Thursday 26 July 2018

Heatwave Europe: The New Normal?
















They say that a picture is worth a thousand words, and this picture sums up the difference between 1976 and 2018.

As Meteorologist Simon Lee tweeted:

The big difference between the heatwaves of 1976 and 2018.

June 1976: the UK was one of the warmest places relative to normal across the globe, with most areas cooler than average.

June 2018: the UK was just another warm blob in a mostly warmer than normal world.


And you can see that in the picture. On the right is a red blob, mostly over the UK, while on the left, the heat suffuses all across Europe and North America.

As Adam Vaughan,  reported:

"A stationary high-pressure weather system has left the UK and much of continental Europe sweltering. Iceland, by contrast, has been hit with clouds and storms that would normally come further south."

Jennifer Francis of Rutgers University suggested that the jet stream, which is driven by collisions between cold air coming south and warm air moving north, was regularly stalling as a result of accelerated warming in the Arctic.

Back in March and April, this had the opposite effect, keeping cold air, snow and freezing conditions persisting over the Northern hemisphere

It seems that the result of blocking patterns is long term extreme weather events, such as prolonged periods of cold or heat. A major block can produce long stretches of blazing heat in the summer or bitter cold in the winter.

A recent peer-reviewed paper on "Warm Arctic episodes linked with increased frequency of extreme winter weather in the United States" states that:

"Anthropogenic global warming is widely expected to increase certain types of weather extremes, including more intense and frequent heat waves and droughts as well as heavy precipitation events. ...Over the past two to three decades, the increase in extreme weather has included more (not fewer) severe cold-air outbreaks and heavy snowfalls observed both in North America and Eurasia."

And the Independent warns: "Amid the chaos, a stark message is emerging, that this is the “new normal” and from this point on we can only expect heatwaves to get worse."

Previously climate change only focused on an average trend in increasing global temperatures, but the recent extreme weather events this year and last have shown that the average is in fact a very poor indicator, as it smooths out the extremes. The world has on average warmed by around 1C since the 19th century, but the intensity of extreme weather events suggests that figure tells only a small part of the story.

Just as the increase in severe gales means greater propensity for flooding - as more are likely to coincide with high tidal conditions, so the increase in severe weather events such as the current heatwave means that our lives will be considerably more stressed by the effort of coping in an increasingly hostile environment.

As Matthew Huber, professor of earth and atmospheric science at Purdue University comments:

“Whole countries would intermittently be subject to severe heat stress requiring large-scale adaptation efforts. One can imagine that such efforts, for example the wider adoption of air conditioning, would cause the power requirements to soar, and the affordability of such approaches is in question for much of the Third World that would bear the brunt of these impacts. In addition, the livestock on which we rely would still be exposed, and it would make any form of outside work hazardous.”

We have cause to be alarmed.

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