How to explain the anomalous heat — climate change or the weather?

Warm and cold temperature extremes.

July 2, 2013. Southwest United States swept the record heat. June 30 at Death Valley was recorded temperature 53 ° C — A little more, and will be broken record (57 ° C!), Established July 10, 1913. On the same day due to forest fire in Arizona killed 19 firefighters — The biggest tragedy since 1933.

What is behind this heat? What is the role played by global warming? As recent events relate to others? Responsible climatologist Martin Tingley of Harvard University, who along with Peter Hyuybersom showed recently that 2005, 2007, 2010 and 2011. were the warmest in the last 600 years.

According to the meteorological data, the responsibility for the heat can be blamed on the phenomenon of blocking in the atmosphere when a particular configuration of the jet stream (high-speed flow of air wrapped around the Northern Hemisphere from the east to the west, like a giant conveyor belt) remains an unusually long time. On the west coast of the United States established a high pressure area, and on the east — low. Therefore, in the state of Massachusetts is raining all the time, and on the shores of the Pacific Ocean is very hot.

Babbitt thinks very simple categories: if suddenly become cold, he laughs at the talk about global warming, but if the opposite — begins to panic and piously believe in climate change. Of course, he was twice mistaken. Even now, scientists are afraid to say that 2013 will be a record warmest year on record, as we must wait for the end of it and analyze data from all over the world.

Working with paleoclimatic data (tree rings or ice cores), the researchers could not determine that such a place for such a week of summer so and so was the weather. Tingley and Hyuybers just comparing hot (on average) with a cool summer and found out that the recent warm extremes average summer temperatures in the high northern latitudes have no analogues in the last 600 years.

Simple and inaccurate analogy: if your height is 190 cm, there is a high chance that you will accidentally taken before any person from the crowd, because this is the distribution of body height in humans. But if you take a sample of the thousands of people, then your chances of getting the highest fall sharply, and the statistics on you do not deliver.

On the same grounds say, statistically the probability is high that 2011 was the hottest since 1400. Was it really any warmer accidentally given year and whether it was really the hottest for 600 years — is another matter.

Of course, to draw conclusions based on only one sample is risky, so scientists have made a statistical model, in which they estimated four thousand equally possible options climate, based on paleoclimate data. After that, you can ask which of these alternative histories of the planet in 2011 was the warmest.

Climatologists like to compare the effects of global warming with loaded dice: not everyone will throw six points, but a dishonest player will throw six points more honest. Therefore, for each particular hot weather can be attributed to human influence on climate is very conditional. Correct to say only that there is a trend toward more frequent temperature peaks and reduce the number of cold lows. This pattern — the predicted result of human activity.

At the same time, the question remains, how to change the frequency and strength of heat and other extreme weather events in the future. How, for example, react weather, if the average temperature will rise by half a degree? …

Based on: National Geographic
Source: Kompyulenta

 

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