These leaders are at the front lines of the link between global warming and hurricanes. They understand that with warmer air comes warmer water, which evaporates quickly, putting water vapor into the atmosphere. In turn, the warm air holds the vapor longer, so when a storm happens, it drops more rain. At the same time, the extra heat in the air and water means there is more energy to feed the storm, raising the wind speed of the hurricane. Finally, higher sea levels (also a result of warmer water) leads to storm surge.

Many of these impacts are avoidable. But the longer we take to reduce greenhouse gas emissions from fossil fuels, the worse these impacts will be, and the steeper the human and economic costs. A few years ago, I contributed to a report for the Risky Business Project, a bipartisan group set up to assess economic impacts of climate change. We estimated that rising seas would likely swallow between $5.6 and $14.8 billion of coastal Florida property by 2030. Using historical hurricane data, we estimated that rising sea levels would likely cost the Lone Star state $3.9 billion per year by 2050.

Our one-in-twenty and one-in-one hundred projections were far more severe, and much closer to what we've actually seen in the past few weeks. In fact, the most recent cost estimate of the damages from Irma and Harvey is $290 billion. That figure doesn't include the extra cost of higher gas prices across the country as Houston's fossil fuel facilities slowly come back online. It doesn't account for the damage to fragile ecosystems. And it doesn't even begin to account for the lives lost, the loss of community as families are displaced and homes, schools and places of worship are destroyed.

That's the thing about climate change—as long as we continue on our current emissions pathway, what was once a remote possibility becomes a likely outcome. To change the trajectory, we must alter our path.

We can start with better planning that takes climate science into account. Across the country, local policy makers must incorporate climate change into their infrastructure and planning decisions, especially when those decisions have decades-long consequences. We can no longer afford unlimited development in flood-prone areas, or to deliberately ignore how the ocean is reclaiming entire neighborhoods with sea level rise. We must make our energy grid more resilient with solar and wind technology-both of which are quick to begin producing energy after a disaster.

When politicians spend public funds without considering climate change, they squander taxpayer money and put their constituents in danger. With the federal government in denial, it's up to city and state leadership to listen to scientists, recognize what is happening all around them, and plan accordingly. As Harvey and Irma demonstrate, doing nothing on climate change is a radically risky choice, one that comes with a price tag no one is happy to pay.

Commentary by Kate Gordon, a senior advisor at the Paulson Institute, where she provides strategic support on issues related to climate change and sustainable economic growth, and a nonresident fellow at the Center on Global Energy Policy at Columbia University. She is also the founding director of the Risky Business Project, an initiative that assesses the economic risks of climate change, and the author of the 2015 report "Come Heat and High Water: Climate Risk in the Southeastern U.S. and Texas." Follow her on Twitter @katenrg.

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