Across Oahu and other parts of Hawaii, recent flooding has left thousands of families displaced, 400 homes destroyed, many more damaged, and communities facing a long road to recovery. The economic toll exceeds $1 billion, with agricultural losses alone at $10 million. And Hawaii is not alone: Across the Pacific, multiple tropical cyclones are currently churning through vulnerable island communities, underscoring how quickly disasters can cascade across the region.
But the rebuilding effort now taking shape carries a less visible risk. If Hawaii does not plan carefully for the cement, sand, timber and other materials that reconstruction will require, recovery itself could drive up costs, damage ecosystems, and weaken the long-term resilience it is meant to restore.
Disasters on this scale do not just destroy homes and roads. They create a sudden, massive demand for the materials needed to replace them. Globally, major disasters routinely destroy or damage hundreds of thousands of buildings at once, generating the equivalent of five to 15 years’ worth of reconstruction demand in a matter of days. When demand spikes that sharply, supply chains buckle, materials grow scarce and prices jump — often by 30% to 40% or more.
The result: Recovery slows, and rebuilding becomes more expensive.
That scramble for materials can shift environmental and societal impacts elsewhere, with cascading effects across rivers, forests and communities.
It can mean sand mining that erodes riverbanks and destroys aquatic ecosystems, as seen in Sri Lanka in the wake of the 2004 Indian Ocean tsunami. Or it can mean expanded quarrying and cement production, as seen in Haiti following the 2010 earthquake, where intensive quarrying around Port-au-Prince degraded land, consumed water and generated significant pollution.
Disasters also leave behind staggering amounts of debris — from concrete and masonry to twisted metal and hazardous materials — that create a different kind of danger. The 2023 Türkiye–Syria earthquake generated an estimated 100 million cubic meters of rubble — enough to fill roughly 40 Great Pyramids of Giza. In the aftermath of Typhoon Haiyan in the Philippines, more than 500,000 cubic meters of debris clogged waterways and ended up dumped in wetlands.
Left unmanaged, this debris becomes more than a cleanup challenge. It becomes a hazard to public health and the natural systems communities depend on.
There is also a climate cost. Cement and concrete production already account for roughly 12% of global greenhouse gas emissions. When disaster recovery sharply increases demand for those materials, emissions rise with it, adding to a destabilized climate that makes future disasters more destructive and recovery more costly.
The good news is that the methods to rebuild more efficiently and with less collateral damage already exist: tools to measure the full lifecycle impact of materials, systems to map damage and anticipate supply needs, and techniques to reuse and recycle debris instead of dumping it. The problem is not a lack of solutions. It’s that no system ensures they are used consistently or at scale.
Hawaii is one of the most challenging places to build, shaped by geographic isolation, regulatory constraints, labor limitations, and intense demand pressures. Climate change has compounded these challenges. When disasters such as this year’s flooding and the 2023 wildfires strike the archipelago, the path forward becomes even more difficult.
But Hawaii also has an opportunity to lead by hardwiring resilience into how it rebuilds. Across the islands, local builders, community organizations and others are already developing innovative, sustainable approaches tailored to Hawaii’s unique constraints. State and local leaders can build on this momentum by making materials planning a central component of disaster reconstruction from the outset.
That means anticipating supply bottlenecks before they drive up costs, prioritizing lower-impact materials over the fastest available options, and designing systems to sort, reuse, repurpose and recycle debris at scale — turning waste into a resource. Just as important, recovery efforts must be held accountable for whether they reduce environmental and societal harm rather than simply shifting it elsewhere.
The true test of resilience comes after floodwaters recede and communities begin to recover. Hawaii’s goal should not be merely to replace what was lost as quickly as possible, but to rebuild in ways that protect the land and sea, reduce future risk and leave communities stronger than before.
Anita van Breda is senior director of environment and disaster management for the World Wildlife Fund.