Urban heat

There are hot islands, there are really hot islands, and then there are urban heat islands [PDF] — cities that are hotter, often considerably, than their more rural surrounds. Sound a little strange? Well, you can tell your foil hat-wearing, climate-denying friends it’s nothing new, having been documented as far back as 1810. Simply put, cutting down all the trees, paving over every inch of earth, burying streams in storm drains, and building enormous structures warms things up a bit.

Hot and Bothered - small x  200
Susie Cagle

Some may like it hot, but the good folks of Louisville, Ky., will tell you that it’s not always a good thing. Cursed with often stagnant wind conditions, a dense urban center, and fewer trees than Paul Bunyan’s backyard, Louisville has seen temperatures rise 1.67 degrees F every decade since 1961. If the pattern holds, by the year 2112, we’ll be able to cook lentils in the average tumbler of bourbon.

And what’s worse than one urban heat island? (You’re going to kick yourself when you see the answer.) Two urban heat islands! And that’s just what Baltimore, Md., the Paris of the mid-Atlantic, is facing. Baltimore already suffers from serious second-city syndrome, but being downwind from Washington, D.C., causes climate problems as well. D.C.’s considerable heat island slows down the wind that would otherwise cool off Charm City. Baltimore’s urban heat island is so intense, the growing season has been altered, spring is coming two weeks earlier, and the crabs arrive pre-steamed.