As some degree of climate change is already evident, scientists are beginning to look at whether slightly warmer temperatures in American cities could have some indirectly positive benefits.

Obviously, most of the events associated with climate change are anything but positive: ie. flooding and hotter summers. But along with studying how to mitigate those factors, scientists are looking at ways cities could use those warmer temperatures to fight climate change.

A New York Times article published yesterday looks at the heat island effect in cities (which is very present in Louisville) and how those cities could show how the rest of the planet will adapt as the world warms. Warmer cities could help plant growth, which could then help reduce the carbon dioxide in the air.

“The city is our baseline for what might happen in future decades, and with all the negative effects global warming may have, there may be a bit of a silver lining,” said Stephanie Searle, a plant physiologist who led a Columbia University research project on tree growth, and now works as a biofuels researcher at the nonprofit International Council on Clean Transportation. “Higher nighttime temperatures, at least, may boost plant growth.” Robust growth takes more carbon dioxide out of the atmosphere.

Still, some emissions are not helpful to plants. There are also plenty of modern pollutants, like ozone and heavy metals, which are toxic to plants, to humans or to both. And so far, the long-term effects on plant life on a heated planet are unclear. “I try to avoid words like ‘good,’ ‘bad,’ ‘detrimental’ or ‘beneficial,’ ” said Kevin L. Griffin, an ecophysiologist at Columbia University who participated in a study about the “heat island effect” on the red oak trees in New York.

The effects of higher, mostly urban emissions are what prompted Dr. Ziska to reappraise global warming as a potential benefit to humanity. In an essay last summer in the journal Proceedings of the Royal Society B, Dr. Ziska and a group of colleagues from across the world argued that an expected increase in world population to 9 billion people from 7 billion by 2050 necessitated a “green revolution” to enhance yields of basic grains. Carbon dioxide, the group suggested, could be the answer.

This evidence would suggest as Louisville plants more trees–a stated goal of the Tree Commission–it could help the heat island effect and reduce carbon dioxide emissions. But the article warns that some pollutants are detrimental to plant growth…and those include ozone, which is still prevalent in Louisville in the summer.

Erica Peterson is WFPL's Assignment Editor.