to several experts.
Today's study focuses on the Arctic as the main culprit for the extreme winter weather. Previous research has suggested that the warming Arctic may disrupt the polar vortex, a ring of swirling cold air circling the North Pole. Think of the polar vortex as a river, says study co-author Judah Cohen, a climatologist and director of seasonal forecasting at Atmospheric and Environmental Research. The fast flow of this river locks up the cold air over the Arctic. But as the Arctic warms -- especially in some areas like the Barents-Kara seas north of Europe and Russia -- a boulder springs up in this river, disrupting the polar vortex and allowing the freezing Arctic air to flow south, Cohen says. -
Extreme Winter Weather In the US Linked To a Warming Arctic (theverge.com)
A new study shows how global climate change can have ripple effects at the local level. According to the research, extreme winter weather is two to four times more likely in the eastern U.S. when the Arctic is unusually warm. The Verge reports: Researchers analyzed a variety of atmospheric data in the Arctic, as well as how severe winter weather was in 12 cities across the U.S. from 1950 to 2016. Since 1990, as the Arctic has been warming up and losing ice, extreme cold snaps and heavy snow in the winter have been two to four times more frequent in the eastern U.S. and the Midwest, while in the western U.S., their frequency has decreased, according to a study published today in Nature Communications. The study, however, only shows there might be a correlation -- not a direct causal link -- between the warming Arctic and severe winters in the U.S. And it doesn't show how exactly the two are connected, so it doesn't really add much to what scientists already knew, according to several experts.
Today's study focuses on the Arctic as the main culprit for the extreme winter weather. Previous research has suggested that the warming Arctic may disrupt the polar vortex, a ring of swirling cold air circling the North Pole. Think of the polar vortex as a river, says study co-author Judah Cohen, a climatologist and director of seasonal forecasting at Atmospheric and Environmental Research. The fast flow of this river locks up the cold air over the Arctic. But as the Arctic warms -- especially in some areas like the Barents-Kara seas north of Europe and Russia -- a boulder springs up in this river, disrupting the polar vortex and allowing the freezing Arctic air to flow south, Cohen says. -
How Two Scientists Accurately Predicted Global Warming in 1967 (medium.com)
Slashdot reader Layzej shares an article from this spring marking the 50th anniversary of the first accurate climate model: Astrophysicist Ethan Siegel looks at a climate model (MW67) published in 1967 and finds "50 years after their groundbreaking 1967 paper, the science can be robustly evaluated, and they got almost everything exactly right."
An analysis on the "Climate Graphs" blog shows exactly how close the prediction has proven to be: "The slope of the CO2-vs-temperature regression line in the 50 years of actual observations is 2.57, only slightly higher than MW67's prediction of 2.36" They also note that "This is even more impressive when one considers that at the time MW67 was published, there had been no detectable warming in over two decades. Their predicted warming appeared to mark a radical change with the recent past:" -
2014 Was Earth's Warmest Year On Record
An anonymous reader writes: A lengthy report compiled by the U.S. National Oceanic and Atmospheric Administration using work from hundreds of scientists across 58 countries has found that 2014 was the hottest year on record. "The warmth was widespread across land areas. Europe experienced its warmest year on record, with more than 20 countries exceeding their previous records. Africa had above-average temperatures across most of the continent throughout 2014, Australia saw its third warmest year on record, Mexico had its warmest year on record, and Argentina and Uruguay each had their second warmest year on record. Eastern North America was the only major region to experience below-average annual temperatures." They've also published a page showing highlights of the major findings. Greenhouse gas concentrations continue to rise, the global sea level reached a record high, and average sea surface temperatures reached a record high. -
There's No Wind Chill On Mars
sciencehabit writes: Even though daytime temperatures in the tropics of Mars can be about –20C, a summer afternoon there might feel about the same as an average winter day in southern England or Minneapolis. That's because there's virtually no wind chill on the Red Planet, according to a new study — the first to give an accurate sense of what it might feel like to spend a day walking about on our celestial neighbor. "I hadn't really thought about this before, but I'm not surprised," says Maurice Bluestein, a biomedical engineer and wind chill expert recently retired from Indiana University–Purdue University Indianapolis. The new findings, he says, "will be useful, as people planning to colonize Mars need to know what they're getting themselves into." -
Stronger Winds Explain Puzzling Growth of Sea Ice In Antarctica
vinces99 writes "As NOAA announces a new record for the extent of sea ice in Antarctica, a new modeling study to be published in the Journal of Climate shows that stronger polar winds lead to an increase in Antarctic sea ice, even when Earth's overall climate is getting warmer. The study (abstract) by Jinlun Zhang, a University of Washington oceanographer, shows that stronger westerly winds swirling around the South Pole can explain 80 percent of the increase in Antarctic sea ice volume during the past three decades. The polar vortex that swirls around the South Pole is not just stronger than it was when satellite records began in the 1970s, it also shoves the sea ice together to cause ridging. Stronger winds also drive ice faster, which leads to still more deformation and ridging. This creates thicker, longer-lasting ice, while exposing surrounding water and thin ice to the blistering cold winds that cause more ice growth. A computer simulation that includes detailed interactions between wind and sea shows that thick ice — more than 6 feet deep — increased by about 1 percent per year from 1979 to 2010, while the amount of thin ice stayed fairly constant. The end result is a thicker, slightly larger ice pack that lasts longer into the summer." -
'Half' of 2012's Extreme Weather Impacted By Climate Change
sciencehabit writes "2012 was a year of extreme weather: Superstorm Sandy, drought and heat waves in the United States; record rainfall in the United Kingdom; unusually heavy rains in Kenya, Somalia, Japan, and Australia; drought in Spain; floods in China. One of the first questions asked in the wake of such extreme weather is: 'Could this due to climate change?' In a report (huge PDF) published online today, NOAA scientists tackled this question head-on. The overall message of the report: It varies. 'About half of the events reveal compelling evidence that human-caused change was a [contributing] factor,' said NOAA National Climatic Data Center Director Thomas Karl. In addition, climate scientist Peter Stott of the U.K. Met Office noted that these studies show that in many cases, human influence on climate has increased the risks associated with extreme events." -
Same Programs + Different Computers = Different Weather Forecasts
knorthern knight writes "Most major weather services (US NWS, Britain's Met Office, etc) have their own supercomputers, and their own weather models. But there are some models which are used globally. A new paper has been published, comparing outputs from one such program on different machines around the world. Apparently, the same code, running on different machines, can produce different outputs due to accumulation of differing round-off errors. The handling of floating-point numbers in computing is a field in its own right. The paper apparently deals with 10-day weather forecasts. Weather forecasts are generally done in steps of 1 hour. I.e. the output from hour 1 is used as the starting condition for the hour 2 forecast. The output from hour 2 is used as the starting condition for hour 3, etc. The paper is paywalled, but the abstract says: 'The global model program (GMP) of the Global/Regional Integrated Model system (GRIMs) is tested on 10 different computer systems having different central processing unit (CPU) architectures or compilers. There exist differences in the results for different compilers, parallel libraries, and optimization levels, primarily due to the treatment of rounding errors by the different software systems. The system dependency, which is the standard deviation of the 500-hPa geopotential height averaged over the globe, increases with time. However, its fractional tendency, which is the change of the standard deviation relative to the value itself, remains nearly zero with time. In a seasonal prediction framework, the ensemble spread due to the differences in software system is comparable to the ensemble spread due to the differences in initial conditions that is used for the traditional ensemble forecasting.'" -
Political Ideology Shapes How People Perceive Temperature
benfrog writes "In what likely isn't that much of a surprise, a study has shown that political ideology shapes how we perceive temperature changes (but not drought/flooding conditions). (An abstract of the study is here. 8,000 individuals were asked about temperatures and drought/flood events in recent years, then their political leanings. Answers regarding drought/flood events tended to follow the actual changes in conditions, while answers regarding temperature tended to follow people's political beliefs."