Thirsty Dog Sights Ice [ YouTube ]
How to use the subway to ventilate NYC, in 3 easy steps:
1) Sail an iceberg down from Greenland.
2) Anchor it next to a subway station, on a line that connects to many other lines.
3) Throw a giant tarp over it so that, as it melts, the cold air is directed into the subway tunnel.
We might need some fans to disperse the cold air, but since sweaty summer heat seems to find its way into every corner of the subway all by itself, probably not.