Wildfires are "absolutely" linked to global warming and increasingly intense heatwaves, the UN climate chief has said, as bushfires burned out of control in Australia.
The comments come as debate rages in Australia - whose new Prime Minister Tony Abbott once described the science behind man-made climate change as "absolute crap" - about whether there is a link between the infernos and global warming.
Asked on CNN if there was a link between climate and wildfires, Christiana Figueres, the executive secretary of the United Nations Framework Convention on Climate Change, said "yes there is, absolutely".
"The World Meteorological Organisation has not established a direct link between this wildfire and climate change - yet," Figueres said. "But what is absolutely clear is the science is telling us that there are increasing heatwaves in Asia, Europe and Australia, that these will continue, that they will continue in their intensity and in their frequency."
Australia's Bureau of Meteorology data shows 2013 is on track to become the country's hottest year on record, surpassing the previous mark set in 2005, according to the non-profit think tank Climate Council.
Last month was the hottest September recorded in Australia, with national average temperatures 2.75 degrees Celsius higher than the long-term average.
Debate has raged about whether climate change has contributed to the bushfires blazing out of control west of Sydney, which have destroyed several hundred homes and cost one man his life.
Firefighters yesterday deliberately merged two major blazes in a desperate bid to manage the advancing infernos ahead of weather conditions that are expected to worsen the situation.
Crews made up largely of volunteers worked tirelessly along trails in heavily forested areas to try to prevent the blazes becoming one out-of-control "mega-fire" that could race towards a third blaze nearby.
New South Wales state Rural Fire Service commissioner Shane Fitzsimmons warned: "There is a very real potential for more loss of homes and loss of life."
He urged anyone who did not need to be in the Blue Mountains region, home to 75,000 residents, to leave, although no mass evacuations were planned.
"The forecast and scenario for tomorrow is about as bad as it gets," said the fire chief. Temperatures in the mid-30s Celsius, lower humidity and wind gusts of up to 100km/h are predicted today before more favourable conditions from tomorrow.
In the state's worst fire emergency in almost 50 years, dozens of blazes have been extinguished or contained, but 57 are still alight, 17 deemed out of control.
The Blue Mountains is the main focus of concern because of a huge fire in the Lithgow area.
Figueres said Abbott's decision to repeal a carbon tax on emissions designed to combat climate change put in place by the previous government would come at a high price politically.
"We are really already paying the price of carbon," she said. "We are paying the price with wildfires, we are paying the price with droughts.
Figueres called for action to address rising greenhouse gas emissions. "What we have seen are just introductions to the doom and gloom that we could be facing."