May 16, 2002 A region in the western tropical Pacific Ocean may
help scientists understand how Venus lost all of its water and
became a 900-degree inferno. The study of this local phenomenon
by NASA scientists also should help researchers understand what
conditions on Earth might lead to a similar fate here. The
phenomenon, called the ‘runaway greenhouse’ effect, occurs when
a planet absorbs more energy from the sun than it can radiate
back to space. Under these circumstances, the hotter the surface
temperature gets, the faster it warms up. Scientists detect the
signature of a runaway greenhouse when planetary heat loss
begins to drop as surface temperature rises. Only one area on
Earth – the western Pacific ‘warm pool’ just northeast of
Australia – exhibits this signature. Because the warm pool
covers only a small fraction of the Earth’s surface, the Earth
as a whole never actually ‘runs away.’ However, scientists
believe Venus did experience a global runaway greenhouse effect
about 3 billion to 4 billion ye