To see how helpful greenhouse gas reductions could be, the authors evaluated the possible health improvements that could be achieved over the next two decades in Sao Paulo (Brazil), Santiago (Chile), Mexico City and New York.

BBC: Olympic flame and rings at dusk PA

The best economic prospects in this region lie in more modestly sized cities like Santiago, the capital of resource-rich Chile, and even Campinas, Brazil, a growing smaller city--with 3 million residents--that lies outside the congested Sao Paolo region.

FORBES: New Geographer