Coastal Crisis Ahead: Higher Warming Means Higher Costs and Inequities

New research published in Nature; Natural Hazards reveals that future coastal damages and adaptation costs will rise sharply as global temperatures exceed 1.5 °C. If warming surpasses 2.5 °C, not only do extreme coastal damages increase, but all damages become worse, threatening lives, livelihoods, and economies, especially across the Global South. 

The study shows that high-end damages nearly double when warming crosses 1.5 °C (increasing from $1.3 trillion to $2.3 trillion USD), driven largely by the risk of rapid Antarctic ice sheet disintegration, which could trigger multi-meter sea-level rise. These impacts worsen substantially beyond 2.5 °C (damages increase substantially, from $1.2 trillion to $1.6 trillion USD), with rising damages even in moderate emissions scenarios like SSP2–4.5. 

Unequal vulnerability is a key concern: regions such as Latin America, East Asia, the Pacific, and Sub-Saharan Africa are projected to suffer economic damages well above the global average. Meanwhile, wealthier regions like Europe and Central Asia may fare far better, highlighting stark climate injustice. 

Without proactive mitigation and adaptation, flood costs could soar to trillions of dollars annually by 2100. Sea-level-driven migration may also more than double if Antarctic tipping points are crossed, affecting tens of millions of coastal residents. This highlights the urgent need for targeted investments in coastal resilience, equitable adaptation financing, and stronger international support to protect the most vulnerable communities. 

The study uses an integrated modeling framework to trace the links between emissions, warming, polar change, sea-level rise, and coastal impacts, emphasizing the urgent need for emissions cuts and adaptive planning. Future coastal protection must anticipate high-end risks and be dynamically updated as new scientific insights emerge. 

Feature image: Adaptation costs and damages, %GDP for each region is shown relative to global average and simulations use a constant discount rate of 4%. Credit: (Wong et.al, 2025). 

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