« Return to this article

Know the West

Climate-change clues — in tropical glaciers


To understand why nearly every climate expert on the planet believes our hundred-year binge on fossil fuels has set the stage for today’s wrenching weather disruptions, you have to take the long view, looking beyond a single hurricane or heat wave.

If you do that, the news gets worse. And if you really wish to scare yourself, a good place to start is a new book by Mark Bowen, a physicist and mountain climber.

Thin Ice: Unlocking the Secrets of Climate in the World’s Highest Mountains provides a thorough and readable introduction to the evolving science of global warming. But the book’s primary contribution is its vivid description of work on tropical glaciers. Most global-warming coverage focuses on polar regions; Bowen presents compelling evidence that what’s happening at the equator is even more important — and more alarming — than what’s happening in Antarctica, Alaska and Greenland.

Bowen accompanies researchers who extract core samples of ice from high-altitude tropical glaciers, some of which have persisted for more than half a million years. Those samples preserve a record of the climate and conditions that prevailed when the precipitation originally fell.

Global climate dynamics appear to be strongly affected by the amount of solar energy reaching the Earth’s surface. Most of that energy enters the atmosphere over the equator, which gives the record preserved in tropical ice particular importance.

Not coincidentally, that ice is rapidly vanishing. The famous snows of Kilimanjaro? Gone in 15 years, at the current melt rate. The same thing is occurring in the Himalayas and the Andes, and in North America, where the glaciers of Glacier National Park will have vanished by 2030. Arctic sea ice coverage is declining by 3 percent a decade and recently reached a record low.

Climatologists at the Goddard Institute for Space Studies found that the global average temperature last year was the highest in the era of recorded data, which reaches back to the 1890s.

And all of the evidence points to a much hotter future. That should be enough to send chills down anyone’s spine.