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Climate change risk to one-third of global GDP: Report

A home destroyed by bushfire as seen on October 21, 2013 in Winmalee, Australia.
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Around one-third of the world's economy by 2025 will be based in countries at "high" or "extreme" risk from the economic impact of climate change, according to risk consultancy Maplecroft.

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Thirty-one percent or $44 trillion of output will be based in countries classified as most at risk from climate change in Maplecroft's Climate Change Vulnerability Index, which considered a nation's exposure to extreme weather events over the next 30 years alongside its capacity to cope with the impact.

"Future projected changes in the frequency and intensity of forest fires, severe weather events, droughts and flooding will affect the population, economy and infrastructure of a country. The effects of rising temperatures, shifting rainfall patterns and rising sea level will also be felt globally, impacting coast lines, plant and animal species, agriculture and human health," the consultancy said in a report on the index published on Wednesday.

(Read more: Your energy stock portfolio's biggest threat: a calculator)

Investing in environment-themed equities

Emerging economies were most at risk, the report found, with India, Vietnam, Indonesia and China among those set to feel the economic impact of climate change.

However, several developed world cities were also judged as vulnerable, including Osaka and Tokyo in Japan and Sydney in Australia.

(Read more: Australian wildfires put heat on climate change skeptics)

The report also warned that water, energy and food supplies will come under pressure, which in turn will affect people and ecosystems. "Growth markets seeking energy security are increasingly faced with water security challenges, with businesses and governments alike looking to achieve more sustainable water and energy use," said Maplecroft.

The Intergovernmental Panel on Climate Change estimates that the mean world temperature between 0.3 Celsius and 0.7 Celsius from 2016 to 2035, with the increase likely to be larger in the Tropics and Subtropics.

(Read more: Forget the lottery, invest in climate change solutions)

—By CNBC's Katy Barnato