Date: Tue, 27 Jan 1998 17:56:39 -0500
From: Louis Proyect <lnp3-AT-columbia.edu>
Subject: M-I: Amazon forest fires; rapid climate change


January 27, 1998

Brazil Says Recent Burning of Amazon Is Worst Ever

By DIANA JEAN SCHEMO

RIO DE JANEIRO, Brazil -- Destruction of the Amazon rain forest nearly
tripled between the 1990-91 and 1994-95 burning  seasons, surpassing the
years of deforestation that set off an international outcry to save the
forests, according to data issued by the Brazilian government Monday. 

The figures show that 11,196 square miles of Amazon rain forest were
destroyed in the 1994-95 burning season, an area larger than New Jersey. In
contrast, on the eve of the 1992 Earth Summit here, deforestation had
dipped to 4,247 square miles. 

The release of the figures was delayed while Brazil attended the world
conference on global warming in Kyoto, Japan, last month and while it
petitioned the world's seven richest industrial nations to step up
environmental aid at a meeting in Manaus, Brazil, in late October. 

The Brazilian Amazon, roughly the size of Western Europe, contains the
world's largest collection of plant and animal species -- many of which
have yet to be studied for their potential medicinal, nutritional or
ecological value -- as well as 20 percent of the world's fresh water supply. 

The figures issued Monday show that 6,950 square miles of the Amazon were
destroyed from 1995 to 1996, less than in the previous year, but sharply up
from the average annual levels in the rest of the decade. 

"It shows the situation was not under control as the government kept
insisting over the last two years," said Garo Batmanian, head of the
Brazilian office of the World Wildlife Fund. "We're destroying our
biodiversity. Humanity is becoming poorer." 

Earlier this month, a separate study issued by a congressional commission
showed that 22,393 square miles of the Amazon were being destroyed each
year through deforestation -- which shows up on satellite images -- as well
as through logging, ground fires and thinning of previously virgin forest,
which may occur undetected by satellite images beneath the forest canopy. 

The Woods Hole Research Institute, studying the same phenomenon, concluded
last year that the Amazon is reaching an unprecedented level of dryness,
raising the threat that rain forest could catch fire and burn out of control. 

The last time government officials released deforestation figures, two
years ago, they showed a 34 percent increase over the 1990-91 period. As
they did then, officials announced a series of proposals to reduce
deforestation. 

These included steps to regulate forest burnings and logging concessions,
to appropriate large landholdings, and to coordinate policies between the
Government's land reform and environmental agencies. 

But many of the measures announced, Batmanian said, lacked the money of the
legislation to become effective, and represented a "wish list" more than a
plan of action. 

On Tuesday, the Brazilian Congress is scheduled to vote on a bill that
would establish criminal penalties for some acts of environmental harm and
to grant the federal environmental agency legal authority to enforce
environmental statutes. The bill has languished in Congress for seven years. 

Without such authority, the agency charged with protecting the environment
is largely ignored by the people and industries it is supposed to regulate.
According to government figures, it collects only 6 percent of the fines it
levies. 

While the bill, which is expected to pass, is critical to establishing an
environmental policy, under pressure from the industrialists' lobby the
Government watered down stiff penalties that originally included possible
prison time. 

"Clearly it's a long overdue step for the Brazilian government to give its
environmental agency statutory authority, but the way they're doing it --
loosening the laws, giving away the farm to the special interests -- is
going to make it very difficult for Brazil to effectively prosecute
multinational companies logging illegally," said Stephan Schwartzman,
senior scientist at the Environmental Defense Fund, a nonprofit group based
in Washington. 

Environmentalists here have long contended that destruction of the rain
forest is linked more closely to the state of the economy than to any
Government step to protect the environment. 

An economic slump in 1996 appeared to account for a decline in
deforestation that year. The data issued Monday showed deforestation
breaking all previous records in the period when the government's economic
stabilization plan got under way, reducing the price of land and making it
more profitable to farm and ranch land than holding it as an investment. 

"It's clear from the amount of increase, and the fluctuations in it, that
government environmental policy has had precious little influence on this
process in the 1990s," said Schwartzman. Figures from 1978 to 1988, which
caused a global protest, showed that the average annual destruction of the
forests was 8,158 square miles. 

The government added to the controversy Monday by contending that a large
share of the deforestation was a result of agrarian reform, on the basis of
data showing that most of the deforestation was a result of fires of less
than 247 acres in size. 

According to the congressional report released earlier this month, the
government has settled landless peasants on 18,146 square miles of virgin
rain forest. 

Occupying land in the Amazon rain forest, said the report's author, Gilney
Viana, "has a low financial cost and a high environmental cost, aside from
exporting the settlers to places where the conditions of survival are
difficult and opening the road for loggers to come in." 

But Marcio Nogueira Barbosa, director of the Brazilian Space Agency, said
the satellite images do not show any link between agrarian reform and
deforestation. New settlers, he said, account for no more than 10 percent
of the deforestation totals. 

The Space Agency issued partial data for 1997 projecting a sharp drop in
deforestation, back to 1992 levels, based on a survey through August of
areas where deforestation has occured in the past. Environmentalists
rejected the figures as untrustworthy, though Barbosa contended they were
correct within a five percent margin of error. "The fact that it's in a
descent is no reason for celebration," he said. 

Copyright 1998 The New York Times Company 

**********************

January 27, 1998

If the Climate Changes, It May Do So Fast, New Data Show

By WILLIAM K. STEVENS

In the debate over global warming, there has been a widespread assumption
that if humans are changing the earth's climate, the effects will be felt
gradually and smoothly, making it easier to adapt to the change. 

But a growing accumulation of geological evidence is making it ever clearer
that in the past, the climate has undergone drastic changes in temperature
and rainfall patterns in the space of a human lifetime, in a decade or in
even less time. 

The implications for federal and international climate policy are enormous
because heat-trapping carbon dioxide produced by the burning of fossil
fuels like coal and oil is steadily accumulating in the atmosphere and
putting increasing pressure on the climate system. 

Many experts believe that late in the next century, concentrations of the
gas will be double their pre-industrial levels. If that happens, mainstream
scientists say, the average surface temperature of the globe will rise by 2
to 6 degrees Fahrenheit, compared with a rise of 5 to 9 degrees since the
depths of the last ice age. That much warming, the scientists say, would
lead to rising seas and more severe droughts, rainstorms, heat waves, and
floods, as well as broad shifts in climatic and agricultural zones that
would benefit some regions and harm others. 

Could the pressure exerted on the climate system by carbon dioxide and
other greenhouse gases trip a trigger at some point, forcing these changes
on humanity suddenly rather than gradually? 

Scientists do not know for sure, but the question gives them pause. 

"The climate system is an angry beast and we are poking it with sticks,"
said Dr. Wallace Broecker, of Columbia University's Lamont-Doherty Earth
Observatory, who was one of the first to raise the alarm about abrupt
climate change. "We don't know whether it's going to pay attention to the
pokes. But if it does, it might rise up and do something we don't like." 

In uncovering one of the latest pieces of evidence of abrupt climate
change, American scientists led by Dr. Jeffrey Severinghaus, of the
University of Rhode Island, examined climatic clues taken from corings of
ancient ice in Greenland. 

The Severinghaus team determined that when the world began its final ascent
out of the last ice age more than 11,000 years ago, temperatures in
Greenland initially spiked upward by about 9 to 18 degrees Fahrenheit -- at
least a third, and perhaps more, of the total recovery to today's warmth --
in, at most, mere decades and probably less than a single decade. They also
found that the impact of the sudden warming had been felt at least
throughout the Northern Hemisphere. 

That amount of heating, coming so quickly, is astounding, said Dr. Richard
Alley, of Pennsylvania State University, a member of the study team.
Another recent study, by Dr. Peter deMenocal, a paleoclimatologist at
Lamont-Doherty, examined clues in Atlantic Ocean sediments off subtropical
North Africa. He discovered that every 1,500 years or so since the end of
the ice age, ocean temperatures there have fluctuated widely and abruptly. 

In a cold phase, they fell by 5 to 15 degrees, and seasonal rains on the
continent were severely curtailed -- all within no more than 50 to 100
years, and possibly less (the sediment analysis is not fine enough to
tell). Then, in another 1,500 years, the picture reversed just as abruptly,
causing flooding rains and creating widespread lakes in what is now the
Sahara. 

"The transitions are sharp," deMenocal said. "Climate changes that we
thought should take thousands of years to happen occur within a generation
or two" at most. The changes may have wreaked havoc on nascent
civilizations in Africa and the Middle East. "It was certainly something
that would have rocked somebody's world," deMenocal said. 

Until recently, scientists thought that the climate system responded to
what they call "forcings" -- like, for instance, rising atmospheric
concentrations of carbon dioxide or stronger solar radiation -- much as a
stereo set does: turn up the volume and the sound gets gradually louder.
But now it is increasingly evident that the system behaves, at least some
of the time, more like an electrical switch: increasing pressure has no
effect (or a relatively small effect, in the case of climate) until a
certain threshold is reached, and then the switch clicks, initiating a new
state. 

Dr. Kendrick Taylor, a paleoclimatologist at the Desert Research Institute
of Nevada at Reno, a division of the University of Nevada, says there is "a
growing awareness" that the question of climatic thresholds is serious.
Taylor, like Severinghaus, has also found that the warming in Greenland at
the end of the ice age was abrupt. 

"If we find out that we're far away from one of these thresholds, we might
be able to change atmospheric carbon dioxide a lot and not have any
impact," Taylor said. "On the other hand, we may find we're very close to
one of these thresholds and that as a society it may behoove us to pay more
attention." 

There are other uncertainties as well. For one thing, no one knows at what
point in the future the climate switch might be tripped, naturally or
otherwise, or where various thresholds might lie. It is "like walking the
plank blindfolded," said Dr. Thomas Crowley, a paleoclimatologist at Texas
A&M University, in College Station. 

It is also unclear to what extent the big, abrupt climatic shifts in
Greenland affected the rest of the world. Changes in global temperature
tend to be more extreme at high latitudes like Greenland than they are
farther south, and the biggest jumps could have been limited to the North
Atlantic region. 

But the idea that thresholds exist is becoming widely accepted, and the
suspicion that they may be the dominant mode of climatic change is growing. 

The question surged to prominence in 1993, when scientists reported on the
basis of Greenland ice corings that the climate of the last interglacial
period, a 10,000-year warm period that began about 130,000 years ago and at
some times was slightly warmer than today, fluctuated widely from warmth to
extreme cold in spans of decades or less. 

Another Greenland coring, however, suggested that the climate of this
long-ago interglacial interval, called the Eemian period, had been in a
stable state of warmth. Scientists said the first ice sample had apparently
been distorted when the bottom of the flowing glacier from which it was
taken passed over uneven ground. 

But ice core studies in the last five years have avoided that problem by
focusing on more recent strata within the ice, most notably those
representing the climate in and around a centuries-long period, called the
Younger Dryas, that began about 12,000 years ago. The Younger Dryas was the
last gasp of the last ice age, a relatively brief plunge back into glacial
cold after the climate had already warmed up. 

In 1993, a team headed by Alley found that the accumulation of snow in
Greenland had doubled sharply, in possibly one to three years, as the
Younger Dryas gave way to warmer temperatures. In sub-Arctic latitudes like
Greenland, more snow and ice accumulate in warm periods, when there is more
moisture in the atmosphere, than in cold ones. 

Last October, a team headed by Taylor reported that it had analyzed another
Greenland core segment and discovered that most of the transition from the
deep freeze of the Younger Dryas to the warmth of the last 10,000 years,
called the Holocene period, had come in two quick temperature jumps, each
of nearly 10 degrees and each lasting less than a decade, within a 40-year
transition period. 

Severinghaus and his colleagues have made a similar discovery, and, in
addition, have found evidence that the climatic change signified by the ice
corings extended beyond Greenland to the wider world. The discoveries were
reported in the Jan. 8 issue of the journal Nature. 

Scientists have a number of ways to detect climatic changes preserved in
ancient ice. They can analyze bubbles in the ice for the presence of
lighter or heavier forms, or isotopes, of oxygen; the changing ratios of
the two forms allow researchers to infer temperature change. They can
analyze the dust content of the cores to infer cold periods (colder is
drier) and warm ones (warmer is wetter). 

Severinghaus used yet another technique, one especially suited to detecting
abrupt change. The technique analyzes the behavior of relatively lighter
and heavier isotopes of nitrogen. 

In a stratum of ice representing a time period when the temperature changed
sharply, the lighter forms migrate to the top while heavier ones gravitate
to the bottom. Applying this analysis to the Younger Dryas-Holocene
transition, the Severinghaus team discovered that the transition had begun
with a sharp rise of about 9 to 18 degrees Fahrenheit, on the way to an
increase of about 27 degrees. A computer analysis of the nitrogen isotopes'
behavior suggested that the initial jump had taken place in less than a
decade. 

The team also looked for methane, which in cold times is locked up in
frozen wetlands but in warm ones is liberated into the atmosphere as the
wetlands thaw. The ice core record showed that within no more than 30 years
after the initial spike of warming that ended the Younger Dryas,
atmospheric methane had increased. Because the thawing wetlands were
presumably far from the permanently frozen Greenland ice cap, the
scientists inferred that the climatic change after the Younger Dryas had
extended at least through the Northern Hemisphere. 

The methane results say nothing, however, about how large the abrupt
temperature change was in lower latitudes, away from Greenland. Since the
average global temperature of the world is now 5 to 9 degrees higher than
in the ice age, compared with the 27-degree rise detected in Greenland, it
suggests that the impact of the sudden initial warming following the
Younger Dryas was somewhat more muted in what is now the United States than
in the sub-Arctic. Crowley said computer simulations suggested that the
size of the temperature changes in the northeastern United States might be
about 20 percent of those in Greenland. In the case of the rebound from the
Younger Dryas' chill, that would be about 2 to 3.5 degrees. 

But even modest changes can have big effects. The sulfuric haze cast aloft
by the 1991 eruption of the Mount Pinatubo volcano in the Philippines, for
instance, reflected sunlight and cut the global average temperature by
about 1 degree in 1992. But that small drop was accompanied by record low
temperatures that effectively aborted summer in much of the northeastern
United States and Upper Midwest. 

"The extreme events that accompany moderate global change may be more
dramatic and important than the small change in the global average," said
Dr. James Hansen, a climatologist who directs the NASA Goddard Institute
for Space Studies, in New York. 

It is unclear what causes climatic triggers to trip suddenly. Some
scientists say that abrupt shifts in atmospheric circulation could be
responsible. But the most favored candidate appears to be a change in the
strength of great ocean currents that transport heat, or even a temporary
cessation of the currents. 

One way in which this might happen is that an atmosphere that had already
begun to warm could produce more precipitation and melt more ice and snow
in Arctic areas. That could flood with fresh water the critical current
that transports heat to the North Atlantic, diluting the salt content on
which the current's functioning depends. With this heat-conveying current
halted or greatly weakened, parts of the North Atlantic region, especially
Europe, could become much colder than today. One study, reported last fall
in Nature, suggested that the current could shut down altogether if
atmospheric concentrations of carbon dioxide doubled within 100 years, as
many scientists believe is inevitable.

"It's kind of ironic," Taylor said, "but it's possible that the greenhouse
warming we are likely to be producing now may lead to a warming period
followed by a dramatic cold period."

Copyright 1998 The New York Times Company




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