People in the world's smallest countries, those that contribute the least to climate change, are the hardest hit, especially by flooding. And the situation is getting worse. These are the results of a study conducted by the University of Bristol and published Nov. 10 in the journal Environmental Research Letters. The research found that, on average, nearly one in five people among the inhabitants of small island developing states - about 8.5 million people in total - are currently affected by coastal and inland flooding. Three of these 57 countries, concentrated in the Pacific, Caribbean, Indian Ocean and South China Sea, namely the Bahamas, Guyana and Tuvalu, tripled that percentage to more than 60 percent of the population, according to the findings.

Against the backdrop of record rainfall and catastrophic flooding in Valencia, Spain, the findings further emphasize the serious risk of flooding to people in all parts of the world. Lead author of the study Leanne Archer, Research Fellow at the Cabot Institute for the Environment at the University of Bristol, said: “Flooding is now a real and worrying threat to so many people around the world. This study shows that small developing island nations, often overlooked, already suffer from disproportionate levels of flood exposure, even though they contribute less to climate change.”

The projections also showed that the number of people affected by sea level rise, storm surges and extreme rainfall events, including tropical cyclones, in these countries will increase significantly in the future, even under the least worst-case scenario of global warming. “The results should be a call to action to support these countries in adapting and mitigating these extreme impacts, even in the lowest emissions scenario,” Lynn said confidently. SIDS is a group of island nations and territories with smaller populations of between 1,000 and 7,000,000 people that the UN believes are particularly vulnerable to the impacts of climate change.

Coastal flooding is an important flood risk factor because populations are often more concentrated along the coastline. The results showed that inland flooding is actually also a huge problem for SIDS, which accounts for the vast majority of the population's overall risk - 81%.

Lynn, who conducted the research for her PhD, said, “Previous studies have only focused on coastal flooding, which represents a significant underestimation of the impact. This is also the first time a comprehensive picture of flood risk has been mapped across all 57 countries. The modeling provides striking evidence that climate change is having an unfair impact on places and people that have contributed at least to greenhouse gas emissions.”

Going forward, the situation will only get worse.