Global Warming May Decrease Forest Carbon Storage, Not Increase

There have been hopes in the scientific community that as the increased levels of carbon dioxide in the atmosphere warmed the planet’s climate, the forests would grow and increase their carbon storage capacity. But new research suggests that another factor — increased litterfall — may turn about any increased carbon storage.

Litterfall is any dead plant material, such as leaves, bark, and twigs, which fall to the ground. Increasing the amount of litterfall may, according to the researchers who were led by scientists from the Centre for Ecology & Hydrology and the University of Cambridge, UK, affect the amount of carbon stored in the soil.

The research team studied results from a six-year experiment in a rainforest at the Smithsonian Tropical Research Institute in Panama, Central America. The project was focused on the study of how increases in litterfall may affect carbon storage in the soil.

What they found was that the extra litterfall triggers an effect known as priming. Priming is when fresh carbon from plant litter provides energy to micro-organisms which in turn stimulates the decomposition of carbon stored in the soil.

“Most estimates of the carbon sequestration capacity of tropical forests are based on measurements of tree growth,” said lead author Dr Emma Sayer from the UK’s Centre for Ecology & Hydrology. “Our study demonstrates that interactions between plants and soil can have a massive impact on carbon cycling. Models of climate change must take these feedbacks into account to predict future atmospheric carbon dioxide levels.”

The study concludes that even though forest growth may allow the trees to store more carbon, the loss through the soil could unbalance that increase.

Their estimates suggest that a 30% increase in litterfall could release approximately 0.6 tonnes of carbon per hectare from lowland tropical forest soils each year.

This estimate amounts to more than the estimates of increased carbon storage in trees.

Given how much of our planet is covered by tropical forest, and the resulting level of carbon stored in the soil, such an increase could have dramatic and devastating global consequences.

Source: Centre for Ecology and Hydrology
Image Source: tylerhoff on Flickr

11 thoughts on “Global Warming May Decrease Forest Carbon Storage, Not Increase”

  1. The article does not mention why litterfall would increase. 30% seams to be a big increase. Is this a 30% increase in the number of trees that then drop 30% more leaves?

  2. Several of these comments are breathtakingly disturbing and depressing, esp. given the overwhelming scientific evidence that they refuse to acknowledge.  Clearly, more must be done to close the gap between what people beleive about climate change and what scientists KNOW about climate change.

  3. This is an interesting study. It again shows how many variables interact to influence the climate and ecosystem.

    “CO2 fertilization” of tree / forest growth (and Net Primary Production) is limited by nitrogen availability, as Norby et al showed. That is, the growth increase reduces bioavailability of soil nitrogen (which must be “fixed” by microbes)…so, given litterfall, one would think that decomposition (by miucrobes and oxygen))of the biomass would return some nitrogen to the soil, but perhaps the majority (along with the CO2) is put back into the atmosphere.

    This component does not seemed to be addressed. It would be helpful if the researchers broke down (for us) the cycle that is at work here, or, that is being studied.

    You can find info on the Norby study here:

    1. Ha!….certainly, methane gas (out-gassing) is a wild card in climate change…there is evidence showing that the Triassic (marine) extinction was caused by a massive release of methane…whether another would wipe out land animals/plants is speculative…but possible if sufficiently global.

  4. I CANNOT believe you folks are STILL pushing this 100% discredited fraud of an issue … JUST GIVE IT UP and go live your life. The greenhouse gas arguments are a pure FICTION, yet you continue to peddle the BIG LIE. We should already be ‘boiling’ to death according to all your debunked armageddon theories, but it isn’t happening at all is it, so you simply find another chicken-little angle of attack. Go away.

    1. Are you off your rocker? First of all, we ARE seeing scorching heat, record flooding (New York just set its one-day flooding record), and plenty of other things climate scientists predicted. 2nd, 97-98% of leading climate scientists have not been convicted of any fraud at all — all investigations into the matter just further back up what they are telling us — that humans are causing accelerated climate change that is ALREADY wreaking havoc on humans across the world.

      the fraud was the publishing of out-of-context quotes in such a way as to make climate scientists look like the criminals. Fraud, indeed, but on the other side.

  5. Man made global warming has been to shown as the hoax it is.
    The faked emails by the East Anglica Univ were yet another nail in this frauds perpetuation. No one has explained how 1 mile of ice was melted over Manhattan NY 15,000 years ago. Man’s impact with a population under 10 million globally in 12,000 BCE surly had no impact.
    The Earth simply warms & cools cyclically. Use your mind the facts exist!!!

    1. Jeez, another off their rocker, misinformed commenter (love how you come to our site in teams). The fraud was clearly not on the side of the scientists — every independent investigation has shown that. But who broke into Univ emails? Who published quotes completely out of context to make scientists look like they were doing something wrong, when they clearly weren’t? Who is really the criminal?

      97-98% of publishing climate scientists show that humans are causing ACCELERATED climate change today, and NUMEROUS OVERARCHING SCIENTIFIC organizations have backed them up now. NONE have backed up the deniers.

      Yes, get your facts straight. You may think that you understand climate science from reading a few denier blogs, but these are REAL SCIENTISTS who have been studying climate science for decades and come to very sound conclusions, taking all of the natural factors into account as well. Get your facts straight and use your own mind.

      1. Interesting how the first denier ends his comment with ‘go away” yet it was he/she that came here!

        Stepping back from the complex science for a moment might help the deniers come to a realization: the belief that the atmosphere and oceans have an unlimited capacity to absorb CO2 and GHG pollution, without ANY consequence or causal change…is clearly, obviously wrong.

        Deniers: consider starting a barbeque in your living room sometime…invite all you friends and neighbors…making sure to close all windows/doors/vents…how long before people are braking down the walls?

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