While ice reflects around 80 percent of the sun's heat, having a cooling effect, blue sea water can absorb up to 95 percent of solar radiation, warming up the sea and accelerating the melting process further.

CNN: Arctic melt worse than predictions

Greenery is critical to counterbalance the "urban heat island" effect from hotter, drier summers, when night-time temperatures remain high because of heat retained by brick and tarmac.

BBC: Time to leave the comfort zone

Heat advisories are in effect for parts of 17 states, with forecasters saying there is no relief in sight: "Hot and hotter will continue to be the story from the plains to the Atlantic Coast for the next few days, " the National Weather Service said.

BBC: US storm-hit millions swelter in heatwave

If the urban heat island effect were large, you would expect to see a bigger trend for calm days when more of the heat stays in the city.

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"Heat, of course, is a cumulative effect, " Watling said.

CNN: Heat expected to fry mid-Atlantic states

Repeated efforts by policymakers to take the heat out of housing have not had a noticeable effect.

ECONOMIST: The latest attempt to prick a bubble

It's important to remember that even as the effect of Superstorm Sandy recedes from the news, there are still devastated areas that are without electricity, heat or hot water.

CNN: Let's not forget Superstorm Sandy's victims

Water is much more efficient than air at absorbing heat and so even with tiny amounts of liquid flowing through the system the researchers saw a significant effect.

BBC: IBM aims to cool chips with water