From the UNIVERSITY OF WATERLOO
Water reservoirs created by damming rivers could have significant impacts on the world’s carbon cycle and climate system that aren’t being accounted for, a new study concludes.
The study, conducted by researchers at the University of Waterloo and the Université libre de Bruxelles, appears in Nature Communications. It found that man-made dam reservoirs trap nearly one-fifth of the organic carbon moving from land to ocean via the world’s rivers.
While they can act as a significant source or sink for carbon dioxide, reservoirs are poorly represented in current climate change models.
“Dams don’t just have local environmental impacts. It’s clear they play a key role in the global carbon cycle and therefore the Earth’s climate,” said Philippe Van Cappellen, a Canada Excellence Research Chair in Ecohydrology at Waterloo and the study’s co-author. “For more accurate climate predictions, we need to better understand the impact of reservoirs.”
There are currently in excess of 70,000 large dams worldwide. With the continuing construction of new dams, more than 90 per cent of the world’s rivers will be fragmented by at least one dam within the next 15 years.
The study’s researchers used a novel method to determine what happens to organic carbon traveling down rivers and were able to capture the impact of more than 70 per cent of the world’s man-made reservoirs by volume. Their model links known physical parameters such as water flow and reservoir size with processes that determine the fate of organic carbon in impounded rivers.
“With the model used in this study, we can better quantify and predict how dams affect carbon exchanges on a global scale,” said Van Cappellen, a professor in Waterloo’s Department of Earth and Environmental Sciences.
In similar recent studies, the group of researchers also found that ongoing dam construction impedes the transport of nutrients such as phosphorus, nitrogen and silicon through river networks. The changes in nutrient flow have global impacts on the quality of water delivered to wetlands, lakes, floodplains and coastal marine areas downstream.
“We’re essentially increasing the number of artificial lakes every time we build a dam,” said Taylor Maavara, lead author and a PhD student at Waterloo. “This changes the flow of water and the materials it carries, including nutrients and carbon.”
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Dams and the associated irrigated agriculture increase the evaporation and evapotranspiration locally and regionally [if they are large]. This is known as cold-island effect that counters the heat-island effect. These cause direct impact on climate [like land ocean temperature differences] — though they are local/regional in nature through summation it goes in to global climate. In fact this lead satellite data forming less than half of the ground based data.
With regard to other factors as reported in the article, even with the dams large part of flows join seas/oceans during flood years and protect the environment in less floods years. For example the two mighty rivers of India, Ganga & Brahmaputra are the examples.
The whole process is not as simple as that of the article author thinks.
Dr. S. Jeevananda Reddy
I watched a TV program on beavers last night.
It was the best dam program I have ever seen.
Damn!
Lakes are BAD.
That is why humans like them so much.
I guess the BAD fish also like them and the birds and the reptiles/mammals that congregate around them and the insects and the plants that grow next to them.
All lakes and all life is therefore BAD. Water and wildlife are not environmentally sustainable.
What is it that saps critical reasoning skills from climate scientists? Can’t this “department chair” and “co-author” see the utter contradiction between these two sentences, quoted in same paragraph no less:
(1) “Dams don’t just have local environmental impacts. It’s clear they play a key role in the global carbon cycle and therefore the Earth’s climate,”
(2) “For more accurate climate predictions, we need to better understand the impact of reservoirs.”
If you need a better understanding of the “impact of reservoirs” on climate (the plea for research money), how can you already have reached the conclusion that reservoirs play a “key role in . . . the Earth’s climate (the promise of how your research will turn out if you do get the money)?”
There is no contradiction. I do not understand what you are thinking to believe there is a contradiction.
It is obvious that one can identify something as an important contibutor to an effect but also understand that you do not know the exact magnitude of that contribution. Therefore there is no contradiction between identifying a key role and saying better understanding is needed for more accurate predictions.
That is the logical argument, but to illustrate we can use an analogy. You see an army marching towards your border. It would be true to say that the approaching army could play a key role in your countries immediate future.
For a more accurate prediction on the effect on your country, it would be true to say that a better understanding of the approching army is needed.
Please note that the analogy is for illustrative purposes only and does not form part of the actual argument.
Iimnology is the area of study concerning fresh water bodies and systems. They apparently cycle as much carbon as an ran despite freshwater being tiny fraction of the oceans. They act as net sinks or we would hear about it.
It’s “Limnology,” not “Iimnology.”
Because they might adversly affect climate we must immediately get rid of all devices and structures that hold water or affect its natural flow in any way. That means no more hydroelectric power or any form of indoor plumbing. All streets and roads artificially affect the flow of water so they should be removed as well including all other structures made by Man. You’r not even allowed to cup water in your hands for drinking because it may adversley affect global climate. This is in addition to the idea that we all need to stop making use of any goods and services that make use of fossil fuels in any way. I am sure that if we all abide by what I am saying here we will have a better world.
This one comes under Scott Adam’s “An absurd absolute”, where the loser of the argument restates the other person’s reasonable position as an absurd absolute.
Anthony, your site gives me the update Chrome spam.
WordPress…
Forrest refuses to engage with science that is not settled.
Science is about exploring what could be. If all you want is what we already know is, you are not interested in science.
I will quote you: ” I look forward with keen interest to reading what IS, not what COULD BE.”
When you read what could be, you stopped reading. When someone interested in science reads what could be, they continue because they are interested in what could be.
Now who am I to pick on respected scientists…. but here goes anyways.
This is from the article:
“Dams don’t just have local environmental impacts. It’s clear they play a key role in the global carbon cycle and therefore the Earth’s climate,” said Philippe Van Cappellen, a Canada Excellence Research Chair in Ecohydrology at Waterloo
Now one of my fervent beliefs is that people will always overstate the importance of their work and this is a primary drive in alarmism. This is a perfect example.
What is a dam? It is simply a barrier that changes a river into a lake. Now, to state the obvious, there are a shit load of lakes out there already and dams have only added a tiny fraction of lakes.
So are dams really a “key” player in the global carbon cycle? Of course not. They may be key in the unknown portion of the global cycle though.
Has anybody ever heard of a scientist stating “This work is a tiny sliver of new information that we can use to help understand nature”. Nope, I didn’t think so.
Probably alarmed it will also reduce SLR and recharge aquifers. I’ve suggested using selected impoundment to recharge large reservoirs like the Ogallala (world’s largest?) that stretches from Iowa to Texas and San Joaquin Valley, CA. I’ve often wondered why damage designs didn’t include lifting silt sufficient to maintain the river’s burden of silt downstream – a self cleaning system operating hydraulically. Silt is no good for a dam either.
‘dam designs’ (illiterate #*¿§¶ language benders).
Why do Leftists hate reliable electricity? Yeah, rhetorical.
Let me get this straight. We turn countless square miles of desert into lakes and they conclude that man just changed the climate? No kidding…but what does that have to do with CO2?
Seeing the Forest Through the Trees; Political Ideology and Federal Grants are Blinding Climate “Scientists” From Seeking the Truth
Really? Changes in the carbon in rivers vs lakes is the important factor when building a dam and measuring its impact on climate change? The claim is so absurd it is laughable, and highlights just how corrupt and wasteful Federal spending on climate research truly is. Yes, I know that particular study was paid for by the Canadians, but the same thing happens in the US.
https://co2islife.wordpress.com/2017/05/22/seeing-the-forest-through-the-trees-political-ideology-and-federal-grants-are-blinding-climate-scientists-from-seeking-the-truth/
Thanks, Anthony! Unbeknownst to many, the reservoirs associated with dams are a substantial source of methane produced from microbial digestion of the organics in the sediment. https://www.washingtonpost.com/news/energy-environment/wp/2016/09/28/scientists-just-found-yet-another-way-that-humans-are-creating-greenhouse-gases/?utm_term=.9b535b4cfdf1