Fig. 4: Changes in cloud amount due to COVID-19 emissions reductions. Source: Abrupt emissions reductions during COVID-19 contributed to record summer rainfall in China

Claim: Chinese Covid Shutdown Triggered Record Floods

Guest essay by Eric Worrall

Climate mitigation causes more rain? According to scientists analysing the 2020 Chinese floods, the drop in greenhouse gas emissions and coal smoke aerosols during the 2020 Covid shutdown led to increased rainfall.

Climate change: Covid shutdown linked to record rainfall in China

By Matt McGrath
Environment correspondent

Scientists say that a rapid drop in emissions because of Covid played a key role in record rainfall in China in 2020. 

The decline in greenhouse gases and small particles called aerosols caused atmospheric changes that intensified the downpours. 

Hundreds of people died and millions more were evacuated during a summer of record rainfall. 

But long-term cuts in emissions are unlikely to trigger similar events.

Many parts of eastern China experienced severe flooding in June and July in 2020. The researchers say the reductions in emissions contributed about one third of the extreme summer rain.

A number of scientific studies have looked at what caused the flooding events, some pointing to the extreme conditions in the Indian Ocean. 

Now an international team has put forward a new theory. They argue that the abrupt reduction in emissions of greenhouse gases and aerosols, caused by shutdowns during the Covid-19 pandemic, was a key cause of the intense downpours.

“There was heating over land due to aerosol reductions but also cooling over the ocean due to a decrease in greenhouse gases, which intensified the land/sea temperature difference in the summer,” explained lead author Prof Yang Yang from Nanjing University of Information Science and Technology, in China.

“This in turn, increased sea level pressure over the South China/Philippines sea and intensified the winds bringing moist air to eastern China which then saw intense precipitation.”

Read more: https://www.bbc.com/news/science-environment-60423329

The abstract of the study;

Published: 

Abrupt emissions reductions during COVID-19 contributed to record summer rainfall in China

Yang YangLili RenMingxuan WuHailong WangFengfei SongL. Ruby LeungXin HaoJiandong LiLei ChenHuimin LiLiangying ZengYang ZhouPinya WangHong LiaoJing Wang & Zhen-Qiang Zhou 

Abstract

Record rainfall and severe flooding struck eastern China in the summer of 2020. The extreme summer rainfall occurred during the COVID-19 pandemic, which started in China in early 2020 and spread rapidly across the globe. By disrupting human activities, substantial reductions in anthropogenic emissions of greenhouse gases and aerosols might have affected regional precipitation in many ways. Here, we investigate such connections and show that the abrupt emissions reductions during the pandemic strengthened the summer atmospheric convection over eastern China, resulting in a positive sea level pressure anomaly over northwestern Pacific Ocean. The latter enhanced moisture convergence to eastern China and further intensified rainfall in that region. Modeling experiments show that the reduction in aerosols had a stronger impact on precipitation than the decrease of greenhouse gases did. We conclude that through abrupt emissions reductions, the COVID-19 pandemic contributed importantly to the 2020 extreme summer rainfall in eastern China.

Read more: https://www.nature.com/articles/s41467-022-28537-9

Reading the study, what they are saying is the Covid shutdown reduced coal smoke aerosols, which in turn caused the land to heat more than usual, triggering a massive updraft which drew in wet monsoon air from the sea. The enhanced rainfall washed even more aerosols out of the air, causing a positive feedback loop which led to widespread flooding.

They also claim reduced greenhouse gas emissions helped strengthen the weather pattern, by reducing ocean heating, leading to a greater temperature difference between land and sea.

Would a long term emissions and aerosol reduction lead to a long term increase in flood risk?

… “It’s a good question,” said Prof Yang. 

“Because emissions were reduced dramatically in early 2020 when the Covid-19 pandemic emerged, it caused an immediate and abrupt change in various components of the climate system.”

“Such sudden change of the climate system would be very different from changes in response to continuous but gradual policy-driven emissions reductions.” …

Read more: https://www.bbc.com/news/science-environment-60423329

It is an interesting theory. Living in the subtropics by the sea I regularly see onshore winds, presumably triggered by land heating relative to the sea, which seem to lead to towering thunderheads forming near the sea shore.

The authors themselves advise caution, the study is model heavy.

But the study is interesting in that it goes against the flow of most claims, that climate change causes more rain. In this case, scientists are suggesting that climate mitigation, both through Xi Jinping’s efforts to reduce air pollution, and the 2020 Covid shutdown, triggered the deadly floods – although they are more cautious about predicting the outcome of long term, more gradual mitigation.

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February 18, 2022 10:29 pm

One little, tiny problem with this hypothesis. CO2 emissions decreased – but the level in the atmosphere (at least as measured at “gold standard” Mauna Loa) did NOT. Any cooling in the Indian Ocean had nothing whatsoever to do with the effects from the pandemic panic.

Climate believer
Reply to  writing observer
February 19, 2022 3:48 am

Increasing atmospheric CO 2 concentrations drives global warming, except when it doesn’t.

CO² temperature graph.png
H B
Reply to  writing observer
February 19, 2022 7:29 am

CCP trying to distract from the coming revolt of the Chinese people by denying the “mandate of heaven”

Alexy Scherbakoff
February 18, 2022 11:05 pm

Utter BS. They’ve had floods in China on a regular basis throughout recorded history.

Roald J. Larsen(@roaldjlarsen)
Reply to  Alexy Scherbakoff
February 19, 2022 12:06 am

The grant & rent seeking crowd of activists and “green” parasites are desperate to keep their scam alive, at the same time too stupid to see how stupid their claims are ..

Great fun for normal people though 🙂

Tom Abbott
Reply to  Alexy Scherbakoff
February 19, 2022 7:15 am

“Utter BS”

That’s what I thought when I read it, too.

Herbert
Reply to  Alexy Scherbakoff
February 19, 2022 10:23 am

Alexy,
Exactly!
If you Google “Yangtze River Peaks in China”at history.com or “1931 China Floods” at Wikipedia you will see that in August 1931 some 3.7 million people were killed by flooding, starvation and disease over the period from July to November 1931.
This is acknowledged as one of the greatest disasters in human history.
And now we are told that recent flooding in China which killed several hundred people was “ unprecedented”.
These people treat the public as fools.

Graham McDonald
Reply to  Herbert
February 19, 2022 4:58 pm

G’Day Herbert and others;

Over the centuries the Chinese have kept good records of flooding. I recommend the following listing – from 4AD to 1900AD – of world wide ‘weather’ reportage. (From memory – about 1,400 pages)

http://www.breadandbutterscience.com/weather.pdf

I just did a Crl-F search on that document for “China”. When it passed 50,000 I shut it down. Yes, good records.

John in Oz
Reply to  Alexy Scherbakoff
February 19, 2022 3:24 pm

From ‘Dirt – The Erosion of Civilisations’ by David R. Montgomery (my bold)

Today, the Chinese people overwhelmingly live on the alluvial plains
where great rivers descending from the Tibetan Plateau deposit much of
their load of silt. Flooding has been a problem for thousands of years on the
Huanghe, better known in the West as the Yellow River, a name imparted
by the color of dirt eroded from the river’s deforested headwaters. Before
the first levees and dikes were constructed in 340 bc, the river meandered
across a broad floodplain. In the second century bc the river’s Chinese name
changed from Great River to Yellow River when the sediment load
increased tenfold as farmers began plowing up the highly erodible silty
(loess) soils into the river’s headwaters.
The earliest communities along the Yellow River were situated on elevated
terraces along tributaries. Only later, after the area became densely
populated, did people crowd onto the floodplain. Extensive levees to protect
farmlands and towns along the river kept floodwaters, and the sediment
they carried, confined between the levees. Where the river hit the
plains, the weakening current began dropping sediment out between the
levees instead of across the floodplain. Rebuilding levees ever higher to
contain the floodwaters ensured that the riverbed climbed above the alluvial
plain about a foot every century.
By the 1920s the surface of the river towered thirty feet above the floodplain
during the high-water season. This guaranteed that any flood that
breached the levees was devastating. Floodwaters released from the confines
of the levees roared down onto the floodplain, submerging farms,
towns, and sometimes even whole cities beneath a temporary lake. In 1852
the river jumped its dikes and flowed north, flooding cities and villages and
killing millions of people before draining out hundreds of miles to the
north. More than two million people drowned or died in the resulting
famine when the river breached its southern dike and submerged the
province of Henan during the flood of 1887–89. With the river flowing
high above its floodplain, levee breaches are always catastrophic.

Kazinski
February 18, 2022 11:37 pm

Their theory is absurd on its face, at least the part that fewer co2 emissions caused almost immediate temperature change over the ocean.

The part about the aerosols is plausible, but the co2 part eviscerates my confidence.

Unless of course this:
“They also claim reduced greenhouse gas emissions helped strengthen the weather pattern, by reducing ocean heating, leading to a greater temperature difference between land and sea.”
Is a spin thrown in by Nature, by someone that thinks co2 is a magic gas, and can’t be blamed.on the scientists that wrote the paper.

Roald J. Larsen(@roaldjlarsen)
Reply to  Kazinski
February 19, 2022 12:07 am

In the real world there’s still no “Greenhouse Gases”! A greenhouse prevent convection, no known gases, or mixes of gases in the known universe has that ability.

What ever characteristics (properties) the different molecules might have at the altitude where they actually could have an effect is irrelevant for the earth’s surface temperature because of distance, temperature difference, pressure and mass.

Remember, the atmosphere is warmed by the earth’s surface, not the other way around!

Peta of Newark
Reply to  Kazinski
February 19, 2022 3:30 am

What sort of aerosols are they talking about?

1/ Are they molecules of the oxides of Nitrogen and Sulphur accumulating water molecules around themselves – there is your ‘white’ cloud of aerosol.
High albedo, reflects sunlight, OK
But how are those clouds any different from Cirrus Clouds or even aircraft contrails = things that supposedly create warming?
Except when Climate Science shoots the stuff into the sky in the form of Geo-engineering to try create cooling?

2/ But are these aerosols = clouds of soot, smoke and general grime rising up from factories, roads and city streets?
Supposedly they stop sunlight reaching the ground and yes they do. But what do those clouds do with the sunlight – they are not reflecting it back into space or, heaven forbid, back to Sol itself and causing horrible runaway Solar Gaga Gas Heating

Those clouds of black will be absorbing incoming solar energy, as Tyndall observed in his CO2 experiments and how OCO2 Sputnik operates ##
But that will be warming the atmosphere – how is that different from the Original And Best Green House Gas Theory = Global Warming and leading to a wasted world?

A warmer atmosphere will lead to *less* convection = the original, basic and most fatal flaw in the entire theory of CO2 and the GHGE

Next, where would these clouds of aerosol, either soot/smoke or droplets of nitric/sulphurous acid go if not float out over the ocean.
Would that heat or cool the ocean?

## Is it *really* beyond the bounds of possibility that what Tyndall observed in his experiment is The Actual Cause of the rising temperature of the atmosphere?
Combined with, as I rave about here, the dust we are creating from cities, quarries, roads, forest fires (wild and deliberate) and not least, farming & tillage?
(The clue is within Wien’s Law and the temperature source & the temperature reference that Tyndall used)

Extra CO2 will be soaking up extra incoming solar energy at wavelengths corresponding to temps of 800°C and 400°C – both of which must surely Shirley have a heating effect on the atmosphere.
BUT BUT BUT, Lapse Rate combined with Entropy (and or the 2nd Law) say that that warmth cannot come down to the ground.
Is the Surface (dirt, soil, plants and trees) actually cooling because of lower energy reaching the ground?

Or is something else happening?
So what is really going on?

Last edited 3 months ago by Peta of Newark
Coeur de Lion
February 18, 2022 11:49 pm

The interesting point about the Moana Loa CO2 record is that the detailed shape of the northern hemisphere vegetation induced sawtooth is idiosyncratic and unchanged by the Covid economic disaster. Rethink carbon cycle and human influence.

Peta of Newark
Reply to  Coeur de Lion
February 19, 2022 3:44 am

Absolutely rethink the Carbon Cycle.
Start here

If you successfully get to my Dropbox and the Poldean Farm pdf document, look to Figure 3.9

It says that over the course of 12 months, A Ploughed Field in South West Scotland (not all that far from my old place) – it says that 0.8kilograms of Carbon was released from every single square metre of ploughed land.

If that is correct (= elemental) Carbon, multiply by 2.44 to get Carbon Dioxide

Then consider that maybe 3E13 square metres of Earth’s surface are freshly ploughed annually (that includes paddy fields and land that has been Rounded Up ##) – what figure do you get for total CO2 emissions from farmland?
I get 58.5 Gigatonnes annually

Maybe also take half of that figure over 2E13 square metres to include farmland that is being overgrazed
There’s another 19.5 Gigatonnes per year

That is why the Hawaiian volcano didn’t flinch during lockdown – farming didn’t stop while ‘most everything else did.

## Bad news to all you fans of Low-Till and No-Till.
Roundup does exactly the same thing as ploughing does = destroys vegetation and leaves bare soil exposed to the sun

Enthalpy
February 19, 2022 12:01 am

La Niña anyone? 2 years in a row – Australia has certainly noticed it

Thomas Gasloli
February 19, 2022 12:06 am

And it took 16 PhDs to come up with an idea this dumb.

griff
February 19, 2022 12:09 am

It didn’t.

Because we have two other similar 1 in 1000 year rain events in the same period – Germany and NW USA/Canada to consider.

In neither of those cases was there coal or aerosol decrease due to the pandemic.

This is raw climate change.

Lorne WHITE
Reply to  Eric Worrall
February 19, 2022 4:06 am

An excellent idea, if only you could solve these Nuclear problems:
– Unaffordable
– Uninsurable
– Undisposable radioactive waste
(unsolved during the 75year lifetime of peaceful Nuclear power!)
– Unreplaceable

“Whom the gods would destroy, they first make proud.”
~ancient Greeks

Melvyn Dackombe
Reply to  Lorne WHITE
February 19, 2022 4:14 am

France has used nuclear as the main power source for over 40 years without any problems.

Lorne WHITE
Reply to  Melvyn Dackombe
February 19, 2022 11:49 am

So has Ontario since ~1972 without leaks or explosion.

That’s Not the 4 issues I raised / please disprove those points.

Nuclear generates 60% of Ontario’s electricity and is terribly costly because the zirconium boiler tubes unexpectedly change chemistry & break under the intense radiation of our CANDU Heavy Water plants. Imagine how much it costs to replace snd refurbish those Nuclear plants.

Pickering was the first plant, lost 2 of 8 reactors ~1992 when they discovered the zirconium problem and began replacing boiler tubes in other reactors rather than retire them and buy surplus electricity from Hydro Québec and Manitoba Hydro. (Jacques Cousteau also discovered an unknown 1,000,000 year old fault running directly under the Pickering plant. It’s highly unlikely to cause problems, but shows how easy it is for engineers to miscalculate, cf. Windscale, Chernobyl, Fukushima, etc.)

When Pickering closes fully in 2025, Ontario will have a 15% shortfall of electricity production. Since our government chose to close a poorly designed Renewable Energy FIT programme, they now propose to install an under-Lake Erie cable (whose bottom Cousteau showed was scoured by winter ice) to import Pennsylvania coal electricity, and occasionally export ‘clean’ Ontario Nuclear electricity.

Pickering and most Nuclear plants are lasting only 50-60 years. Then then they are decommissioned and radioactive waste will be stored:
300,000 years for spent fuel
10,000 years for boilers, steel, concrete

Finland is installing a French Areva plant and has constructed a permanent millennia-long storage site.
=> Documentary “Into Eternity”.
They’re the Only country I know that has solved the Disposal problem in 75 years!

Now Mr Dackombe, PLEASE discuss:
– Unaffordable
– Uninsurable
– Undisposable
– Unreplaceable

Mr.
Reply to  Lorne WHITE
February 19, 2022 9:57 am

People imagine all sorts of hobgoblins are out to get them throughout life.

As Mark Twain sagely observed –
” I’ve had many big problems to worry about in my life, but most of them never existed”.

Lorne WHITE
Reply to  Mr.
February 19, 2022 12:05 pm

Samuel Clemens thought short-term, only of his mere Halley’s Comet 76 year circuit-of-Sol lifetime.

Clyde Spencer
Reply to  Lorne WHITE
February 19, 2022 10:29 am

Undisposable radioactive waste

(unsolved during the 75year lifetime of peaceful Nuclear power!)

It is a political problem, not a technological one. Jimmy Carter issued an Executive Order prohibiting reprocessing of spent reactor fuel because of concerns that terrorists might get access to the reclaimed uranium or plutonium. However, that did nothing to prevent them from obtaining U or Pu from other countries, which has never happened. If the very radioactive, short-lived fission products were the only thing necessary to be disposed of, the problem would be both technologically and politically easier to address. It was short-sighted of Carter to do what he did, and no president since has had the courage or wisdom to undo the damage.

“Whom the gods would destroy, they first make proud mad.”

Lorne WHITE
Reply to  Clyde Spencer
February 19, 2022 11:58 am

Exactly my point:

– absolutely no one wants a NuclearWaste dump near them

– none of us will give up our luxurious lifestyles and consume less electricity (ditto for the changes needed IF one believes the CAGW Religion our politicians have bought)

– none of us care about our far distant descendants who will be radiated by our ~50 years of NuclearWaste looonnng into the future.

Politicians have neither ability nor desire to solve this massive mess. They’ll be retired 🤞🏽before it becomes a problem.

Last edited 3 months ago by Lorne WHITE
Mr.
Reply to  Lorne WHITE
February 19, 2022 12:18 pm

absolutely no one wants a NuclearWaste dump near them

Oh, I dunno about that.

The few remaining inhabitants of some Panamanian region countries might be quite eager to accept a few $billion per year to live in harmony with nuclear waste facilities.

I’m sure they’d be enjoying a better standard of living than what prevails for them now.

Redge
Reply to  griff
February 19, 2022 12:57 am

Griff, mate,

You’ve been given evidence to the contrary every time you make this absurd claim.

Only yesterday, I showed the Met Office disagree with you and yet here you are again showing your ignorance

Are you incapable of understanding or is it part of some weird fetish to be admonished on a daily basis?

fretslider
Reply to  griff
February 19, 2022 2:14 am

“ This is raw climate change.”

Nah

It’s weather

LdB
Reply to  griff
February 19, 2022 2:37 am

Griff a minute agro you were saying Climate change caused droughts?

Griff logic more rain produces more droughts 🙂

AndyHce
Reply to  LdB
February 19, 2022 2:26 pm

If there is only so much rain to go around, more in one place has to mean less in another

LdB
Reply to  AndyHce
February 20, 2022 5:00 am

ROFL sure 🙂

Climate believer
Reply to  griff
February 19, 2022 3:18 am

Oh dear, I was hoping Henny Penny might have been blown away by Eunice…

Lorne WHITE
Reply to  griff
February 19, 2022 3:57 am

“This is raw climate change.”

No, it’s a strange, poorly recorded natural cycle.

The “atmospheric river” that hit NW USA/Canada would seem to be the cause of the incredible flooding that caused California’s 300×50 square mile Central Valley to become a 20ft deep LAKE after 6 straight weeks of rain in 1861-62. Geologists drilling for earthquake data found that this flood repeats irregularly every ~150-200 years. #BePrepared.

Joao Martins
Reply to  griff
February 19, 2022 4:23 am

This is raw climate change.

From your derogatory explanation I can conclude that you like better climate change cooked or roasted… so whay are you so highly concerned with global warming?

Last edited 3 months ago by Joao Martins
Herbert
Reply to  griff
February 19, 2022 10:38 am

griff,
the claim that any of these events are one in 1 thousand year events is fanciful nonsense.
The German floods last year were not “unprecedented” nor once in a thousand year events.They were not dissimilar to flooding in 1803 and 1910.
As to China,Google “Yangtze River Peaks in China” at history.com or “1931 China Floods” at Wikipedia.
3.7 million people died in July to November 1931 in China from flooding and consequent starvation and disease.One of the greatest disasters in human history.
Now you want to claim the Chinese floods and the others are “unprecedented”.
It is not “raw Climate Change” but just another weather event.
You are impervious to clear evidence and waste my time and your own by peddling demonstrable propaganda.

Dave Fair
Reply to  griff
February 19, 2022 12:37 pm

Griff, please name a year in which three 1 in 1,000-year events did not occur around the globe.

TonyG
Reply to  Dave Fair
February 20, 2022 7:55 am

Dave, they ONLY ever occur within the last year! By next year, this year’s won’t have happened.

Alex
February 19, 2022 1:29 am

Maybe it was the wrath of God punishing communist China for launching the pandemic. My theory is as plausible as this report, scratch that. My theory is more plausible than this stupid report which encapsulates the cli-myth-ologists hubris. That these self-declared demigods have failed in every prediction that they have been making since 1974 (The Ice Age is Coming) is more than proof enough of their hubristic character.

fretslider
February 19, 2022 1:56 am

“ Modeling experiments show “

Whatever we assume…

Ed Zuiderwijk
February 19, 2022 3:48 am

The drop of my pants also leads to more rainfall. In my bathroom.

Right-Handed Shark
February 19, 2022 4:38 am

Climate science.. Start with a conclusion, work backwards. No convoluted, dumbass, impossible assumption too ridiculous.

Tom
February 19, 2022 4:44 am

By disrupting human activities, substantial reductions in anthropogenic emissions of greenhouse gases and aerosols might have affected regional precipitation in many ways. Here, we investigate such connections and show that the abrupt emissions reductions during the pandemic strengthened the summer atmospheric convection over eastern China, resulting in a positive sea level pressure anomaly over northwestern Pacific Ocean.”

It may be something that was lost in the translation, but WTH is a “summer atmospheric convection”, or a “positive sea level pressure anomaly”. It looks to me like the authors are using “baffle with BS” to either promote their brilliance, or, more likely, to hide their ignorance.

bluecat57
February 19, 2022 5:13 am

Those idiots don’t know the difference between coincidence and cause.

Steve Keohane
February 19, 2022 5:46 am

China is working to mitigate climate change? How absurd.

Rick C
February 19, 2022 5:58 am

Prevent Floods – Burn More Coal.

We humans have yet another lever to control the weather. What awesome power.

edward
February 19, 2022 7:32 am

This is bullshit …

Dave Fair
Reply to  edward
February 19, 2022 12:44 pm

But it will be cited in the UN IPCC CliSciFi AR7.

Ulric Lyons
February 20, 2022 8:44 pm

Claim:
“In the last four decades, summer precipitation over eastern-central China has decreased significantly”

Not according to this article:

The recent increase in central eastern China summer rainfall and its possible mechanism:

“This study investigated interdecadal variations in summer rainfall in central eastern China before and after the mid-1990s. The mean difference in rainfall between the two epochs (average rainfall in the 1981–1995 period: 5.0 mm day−1; average rainfall in the 1996–2010 period: 6.0 mm day−1) was significant at the 95% confidence level. This study explored the cause of the recent increase in summer rainfall in central eastern China by analyzing the difference in average rainfall between 1996–2010 (hereafter, Epoch II) and 1981–1995 (hereafter, Epoch I). Analysis of rainfall revealed that positive anomalies were observed in a southwest–northeast direction across the south-central region of eastern China, Korea, and Japan, while negative anomalies were observed at latitudes of 40–50°N and in most areas in the western North Pacific region.”
https://www.tandfonline.com/doi/full/10.1080/16000870.2020.1803668

The regime change in the mid 1990’s is when the solar wind weakened from, and when the AMO warmed from.

Low altitude aerosols exacerbate daytime maximum land surface temperatures, I can think of two record highs in the UK during high air pollution levels, late Feb 2019 and Easter 2011. The forest fire smoke in the Moscow summer 2010 heatwave, and the record high with the ‘Lucifer’ heatwave in Syracuse Sicily fell sharply by about 8°C later in the afternoon when smoke from a nearby fire had cleared.

Last edited 3 months ago by Ulric Lyons
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