October 11, 2016

Frequently Asked Questions about Hurricane Matthew and Climate Change

Did climate change cause this hurricane?

In general, hurricanes just happen. They need warm water, moist air and converging winds to form. But, a number of studies have found that warmer ocean temperatures are fueling stronger North Atlantic hurricanes.

The number of North Atlantic Category 4 and Category 5 hurricanes has roughly doubled since the 1970s. In the case of Matthew, ocean waters were at record high temperatures. The oceans have absorbed most of the extra energy from global warming and the North Atlantic has warmed more than other oceans—0.7°C since the 1980s.

Did climate change make Matthew worse?

Hurricanes now cause more damage because of climate change. Sea level rise has made storm surge flooding worse. Globally, sea level has risen around 8 inches, and local factors have caused greater increases in some places, especially on the East Coast.

Since the early 1900s, seas have risen about 10 inches at Mayport, Florida, and about 12 inches at Fort Pulaski, Georgia, and Charleston, South Carolina (based on NOAA tide gauges). This means that storm surge in those areas is riding in on seas 10 and 12 inches higher, and as a result the surge reaches further inland. Keep in mind, the water keeps moving inland until the ground rises slightly, and many states in the Southeast are very flat near the coast.

Climate change is also affecting rainfall. Warm air holds more moisture, so as the atmosphere warms, rainfalls are more likely to come in heavier downpours.

UCS looked at how storm surge affects historic sites, military installations and the electricity grid along the East and Gulf coasts and measured how the impacts will grow worse over time with sea level rise.

  • Our analysis "Landmarks at Risk" shows climate change—including sea level rise and increasingly intense North Atlantic hurricanes—is putting at risk landmark historic sites around the country. Those in the path of Matthew included NASA's Kennedy Space Center, Canaveral National Seashore; Castillo de San Marcos and St. Augustine’s Historic District, in Florida; and Charleston’s Historic District.
  • Our analysis “Lights Out? Storm Surge, Blackouts, and How Clean Energy Can Help” looked at how power plants and substations are likely to be affected by storm surge flooding from various categories of hurricanes now and in the future in five metropolitan regions, including the Delaware Valley, southeastern Virginia, the South Carolina Lowcountry, southeastern Florida and the central Gulf Coast. We found if a Category 3 hurricane hit Charleston 14 out of 16 substations and the only power plant in the city could be in the path of anticipated storm surge.
  • Our analysis “The US Military on the Front Lines of Rising Seas" found that hurricane storm surge at military installations will worsen significantly over time. If sea level rises with current high carbon emissions—about six feet by 2100—by the end of the century:
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    • A Category 2 storm that hit Naval Station Mayport in Jacksonville, Florida, would produce storm surge flooding deeper and more severe than a Category 3 storm today with the majority of the flooding at the station being about 10-15 feet deep. A Category 4 storm would expose about 80 percent of the station to flooding that is about 15 feet or more deep, compared to roughly 50 percent today.
    • A Category 1 storm that hit Hunter Army Airfield in Savannah, Georgia, would produce storm surge flooding equivalent to a Category 2 storm today, and would expose about 45 percent of the Airfield to flooding, compared to 25 percent today.
    • A Category 1 storm that hit Naval Submarine Base Kings Bay in St. Marys, Georgia, would produce storm surge flooding roughly equivalent to a Category 2 storm today. A Category 4 storm would flood nearly 95 percent of the base, and more than half of the base would be under 20 feet or more of water, compared to almost none of the base today.
    • If the Paris Climate Agreement were fully implemented, it would limit global sea level rise to 11–24 inches.

Do hurricanes create public health hazards?

Yes, they can. There are the immediate threats to life and limb caused by high winds, storm surge and flooding. There are also longer term health risks that can persist long after a storm is over.

Our analysis “After the Storm: The Hidden Health Risks of Flooding in a Warming World” described the top five health risks of extreme precipitation and flooding: drowning while attempting to drive through rising water, drinking contaminated tap water, being exposed to fouled water bodies, coming into contact with backed-up sewage in the home, and being exposed to mold.

The report points out that heavy rains can contaminate drinking and recreational water with sewage, petroleum products, pesticides, herbicides, and waste from farm animals, wildlife and pets. Floodwaters may contain more than 100 types of disease-causing bacteria, viruses and parasites.

Is the country preparing for more damaging hurricanes in the future?

The emergency response at the federal, state and local levels in the last week or so has been tremendous. That said, Americans continue to live, relocate to, and build in places that are at high risk of being hit by hurricanes, flooding and other types of disasters. This pattern is putting more people and property in harm’s way, creating a growing challenge for first responders trying to keep people safe and increasing the cost of damages.

As coastal states rebuild after Matthew, decisions must be made with climate change in mind, and investments, often taxpayer-funded, should help communities become more resilient. The country grappled with these issues after Sandy and some uneven progress was made at best. UCS has created a set of principles—"Toward Climate Resilience: A Framework and Principles for Science-Based Adaptation"—that outlines criteria that can help guide rebuilding.

Overall, the Obama administration has taken important steps to help the nation prepare for climate change and other types of disasters, such as updating the federal flood risk management standard, integrating climate change into agency planning processes and creating a climate resilience toolkit. But much more needs to be done at the federal, state and local levels. Congress must play a role in legislating a more comprehensive response to disasters and climate change, beyond addressing immediate disaster aid.

Are disasters hitting any communities harder than others?

Yes. When a disaster strikes we see the same old pattern: while all people in an affected zone are impacted, some communities are hit harder than others.

Communities with high numbers of elderly, very young, or low-income residents, or residents with ill health, may have fewer resources to prepare for disasters or a limited ability to relocate. They may have less economic or political clout to ensure they get the attention needed from disaster relief agencies, and may be more likely to have livelihoods and living conditions devastated by extreme events. In the event of a storm that brings flooding, for example, low-income families and individuals may lack transportation to get out of harm’s way, live in places that are more prone to flooding, or live or in older, less safe housing.

Many minimum wage earners on the coast work in service industries that are vulnerable to storms, such as the tourism industry. Flooding can close businesses and shut down roads and bridges used to get to work, leaving people without a paycheck during a time when it’s needed most. Low- and fixed-income households also may not be able to afford to pay for insurance that could help them rebuild and recover.

Our analysis “Surviving and Thriving in the Face of Rising Seas” focused on low-income and minority communities on the frontlines of climate change, and called on federal government agencies, including FEMA and HUD, and state agencies that make funding allocation decisions to target disaster aid and preparedness- and recovery- funding to vulnerable communities. The report provided a screening tool that agencies can use to help identify these communities.

 

The Union of Concerned Scientists puts rigorous, independent science to work to solve our planet's most pressing problems. Joining with people across the country, we combine technical analysis and effective advocacy to create innovative, practical solutions for a healthy, safe, and sustainable future.