Climate modelers have recognized the possibility of abrupt climate changes caused by a reorganization of the North Atlantic's current pattern (technically known as a thermohaline circulation collapse). This circulation system now warms north-western Europe and transports carbon dioxide to the...

Like today, one hundred years ago air pollution was a matter of grave concern in the world's most polluted cities. In the wake of its famous 1908-9 social survey, the City of Pittsburgh commissioned an "Economic Survey of Pittsburgh" from John T. Holdsworth, a prominent institutional economist...