Despite the usual "coal-fired car" taunts of naysayers, most research suggests that electric vehicles are green and they will only get greener. (Of course, walking and cycling are even greener still — but everything is relative.) Encouragingly, electric cars may also have ancillary benefits way beyond their tailpipe emissions. 

We already know about vehicle-to-grid applications, in which our cars provide energy storage capacity for the electrical grid, smoothing out peak demand and facilitating a greater integration of intermittent renewables. A recent study in the journal Nature suggests another huge benefit: Battery electric vehicles may dramatically reduce the urban heat island effect

The urban heat island effect — a phenomenon in which cities can be a full 10 degrees (Fahrenheit) hotter than their surrounding rural areas — is caused by a multitude of factors, including lots of hard, dark, heat-absorbing surfaces and a relative lack of vegetation. Conventional cars and air conditioning units also play a contributing role, kicking out heat which then gets trapped in the urban environment.

And that's where electric cars come in.

Because electric cars produce significantly less heat than their internal combustion engine-driven counterparts, if adopted on a broad scale, they could significantly reduce the direct contribution of vehicles to urban heat. Better than that, there'd be an indirect contribution too — because less heat means less air conditioning use which in turn means, you guessed it, even less heat. And, as if that were not enough, less energy being consumed by air conditioners means a lower contribution to global warming. And lower global warming means less heat island effect.

Neat, huh?

But how big a difference could this really make? Here's the abstract from the paper by lead author Professor Canbing Li of Hunan University: 

EVs emit only 19.8% of the total heat emitted by CVs per mile. The replacement of CVs by EVs in 2012 could have mitigated the summer heat island intensity (HII) by about 0.94°C, reduced the amount of electricity consumed daily by air conditioners in buildings by 14.44 million kilowatt-hours (kWh), and reduced daily CO2 emissions by 10,686 tonnes.
Now, a lower-emission vehicle that also cuts urban heat islands and reduces apartment air conditioner use is a pretty remarkable case of win-win-win if you ask me. But I'm going to go ahead and posit another potential benefit of mass electric vehicle adoption: If there's less urban heat island effect, and lower particulate emissions, in the city environment — that makes a city much more conducive to walking and biking too. 

Do I have the data to back that up? Nope. But I'm a blogger, not a scientist. And as the world's cities start getting serious about electric buses, taxis and electric car sharing too, we should see this experiment play out in the real world. 

With promising signs that bike infrastructure is finally being taken seriously too, I am hopeful that many of our cities will be way cooler than they have ever been before. 

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