Air conditioning is spreading faster than almost any other household technology.
In hot countries it is no longer a but a health measure.
kill mainly the old, the sick and outdoor workers.
A cool room at night is the cheapest protection available.
The is that cooling warms the planet.
Units run on electricity that is still largely produced by coal and gas.
They also leak that trap far more heat than carbon dioxide.
Demand peaks exactly when the is weakest, on the hottest afternoons.
Three responses are being tried.
Efficiency standards remove the worst units from the market.
Building rules require shade, and , which cut the need for cooling.
Solar power matches the demand curve well, since the sun shines when rooms are hottest.
None of these removes the problem, but together they slow it.