Sunday, December 31, 2017

Climate scientist calls Trump's global warming tweet an "often debunked assertion"




Dec. 29, 2017

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"The tweet seemed to imply that the cold weather in the Eastern United States somehow contradicts the notion that the climate is warming -- or warming due to human influence -- which of course is not true. This is a very tired and often debunked assertion," Sobel said.

Sobel explained that winter will not cease to exist and that cold weather can still happen despite global warming.

"If you look at the temperature map for the climate as a whole right now, the entire rest of the planet is warmer than the historical average with the exception of the Eastern United States and Canada, and the last three years -- 2014, 2015 and 2016 -- have been consecutively the warmest years on record," Sobel said.

He added, "So the notion that 'there's cold weather happening somewhere so global warming is not happening' is well understood by people who take the issue seriously to be false."

Sobel said the most important thing people can do to combat climate change is to vote.

"I think that's the number one most important thing, because we can all take individual actions to reduce our carbon footprint, and we all should, but the problem is too big for individual action," he said.

"It's going to be solved by collective action at the government, national and international, level. The United States has the capacity to lead this issue; we were for a little while. Now this administration has made the problem worse rather than helping."

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https://www.forbes.com/sites/marshallshepherd/2017/12/28/a-response-for-people-using-record-cold-u-s-weather-to-refute-climate-change/#2bef53ee5680


A Response For People Using Record Cold U.S. Weather To Refute Climate Change

Marshall Shepherd
Dec. 28, 2017

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The key thing to convey to that skeptical uncle or vociferous social media friend is that "weather is mood, climate is personality." My University of Georgia colleague Dr. John Knox mentioned this a few years ago, and it has been one of my favorite techniques to use while dealing with this pesky climate communication challenge for the public. Weekly or daily weather patterns tell you nothing about longer-term climate change (and that goes for the warm days too). Climate is defined as the statistical properties of the atmosphere: averages, extremes, frequency of occurrence, deviations from normal, and so forth. The clothes that you have on today do not describe what you have in your closet but rather how you dressed for today's weather. In reality, your closest is likely packed with coats, swimsuits, t-shirts, rain boots, and gloves. In other words, what's in your closet is a representation of "climate."

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What we are seeing right now in the United States is just,.........well......wait for it......"winter".....Even as climate warms, we will always have winter (cold weather, snowstorms, blizzards). Winter is related to how the Earth is tilted on its axis as it moves around the Sun. In a previous Forbes piece, I described how the axial tilt of our planet determines our seasons.

Now having said that, our weather is governed by a series of undulations or wave patterns. The "valleys" (troughs) in those waves allow cold, dense air to ooze into the U.S. The "hills" (ridges) in the waves are typically associated with warm conditions. If you search Arctic Amplification on the Internet, there is some evidence that climate change is causing more wavy, high amplitude "valleys" and "hills" in the jet stream pattern. This could be associated with more extreme cold events and more extreme heat/drought events. The science is still emerging on this process, but it should be monitored and not dismissed.

The other thing to point out is that because one part of the world is cold (in that valley), there is likely another part of the world experiencing abnormally warm conditions (in the hill part of the wave pattern). In the temperature map tweeted by long-time weather observer Joe Stepansky, it is clear that on December 28th the United States and parts of Canada are experiencing the anomalously cold weather. If you need a visual of how our three-dimensional atmospheric wave patterns work, consider what happens when you press down on a water bed mattress (for us older folks) or an inflatable bouncy house. One part goes down, another part goes up.

•••••

What we are seeing right now in the United States is just,.........well......wait for it......"winter".....Even as climate warms, we will always have winter (cold weather, snowstorms, blizzards). Winter is related to how the Earth is tilted on its axis as it moves around the Sun. In a previous Forbes piece, I described how the axial tilt of our planet determines our seasons.

Now having said that, our weather is governed by a series of undulations or wave patterns. The "valleys" (troughs) in those waves allow cold, dense air to ooze into the U.S. The "hills" (ridges) in the waves are typically associated with warm conditions. If you search Arctic Amplification on the Internet, there is some evidence that climate change is causing more wavy, high amplitude "valleys" and "hills" in the jet stream pattern. This could be associated with more extreme cold events and more extreme heat/drought events. The science is still emerging on this process, but it should be monitored and not dismissed.

The other thing to point out is that because one part of the world is cold (in that valley), there is likely another part of the world experiencing abnormally warm conditions (in the hill part of the wave pattern). In the temperature map tweeted by long-time weather observer Joe Stepansky, it is clear that on December 28th the United States and parts of Canada are experiencing the anomalously cold weather. If you need a visual of how our three-dimensional atmospheric wave patterns work, consider what happens when you press down on a water bed mattress (for us older folks) or an inflatable bouncy house. One part goes down, another part goes up.

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Oh, and to throw a another counterintuitive thing out there, there are some studies that suggest that a warming climate (because more water vapor is available to a warmer atmosphere) may fuel bigger blizzards or snowstorms. That science is also emerging.
It is a fact that global warming has caused an increase in water vapor in the atmosphere. It would be surprising if if did not lead to heavier rain and snow falls.

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