Termites are spreading as the climate warms and could increase carbon emissions, study finds

Termites are likely to begin expanding their range southwards as the planet’s temperature rises.

The findings of a new global study published in the journal Science show the insects may then accelerate the emission of carbon into the atmosphere as that spread takes place.

Scientists analyzed the roles of termites and microbes in the decomposition of deadwood.

They found microbes behaved according to well-established trends, but the role of termites in breaking down wood became disproportionately higher as the temperature increased.

“We saw an increase in decomposition by termites of up to seven times [for every 10 degrees Celsius increase in temperature],” Alex Cheesman, a senior research fellow at James Cook University in Cairns, said.

“They have this really quite high response to temperature which we weren’t expecting.”

A global study

The idea for the study came at a research workshop in the world heritage-listed Daintree Rainforest in far north Queensland.

More than 100 collaborators became involved, setting up a network of 133 sites across every continent except Antarctica.

Alex Cheesman says more research into termite activity is needed.(ABC Far North: Christopher Testa)

Two blocks of Pinus radiata – a type of wood commonly used in house frames – were placed at each site, to measure the relative roles of termites and microbes in breaking down the wood.

Termites are already found in cooler areas, such as Tasmania, but they typically play a more limited role in wood decay there compared to fungi and microbes.

However, the extent to which termites only found in the tropics might spread southward, or northward in the northern hemisphere, is not yet known, Dr. Cheesman said.

“We are expecting a 2C or 3C rise potentially and that could cause a significant expansion of their home range,” he said.

Still many unknowns

The other implications, including the consequences a termite expansion could have for natural ecosystems, are still to be determined.

But researchers are concerned that as the temperature warms, increased termite activity will send carbon back into the atmosphere faster, fueling further warming.

Lead researcher and University of Miami tropical biologist Amy Zanne said the role of termites in wood decay had until now largely been ignored, meaning the “massive effect” termites could have on carbon cycling and interactions with climate change has not been accounted for.

Termites.
Researchers analyzed the role of termites in decomposing wood, compared with microbes, at more than 100 locations worldwide.(ABC Science)

Dr. Cheesman said termites, unlike microbes, can transfer carbon into methane when they break wood down.

“Many people might know methane actually has a greater warming potential than CO2 itself,” he said.

He said it was important to better understand the risks of “positive feedback loops, which means you have uncontrolled carbon release”.

“If you start looking at the financial implications as well, these unknowns around global warming are going to be the big concern going forward,” he said.

Dr. Cheesman said this research focused on the role of termites in natural systems, rather than the four percent of termites considered pests.

James Cook University researchers will work on another project next month, with their colleagues in Miami, looking at the effect termites have on standing biomass, rather than deadwood.

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