Insects chomping on forest dead wood are responsible for releasing vast amounts of carbon dioxide, a global study involving Irish researchers has found.
he project found dead wood decomposition by hungry insects accounts for emissions equivalent to one-third of those released by fossil fuels.
Much of that is balanced out, as long as forests and soils are healthy and can produce new growth to reabsorb the carbon emitted through the insects’ activities.
Decomposition is important to that process as it releases nutrients back into the soil to aid growth.
However, scientists warn that the cycle could be thrown off balance because insects become more active in warmer temperatures.
As global warming increases, decomposition is likely to become more accelerated, which will lead to more carbon release.
“Insects are cold-blooded, so the warmer it gets, the faster their metabolism,” said Professor John O’Halloran, leader of the team from University College Cork that took part in the three-year study.
“It’s like having too much of a good thing. Forests need decomposition, but the rate at which it happens has other impacts.”
The team carried out their research in Glengarriff Nature Reserve in West Cork, one of the best remaining examples of native Irish woodland.
It was one of 55 forest areas around the world where teams of researchers studied decomposition in 140 tree species.
They found the insects were influenced not only by temperature changes, but by rainfall.
More rainfall combined with higher temperatures accelerated decomposition, but slowed it down in colder areas.
That finding is also important as distortion of rainfall patterns and strength is one of the other most notable effects of climate change.
The study is published in the current edition of Nature and has been hailed as groundbreaking for quantifying the contribution of insects to carbon release from forests.
Prof O’Halloran said every piece of information about how forests work is vitally important in trying to protect them and their role as natural carbon sinks.
“This is helping us to estimate carbon global budgets,” he said.
“We did not have these calculations before, so it enables us for the first time to put a number on the role that insects play.
“It also shows us the importance of forests and how, if we disrupt them – and we’ve seen many examples of that happening – there’s a real impact on the world.”
Forests worldwide are under stress from drought, fires and clearance for farming and timber, so the healthy functioning of remaining trees is crucial.
The study was sparked by research in the Bavarian Forest National Park in Germany, which was replicated by 50 teams on six continents.
“To solve global problems, we have to collaborate globally,” Prof O’Halloran said.
“The local data from Glengarriff is important in itself, but it’s also contributing to helping answer some very big global questions.”