Sunday, 23 February 2020

"It never rains but it pours"

The Guardian appears to be taking this expression literally.

Guardian reader's letter, May 2019:

Weather forecasts are ignoring the drought in England

Paul Brown is spot-on in his criticism of how weather forecasts and presenters ignore the continuing drought (Weatherwatch, 28 May). It is as if they are in a parallel universe where the climate emergency does not exist. Wildlife, gardeners, farmers and all who care about the environment are desperate for proper rainfall, especially in central and southern England.

Linda Lennard, St Albans

Guardian article, Feb 2020:

With every flood, public anger over the climate crisis is surging

Sometimes it has felt as if the rain might never stop. These storms have gone beyond the point of simply being storms now, each blurring into the next to create a strangely end-of-days feeling. Everything is freakishly sodden and swollen, and while the rural flood plain on which I live fortunately hasn’t flooded anything like as badly as some, the rivers are rising alarmingly.

Yet still the lashing winds and biblical downpours keep coming. Suddenly the 40 Days of Action campaign that Extinction Rebellion (XR) will launch on Ash Wednesday (26 February), encouraging people to reflect on the environmental consequences of their actions in a kind of green Lent, feels ominously well named.

So what is it chaps, wetter or drier? (Or would you always have this impression if you compare a month in Spring with one in Winter?)

Oh, surprise surprise, it's neither.

Paul Holmewood summarised rainfall charts for England and Wales 1766 to 2016, and there is no discernible trend, annual rainfall in most years was between 800mm and 1,000 mm:

If you really squint at the ten-year running average, there appears to be a slight upwards trend from the early 1900s (about 850mm) to the 2010s (about 950mm), but most years stayed within the 800mm - 1,000mm range.

As he says himself:

By far the wettest month was October 1903, when 218mm fell. The wettest month in recent years was November 2009, with 192mm.

Again, I can see no evidence of anything unusual occurring in the last decade or so. There is a suggestion, though, that very wet months were not as common prior to the 20thC. This can be better seen by looking at the number of months >150mm per decade. The latest ten years is shown for comparison:

On average, it is fair to say that it is a little bit wetter now than it used to be in the early 19thC. But above all it is the year to year variability which dominates the record, just as it always has.

As to actual 'floods', the chances are these are down to deforestation and dredging/straightening of watercourses upstream; and more urbanisation (building over large contiguous areas, especially in areas prone to flooding) and not enough dredging/straightening of rivers downstream.


A K Haart said...

Severn Trent Water at Carsington Water used to have a small drought-tolerant garden to illustrate the future of gardening in the UK under the impact of climate change. There was also an information board telling us all about it. All gone now for some reason.

Mark Wadsworth said...

AKH, that's a shame. School kids could have come and laughed at it in future decades.

Sobers said...

All unusual weather is evidence of 'Climate Change', didn't you know?

Got to be one of the slickest rebranding episodes ever - going from 'Global Warming' to 'Climate Change'. The former was suffering from a lack of heat, and the brand was being trashed every time it snowed. The latter wins whatever happens. Hot, cold, wet or dry, its all Climate Change!

Penseivat said...

Hopefully, the Extinction Rebellion cretins will show the dangers of (the alleged) flooding due to man made climate change by holding a sponsored "Hold Your Breath Under Water" activity? I'll donate a fiver to the first one who can stay down for 10 minutes.

Mark Wadsworth said...

S and P, agreed and agreed. Dihydrogen monoxide poisoning causes a lot of deaths and XR should be 'raising awareness' of it.

Bayard said...

"The farmer's not a happy man, his heart in is his boots,
For either the rain is destroying his grain or the drought is destroying his roots."

S, yes the answer to people who complain about climate change is to ask them "would you prefer it if the climate got colder then?", to which the reply will most likely be, "no, we want it just to stay the same", when you can then ask, "at what time since the Earth gained an atmosphere has it ever done that?"

Mark Wadsworth said...

B, Sod it, Roman warm period, mediaeval warm period, modern warm period. A great time to be alive!

Physiocrat said...

Then there was the Maunder minimum, a period of reduced solar activity.

One piece of long term evidence of climate change would be records of flowering dates, which have been kept for over three hundred years by botanical gardens such as Kew and Oxford. If the was compelling evidence, I would have expected it on the websites of these organisations, but there is none that I can find.

I am also looking for an explanation, at the quantum/molecular level of how a layer of carbon dioxide less than 4 metres thick could cause the so-called 'greenhouse effect'. (Glass greenhouses do not work by trapping radiation - it goes straight through the glass!)

Dinero said...

Whatever view you have, no-one scientific is documenting a change at a rate that a person could perceive in there own experience.

Physiocrat said...

@Dinero Botanic Gardens such as Kew and Oxford have records going back three centuries. I can't find anything that they might have published on their websites. During that time events such as changes in solar activity and volcanic eruptions will also have had a effect.

Dinero said...

> Physiocrat,
Also for UK farming, the DEFRA website, I see nothing there about a change in farming practices, crops, types, planting, harvesting, yields.
The point is the media, such as the Guardian above, report the subject as if it was a change in current events, but that can not be the case as the time scales being talked about are too long for that.

Physiocrat said...

UK farming is a fleabite on a world scale. The sort of changes which might cause changes in climate are clearance of tropical rainforests and natural grassland for arable or livestock or plantations, irrigation in arid areas, creation of artificial lakes, etc.

Dinero said...

We are in agreement, as you note an absence of records on changes of blooming at Botanic Gardens such as Kew and Oxford also no records at DEFRA either.