Marsh McLennan Launches Flood Risk Index, Mapping the Impact of River Flooding and Coastal Surges in 188 Countries

Sep 2, 2021

NEW YORK, September 2, 2021 — Today, Marsh McLennan (NYSE: MMC), the world’s leading professional services firm in the areas of risk, strategy and people, launched its Flood Risk Index to help governments and organizations better assess their exposure and vulnerability to more frequent and severe flooding.

Over 2.2 billion people are exposed to flooding globally.1 Since 1980, over 4,500 flood disasters resulted in over $1 trillion in damages, accounting for 40% of natural catastrophe losses globally.2,3,4

“Recent disasters in the U.S., Germany and China show that floods are pervasive and routinely underestimated. As climate change, economic and demographic trends, and a chronic shortfall in investment in resilience combine to drive risk higher, it is time for governments and businesses to rethink their approach to flood risk,” said Rob Bailey, Director of Climate & Sustainability, Marsh McLennan and co-author of the Index. “This index will help organizations gain a greater understanding of where their people, assets, and supply chains are most at risk, and take steps to mitigate the worst potential impacts of flood.”

The Flood Risk Index sets out the potential impact of flooding on populations and economic assets in 188 countries, analyzing the risk on a country-by-country basis, by the type of hazard (river or coastal flooding), exposure to flood risk (the total people and assets in harm’s way) and vulnerability to flood damage (the susceptibility of people and assets to harm) for each nation.

The Index also allows users to compare scores for hazard, exposure and vulnerability between two countries, or between one country and the global average. Users can also gain insight from geospatial data sets made available by multiple research institutions and international organizations to visually assess the potential impacts of river and coastal flooding on urban and rural areas.

According to the Marsh McLennan Flood Risk Index, the world’s largest economies are all severely threatened by flooding. In the United States, about 11 million people and $3 trillion in asset value are exposed to flooding. Only Japan ($3.7 trillion) and China ($7.5 trillion) have higher economic exposure.

According to the Index, the five G20 countries with the highest hazard scores for river and coastal flood are:
1. Germany
2. Argentina
3. China
4. France
5. Russia

The five G20 countries with the largest shares of population and economic assets exposed to flooding are:
1. China
2. India
3. Argentina
4. Russia
5. Germany

In the event of flooding, the five G20 countries where people and economic assets are most vulnerable to harm are:
1. Indonesia
2. Brazil
3. India
4. Russia
5. Mexico

The Index accompanies Marsh McLennan’s Rethinking Flood, a four-part series examining the implications of flood risk for corporations, governments, and society. It follows the recent report, Sunk Costs: The Socioeconomic Impacts of Flooding

Through its four businesses, Marsh McLennan is helping its clients adapt to climate change, from navigating the transition to a low-carbon economy to managing the physical risks associated with extreme weather events like flood. The Company delivers insights, analysis, and reflections on conversations, developments and innovations related to a warming world via its Climate Hub.


About Marsh McLennan

Marsh McLennan (NYSE: MMC) is the world’s leading professional services firm in the areas of risk, strategy and people. The Company’s 78,000 colleagues advise clients in 130 countries.  With annual revenue of $18 billion, Marsh McLennan helps clients navigate an increasingly dynamic and complex environment through four market-leading businesses. Marsh provides data-driven risk advisory services and insurance solutions to commercial and consumer clients. Guy Carpenter develops advanced risk, reinsurance and capital strategies that help clients grow profitably and pursue emerging opportunities. Mercer delivers advice and technology-driven solutions that help organizations redefine the world of work, reshape retirement and investment outcomes, and unlock health and wellbeing for a changing workforce. Oliver Wyman serves as a critical strategic, economic and brand advisor to private sector and governmental clients. For more information, visit, follow us on LinkedIn and Twitter or subscribe to BRINK.


1For a 1-in-100 year return period. Rentschler, J., & Salhab, M. (2020). People in Harm’s Way: Flood Exposure and Poverty in 189 Countries. The World Bank.
2EM-DAT: OFDA/CRED International Disaster Database, Université Catholique de Louvain, Brussels, Belgium.
3Ritchie, H. & Rose, M. (2019). Natural Disasters. Retrieved August 30, 2021.
4Munich Re. (n.d). Risks from floods, storm surges and flash floods: Underestimated natural hazards. Retrieved August 30, 2021