Largest study of Asia’s rivers unearths 800 years of paleoclimate patterns

The SUTD study will be crucial for assessing future climatic changes and making more informed water management decisions.

SINGAPORE UNIVERSITY OF TECHNOLOGY AND DESIGN

Research News

IMAGE
IMAGE: MAP OF THE ASIAN MONSOON REGION; RIVER BASINS INVOLVED IN THIS STUDY ARE HIGHLIGHTED BY SUBREGION, RIVERS BELONGING TO THE WORLD’S 30 BIGGEST ARE SHOWN WITH NAMES INDICATED IN BLUE…. view more CREDIT: SUTD

813 years of annual river discharge at 62 stations, 41 rivers in 16 countries, from 1200 to 2012. That is what researchers at the Singapore University of Technology and Design (SUTD) produced after two years of research in order to better understand past climate patterns of the Asian Monsoon region.

Home to many populous river basins, including ten of the world’s biggest rivers (Figure 1), the Asian Monsoon region provides water, energy, and food for more than three billion people. This makes it crucial for us to understand past climate patterns so that we can better predict long term changes in the water cycle and the impact they will have on the water supply.

To reconstruct histories of river discharge, the researchers relied on tree rings. An earlier study by Cook et al. (2010) developed an extensive network of tree ring data sites in Asia and created a paleodrought record called the Monsoon Asia Drought Atlas (MADA). SUTD researchers used the MADA as an input for their river discharge model.

They developed an innovative procedure to select the most relevant subset of the MADA for each river based on hydroclimatic similarity. This procedure allowed the model to extract the most important climate signals that influence river discharge from the underlying tree ring data.

“Our results reveal that rivers in Asia behave in a coherent pattern. Large droughts and major pluvial periods have often occurred simultaneously in adjacent or nearby basins. Sometimes, droughts stretched as far as from the Godavari in India to the Mekong in Southeast Asia (Figure 2). This has important implications for water management, especially when a country’s economy depends on multiple river basins, like in the case of Thailand,” explained first author Nguyen Tan Thai Hung, a PhD student from SUTD.

Using modern measurements, it has been known that the behaviour of Asian rivers is influenced by the oceans. For instance, if the Pacific Ocean becomes warmer in its tropical region in an El Nino event, this will alter atmospheric circulations and likely cause droughts in South and Southeast Asian rivers. However, the SUTD study revealed that this ocean-river connection is not constant over time. The researchers found that rivers in Asia were much less influenced by the oceans in the first half of the 20th century compared to the 50 years before and 50 years after that period.

“This research is of great importance to policy makers; we need to know where and why river discharge changed during the past millennium to make big decisions on water-dependent infrastructure. One such example is the development of the ASEAN Power Grid, conceived to interconnect a system of hydropower, thermoelectric, and renewable energy plants across all ASEAN countries. Our records show that ‘mega-droughts’ have hit multiple power production sites simultaneously, so we can now use this information to design a grid that is less vulnerable during extreme events,” said principal investigator Associate Professor Stefano Galelli from SUTD.

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mikebartnz
January 3, 2021 10:34 pm

Quote “An earlier study by Cook et al. (2010) developed an extensive network of tree ring data sites in Asia and created a paleodrought record called the Monsoon Asia Drought Atlas (MADA). SUTD researchers used the MADA as an input for their river discharge model.”
Having read that I stopped reading instantly.

fred250
Reply to  mikebartnz
January 4, 2021 3:38 am

I hope that wasn’t John Cook of SkS cartoonery, and Lewendopey’s piece on the side..

That would make the whole effort TOTALLY WORTHLESS. !

MarkW
Reply to  mikebartnz
January 4, 2021 8:11 am

Just because tree rings are not good temperature proxies is not evidence that tree rings are totally useless.
Tree rings are good drought proxies.

Ben Vorlich
Reply to  MarkW
January 4, 2021 10:16 am

But as an input to a model, a guess, is a proxy which is an estimate going to give a useful answer?

mikebartnz
January 3, 2021 10:40 pm

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Reply to  mikebartnz
January 3, 2021 11:40 pm

Perhaps you should complain to Google that their biased algorithms are forcing web sites to run lower quality advertising to compensate for the resulting revenue losses.

Ken Irwin
Reply to  mikebartnz
January 3, 2021 11:40 pm

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mikebartnz
Reply to  Ken Irwin
January 4, 2021 12:08 am

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saveenergy
Reply to  mikebartnz
January 4, 2021 2:33 am

I’ve used DuckDuckGo in Firefox with ‘adblock+‘ & ‘Ghostery‘; haven’t seen an ad for years, they also stop lots of other nastys.

beng135
Reply to  saveenergy
January 4, 2021 12:08 pm

Same w/me. Plus a massive host file blocking ad sites.

Reply to  mikebartnz
January 4, 2021 12:20 am

I run U block Origin and cintribute via paypal instead. I don’t have even a single recommended banner.

Mr. Lee
Reply to  mikebartnz
January 4, 2021 10:22 am

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Redge
Reply to  mikebartnz
January 4, 2021 11:08 am

It’s 2021 and you still don’t understand the ads are based on your or your family’s search history.

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mikebartnz
Reply to  Redge
January 4, 2021 12:23 pm

Unless Google connects to the Duckduckgo servers I don’t think so.

Redge
Reply to  mikebartnz
January 4, 2021 1:47 pm

in that case you’re getting random ads which is the same as me as I keep shields down for this site

lee
January 3, 2021 10:52 pm

“The researchers found that rivers in Asia were much less influenced by the oceans in the first half of the 20th century compared to the 50 years before and 50 years after that period.”

So perhaps something else entirely or something in conjunction. The Indian Ocean Dipole?

Tom Abbott
Reply to  lee
January 4, 2021 8:52 am

Sounds like a cycle.

gringojay
January 3, 2021 11:13 pm

During the 1,100s & again during the 1,400s the river delta shared by current nations India & Bangladesh shifted eastward. Then in the 1,500s the Ganges river course altered eastward to join the Brahmaputra river feeding the delta & a central delta channel (Bidyadhari) silted up in the 1,500s. By the mid 1,700s the Ganges & Brahmaputra had shifted so far east that they then debouched into the Meghna river.

Peta of Newark
January 4, 2021 12:09 am

Quote:
“”To reconstruct histories of river discharge, the researchers relied on tree rings“”

My Mum, bless her and RIP, always asserted that “Trees Like A Lot Of Water

And here we all are safe, sure and (dis) comforted by Settled Science that trees are= Thermometers ##

No matter.
This little message was/is to report one of my more wicked thoughts/projection/predictions.
Based on a well-known and oft mocked Climate Change projection

Really rather scary and as applicable to Iceland as to Easter Island and what is now, The Sahara. Plenty other places too

Never mind snow. There’ll be plenty of that. Think Antarctica, what are Palm Tree remains doing there?
)Sorry, that was silly)

I predict:
Children Are Not Going To Know What Trees Are

Not because of Climate Change but because ‘someone’, hounded by an imaginary Hobgoblin & Junk Science cut them all down and burned them
And it was THAT that ‘changed the climate’
Deny it if you dare

## The most blatantly mis-named pieces of kit there ever was.
Therm‘ refers to energy – not just in the Imperial System of Units.
i.e. Actual real measurable stuff.

Thermometers record temperature, a dimensionless and artificial (fake) construct.
Yet one more example of where Climate Science came off the rails

Last edited 1 month ago by Peta of Newark
ATheoK
Reply to  Peta of Newark
January 4, 2021 4:53 am

You are assuming and conflating oddities. Europe and North America forests are mostly regrown.

The Amazon rain forest were farms during pre-Columbian times; yet forests and jungle quickly reclaimed al of that land when the Amazon was depopulated. (European diseases).

The latest studies about Easter Island repudiate the old claims about them burning all of their forests to make lime.

e.g.

Abstract

Easter Island deforestation has traditionally been viewed as an abrupt island-wide event caused by the prehistoric Rapanui civilization, which precipitated its own cultural collapse.

This view emerges from early palaeoecological analyses of lake sediments, which showed a sudden and total replacement of palm pollen by grass pollen shortly after Polynesian settlement (800-1200 CE).

However, further palaeoecological research has challenged this view, showing that the apparent abruptness and island-wide synchronicity of forest removal was an artefact due to the occurrence of a sedimentary gap of several millennia that prevented a detailed record of the replacement of palm-dominated forests by grass meadows.

During the last decade, several continuous (gap-free) and chronologically coherent sediment cores encompassing the last millennia have been retrieved and analysed, providing a new picture of forest removal on Easter Island.

According to these analyses, deforestation was not abrupt but gradual and occurred at different times and rates, depending on the site.

Regarding the causes, humans were not the only factors responsible for forest clearing, as climatic droughts as well as climate-human-landscape feedbacks and synergies also played a role. In summary, the deforestation of Easter Island was a complex process that was spatially and temporally heterogeneous and took place under the actions and interactions of both natural and anthropogenic drivers. In addition, archaeological evidence shows that the Rapanui civilization was resilient to deforestation and remained healthy until European contact,”

European missionaries and visiting ships brought European diseases which depopulated Easter Island, and goats which are notorious for denuding landscapes. Including small trees and seedling trees.

Last edited 1 month ago by ATheoK
Ian Magness
January 4, 2021 12:10 am

1) A drought in one area may be mirrored in an adjacent area. Who knew? More major studies needed to finance research teams.
2) “To reconstruct histories of river discharge, the researchers relied on tree rings”. What? A tree ring pattern maps river discharge? A drought local to a tree, possibly, in some instances. The low-to-high discharge of rivers over 1,000 miles long? As we say in Britain – pull the other one, it’s got bells on.

tugrus
January 4, 2021 1:51 am

When tree rings can be affected by temperature, sunlight, rainfall & fertilisation you know they can’t be used to measure any independent of the others.

Great Greyhounds
January 4, 2021 3:18 am

I guess reading the paper by Cook et al, and building models was easier than drilling in the deltas and collecting real data…

ATheoK
January 4, 2021 4:19 am

“For instance, if the Pacific Ocean becomes warmer in its tropical region in an El Nino event, this will alter atmospheric circulations and likely cause droughts in South and Southeast Asian rivers. However, the SUTD study revealed that this ocean-river connection is not constant over time. The researchers found that rivers in Asia were much less influenced by the oceans in the first half of the 20th century compared to the 50 years before and 50 years after that period.”

If, likely, we think it happened, we know it didn’t always happen…
Nebulous waffle words and contradictory finds…

It appears that the research was performed with the aim of proving their assumptions and they failed to find that proof.

This research is of great importance to policy makers; we need to know where and why river discharge changed during the past millennium to make big decisions on water-dependent infrastructure.”

In spite of their utter failure to prove their assumptions, these researchers claim their research is of “great importance” and is necessary for policy makers to make “big decisions“…

The ultimate ‘give us more money‘ claim; and in the meantime make “big decisions” based on the fallacies we believe.

No more grants for these charlatans, please.

Last edited 1 month ago by ATheoK
Rich Davis
Reply to  ATheoK
January 4, 2021 9:37 am

I agree. The goal seems to have been to prove that if oceans warm, billions of people will face starvation from drought, therefore … Climate Emergency!

Waza
January 4, 2021 4:32 am

I’ll call bs on the whole study.

The River Thames probably has the best historical records of flows of any river in the world.
The Thames river basin is only 16000sqkm but has several different geological regions and has had many changes to land use over the centuries. Different land use and soil types greatly impacts evaporation and amount of runoff. As rainfalls are not always basin wide, it is not possible to link historical river flows to historical rainfall.
A wet year usually means high flows but even for the Thames accurately quantifying this is not possible.

The chao praya river at 160,000sqkm in Thailand is one of the smaller rivers in this study.
Even if you had accurate flow gauges downstream it would not be possible to link rainfall to flow without knowing land use change over the centuries.

Insufficiently Sensitive
January 4, 2021 8:02 am

“This research is of great importance to policy makers;

THOSE guys? The ones who hope to be in position to dictate to everyone else how they are to live?

DrTorch
January 4, 2021 8:09 am

So sometimes ocean temps affected rainfall, sometimes they didn’t.

I’m not sure this adds a lot of value…

January 4, 2021 10:00 am

It’s kind of crazy to think that 800 years ago, the Mongols were running rampant killing everyone all over the Asian continent (and a bit of Europe and Africa).

beng135
January 4, 2021 12:04 pm

Our records show that ‘mega-droughts’ have hit multiple power production sites simultaneously, so we can now use this information to design a grid that is less vulnerable during extreme events,” said principal investigator Associate Professor Stefano Galelli from SUTD.

One incredibly obvious way to deal w/droughts (or weather conditions in general) regarding reliable electricity production on grids, is fossil-fueled and nuclear plants.

Last edited 1 month ago by beng135
Neo Conscious
January 4, 2021 8:35 pm

Yes, it’s important to understand river discharge variations from previous climate changes to make plans for water needs in those regions, but in Southeast Asia and Eastern India the far bigger geopolitical issue is that the headwaters of all the largest rivers of that region flow through China.

China is in position to cut all those other countries off, for the Brahmaputra (India and Bangladesh), Irrawaddy (Burma), Salween (Thailand), and Mekong ( Laos, Cambodia and Viet Nam) all flow within a hundred miles of the Yangtze at one point in China. A few diversion dams and tunnels could siphon off the lifeblood of most of Southeast Asia and large parts of Southern Asia into the Yangtze.

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