, 2004: Defusing the global warming time bomb. Sci. Amer., 290, no. 3, 68-77.
At present, our most accurate knowledge about climate sensitivity is based on data from the Earth's history, and this evidence reveals that small forces, maintained long enough, can cause large climate change. Human-made forces, especially greenhouse gases, soot and other small particles, now exceed natural forces, and the world has begun to warm at a rate predicted by climate models. The stability of the great ice sheets on Greenland and Antarctica and the need to preserve global coastlines set a low limit on the global warming that will constitute "dangerous anthropogenic interference" with climate. Halting global warming requires urgent, unprecedented international cooperation, but the needed actions are feasible and have additional benefits for human health, agriculture and the environment.