No doubt Trump will be cackling that “we could do with global warming” to counter today’s record breaking snow storm on the East coast of the USA. Contrary to this simplistic analysis, such storms are exactly what can be expected during the current climate instabiity caused by that warming.
The extra precipitation is because the warm air and waters in the southern North Atlantic push larger and larger amounts of water vapor into the atmosphere, to be carried north and along the East coast by low pressure systems. At the same time, higher wind speeds to the North, again caused by more energy in the global weather system, is pushing the jet stream that goes round the poles further South (and North in the southern hemisphere).
When that cold air meets the warm wet air coming up from the south, it condenses out and falls either as rain or snow. In North America, snow is more likely. In Western Europe, the warming effect of the North Atlantic circulation (AKA the Gulf Stream) produces a slight warming effect. That is why the UK has consistently milder weather than the extremes in the USA on the same latitude and also why it has seen record breaking rainfall and flooding rather than the current blizzards hitting the East Coast.
There is also evidence that the patterns of rainfall in the UK are changing. To use one piece of anecdotal evidence, I live in a converted warehouse built around 1800. It has a sort of elongated M shaped double roof with a drainage channel down the middle as well as from the front and back. The drainage from that central channel involved internal open wooden troughs linking to downpipes on the outside. For 200 years, the pattern of rainfall meant that this worked fine but around 10 years ago the type of rainfall changed to shorter but very much more intense rainfall. That overwhelmed the system for the first time, causing considerable damage and the need for a new roof and pipe system.
Last year the UK, along with many other countries, had its warmest year on record. This year, Spring flowers have been out since last Christmas and temperatures have barely reached down to seasonal norms. The forecast for London for the coming week has high temperatures averaging 13 degrees (from 14 for Sunday and Monday to 10 on Thursday, rising to 12 on Friday). Low temperatures are around 8 degrees — the lowest being 5 on Thursday and the highest low 10 on Tuesday. These are degrees Celcius, not Farenheit and are similar to the “typical” temperatures in late Spring. To put this in context, this is the “travel advice”:
January is the coldest month in London, UK when the winter season is well underway. Throughout the month, the average temperature remains constant at 5-6°C, with almost no variation at all. Daily highs are around 8°C over the course of January, rising above 12°C or going under 3°C very rarely – only one day out of every ten. On the other hand, daily lows are around 3°C, exceeding 8°C or falling under -3°C only one day in ten.
The coming week has 3 days of highs over 12 (2 days at 12) Lows will be 8 on two days and over 8 on two more. If the forecasts are correct, London will see 20 days of above average temperatures this month (there was a cold snap last week which went quickly).
Let me again emphasise — we cannot say weather events are directly caused by global warming however we can say that we are seeing patterns that can be expected in times of climate instability associated with global warming.
If you can take some schadenfreude from this, one of the areas worst affected by recent flooding was in Aberdeenshire where Trump’s infamous golf course is located. In presenting the financial report for the course in October last year, Trump’s son Eric tried to big up the income (both Scottish courses lost money) ….
However, he said future profits could be hurt by the “ongoing dip in the local economy and adverse weather conditions” in the area which would drive away golfers.