1. What is climate change’s effect on the severe storms seen recently, from Maria to Michael?
Before one starts to attribute Americans’ recent bad luck with hurricanes to climate change, it’s important to acknowledge that hurricanes have been wreaking havoc on the United States since before there was a “United States.” The first permanent nonnative settlement on the continent, Jamestown, Virginia, was nearly abandoned after a 1609 hurricane sank some resupply ships en route to the fledgling colony. The subsequent winter became known as Jamestown’s Starving Time.
More than four centuries later, these storms still inflict significant damage. But climate change is making them worse. The strength of hurricanes is directly linked to temperatures on the surface of the ocean, which is why hurricanes are generally confined to the earth’s tropical regions. Ocean temperatures are rising, along with those on the rest of the planet. As a consequence, future hurricanes are projected to be more intense, meaning higher rainfall totals and wind speeds.
Some recent research suggests that climate change can also slow ocean currents, thereby reducing the forward motion of hurricanes. For example, both Harvey in 2017 and Florence this year stalled when they made landfall, causing trillions of gallons of water to be dumped on Texas and the Carolinas, respectively. As the oceans warm, they also expand, and the resulting sea-level rise contributes to higher storm surges during hurricanes. To be honest, there is still quite a bit science doesn’t know about how hurricanes will manifest in a warmer world, but climate change certainly seems to be a threat multiplier.
2. What policies should address these effects, from long-term storm planning to recent weather events?
Investment in hurricane forecasting is probably the single biggest success story about policies related to hurricanes. These valuable public investments have been made over multiple decades. Although early hurricane-tracking services date to the late 19th century, it was only in the 1980s that numerical weather-prediction models began to demonstrate skill in their forecasts. Today, through the National Hurricane Center, Americans get impressively accurate forecasts of storm track, intensity, storm surge, and rainfall days in advance, which enables communities to prepare, evacuate, and position response and recovery resources.
Despite this success, several complicated hurricane-related challenges urgently need attention. The first is reducing the exposure of people, assets, and infrastructure to winds, rain, and storm surge. The difficulty here is that communities are already planned, homes and roads are built, and investments are made in businesses without long-term resilience in mind. Meanwhile, more and more people are moving to coastal communities. Communities need new kinds of resilience-related policies that direct local land use and where to build or rebuild.
A second challenge is increasing the capacity of people and communities to emerge unscathed from severe storms. On this front, the nation has made a lot of progress through building codes and the lessons learned after Hurricane Andrew devastated Florida in 1992. Building higher in flood zones, more-stringent design loads for wind, hurricane ties for anchoring roofs, and impact-resistant glass have all become common features of structures in many coastal regions of the country. As a result, wind has become a much smaller component of hurricane damage than water is—specifically, storm surge and flooding from extreme rainfall. That said, states differ markedly with respect to building codes, which means that different communities have different levels of vulnerability.
Third, policy can help individuals, businesses, and communities recover from damage that can’t be avoided. Insurance is the standard recovery method, but, with flooding becoming the most significant peril from hurricanes and many people lacking flood insurance, thousands of Americans lose everything every year. Since 1968, the National Flood Insurance Program (NFIP) has provided coverage at below-market rates to those whom the private insurance market deems too risky. But low NFIP uptake by homeowners, outdated floodplain boundaries, and the political headwinds of pricing NFIP coverage to reflect the risk mean that every hurricane blows a bigger hole in the federal budget. So a lot of attention now focuses on rethinking when and where the federal government should step in to provide a safety net and figuring out how to empower homeowners and communities to better help themselves.
Overall, policymakers are well aware of the vulnerability of the nation and its communities to extreme weather events, such as hurricanes, which is why the institutions, investments, and practices are currently in place. What policymakers have been slower to appreciate is that the nature of the risk is changing—not just because of climate change but also because of changing patterns of development and the increasing concentration of people and wealth in harm’s way. The question at hand is whether the status quo will continue or approaches to risk management will be reconfigured to better address the trends being seen.
3. How are these storms, which have received a lot of attention in the eastern United States, related to other natural events, such as wildfires in the west and big typhoons in Asia?
Given that the atmosphere is just one massive fluid layer, a disturbance in one location tends to be accompanied by disturbances in other locations, like waves in a pool. For example, recent years have seen a trend toward hot, dry winters in the southwest with cold, wet winters in the northeast—causing winter weather to be labeled “bipolar,” both figuratively and literally. This phenomenon is caused by high pressure over the Pacific Northwest, western Canada, and Alaska, which causes the jet stream to loop down into the U.S. Midwest, bringing Arctic air with it. So completely opposite weather patterns in different parts of the country have a common underlying cause. Similar dynamics occur around the world depending on the loopiness of the jet stream. Recent research has hypothesized that climate change—particularly, the warming of the Arctic—might make the jet stream even loopier. Hence, although it seems counterintuitive, we now often hear “global warming” in the same sentence as “polar vortex” or “snowmageddon.”
4. What has RAND done in this area? How did you get involved and why?
RAND has an impressive history of undertaking research and analysis to support climate-change risk management and enhance disaster preparedness, response, and recovery. The Water and Climate Resilience Center has been RAND’s hub for research to inform decisionmaking on the management of water resources and urban quality in response to changes in climate, population, and land use. RAND has also been a leader in helping cities, the federal government, and philanthropies think about how to make communities more resilient to all types of shocks and stresses. I recently had a role through RAND’s Homeland Security Operational Analysis Center in supporting recovery planning for Puerto Rico’s water sector, which was devastated during Hurricanes Irma and Maria last year. Right now, I am involved in a project to help large multinational companies think about how to successfully navigate the changes in climate policy, technology, and consumer preferences associated with a changing world.