Our Lakes are Stuck in a Loop That’s Speeding Up Climate Change

Scientists have discovered that freshwater lakes appear to be suffering from a feedback effect that could speed up the rate of global warming.

When it comes to climate change, scientists warn that there are certain tipping points and events that may cause the observable warming that we’ve seen over the past few decades to escalate much more quickly than before and in ways that we can’t easily control or prevent.

Climate Feedback Loops in Freshwater Lakes

Some of the events hastening climate change are the result of climate feedback loops, where a process adds to the warming effect which in turn reinforces the conditions that make warming possible.

An example is the Arctic’s peat-lands which release more and more of the greenhouse gas, nitrous oxide, as they warm. This, in turn, will add to the warming effect and cause more gas release, and so on.

Now, researchers from the University of Cambridge have identified a new feedback loop, and it’s happening in our lakes.

Lakes generate methane when microbes living in the lake’s sediment break down plant matter. The scientists in this study wanted to investigate what effect, if any, global warming might be having on this process.

By comparing the methane output of forests with their nearby lakes, the researchers were able to observe an interesting effect. They found that while forest-derived biomass–for example debris from broken trees and other such vegetation–tended to trap carbon, biomass from the aquatic plants that grow in the lakes themselves actually appeared to boost the production of methane — and the effect wasn’t small .

In fact, lake plants being broken down released 400 times the amount of methane as plant waste from nearby coniferous forests. They also observed that 2,800 times the level of methane was produced by aquatic plants breaking down compared to the breakdown of deciduous trees.

Publishing in “Nature Communications“, the researchers explain that because methane is a gas that is a “super insulator”, this feedback loop is particularly concerning.

“Methane is a greenhouse gas at least twenty-five times more potent than carbon dioxide,” study author Dr. Andrew Tanentzap from the University of Cambridge’s Department of Plant Sciences, is quoted as saying. “Freshwater ecosystems already contribute as much as 16% of the Earth’s natural methane emissions, compared to just 1% from all the world’s oceans.”

“We believe we have discovered a new mechanism that has the potential to cause increasingly more greenhouse gases to be produced by freshwater lakes, ” Dr. Tanentzap explains. “The warming climates that promote the growth of aquatic plants have the potential to trigger a damaging feedback loop in natural ecosystems.”

Common Cattail

Common Cattail. Photo credit: Thinkstock.

The researchers then looked at some predictive modeling from around the area known as the Canadian Boreal Shield to try to gauge how this problem might grow as the planet warms.

By identifying just one aquatic plant that seems be flourishing as a result of this feedback loop, known as the common cattail, they used species distribution models to calculate how the plant might grow.

They predict that the numbers of common cattail alone could double in fifty years in just the Boreal Shield. The effect could be worse elsewhere. Further research is needed to explore the rate of methane release in other areas.

This red flag is important for another reason though. Methane production has been underestimated as a driver of climate change, and it’s only in the past decade or so that we have really started to understand just how critical it is that we curb and cut our methane output.

Curbing Methane Production to Fight Climate Change

Clearly, there’s not much we can do about natural processes like lake biomass breakdown, but we can intervene in other areas to try to curb methane production and thereby slow or even reverse global warming and interrupt these feedback loops.

Some of the biggest human-led sources of methane include our use of fossil fuels, specifically fossil fuel extraction and production,  as well as intensive livestock farming. Other notable methane producers are landfills, rice production, and biofuels.

Fossil fuels and livestock are the two largest producers though, making up around 60 percent of human-led methane production. Fortunately they are both relatively easy to reduce, too, if we are prepared to act.

Livestock seems the most actionable for us at the consumer end of the market, as many of us can make the switch to a plant based diet relatively easily and inexpensively, which in time will drive down the demand for intensive cattle farming. F

rom the top down, governments must act by sticking to the Paris Climate Agreement and reducing fossil fuel use and production.

These two actions alone will not be cure-alls, but what emerges from this research is that inaction could cost us dearly as the climate warms and more of these feedback loops are triggered.

Photo credits: Thinkstock.

49 comments

KimJ M
KimJ M3 months ago

tfs

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KimJ M
KimJ M3 months ago

tfs

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KimJ M
KimJ M3 months ago

"We are a plague on the Earth. Either we limit our population growth or the natural world will do it for us..." - Sir David Attenborough.
From 1930 the world population has risen from 2 to over 7.6 billion today. We are destroying the world`s natural habitats at an astounding rate, mostly for food production. Our roads, hospitals, schools, and houses are increasingly cramped. Resource usage per person increases every decade, while our total numbers continue to rush upwards. ALL energy efficiency gains go towards accommodating ever-increasing numbers of people.
WE ARE ALL RESPONSIBLE FOR SPREADING THE WORD: NO MORE THAN 2 CHILDREN PER FAMILY.
"All environmental problems become harder and ultimately impossible to solve with ever more people." - Sir David Attenborough.

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Peggy B
Peggy B4 months ago

TYFS

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Chrissie R
Chrissie R4 months ago

Thank you for posting. Interesting concept.

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Marija M
Marija M4 months ago

tks

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Glennis W
Glennis W4 months ago

Really frightening stuff all the skeptics Thank you for caring and sharing

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Glennis W
Glennis W4 months ago

Very informative Thank you for caring and sharing

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Glennis W
Glennis W4 months ago

Great information and advice Thank you for caring and sharing

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Glennis W
Glennis W4 months ago

Very interesting article Thank you for caring and sharing

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