By Paul Homewood
Yet more junk science from the Guardian!
Summer weather patterns are increasingly likely to stall in Europe, North America and parts of Asia, according to a new climate study that explains why Arctic warming is making heatwaves elsewhere more persistent and dangerous.
Rising temperatures in the Arctic have slowed the circulation of the jet stream and other giant planetary winds, says the paper, which means high and low pressure fronts are getting stuck and weather is less able to moderate itself.
The authors of the research, published in Nature Communications on Monday, warn this could lead to “very extreme extremes”, which occur when abnormally high temperatures linger for an unusually prolonged period, turning sunny days into heat waves, tinder-dry conditions into wildfires, and rains into floods.
“This summer was where we saw a very strong intensity of heatwaves. It’ll continue and that’s very worrying, especially in the mid-latitudes: the EU, US, Russia and China,” said one of the coauthors, Dim Coumou from the Potsdam Institute for Climate Impact Research. “Short-term heatwaves are quite pleasant, but longer term they will have an impact on society. It’ll have an affect on agricultural production. Harvests are already down this year for many products. Heatwaves can also have a devastating impact on human health.”
It only takes a few minutes to completely disprove this latest theory.
First, let’s look at summer trends in the UK, courtesy of the Met Office. In particular, average daily maximum temperatures, rainfall and sunshine hours:
Extremes in any of these categories would be a strong sign of weather blocking. Yet, prior to this summer (obviously not shown) there is little evidence of blocking in recent years. You have to go back to the wet summer of 2012 for any sign of this.
In contrast, earlier years are littered with extremes, both wet and dry, hot and cold, and sunny or cloudy. Arguably recent summers have been notable for the lack of extremes.
We can do a similar check with the US, and again we find no evidence of extremes increasing.
The US is a big place, and sometimes the west coast can counteract the east. So let’s also look at the Northeast region:
Again, we find that variability from year to year has actually been decreasing lately.
Weather blocking, of course, is nothing new. But according to HH Lamb, it was actually much worse in the 1960s and 70s. He blamed it on Arctic cooling:
These variations, perhaps more than any underlying trend to a warmer or colder climate, create difficulties for the planning age in which we live. They may be associated with the increased meridionality of the general wind circulation, the greater frequency of blocking, of stationary high and low pressure systems, giving prolonged northerly winds in one longitude and southerly winds in another longitude sector in middle latitudes.
Over both hemispheres there has been more blocking in these years… The most remarkable feature seems to be the an intensification of the cyclonic activity in high latitudes near 70-90N, all around the northern polar region. And this presumably has to do with the almost equally remarkable cooling of the Arctic since the 1950’s, which has meant an increase in the thermal gradient between high and middle latitudes.
Climate, History and the Modern World – pp267-269
And it was not only Lamb. CC Wallen, Head of the Special Environmental Applications Division of the World Meteorological Organization, had this to say about the consequences of the cooling trend since 1940:
The principal weather change likely to accompany the cooling trend is increased variability-alternating extremes of temperature and precipitation in any given area-which would almost certainly lower average crop yields.
During cooler climatic periods the high-altitude winds are broken up into irregular cells by weaker and more plentiful pressure centers, causing formation of a “meridional circulation” pattern. These small, weak cells may stagnate over vast areas for many months, bringing unseasonably cold weather on one side and unseasonably warm weather on the other. Droughts and floods become more frequent and may alternate season to season, as they did last year in India. Thus, while the hemisphere as a whole is cooler, individual areas may alternately break temperature and precipitation records at both extremes.
And he even gave us these diagrams.
But as far as the current crop of junk scientists is concerned, it is much easier to pretend one summer makes a trend and blame it on “melting Arctic ice”. After all, it will probably guarantee them another nice chunk of grant money!
The Heatwave Of Autumn 1939
If you want a feel for how much hotter and longer summers used to be in the Midwest, read my latest blog post. The US used to be much hotter than it is now.
Global warming is the biggest science scam in history.https://t.co/8BT7pbWBOP pic.twitter.com/1my2Xaqls7
— Steve Goddard (@SteveSGoddard) August 22, 2018