The earth’s climate has been evolving continuously over millennia but the last two centuries have witnessed the development of the greenhouse problem, which threatens to change climate in an unprecedented manner.

A major new mapping study by, A British firm specializing in risk analysis, Maplecroft's tool, the Climate Change Vulnerability Index (CCVI), looks at exposure to extreme weather events such as drought, cyclones, wildfires and storm surges, which translate into water stress, loss of crops and land lost to the sea.

Recent studies, reviewed in a special report by UN‘s intergovernmental panel on Climate Change (IPCC), point to strengthening evidence of linked between global warming and extreme weather event.

They analysing climate change vulnerability down to 25km² [15.625 mile] segments worldwide, has revealed some of the world's fastest growing populations (7billion) are increasingly at risk from the impacts of climate related natural hazards and sea level rise.

Countries Ranking

Maplecroft analyzed risks to 193 countries and territories on a national and sub-national basis, meaning some countries might only score a low or medium risk overall but some regions might be a high risk from storms and flooding, such as Miami in the United States.
At a national level, the CCVI rates 30 countries at 'extreme risk,' with the top 10 comprising of Haiti, Bangladesh, Zimbabwe, Sierra Leone, Madagascar, Cambodia, Mozambique, DR Congo, Malawi and the Philippines.

Many of the Asian countries with the fastest population growth are rated as 'extreme risk'. These include the strategically important emerging economies of Bangladesh (2nd), Philippines (10th), Viet Nam (23rd), Indonesia (27th), India (28th) and Thailand (37th).
Haiti is the country most at risk from climate change, while Iceland is the least vulnerable. Africa is especially exposed to drought, severe flooding and wildfires, the report says.
The first 102 nations are all developing ones. Italy is next, at 124, and like Greece ranks relatively highly due to the risk of drought. The UK is at 178 and the country on Earth least vulnerable to climate change, according to Maplecroft, is Iceland. "Large areas of north America and northern Europe are not so exposed to actual climate risk, and are very well placed to deal with it," explains Charlie Beldon, principal analyst at Maplecroft.

City Ranking

The survey looks at the risks facing the 20 fastest growing cities by 2020, many of which are also in countries ranked in the extreme risk category.

"Population growth in these cities combines with poor government effectiveness, corruption, poverty and other socio-economic factors to increase the risks to residents and business," said Maplecroft.

In a parallel analysis of major cities at risk, Maplecroft pointed to Dhaka, Addis Ababa, Manila, Calcutta and the Bangladesh city of Chittagong as being most exposed. Three other Indian metropolitan areas -  Chennai, Mumbai and New Delhi - also not out of danger.
High risk is Chennai, Mumbai, Kinshasa, Karachi, Lagos, Luanda, Kabul, Lahore, Delhi and Guangzhou, while Khartoum, Shanghai, Beijing and Cairo are medium risk.

As many as 150 million people in the world's big coastal cities are likely to be at risk from flooding by the 2070s, more than three times as many as now. Miami in Florida will remain the city with the highest value of property and infrastructure assets exposed to coastal flooding caused by storm surge and damage from high winds, the report said.

Record droughts in Australia and Africa, floods in Pakistan and central America, and fires in Russia and the United States may all be fuelled in part by climate change, some experts say.

China (98) and the United States (160) - the world's No. 1 and No. 2 carbon emitters - are in the "medium" and "low" risk categories, respectively. At the other end of the spectrum, Iceland, Finland, Ireland, Sweden and Estonia top the list of nations deemed to be least at risk. With the exception of Israel and oil-rich Qatar and Bahrain, the 20 least vulnerable countries are in northern and central Europe.
 
Current warming trends are on track to boost average global temperatures by 3.0 degrees Celsius (5.4 degrees Fahrenheit) above pre-industrial levels, according to some predictions.