Most people who grew up in the
second half of the 20th century believed that climate change was such
a gradual process that it was almost
imperceptible during the course of
an ordinary lifetime.
There may have been times when
that was true, but it is not the case
now. The earth has recently warmed
so much, and the rate of warming is
now so fast, that the effects have
become increasingly obvious to the
scientist and the layman alike.
The decade of the 1990's was very
likely the hottest of the last millennium. And 1998 -- which had temperatures spiked by a large El Niño phenomenon -- appears to have been the
hottest year ever recorded.
The oceans are rising, mountain
glaciers are shrinking, low-lying
coastal areas are eroding, and the
very timing of the seasons is changing, with spring coming as much as a
week earlier in parts of the Northern
Hemisphere. And all indications are
that the warming of the earth in the
21st century will be significantly
greater than it was in the 20th.
If there were such a thing as a
global alarm bell, now would be an
excellent time to ring it.
"With respect to the climate, we
live in a different world than people
lived in even 25 years ago," said Dr.
Michael Oppenheimer, chief scientist of Environmental Defense, a national environmental research and
For most of the last 1,000 years the
earth's temperature varied only
modestly, moving slowly up or down
by less than one degree Fahrenheit.
But that changed with the coming of
the industrial era in the 19th century.
At that point the earth started getting steadily warmer.
As Dr. Oppenheimer put it, "About
1860 we entered a period of about 140
years in which the rate of climate
change kicked up, and most of the
changes were in the positive direction. Between the late 19th century
and now, the total warming has been
about 0.7 to 1.4 degrees Fahrenheit --
a little more than a degree Fahrenheit if you take the average.
"Then, in the last 25 years, the rate
of warming further accelerated, to
about three times that rate of increase. The actual number is approximately 0.35 degrees Fahrenheit
per decade. And if you look forward
over the coming decades, the rate of
increase could double again."
The effects are myriad. "There is
a pervasive retraction of mountain
glaciers worldwide," said Dr. Oppenheimer. "The glaciers in Glacier National Park are shrinking. And the
projection is that if the trend continues, by the end of this century many
of the glaciers will have simply disappeared.
"Another place where we see significant change is on the Antarctic
Peninsula, the northernmost part of
Antarctica where there's been a very
large warming of 4 1/2 degrees Fahrenheit in the last 50 years alone. Ice
shelves -- floating ice that's attached
to the continent -- are starting to
disintegrate, and huge chunks of ice
shelf in recent years have simply
and rapidly cracked apart and floated off into the ocean. The whole ecosystem around the peninsula is
changing, and eventually this will
have a significant effect on the wildlife. If the ice starts to disappear, the
wildlife loses its habitat."
Another inevitable aspect of global
warming is already well under way
-- the swelling of the oceans. Sea
level has been rising for the last
century, and it's thought to be somewhere between four and eight inches
higher globally than it was about 100
Coastal erosion has already taken
a terrible toll on beaches in the United States. And Dr. Oppenheimer offered another dramatic example of
the price to be paid for global warming -- the potential damage to Everglades National Park in Florida.
"We're spending billions to preserve the ecosystem within which
that park exists," he said. "But sometime later in this century, using median projections, not even the worst
projections, a third of that park would
be gone -- drowned, under water -- if
we don't act to stem the buildup of the
What ultimately will happen if our
heads remain in the sand is anybody's guess. Said Dr. Oppenheimer:
"The last time it was as warm as it
probably will be by the end of this
century, globally speaking, was several million years ago. There is no
way we can know for sure that that's
a world we can safely cope with."
Copyright 2000 The New York Times Company