Beetle invasion causes climate change in Canadian forests

An army of rice-grain-sized beetles, attracted by warming weather, has moved into Canada's western forests, where they are killing off swathes of forest, a study said. In so doing, they are causing the mercury to rise yet further.

The voracious horde of mountain pine beetles has invaded about 170,000 square kilometres - a fifth of the forest area of British Columbia, Canada's western-most province, a research team wrote in the journal

The beetles lay their eggs under the bark of pine trees, at the same time injecting a fungus that protects their offspring but kills the trees with the help of the larvae eating their insides.

As trees are felled, the cooling effect of their transpiration, similar to sweating, is also lost.

The researchers measured a corresponding rise in summertime temperatures - about one degree Celsius over the affected areas, said co-author Holly Maness from the University of Toronto.

"The increased surface temperatures we observe are relatively large and may be sufficient to drive further changes in regional climate," she said.