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Why disasters are getting more severe but killing fewer people

An important but overlooked piece of good news about climate change.

A man on a gurney is rushed into an ambulance by EMTs, with voluminous smoke and orange-tinted air from wildfires surrounding them.
Rescue workers transport a California resident in the wake of the 2021 wildfires. Disasters like wildfires are increasingly destructive, but fewer people are dying.
Josh Edelson/AFP via Getty Images
Umair Irfan is a correspondent at Vox writing about climate change, Covid-19, and energy policy. Irfan is also a regular contributor to the radio program Science Friday. Prior to Vox, he was a reporter for ClimateWire at E&E News.

A curious trend has emerged in recent years.

Many types of natural disasters are causing greater destruction as populations have grown in floodplains, wildfire zones, and hot climates. More people means more property, which is part of why the number of disasters with billion-dollar damage tolls is on the rise in the United States.

And humans are making many of these disasters more severe by changing the climate. Rising average global temperatures are worsening heat waves and torrential rainfalls, and lifting sea levels.

“Widespread, pervasive impacts to ecosystems, people, settlements, and infrastructure have resulted from observed increases in the frequency and intensity of climate and weather extremes,” the Intergovernmental Panel on Climate Change wrote in its most recent report.

Yet despite these growing risks, around the world, disasters in general are becoming less deadly. According to the World Meteorological Organization (WMO), the number of disasters over the last 50 years has increased fivefold, but the number of deaths has fallen by two-thirds.

This is a huge accomplishment — perhaps one of the biggest success stories in modern history — yet it’s easy to overlook. These immense gains are the result of the steady, incremental work of forecasters, planners, architects, engineers, and policymakers rather than any single innovation. And the main metric is averted losses, something that’s often hard to appreciate and tricky to value.

Ben Husser (L) of the Cajun Navy, helps emergency workers transfer a patient to their ambulance after the evacuation of a nursing home due to rising flood waters in Lumberton, North Carolina, on September 15, 2018 in the wake of Hurricane Florence.
Volunteers and emergency workers help evacuate residents of a nursing home after Hurricane Florence brought flooding to North Carolina in 2018.
Alex Edelman/AFP via Getty Images

Nevertheless, some world leaders are paying attention and want to carry these advances further. In particular, the United Nations and the WMO are launching a $1.5 billion program to ensure that everyone on Earth is covered by a disaster early warning system over the next five years. The WMO didn’t specify the details of the program, however, and didn’t respond to requests for comment.

“Early warnings and action save lives,” said UN Secretary-General Antonio Guterres in March. “We must boost the power of prediction for everyone and build their capacity to act.”

As countries like the US stare down another summer filled with wildfires, floods, and heat waves — and with the world likely to overshoot climate change targets — saving lives from disasters is a paramount priority. The past century shows that steady progress adds up, but we can’t take this for granted, because climate change is driving up disaster risks and it will take a coherent strategy to counter them.

Improved disaster prediction is a huge, underrated success story

The downward trend in deaths from natural disasters is something to behold. In the early 20th century, annual deaths from disasters sometimes topped a million. By the 1970s, fatalities fell to roughly 100,000 per year, and in the current decade, to half or less of that number. There have been some years that bucked this trend over the last century as particularly severe disasters struck, but the overall decline holds. And keep in mind that there were just 2 billion people in the world in 1900, compared to 7.8 billion today.

Two main factors have saved lives even among increasingly dangerous disasters and growing populations: better forecasting and a greater ability to cope with storms, floods, fires, and heat waves when they do occur.

Disaster prediction has seen dramatic improvements, especially in the era of weather satellites and vastly more powerful computers. For example, the National Hurricane Center can now project the path of a hurricane 72 hours in advance. In 1990, the center could only make such a prediction 24 hours ahead of a storm, and with less accuracy. Now consider that according to the WMO, having 24 hours of warning ahead of a storm reduces damages by 30 percent. Two additional days of lead time and a more precise storm path is a massive improvement that has helped even more people get out of harm’s way.

US President Joe Biden speaks during a virtual briefing by Federal Emergency Management Agency officials on preparations for Hurricane Ida, in the South Court auditorium of the White House in Washington, DC, on August 28, 2021
President Joe Biden delivers a briefing on Hurricane Ida in front of a map forecasting the storm’s track in 2021.
Saul Loeb/AFP via Getty Images

Forecasters have also extended their lead time for extreme weather like heat waves and severe rainfall, as well as longer-term phenomena like seasonal rainfall or expected cyclone activity in a given year. This allows officials to issue warnings for disasters and prepare for other problems, like famine.

Even for disasters that have multiple intersecting factors, namely wildfires, researchers are getting better at anticipating when the next blazes will erupt. In the US, the National Interagency Fire Center publishes seasonal fire outlooks that can help officials allocate firefighting teams and conduct preventative maintenance.

And when fires do ignite, modelers can factor in weather, geography, and vegetation to predict not just the flames, but other associated impacts.

“If you had a decent idea of what was going to occur in terms of how flammable a particular region is, you could use that information to develop forecasts of what you would expect in terms of something like smoke impacts downwind,” said Matthew Hurteau, a biology professor at the University of New Mexico who studies forest fires and climate.

On the other hand, hard-to-predict disasters are still a potent threat. Tornadoes, for instance, form and dissipate rapidly and are difficult to detect with radars and satellites. Tornado research still depends on observers on the ground. So tornado warnings haven’t improved in the same way as hurricane forecasts. According to the National Weather Service, more than half of tornado warnings are false alarms. As a result, tornadoes remain some of the deadliest weather phenomena in the US.

Geological disasters like earthquakes and volcanic eruptions are even more difficult to predict. Even so, scientists have improved their understanding of where such events will occur, and while they have lead times measured in minutes, parts of the world now have earthquake early warning systems. Better earthquake detection and warnings have also improved tsunami warning systems.

The issue is that the places in the world with the most robust forecasting and alert programs for disasters are often the wealthiest regions. Between 1970 and 2019, more than 91 percent of all weather and climate-related deaths occurred in developing countries, according to the WMO. Only half of the world’s countries have early warning systems in place for multiple hazards, and across regions like Africa, Latin America, and island countries, there are large gaps in weather and climate observations.

So building up disaster warning systems for everyone in the world, and doing so in five years, is a monumental task. “It is a wildly ambitious goal but an important one,” Samantha Montano, an assistant professor of emergency management at the Massachusetts Maritime Academy, said in an email.

The devastation of a disaster doesn’t end with the storm

Despite the epochal scale and devastation of events like hurricanes and wildfires, it can be surprisingly difficult to grapple with the full extent of their impacts. One can add up the casualties when the ground is shaking, the wind is blowing, and the rain is falling, but how many deaths and injuries in the aftermath of the event should be added to the tally?

And when it comes to “natural” disasters, it can be difficult to separate which impacts are from forces of nature and which ones stem from human causes, like construction in high-risk areas or a poor disaster response.

“Historically, indirect deaths have been either not tracked at all or very poorly tracked,” Montano said.

Look at the list of deadliest hurricanes in the US and you’ll notice that most of them were decades ago, with some more than a century in the past. There are a couple conspicuous outliers, however. Hurricane Katrina in 2005, a category 5 storm with winds topping 175 miles per hour, officially killed around 1,800 people. Hurricane Maria in 2017, also category 5, killed more than 3,000. But the true toll of these disasters was likely much greater.

In San Juan, Puerto Rico, darkened buildings line streets at night, with the only lights coming from headlights of passing cars.
Puerto Rico’s power outage after Hurricane Maria in 2017 lasted months, contributing to the death toll of the disaster.
Carolyn Cole/Los Angeles Times via Getty Images

While the storms themselves were exceptionally severe, both hurricanes had long tails of destruction. Hurricane Katrina and the subsequent collapse of levees in New Orleans led to flooding and road blockages that lasted more than 40 days. In the wake of Hurricane Maria, Puerto Rico suffered the largest blackout in US history, leaving residents without power for vital medical devices, refrigerators, and lighting for months.

Warnings may have helped some people avoid the acute elements of the storms, but much of the devastation from these disasters came in their aftermath, stemming from failures to prepare and respond.

“The theory is with better warnings, you should see a reduction [in deaths], and in many cases we do. But then you factor in socioeconomics, and even with warnings, you may still have the death tolls that are very high,” said Craig Fugate, who led the Federal Emergency Management Agency (FEMA) under President Barack Obama.

Disaster warnings don’t eliminate the events themselves, and there are wide disparities in who is equipped to evacuate ahead of a disaster and who has the resources to resume their lives in its wake.

For example, in the US, heat waves are the deadliest weather phenomenon. But even with warnings, there is little to do about them besides seeking air conditioning. Access to cooling, however, varies greatly with income and location. The risks can be managed or reduced, but not everyone has access to those tools; the worst effects often fall on the poorest.

Clearly, warnings are not enough on their own to reduce fatalities. People also need the means to act on those warnings.

We can’t take declining disaster deaths for granted

With climate change, many weather-related disasters are getting pushed toward greater extremes, so even places that once could readily endure storms, floods, and fires are struggling to cope. History is no longer a useful guide. “As we keep seeing record-setting events occurring, looking backward isn’t preparing us,” Fugate said.

Saving more lives thus demands a more comprehensive assessment of the threats that lie ahead and of tactics to deal with them. That could entail more access to air conditioning to cope with heat waves, tougher building codes to help withstand earthquakes, better fire-resistant construction for housing, and stronger seawalls in coastal areas. In some areas, it may require people to move away from areas prone to severe fires or flooding. Reducing emissions of the gases heating up the planet is critical as well.

Even in countries with forecasting systems in place, there is still plenty of room for improvement. While researchers can anticipate the path of a hurricane, they still struggle to predict its intensity, a major factor in its destructive potential.

These are all expensive interventions with huge political implications, but without them, some of the progress in saving lives could stall or reverse. “If we continue on the current path of doing relatively minimal mitigation and preparedness at the same time that we see an increase in risk then, yes, it is possible to see an increase in deaths over time.” Montano said.

And while fewer people are dying, the economic costs of disasters are mounting. In 2021, the US experienced 20 separate weather and climate disasters that cost more than $1 billion.

Chart showing disaster costs in the US.
The number of billion-dollar disasters is on the rise in the US.

The rising damage tolls are a result of having more people and property in the paths of dangerous weather events, as such events increase in severity. Costly disasters are a major concern for the economy and the global insurance industry.

Keeping global warming in check is an overwhelming task, but it should not be a cause for despair or complacency. The success in reducing disaster-related deaths shows that there are effective ways to mitigate some of the worst effects of climate change. Closing the gaps in warnings and building up disaster response systems should be an urgent priority and an obligation, particularly for the countries, like the US, that contributed the most to the problem.

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