"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 -- an example of what we may be looking at unless we take actually vigorous action," Christiana Figueres, executive secretary of the U.N. Framework Convention on Climate Change told CNN Monday.
As of Tuesday, a line of wildfires nearly 1,000 miles long raged through Australia's most populous state. Already an area about the size of Los Angeles has been burned.
And last month was considered Australia's warmest September on record.
Australia is the world's highest-per-capita carbon emitter among developed nations.
Elected last month, Prime Minister Tony Abbott's Coalition government aims to scrap the carbon tax -- which went into effect in July 2012 under then-Prime Minister Julia Gillard Labor government -- and take what it considers direct action.
Under the carbon tax system, the country's top 500 polluters are charged $22 for each ton of carbon emitted into the atmosphere and it would have increased to about $23.40 next year.
The coalition's "direct action" plan includes establishing a $3 billion emissions reduction fund, paying for domestic green projects and exploring new carbon technologies.
Asked about the Australian government's proposed plan, the U.N. climate chief told CNN: "What the new government in Australia has not done is step away from its international commitment on climate change. What they are struggling with is not what they are going to do but how are they going to get there."
But Figueres says Australia's direct action plan could be a lot more expensive than pricing carbon.
"They are going to have to pay a very high political price and a very high financial price because the route they are choosing to take to get to the same target agreed by the last government could be a lot more expensive for them, and for the population," she said.
Yet the U.N. official urged putting a price on carbon.
"We are already paying the price of carbon," Figueres told CNN. "We are paying the price with wildfires, we are paying the price with droughts, we are paying the price with all sorts disturbances to the hydrological cycle.
"What we need to do is put a price on carbon so we don't pay the price of carbon," she said.