All things environmental

Musings about the environment and all it touches, from education to city planning

Lions and tigers and bears, oh my! Can they prevent climate change?

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The short answer is no.  Climate change is here, and future change is unavoidable.  As Joe Romm writes, the idea that climate change is reversible is a dangerous myth (he’s referring to the recent op-ed by Joe Nocera).

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But yet, the importance of predators for climate should not be minimized.  I already mentioned the importance of whales: their excrement doesn’t sink, and the fertilizing effect it has is important for carbon sequestration.  Likewise, the presence of wolves scares deer away from tree saplings, allowing for forest re-growth, with the carbon sequestration that that implies.

But now, a new study from BC demonstrates that this applies to most predators. According to Trisha Atwood of UBC, who led the study, “it looks like predators in many types of ecosystems can play a big role in global climate change.”  In the words of Fred Pearce, who reported the study:

Atwood and her team tested the idea in Canada and Costa Rica by temporarily removing fish and insect top predators from ponds, streams and tiny wet ecosystems associated with bromeliad plants. They then logged the impact on the local biomass, including its rate of decomposition – a process which produces emissions. They also monitored how much carbon dioxide was released into the atmosphere.  A consistent pattern emerged: CO2 emissions typically grew more than tenfold after the predators were removed (Nature Geoscience, doi.org/kjm).

Other studies hint at similar effects. Christopher Wilmers of the University of California, Santa Cruz, and colleagues showed last year that vanishing sea otters are linked with higher emissions from North American coastlines (Frontiers in Ecology and the Environment, doi.org/khz). With no otters to eat them, sea urchins thrive and gorge on kelp forests – often called the “rainforests of the oceans” – resulting in major CO2 releases.

According to Atwood, the removal of top predators may have a role in increasing emissions comparable to deforestation.

Thinking that we can stop or reverse climate change with technological fixes like Nocera advocates (carbon burial) is, indeed, foolish.  But that’s not to say that we should try to slow down the problem as much as possible; and that’s a further argument for the protection of wild places and their fauna.  Another reason to protect the Grizzly: climate change!  Who knew!

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Written by enviropaul

March 17, 2013 at 4:33 pm

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