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Global warming ‘widens forest fire zone’

Climate change has doubled the area affected by forest fires in western US over the past 30 years, according to a new study – and scientists predict the danger will spread further.

Since 1984 heightened temperatures and resulting aridity have caused fires to spread across an additional 41,439 square kilometres, the research shows.

Report co-author Park Williams, from Columbia University, says climate change is “running the show” in terms of creating fuel, and we should prepare for bigger fire years.

Average temperatures in forested parts of the US west have risen about 1.5°C since 1970 and are predicted to keep rising, drying out land and vegetation.

Insurance Information Institute figures show last year’s fire season set a record for area burned, with 68,151 wildfires covering about 4.1 million hectares.

Last year’s fires in northern California cost insurers more than $US1 billion ($1.31 billion), while the insured bill for Canada’s Fort McMurray fires earlier this year was $US3.6 billion ($4.74 billion).

The study shows 55% of the increase in forest aridity that is expected to prompt fires can be attributed to human-influenced climate change.

Researchers say climate’s role in increasing aridity has grown since 2000, and is expected to keep doing so. The study did not account for factors that are offshoots of climate change, and may therefore be understating its effect, they say.