Did the Tropical Pacific Drive The World's Warming?

The tropical Pacific slipped into its warm mode in the winter of 1976-77 and has never quite shaken it off. The persistent warm spell in the ocean, computer climate modelers are finding, may have triggered the global climate shift that brought record-breaking warmth to the globe in the 1980's. Some climate researchers suspect that heat was an early sign of global warming from greenhouse gases. If so and if studies by the computer modelers are correct, the tropical Pacific may be a key link in the mechanism of climate change from one decade to the next. This would be a big boost to researchers attempting to understand climatic change as it would allow them to focus on one small, intensively studied region. However, uncertainty continues as a different climatic model identifies a very different ocean source for interdecadal climate change: a regular oscillation in the winds and currents of the North Pacific Ocean that could be masquerading temperarily as greenhouse warming. This article discusses the implications of these different ideas.