Some of the world 's fastest growing population centers in Asia and Africa are at greatest risk from the impact of climate change , according to a new report . The Climate Change Vulnerability Index ( CCVI ) , published by UK-based risk analysis and mapping company Maplecroft , examined the climate risks and adaptive capacity of 193 nations factoring in population concentration , development , natural resources , agricultural dependency and conflict . A total of 30 countries were classified as being at `` extreme risk '' with Haiti , Bangladesh , Sierra Leone , Zimbabwe and Madagascar making up the top five most in peril , while Vietnam , Indonesia and India all ranked inside the top 30 . The analysis , which forms part of Maplecroft 's fourth annual Climate Change and Environmental Risk Atlas , also assesses climate impacts on towns and cities . Six out of the 20 fastest growing cities worldwide , including Calcutta , India , Manila in the Philippines , Indonesia 's capital , Jakarta and Addis Ababa in Ethiopia , were also classified as at `` extreme risk '' by the CCVI . `` Cities such as Manila , Jakarta and Calcutta are vital centers of economic growth in key emerging markets , but heat waves , flooding , water shortages and increasingly severe and frequent storm events may well increase as climate changes takes hold , '' principal environmental analyst at Maplecroft , Charlie Beldon said in a statement . Beldon says the impacts on cities -- where infrastructures are already struggling to cope -- could have far-reaching consequences for not just local people , but for businesses , national economies and international investors . Manila is the commercial center of the Philippines and its population is expected to rise 20 % this decade , says the report . But , as recent back-to-back batterings from typhoons has shown , it is very vulnerable to climate change and has the highest exposure to extreme weather of the top 20 fastest growing cities in the world , according to the report . Thailand is currently dealing with its own climate-related tragedy which has left hundreds dead . According to Maplecroft , the disaster could have negative knock-on effects for business , particularly locally-based technical companies , leading to wider disruptions to global supply chains . Bangkok faces worst flooding yet . `` As these megacities grow , more people are forced to live on exposed land , often on flood plains or other marginal land . The expansion of population must be met with an equal expansion of infrastructure and civic amenities , '' Beldon said in a statement . The best-performing countries in the report are to be found almost exclusively in Northern Europe , with Finland , Ireland , Sweden and Norway all in the top ten . Iceland heads the list of least vulnerable countries , while Qatar is also considered a low climate risk , coming in 10th . The U.S. is categorized as low risk , although some coastal regions , including Florida , Louisiana , Georgia , North and South Carolina were rated as `` high risk . '' Events like Hurricane Katrina , says the report , highlight how even the economically strongest countries with a large adaptive capacity can find themselves extremely vulnerable to climatic events . The report is released just days before the world 's population is projected to reach seven billion . `` A huge task before us '' The United Nations Populations Fund 's executive director Babatunde Osotimehin described the milestone as `` a challenge , an opportunity and a call to action , '' at the launch of The State of the World Population 2011 report in London on Wednesday .
New report assesses vulnerability of different nations to climate change effects . Areas with fastest growing populations most at risk from environmental impacts . Megacities in Asia and Africa most threatened including Calcutta and Addis Ababa . United Nations launch youth focus on eve of seventh billion population milestone .