From the “with models, we can make anything believable” department.
New paper argues for a stronger influence of Arctic sea-ice loss on recent Eurasian cooling, thus causing colder winters and more snow in Europe due to climate change.
A reconciled estimate of the influence of Arctic sea-ice loss on recent Eurasian cooling
https://www.nature.com/articles/s41558-018-0379-3 (paywalled)
Abstract
Northern midlatitudes, over central Eurasia in particular, have experienced frequent severe winters in recent decades1,2,3. A remote influence of Arctic sea-ice loss has been suggested4,5,6,7,8,9,10,11,12,13,14; however, the importance of this connection remains controversial because of discrepancies among modelling and between modelling and observational studies15,16,17.
Here, using a hybrid analysis of observations and multi-model large ensembles from seven atmospheric general circulation models, we examine the cause of these differences. While all models capture the observed structure of the forced surface temperature response to sea-ice loss in the Barents–Kara Seas—including Eurasian cooling—we show that its magnitude is systematically underestimated. Owing to the varying degrees of this underestimation of sea-ice-forced signal, the signal-to-noise ratio differs markedly.
Correcting this underestimation reconciles the discrepancy between models and observations, leading to the conclusion that ~44% of the central Eurasian cooling trend for 1995–2014 is attributable to sea-ice loss in the Barents–Kara Seas.
Our results strongly suggest that anthropogenic forcing has significantly amplified the probability of severe winter occurrence in central Eurasia via enhanced melting of the Barents–Kara sea ice. The difference in underestimation of signal-to-noise ratio between models therefore calls for careful experimental design and interpretation for regional climate change attribution.
Data availability
The monthly SST and SIC in HadISST33 are available from the Met Office website (www.metoffice.gov.uk/hadobs/hadisst/). The ERA-Interim reanalysis data sets44 are available from the ECMWF website (http://apps.ecmwf.int/datasets/). The six additional AGCM outputs analysed are freely available from the NOAA FACTS website (https://www.esrl.noaa.gov/psd/repository/alias/facts/). The MIROC4 AGCM output generated and analysed in this study is available from the corresponding author upon reasonable request.
Comments by climate scientist Reto Knutti on Twitter:
The tricky question is whether that is just due to a random series of unusual years or partly due to Arctic warming. In our simulations we found no link.https://t.co/2NXkdICrh6
The new paper argues the real link is stronger than in models.— Reto Knutti (@Knutti_ETH) January 15, 2019
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“In summary, we argue that recent anomalously cold winters may not be triggered by sea ice or SST anomalies alone”
Correct.
The proposed mechanism is more complicated than that …..
https://cyber.sci-hub.tw/MTAuMTAyOS8yMDExZ2wwNDk2MjY=/cohen2011.pdf
Essentially, a more open Arctic ocean in late Autumn and early winter, allows more sensible, latent heat and therefore WV to enter the atmosphere there. Resulting in more snowfall over Siberia at that time. There is seen to be a correlation between a fast expanding Eurasian snowfield during October and the intensity of the Siberian High in early winter …. this leading to a more significant later winter Arctic high. The mechanism here is heat flux into the stratosphere as air is drawn over the Himalayas and diverted over and above to cause a SSW (Sudden Stratospheric Warming event). One such is occurring now and the surface effects are lagged some weeks later, to often (but not always) give rise to v cold Eurasian air to advect east into western Europe. The same mechanism also causes a portion of the Arctic PV to sink into Canada and the eastern US. NWP forecasts bring v cold Eurasian air into the UK during the last week of Jan.
Interesting. But it doesn’t explain the 180 degree pivot from what the “experts” claimed was happening 15 years ago. Remember? No more European ski industry, the end of reindeer, extinction of polar bears, Mediterranean on the North Sea, etc. Have the models changed or just the inputs?
The science of SSWs has come a long way in 15 years, as has Arctic seaice decline.
The warming will still cause the average freezing level to rise and so reliable seasonal snow in the lower alpine ski resorts much more variable on weather rather than climate. BTW. Siberian winds are dry and they give the UK snowfall because of a Lake effect as they cross the North Sea.
The heavy snowfall in Austria and Germany recently was due to an unstable, moist northerly …. not unusual in an average winter – its persistence and it’s moisture content was.
The forecast of the stratospheric polar vortex indicates the inflow of Arctic air to Europe.
Glaciations are cases of extreme global warming.
During periods of very low solar activity, ozone is not pushed out from the polar circle.
Doublethink claim: Global Warming is actually Global Cooling.
Don’t you know that the cold air has to migrate south because it’s too hot at the pole?
I hate to repeat myself, but this ‘science’ is so similar to astrology, in that no matter what happens, believers can show how it was ‘predicted’ – at least after the fact.
Again, if there is no result that can prove CAGW false, then I don’t see how it can be science.
I believe in God… but it is my BELIEF, not science. They really need to change this movement’s name to ‘Climate Religion’, not climate science. It drags down all science.
“Global warming causes colder winters and more snow in Europe”
Of course it does. It causes everything.
“Northern midlatitudes, over central Eurasia in particular, have experienced frequent severe winters in recent decades”
They were more frequent and severe, decades before recent decades.
All this is a sign of a planet reversing roles from warming to cooling. Climate spin has been becoming popular over recent years where what ever just happened, even if not as bad as before is now the new scapegoat.
I remember a winter in Germany in the 1980th when I walked in t-shirt alongside the Havel in Berlin the 24. december. Toda there is some snow,ok. its wintertime in Europe. Nothing new. But in the eyes of the hardcore alarrmist its CAGW- we’re all doomed.
“Correcting this underestimation reconciles the discrepancy between models and observations, leading to the conclusion that ~44% of the central Eurasian cooling trend for 1995–2014 is attributable to sea-ice loss in the Barents–Kara Seas.”
Between 1940’s and 1970’s there was central Eurasian cooling trend and yet there were increases in sea ice in the Barents-Kara Seas. This trend lasted longer than the timeline quoted here.
These both contradict each other so there is a high chance that sea ice change in the Barents-Kara Seas has no influence in Eurasian trends.
What actual global climate parameter has changed during 1994 and 2014 that explains changes in atmospheric pressure systems? With trends compared with the AO and NAO for example showing changes in the polar jet stream.
Solar activity has declined and these out breaks of frequent severe winters in Europe tend to occur more often when there are few or no sun spots for extended periods.
This winter 2018/19 was myself predicted to have one of these events because of the sun’s decline to mostly no sun spot days over recent months before December. (with other teleconnections favourable)
The Barents-Kara Seas was low the year before and year before that and could go on too, but there were no European severe winter episodes back then?
So why did this not occur over previous low sea ice years because there were more active sunspots indicting a more active sun during those years. This helps drive the jet stream in becoming more zonal especially during the northern hemisphere winter. This zonal pattern maintains colder air in the Arctic with Europe avoiding the severe freezes.
SSW’s events occurred more often during the colder winters between the 1950’s and 1970’s in USA/Europe. Warm air has to be moved towards the Arctic to displace the colder air to mid latitudes around the northern hemisphere. This science has been known for decades, but some so called climate scientists think it is something new.
THE ANALYST’S DILEMA:
Knowing more and more about less and less leads ultimately to knowing everything about nothing!
Cheers
Mike