Forecasting the weather, its effects and how we ought to plan is based on the idea that we understand the world. We certainly know how much it has rained in the past, how hot or cold it got, how many hurricanes barreled through our communities and how many droughts parched them. And we know the cost of this weather in the loss of lives, property and peace of mind.

But what if past performance isn’t an accurate indicator? What if the history we use to judge the risks Mother Nature presents, and to plan accordingly, tells us less than we’ve always thought?

If that’s so, then the future could be devastatingly unpredictable. Severe weather will become far more intense and far more common. That’s particularly frightening in light of how little we’ve done to respond to the lesser risks we did understand.

With Hurricanes Harvey and Irma, we have two all-time champion weather events in just over a week.

With the more than 50 inches of precipitation it dumped on Texas, Harvey delivered the largest rainfall in the history of the continental United States.

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The odds of a “500-year storm” occurring in one location in any year, if the historical record is to be believed, are 1 in 500. Harvey, preceded by Allison in 2001 and Claudette in 1979, was the third such storm to hit Houston in 39 years. As Irma marauded over the Caribbean, it packed astonishing winds exceeding 185 mph for more than 24 hours. That’s the longest such period ever recorded for any storm. Hurricane Jose is right behind Irma, and Katia struck Mexico Saturday with deadly force.

There are three ways that changing climate patterns are making such storms more dangerous than they otherwise would have been.

  • Ocean levels are up. The sea level off Miami has risen by at least 3 inches since 1992, and is rising about another inch every three years. That means storm surges roll farther inland, and “sunny-day flooding” waterlogs neighborhoods even without bad weather, a problem on the South Shore of Long Island, too. Water levels in the metropolitan area are up about 18 inches since the mid-1800s. That’s why Sandy’s storm surge was so devastating in 2012.
  • Water temperatures have been rising, with the Atlantic Ocean heating by 2 degrees Fahrenheit over the past 100 years. Warmer oceans create hurricanes with stronger winds, like Irma’s.
  • Air temperatures are up, too, more than 1 degree since 1979. Warmer air can hold more moisture, and that means what would have been heavy rains at a lower temperature can be torrential thanks to higher ones.

All of this means our history of storms and the damage they caused might not tell us much about the frequency or effect of future storms. Record precipitation events have quadrupled, on average, since 1990 worldwide. As a result, Americans and our governments have been failing to deal properly with even the risk level we did understand, in two ways:

  • We are building too near oceans and in flood plains, even those devastated by previous storms. Hurricane Andrew crushed South Florida in 1992, killing 65 people and inflicting more than $25 billion in damage. But in the past 35 years, the population in that region has grown by 6 million people. Insurance experts projected that Irma could cause damage in Florida costing $100 billion, though more rigorous construction standards put in place since Andrew might help prevent the loss of life.
  • We have refused to properly price the federal flood insurance program and failed to force people to maintain policies they are required to carry. As a result, the National Flood Insurance Program is $25 billion in debt, and it’s estimated that at least half the people in the United States who are mandated to have flood insurance do not. At some point, there may not be any insurance available to cover coastal properties.

When storms like Irma and Harvey and Sandy hit, our interest is to save lives, help people financially and get communities back on their feet. That’s as it should be, and how well we do it is one measure of both our government and our society.

But it’s becoming increasingly clear that if we want to keep doing all that, these communities must be built very differently. They might have to be built higher, with different construction methods, with more protections or even in different places.

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Smart planning has to take precedence over short-term booms. Entire cities, such as Houston, can’t be so low-lying and covered in cement that they essentially become swimming pools once the waters arrive. Expensive taxpayer-funded infrastructure to serve construction in areas that may be underwater in 50 years shouldn’t exist, nor, really, should the homes and businesses it serves.

And the price for oceanfront living will in the end have to be borne by the people enjoying the views, not all the other taxpayers inland.

The storms are coming, faster and more furiously than anyone might have predicted. The way we structure our world has to reflect that.