Building Urban Flood Resilience: How Ecosystem Services Can Help Protect Communities and Business

The Liberty Mutual Climate Transition Center and the Boston College Center for Corporate Citizenship (BCCCC) have partnered to publish the report, Building Urban Flood Resilience with Ecosystem Services , which addresses the growing challenge of urban flooding and offers insights and recommendations for corporate leaders, policymakers, and communities to mitigate flood risks and build resiliency.

This report synthesizes empirical literature on urban flooding, impervious surface coverage, ecosystem services, nature-based solutions, corporate responsibility, and flood risk management in the context of climate change.

What is urban flooding?

Climate change is intensifying precipitation, raising sea levels, and ensuring that yesterday's infrastructure is increasingly mismatched to tomorrow's storms. Globally, it is estimated that 2 billion people, a quarter of the human population, live on floodplains. With cities sitting across all these vulnerable landscapes: in active river floodplains, coastal plains, filled wetlands, and low-lying estuarine zones.

This is not driven solely by increased precipitation. A growing body of scientific evidence reveals that the way we build - the expansion of impervious surfaces through roads, rooftops, parking lots, and commercial developments - fundamentally alters the hydrological cycle in ways that amplify flood severity, frequency, and geographic extent.

What role does nature-based ecosystem play in community resiliency against floods?

Nature-based ecosystems act as first-line defenses by absorbing and slowing runoff, reducing peak flows, and lowering localized flood exposure. Science tells us that nature-based approaches, like reforestation and wetland restoration, are the most cost-efficient and effective resilience measures to reduce urban flood risk. Nature-based solutions show benefit-cost ratios from 1.6:1 to 2.8:1 when ecosystem co-benefits like carbon sequestration, reduced disaster damage, and improved health are included.

Communities can get ahead of flood risk taking proactive steps including keeping new developments out of floodplains, reducing paved surface expansion in favor of nature-based infrastructure, protecting forests and wetlands, and upgrading old drainage systems. They can also find businesses and supply chains at risk, encourage safer locations, and develop backup plans.

How can companies support flood resiliency for the communities they operate in?

Flooding will continue to increase costs for companies. Eventually, these costs may become unrecoverable with insurance alone. These risks can be mitigated and costs reduced, but companies can't lead this work alone. Coordination and collaboration between companies, communities, and governments can help maximize returns:

• Land-use decisions embedded in community stakeholder engagement, corporate real estate, supply chain, logistics, and development operations are linked to community flood vulnerability and company resilience.
• Corporate participation in the development of green infrastructure, ecosystem restoration, and nature-based flood mitigation can generate returns that align financial performance with societal resilience.
• Emerging policy and financial frameworks - from green bonds and blended finance to payments for ecosystem services - can create new scalable pathways for corporate leaders to reduce flood risk and ensure resilient business continuity, thereby improving risk profiles and business results.

Why is combatting urban flooding important to Liberty Mutual?

For Liberty Mutual, we define climate resiliency as the ability to prepare for, adapt to, and recover from the physical impacts of extreme weather. Leveraging our risk expertise, we aim to advance the fortification of the built environment, help individuals and communities increase preparedness for natural hazard events, and increase engagement and support for resiliency efforts.​

Through a combination of Liberty Mutual's risk expertise and BCCCC's stewardship and corporate engagement platform, this collaboration aims to test scalable models, measure real-world resilience outcomes and mobilize businesses to invest in ecosystem services as a cost-effective complement to traditional infrastructure, shifting the conversation from recovery to long-term prevention.

For more information and insights, read the full paper .