Climate Change Raises Manhattan's Death Toll by 20 Percent in Summer

Things are about to get a bit hotter in Manhattan--and it's likely to take a toll. Researchers have discovered that rising temperatures will increase the death toll linked to a warming climate by as much as 20 percent by the 2020s. That will make you think twice before taking those sweaty subways.

During the summer and winter in New York, there are always deaths related to either warm or cold temperatures. People die of heat stroke, hypothermia or exposure. Yet as the climate changes, so too do these deaths. Warmer winters mean that there may be less cold-related deaths while hotter summers mean that there will be more heat-related deaths.

In order to examine how changing temperatures might affect the Big Apple, researchers examined temperature readings throughout the city. They found that, in general, temperature was already drastically increasing. In fact, daily records from Manhattan's Central Park showed that average monthly temperatures already increased by 3.6 degrees Fahrenheit from 1901 to 2000--that's substantially more than global and U.S. trends.

Yet the warmer temperatures in Manhattan aren't all that surprising. Cities tend to concentrate heat, which means warmer temperatures only exacerbate the problem. In each of the past three years, the city has seen temperatures at or above 100 degrees Fahrenheit, and projections for the future foresee average increases of 3.3 to 4.2 degrees more by the 2050s and 4.3 to 7.1 degrees by the 2080s.

How do these temperatures affect mortality rates, though? Researchers examined temperature projections from 16 different climate models, downscaled them to Manhattan and then put them against two different backdrops. One assumed rapid global population growth and few efforts to limit emissions. The other assumed slower growth and technological changes that would decrease emissions by 2040. In order to create a baseline for estimating temperature-related deaths, the scientists used the 1980s when an estimated 370 people died of heat and 340 people died of cold in Manhattan.

So what did they find? The projections indicated that there would be increased mortality under both scenarios. In the 2020s, there was an increase of 20 percent in heat-related deaths set against a decrease of 12 percent in cold-related deaths. There was, unfortunately, a five to six percent increase overall in deaths. Yet these projections worsened further in the 2050s and 2080s. There was a net increase of 15 to 30 percent of temperature-related deaths, which would mean about 1,000 annual deaths in Manhattan

"This serves as a reminder that heat events are one of the greatest hazards faced by urban populations around the globe," said co-author Radley Horton, a climate scientist at the Earth Institute's Center for Climate Systems Research.

The findings reveal the importance of combating heat through preventative methods. Already, Manhattan is planting trees on roofs, opening air-conditioned centers and making surfaces more reflective. These efforts could help stem the tide of heat-related deaths in the future.

The findings are published in the journal Nature Climate Change.