It should be common knowledge at this point that the effects of climate change on individual weather events can’t easily be pinned down. We know that the climate is warming; we know the reasons why it’s warming. Scientists have a general understanding of what the effects of that warming will be, especially when it comes to equatorial, warm-water weather patterns—hurricanes and typhoons. Warmer temperatures will provide the energy to power larger, more powerful storms. Warmer temperatures farther from the equator will cause tropical storms to maintain their strength longer, and threaten places that seldom needed to worry about such storms before. Rising ocean levels, due both to thermal expansion and the rapid melting of ancient glaciers, will compound the resulting damage.

When it comes to specific storms, however, the complexity of the problem makes it impossible to tease out just what percentage of a named, damaging storm was “caused” by the warmed climate. If Houston floods or the Gulf Coast gets hit with record storm surge, that’s not climate change. That’s weather. Climate change affects weather events, but there’s no way to measure whether an individual storm might not have happened had carbon levels in the atmosphere not risen so dramatically. Scientists have to ask smaller, more measurable questions.

A new study published in Nature aims to estimate the economic costs of climate change in just one modern storm. In 2012, Hurricane Sandy slammed into New York City and the surrounding area, causing widespread damage and flooding. Damage estimates would later pin the economic costs at roughly $60 billion, a gargantuan amount for a single storm. The storm came ashore at high tide, and from an angle that nearly maximized storm surge. It was a worst case scenario.

It’s impossible to know if the same storm would have happened in the same place in a world without rising temperatures, and it’s folly to try to guess. Researchers instead set out to ask a much, much smaller question: Given this storm and its now fully tallied damages, how much did rising sea levels alone contribute to the damage totals?

Now that’s a question that can roughly be answered. We now have extremely detailed maps of the elevation of Manhattan and the surrounding terrain. We know that sea level rise due to climate change varies slightly globally, but past research suggests that anthropogenic climate change has added roughly 8.9 centimeters to New York City’s sea level. We know that the effects of high water are not strictly linear, or as the researchers put it, “many prior studies have shown that there can be nonlinear interactions between coastal floods and sea level rise,” so it’s not just a question of subtracting 8.9 centimeters from flood levels and calling it done. Instead, hydrodynamic modeling of the terrain and flooding was used to generate an accurate picture of both how Hurricane Sandy’s flooding took place and how it would have taken place if local sea levels were just 8.9 centimeters lower.

Short version: It’s a job for a big computer, the best maps that can be found, and a terrifying number of calculations.

When the results were calculated out, the research team was able to estimate roughly 13% of Hurricane Sandy’s resulting damage would not have happened if sea levels had not risen that seemingly insignificant amount of 8.9 centimeters. That comes out to about $8.1 billion of U.S. damage that can be attributed only to fewer than 9 centimeters of local sea level rise, for one storm, in one particular year.

That is … bad. $8.1 billion in damages from an 8.9 centimeter sea level rise doesn’t bode well for storms in other hurricane-threatened areas, like Florida or the Texas coast. $8.1 billion is money that we would rather be spending in countless other ways rather than simply scraping it into regional landfills.

The intriguing bit of this research is that it does seem to be a valid method for estimating coastal storm damages attributable to sea level rise in other major cities. It doesn’t pretend to calculate true total damages, but only the portion attributable to rising sea levels. Individual storms are predicted to become more powerful as ocean waters warm, resulting in higher wind speeds, higher storm surges, and damage zones that reach farther inland—none of that is accounted for.

But if just small changes in sea level can so dramatically impact the resulting damage, it may shake faith in notions that adding a few more seawalls might be enough to get through it. Coming up with accurate estimates for just how much more danger coastal cities are in with every new approaching storm is a good answer to those who believe climate change is “too expensive” to combat. What will the damages be once sea level rise tops 1 foot? 3? 10?