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It could have been so much worse. Over 100 tornadoes ripped through several Plains states in just 24 hours over the weekend. Cars were tossed through the air and houses were pulverized. Hail the size of baseballs fell from the sky, crushing anything left in the open. More than what is ordinarily a month's worth of cyclones struck in a single day, yet miraculously, only one, in the Oklahoma town of Westwood, proved fatal, killing six victims who lived in and around a mobile-trailer park. "God was merciful," Kansas Governor Sam Brownback told CNN on Sunday.

But it wasn't just God or chance. The low death toll was also due to a faster and more insistent warning system by weather forecasters, who put the word out early and often and over many platforms that the past weekend could be a dangerous one for the Midwest, thanks to an unusually strong storm system. The National Weather Service's Storm Prediction Center took the unusual step of alerting people in the region more than a day before what was termed a possible "high-end, life-threatening event." Warnings went out over radios, smart phones and TVs, urging people to stay underground or in a tornado shelter for the duration of the storm. And with memories of the more than 500 people who died in cyclones last year still fresh, residents in the affected areas paid attention and stayed out of harm's way.

In the age of climate change, a lot of science and press coverage have been given over to determining whether warming really does make extreme events like heat waves, floods, storms or tornadoes more frequent or more powerful. That's understandable: gradual warming over years or decades doesn't get a lot of attention, but a megastorm like Hurricane Katrina in 2005 or the bursts of killer tornadoes last spring certainly do. It's not just a matter of focusing public attention, however; extreme-weather events kill tens of thousands of people every year, and take a sizable chunk out of the global economy — not something anyone's likely to fail to notice. Last year the U.S. experienced a dozen natural disasters that caused a billion or more dollars in damages, ranging from Hurricane Irene in September to the lingering drought in Texas and the Southwest. If climate change is really supercharging extreme weather — causing death and mayhem — that's one more reason to get a grip on carbon emissions fast.

As it happens, the U.N.'s Intergovernmental Panel on Climate Change published an assessment on the science of extreme weather and global warming just last month — but the answers are cloudy. The panel found that it was likely that man-made carbon emissions are leading to extreme heat, something that should resonate on an April day that was so unseasonably hot that runners were warned away from the Boston Marathon. There was also medium confidence that carbon emissions and other anthropogenic factors are leading to more extreme rainfall — like the Pakistan floods of 2010 — and more intense droughts, like the one much of the U.S. is suffering through right now.

But there's much less certainty on whether carbon emissions are supercharging hurricanes, tropical cyclones or tornadoes. That's due in part to limitations in past data. Today, every tropical depression gets named and tracked, so there's no chance that a hurricane could somehow form without being noticed. And both professional and amateur storm trackers keep a close eye on tornadoes, so even in a cyclone that touches down for a few moments goes into the record books. But in the past, hurricanes were often just sketchily documented and only the strongest tornadoes — or the ones that actually caused damage — likely would have been recorded. The occurrence of strong and violent tornadoes may well have remained relatively stable over the long term; the fact that we're seeing more tornadoes overall now might simply mean that we're noticing storms we might have missed 30 or 40 years ago.

There's no doubt that the actual cost of extreme weather is on the rise, with U.S. insured losses from weather disaster soaring from $3 billion a year in the 1980s to about $20 billion a year in the past decade, adjusted for inflation. But it doesn't automatically follow that those higher costs are due to climate-change-powered superstorms. The U.S. and the world at large are both richer and more populated than they were 30 years ago, and much of that wealth is now concentrated along highly vulnerable areas like coastlines. When a hurricane like Irene rakes the East Coast as it did last summer, it can affect far more people and valuable property than it would in the past. That translates to greater potential losses.

The fact that it's impossible to draw a straight line between climate change and the seemingly more turbulent weather doesn't mean we should act as if the two aren't linked. There's no doubt that warming raises at least the risk of extreme-weather events, something we're thinking about more in the early part of what is shaping up to be a brutally hot year in the U.S. But the fastest way to reduce the death and damage from extreme weather is through adaptation, whether that takes the form of better tornado warnings or micro-insurance policies that allows subsistence farmers in sub-Saharan Africa to bounce back from drought.

There's a reason that 95% of the deaths from natural disasters occur in the developing world; poverty leaves populations unprepared for extreme weather. That's true even within rich nations; it wasn't a coincidence that the handful of deaths caused by tornadoes in the Midwest occurred in a trailer park. But even poor countries or regions can learn to protect themselves. In 1970 a Category-3 cyclone killed an astounding 300,000 people in Bangladesh, yet an even stronger storm struck the country in 2007 and claimed only 4,200 lives — still a heartbreaking loss, but a far smaller one. Climate change and poverty can make extreme weather worse, but it doesn't have to claim lives.

• Bryan Walsh
• An outbreak of 100 tornadoes raises alarms -- and questions