Humble humans

Posted: May 22, 2003 12:00 AM

WASHINGTON--Ira Gershwin didn't know the half of it. He said the Rockies may crumble, Gibraltar may tumble. But terra firma itself is far from firm.

Even the continents are wandering, half an inch to four inches a year. The Earth is a work in violent progress. The engine of its evolution is heat--boiling gas, molten rock and other stuff--left over from the planet's formation 4.5 billion years ago. The heat frequently bursts through Earth's crust, although rarely as catastrophically as it did 120 years ago on the island of Krakatoa.

If Simon Winchester is correct in his new book--Krakatoa: The Day the World Exploded, August 27, 1883'--the current trial in Indonesia of accused perpetrators of last year's terrorist bombing in Bali may be part of the lingering reverberation of the volcanic eruption--the loudest sound in modern human experience, heard 3,000 miles away--that made an island disappear.

Billions of tons of material--six cubic miles of it--were hurled 120,000 to 160,000 feet in the air. They filtered sunlight, lowering the Earth's temperature and creating spectacular sunsets that for months inspired painters and poets.

And in the East Indies outpost of the Dutch empire, where a notably relaxed and tolerant Islamic faith had long flourished, Krakatoa, by terrifying and dispossessing people, may have catalyzed the much fiercer form of Islam that fused with anticolonialism. It is alive and dealing death today.

Although the people of the East Indies will be forgiven for not appreciating this at the time, Winchester says volcanoes are part of what makes this planet hospitable to humans. They do not erupt so promiscuously as to render the planet unfit for life. And by churning the Earth's mantle, they bring fertile soil and useful minerals to the surface, thereby sustaining the outer earth and the biosphere. For a while.

As Earth heads for frigid lifelessness, the leakage of heat from the Earth's interior causes currents of matter to flow--movements measured in millimeters a year--above the molten core and below the crust. Just as, writes Winchester, ``one sees working in a vat of vegetable soup simmering on the stovetop.''

Science in the 1960s at least explained what had long pricked curiosity--the matching concavity of Africa's west coast and the convexity of South America's east coast. According to the study of plate tectonics, there are, depending on how they are defined, between six and 36 rigid plates on the Earth's surface. In ``subduction zones,'' where one plate slips beneath another, the descending plate pulls down untold billions of tons of material and water. This fuels white-hot seas of soup in immense chambers, from which energy seeks to break through the Earth's surface.

Which is what happened in 1883 in the archipelago that now is Indonesia. Krakatoa's eruption resulted in the destruction of 165 villages and the death of 36,417 people. Most died not from the searing ash, pumice and gas but from giant sea waves produced by the Earth's spasm.

The shock wave circled the Earth seven recordable times. Sea surges were detectable in the English Channel. Three months after the eruption, firemen in Poughkeepsie, N.Y., scrambled in search of what they thought was an immense conflagration that caused the sky to glow. Actually, the glow was light refracted by Krakatoa's debris.

The first major catastrophe to occur after the invention of the telegraph and undersea cables, Krakatoa produced an intimation of the ``global village'' 77 years before Marshall McLuhan coined that phrase to describe the world-contracting effect of television. Krakatoa was, Winchester argues, ``the event that presaged all the debates that continue to this day: about global warming, greenhouse gases, acid rain, ecological interdependence.'' Suddenly the world seemed to be less a collection of isolated individuals and events and more ``interconnected individuals and perpetually intersecting events.''

As an epigraph for his book, Winchester chose this from a W.H. Auden poem written in 1944, when the world was in agony and, unbeknownst to Auden, potentially world-shattering knowledge was being acquired at Los Alamos, N.M.:

At any given instant
All solids dissolve, no wheels revolve,
And facts have no endurance--
And who knows if it is by design or pure inadvertence
That the Present destroys its inherited self-importance?

Geology has joined biology in lowering mankind's self-esteem. Geology suggests how mankind's existence is contingent on the geological consent of the planet. Although the planet is hospitable for the moment, it is indifferent--eventually it will be lethally indifferent--to its human passengers.