It was an odd juxtaposition:
As news outlets were reporting last winter about astonishingly
frigid conditions in Russia, where nearly 40 deaths had been linked
to temperatures as low as 24 degrees below zero, they were also
reporting an announcement by climate experts that 2005 was the
hottest year worldwide in more than a century.
There, in
a nutshell, is the difference between weather and climate. Although
that distinction is lost on many people, leading to considerable
public confusion about whether global warming is a real threat or
just a scare tactic by radical environmentalists bent on prying
Americans from their SUVs, it is an important one to make. To
understand why nearly every climate expert on the planet believes
the industrial world’s hundred-year binge on fossil fuels has set
the stage for wrenching disruptions, you must look beyond the
events of a season or a year.
If you do that, the news
only 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.
It is
part adventure story, bearing passing resemblance to
journalist-climber John Krakauer?s bestselling account of disaster
on Mount Everest, Into Thin Air. But Bowen’s
book also provides a thorough and readable introduction to the
evolving science of global warming. The researchers he accompanies
spend their time drilling into high-altitude glaciers in the
tropics, analyzing ancient ice for clues to the mechanisms and
patterns of climate change over millennia.
According to
climatologists at the Goddard Institute for Space Studies, the
global average temperature last year was the highest in the era of
recorded data, which reaches back to the 1890s.
The five
warmest years on record have occurred within the past eight years,
the scientists reported, reflecting an apparent acceleration in the
rate at which the planet is growing warmer. Average global
temperature has risen 1.44 degrees in the past century, but 1.08
degrees of that increase have occurred in the past 30 years, they
reported.
A century, while a significant span of time in
human terms, is not really very long. As every schoolchild learns
from picture-book depictions of ice sheets and woolly mammoths, the
planet’s climate has undergone extreme shifts over longer periods.
Until relatively recently, scientists had little idea what caused
those shifts, or even how big they were.
That’s where
researchers such as those in Bowen’s book enter the picture. For
decades, they’ve been trundling around the world, looking for ice
in the unlikeliest of places: the tropics. Using ingenious
machinery, they have bored holes thousands of feet deep into
mountaintop glaciers and ice fields, some of which have persisted
for more than half a million years, extracting core samples that
preserve in their chemistry a record of climate and other
conditions prevailing when the precipitation originally fell from
the sky.
Ice cores from the polar regions have long been
analyzed for similar purposes, but they provide an incomplete
picture of global climate dynamics, which appear to be strongly
affected by the amount of solar energy falling onto 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 incidentally, that ice is
rapidly vanishing. The famous snows of Kilimanjaro? Gone in 15
years, at the current rate of melting. The same thing is occurring
in the Himalayas and the Andes. For that matter, it is also
happening in North America, where the glaciers of Glacier National
Park will have vanished by 2030, and the Cascades and Sierra Nevada
will have lost all or most of their permanent
ice in the same span. Alaska’s glaciers are receding so fast you
can practically see it happening. Arctic sea ice coverage is
declining by 3 percent a decade and recently reached a record low.
Four years ago, the Larsen B ice shelf in Antarctica
— a slab the size of Rhode Island — collapsed and
disintegrated.
It may have been a bitterly cold winter in
Moscow, but the evidence all points to a much hotter future. And
that should be enough to send chills down anyone’s spine.
John Krist is a contributor to Writers on the Range, a
service of High Country News (hcn.org). He is a
senior reporter for the Ventura County Star in
California.
Republish our articles for free, online or in print, under a Creative Commons license.
