“We were surprised how intensively these regions were being affected”
by human presence, says K. Heinz Erb, an ecologist at Klagenfurt
University in Vienna. “Only one-third of the natural productivity is
left for all the other species.”

“Some scientists now wonder: At what point do the world’s ecosystems
begin to break down? Or, more frighteningly, has that process already

“If the whole world begins to look like Iowa cornfields, …. that
leaves a lot less for other things,” says Foley.

“Foley continues. ‘At what point does this get to be scary?’ ”

Science News
Week of Oct. 13, 2007;  Vol. 172, No. 15

Invasive, Indeed

One species-Homo sapiens-consumes nearly a quarter of Earth’s natural

Sid Perkins

Some people live lightly on the land: Bedouin clans roam the deserts
of the Middle East and North Africa; small groups of indigenous
people follow reindeer herds across frigid Arctic terrain; and tribes
of hunter-gatherers forage the plains of southern Africa and the
forests of Amazonia and Papua New Guinea.

Then there’s the other 6.6 billion of us.

When we farm, clear forests, and build cities, dams, and roads, we
dramatically alter the landscape. In some places, we increase the
land’s productivity-measured as the amount of plant life at the base
of the food chain-by adding immense amounts of water and fertilizer.
New research indicates that on the whole, however, human presence
significantly decreases Earth’s biological productivity. For
instance, many of today’s cities occupy large patches of what had
been some of the world’s most fertile land.

Of the biological productivity that remains, people are gathering an
ever-increasing share, sometimes by boosting their quality of life,
but often merely by dint of their burgeoning numbers. In some
regions, each spanning millions of square kilometers, human activity
consumes almost two-thirds of the biological productivity that would
otherwise be available.

“We were surprised how intensively these regions were being affected”
by human presence, says K. Heinz Erb, an ecologist at Klagenfurt
University in Vienna. “Only one-third of the natural productivity is
left for all the other species.”

Overall, nearly one-quarter of Earth’s land-based biological
productivity ends up in people’s hands and bellies, Erb and his
colleagues estimate. Other research suggests that people appropriate
a comparable, but slightly smaller, share of the ocean’s
productivity-defined as the mass of photosynthetic organisms at the
base of the sea’s food chain.

A projected 25 percent increase in the world’s population by 2030 is
bound to strain ecosystems even further. Increasing agricultural
efficiency by irrigating and fertilizing the land can add to the
strain by boosting erosion and the nutrient runoff that creates toxic
algal blooms and large anoxic zones in oceans. Adding insult to
injury, proposals to transition from fossil fuels to renewable
biofuels would place yet more of Earth’s productivity in people’s

Some scientists now wonder: At what point do the world’s ecosystems
begin to break down? Or, more frighteningly, has that process already

Reaping, sowing

Before people invented agriculture, they roamed the landscape in
search of sustenance. When resources became too scarce to nourish the
group, it was time to move on. When people began to farm the land,
however, their habits changed considerably, to the detriment of many
ecosystems. Settlers built year-round shelters and often cleared
acreage for their crops.

“The rise of modern agriculture and forestry has been one of the most
transformative events in human history,” says Jonathan A. Foley, an
environmental scientist at the University of Wisconsin-Madison.

Practices vary somewhat, but typically, people heavily farm the most
fertile land, use marginal lands for grazing domestic animals, and
plant single-species tree farms in areas where forests once stood.
Whatever the use, the production of forest or agricultural goods
comes at the expense of natural ecosystems, observes Foley.

Today, croplands and pastures are among the largest ecosystems on the
planet. People farm about 12 percent of the land outside of
Antarctica and Greenland and use about 23 percent for grazing, says
Foley. Together, land devoted to these uses equals the 35 percent of
Earth’s surface that natural forests occupy, he notes.

To estimate the effect that humans wreak on the world’s land-based
ecosystems, Erb and his colleagues used agricultural and forestry
statistics compiled for 161 nations that account for 97.4 percent of
Earth’s icefree land. Most of the remaining area is located on small,
uninhabited islands, Erb notes. In their computer model, the
researchers divided the planet’s land surface into grid squares no
larger than 10 kilometers per side.

The team estimates that if people weren’t around to alter the
landscape, the world’s natural vegetation would absorb enough carbon
dioxide from the atmosphere to lock away about 65.5 billion metric
tons of carbon each year. However, in 2000, the year for which the
data were compiled, Earth’s vegetation locked away only about 59.2
billion metric tons of carbon, or 9.6 percent less than it should
have, says Erb. Of that smaller carbon total, human activities
removed about 15.6 billion metric tons-a whopping 23.8 percent-from
the world’s ecosystems. A little more than half of the carbon that
people appropriated was harvested and used as food, forage, and wood,
Erb and his colleagues note in the July 31 Proceedings of the
National Academy of Sciences. Most of the rest was lost to
inefficiencies of agriculture, including the inability of crops to
store as much carbon as natural vegetation would have stored. A small
amount, about 7 percent of the carbon that people take out of the
system, went up in smoke produced primarily by slash-and-burn
agriculture, says Erb. All of this human-appropriated carbon became
unavailable to other species.

Human harvests don’t stop at the shoreline, either. The world’s most
productive fisheries typically lie in and near the shallow waters
that fringe the coasts of large islands and continents, says Daniel
Pauly, a fisheries biologist at the University of British Columbia in
Vancouver. Scientists have divided such coastal waters into 64 large
marine ecosystems. These areas can vary in character and inhabitants
as much as arctic tundra differs from an Amazonian rain forest.

About 95 percent of the world’s fish catch comes from large marine
ecosystems, says Pauly. For the past decade or so, that haul has
represented about 20 percent of the natural productivity of those
regions, as measured by the amount of carbon locked away by organisms
at the base of the ocean’s food chain.

Efficiency matters

While wilderness areas remain relatively unaffected by people, other
parts of the world are packed cheek by jowl with cities, farms, and
other human imprints.

Southern Asia, a 6.7-million-square-kilometer region that includes
India, is one of the most densely populated and heavily irrigated
regions on the planet, says Erb. There, human activity co-opts about
63 percent of the area’s natural productivity each year, he and his
colleagues estimate. In eastern and southeastern Europe, people
appropriate about 52 percent of the land’s productivity.

At the other extreme, in Australia, central Asia, and Latin America,
the percentage of productivity that ends up in human hands ranges
between 11 and 16 percent. Increasing the use of fertilizers and
irrigation could boost those percentages and help meet the needs of a
growing world population. However, long-term irrigation sometimes
renders the soil too salty for crops, and fertilizer, if used
unsparingly, runs off into rivers and streams and ends up in the
ocean, where it overfertilizes algae and thus creates huge zones
devoid of other life. “There’s no free biomass,” Erb cautions.

In the stampede to replace fossil fuels, some scientists have
proposed the large-scale cultivation of crops that can be transformed
into supposedly eco-friendly biofuels. That, too, might be
ecologically unwise.

“If the whole world begins to look like Iowa cornfields, we’ll have
to take an even larger share of global biological production into
human hands, and that leaves a lot less for other things,” says
Foley. “And those other things won’t be just pretty butterflies and
tigers and charismatic animals, they’ll be things that matter to us,
like the things that clean our water, preserve our soils, clean our
atmosphere, and pollinate our crops.”

“At what point does human activity begin to compromise a lot of our
environmental systems?” Foley continues. “At what point does this get
to be scary?”

If you have a comment on this article that you would like considered
for publication in Science News, send it to
Please include your name and location.

To subscribe to Science News (print), go to subServices.asp.

To sign up for the free weekly e-LETTER from Science News, go to


Foley, J.A., et al. 2007. Our share of the planetary pie. Proceedings
of the National Academy of Sciences 104(July 31):12585-12586. Extract
available at

Haberl, H., K.H. Erb, et al. 2007. Quantifying and mapping the human
appropriation of net primary production in earth’s terrestrial
ecosystems. Proceedings of the National Academy of Sciences 104(July
31):12942-12947. Available at

Further Readings:

Harder, B. 2003. Catch zero. Science News 164(July 26):59-61.
Available at

Perkins, S. 2004. Paved paradise? Science News 166(Sept. 4):152-153.
Available at>

Raloff, J. 2000. Sprawling over croplands. Science News 157(March
4):155. Available to subscribers at


K. Heinz Erb
Institute of Social Ecology
Klagenfurt University
Schottenfeldgasse 29
1070, Vienna

Jonathan A. Foley
Center for Sustainablility and the Global Environment
University of Wisconsin, Madison
1710 University Avenue, Room 202A
Madison, WI 53726

Daniel Pauly
Fisheries Centre
Aquatic Ecosystems Research Laboratory (AERL), Room 333
2202 Main Mall
University of British Columbia
Vancouver, BC V6T 1Z4

Copyright (c) 2007 Science Service. All rights reserved.


“As sea levels rise as many as 6000 people have been relocated and
two islands in the Sunderbans already submerged due to climate change.

” ‘I lost everything. That part is the tiger reserve. But the river
comes in- it destroyed my house it also destroyed our crops as the
water is so saline. Earlier it did not flood so often but now it
seems it is flooding ever so often,’ says a resident of the area,
Suryakant Moundal.”

Sunderbans in danger, locals turn climate refugees
Bahar Dutt

Sunderbans (West Bengal): Is global warming for real? As the world
debates climate change and global warming join us on a special
journey as we transverse through the Sunderbans Delta and find out
how wildlife and people are coping with quite literally living on the

Hard to access and a difficult terrain to live in, Sunderbans is home
to over 54 species of mangroves – the only flora that can survive in
these saline waters.

This is a world heritage site and now it’s a climate change hotspot.
There’s a crisis brewing here which may seem local but its causes are

As sea levels rise as many as 6000 people have been relocated and two
islands in the Sunderbans already submerged due to climate change.

“I lost everything. That part is the tiger reserve. But the river
comes in- it destroyed my house it also destroyed our crops as the
water is so saline. Earlier it did not flood so often but now it
seems it is flooding ever so often,” says a resident of the area,
Suryakant Moundal.

Moundal is a distressed man. He does not know about climate change.
What he does know is that the frequency with which he has to move has
gone up and that the river now destroys his home with greater

“We are from santhal tribe. We have lost everything. Where do we go?
There is no land on the island it is already taken,” says another

Any island you visit on the Sunderbans tells the same story. People
have their own coping strategies. Some have put these bamboo
structures to prevent the mud from falling, others have just got used
to moving home more often. So what has made this world heritage site
more vulnerable to climate change?

“Sunderbans is a delta, the river always used to flood but now if you
look many islands are disappearing fast, in fact two of the islands
are already submerged. If you look at these satellite images you will
see the difference,” WWF Senior Coordinator Dr Prakash Rao.

The waters that bring life are also the waters that take it away.
Scientists estimate with rising sea levels there will be cascading

While 60 per cent of Mangrove species will be destroyed, the habitat
of the endangered species like the Royal Bengal tiger will be wiped

Once saline water moves in to the islands, crops will be destroyed.



In coastal areas of the U.S., plants and animals
will be refugees from rising seas.

How will Americans respond?

” …  land managers will sometimes actually have to
embrace non-native invasive species …”

” … we should be looking to preserve land further inland
to give some of these species a chance for preservation,” she said.

Cleveland Plain Dealer (Cleveland, Ohio, US)
Friday, October 12, 2007


Preservationists need to adjust to climate change, expert says

Michael Scott
Plain Dealer Columnist

Groups who seek to preserve parks and natural
areas need to rethink their mission in light of
already advancing changes in plants and animals
because of global climate change, an ecology
expert said this week.

“Forget trying to preserve a site and an
ecosystem exactly as you would like to – as a
close representation of what it was once like
without human effect,” said William Platt, an
ecology professor at Louisiana State University.

Platt spoke Tuesday at the 34th annual Natural
Areas Conference at the Marriott Key Center in
Cleveland. He said the ap proach is a departure
from the long-accepted idea to preserve parkland
as it once was.

He told about 400 parks and natural areas
managers attending the conference that some
species of plants and animals will not be able to
keep up with coming changes. That means land
managers will sometimes actually have to embrace
non-native invasive species which thrive in salt
water, for example.

Platt referred to the bleak forecast for
Louisiana where the Gulf of Mexico is rising at a
rate where 70 percent of the current coast is
projected to be under salt water by 2100 as “a
harbinger of things to come elsewhere,” including

Changes are already evident in the Great Lakes
region, said Kim Herman, president of the Natural
Areas Association, who lives in Michigan’s Upper
Peninsula. She said Platt made sense when he said
that some species would “stretch” inland while
others would be “squeezed” from that advance.

“That means we should be looking to preserve land
further inland to give some of these species a
chance for preservation,” she said.

Climate effect:

An article in this month’s “National Parks” makes
this astonishing point: 73 percent of what was
once ice in Montana’s Glacier National Park is
now bare rock.

Some scientists project that by 2030 – only 23
years from now – there won’t even be a glacier in
the glacier park.

Several national parks managers echoed what Platt
told the Cleveland crowd: Climate change
discussion has moved from whether it’s actually
happening to how to best respond to it.

So national parks are likely to become more and
more “carbon neutral,” using trams to move people
around instead of cars, for example. Many parks
will also use the changes as educational

© 2007 All Rights Reserved.



“We are faced with … rising rates of
consumption that nature can’t match.
Increasingly, we are also threatened by the wave
of privatization that is sweeping across the
world, turning water from a precious public
resource into a commodity for economic gain.”

“The case gained international attention when it
was featured in the film and book Thirst:
Fighting the Corporate Theft of Our Water. The
public finally won out in July, when the city
council voted to get rid of the 20-year contract
and send the corporation packing.”

The late, great Corbin Harney-spiritual leader of the
Western Shoshone People of the dry Great Basin region
of the U.S.-dedicated his life to spreading this very

Our Drinkable Water Supply Is Vanishing

By Tara Lohan, AlterNet
Posted on October 11, 2007, Printed on October 11, 2007

Albert Szent-Gyorgyi, the Hungarian biochemist
and Nobel Prize winner for medicine once said,
“Water is life’s matter and matrix, mother and
medium. There is no life without water.”

We depend on water for survival. It circulates
through our bodies and the land, replenishing
nutrients and carrying away waste. It is passed
down like stories over generations — from
ice-capped mountains to rivers to oceans.

Continue reading


Science is the process of disciplined dissent. The process of
disciplined dissent relies on evidence — evidence that can force a
change of mind by challenging the consensus that scientists had
earlier achieved.

That’s nowhere more true than in climate science, where the consensus
process used by the Intergovernmental Panel on Climate Change has
been challenging its own, earlier consensus about the speed and
seriousness of what lies ahead.  What climate researchers regarded as
mostly likely in 2001 had been seriously challenged by early 2007,
and it now looks very likely that even the better consensus climate
scientists had reached in the spring of 2007 will be seriously
challenged by new evidence expected to come out in November.

Few groups are as prepared to challenge their own consensus as the
science community is. But scientists saw need of change coming, and
you saw the preview when it was posted to this list in October ’06.

” ‘… the extreme scenarios that tend to fall out of the IPCC
process may be exactly the ones we should most worry about,’ he says.”

“Michael Schlesinger, a climate scientist at the University of
Illinois, Urbana-Champaign, points to another example. ‘Things are
happening right now with the ice sheets that were not predicted to
happen until 2100.'”

VOL 314    13 OCTOBER 2006


Trying to Lasso Climate Uncertainty

An expert on climate and population looks for a way to help society avoid a
“Wile E. Coyote” catastrophe

LAXENBURG, AUSTRIA – A few weeks ago, Brian O’Neill hunkered down
around a table with a dozen other climate scientists in Cape Town,
South Africa, to talk about the future of the planet. It was no idle
speculation: Whatever they agreed upon – they knew in advance – would
have clout. They were hammering out the final draft of a chapter on
research methods for the massive “Fourth Assessment” of the
Intergovernmental Panel on Climate Change (IPCC). The product of 3
years of consensus-building among several hundred researchers from
around the world, the IPCC report is the scientific bedrock on which
policymakers will negotiate everything from carbon taxes to long-term
greenhouse gas targets.

But for all its authority, the IPCC exercise left O’Neill with a
nagging concern: What were they leaving out? “It’s important that we
climate scientists speak with a single voice,” he said in an
interview back in his office, high up in the attic of a former
Habsburg palace outside Vienna. But “the extreme scenarios that tend
to fall out of the IPCC process may be exactly the ones we should
most worry about,” he says.

O’Neill, a climate scientist at the InternationalInstitute for
Applied Systems Analysis (IIASA) here, is frustrated to see
uncertainties in research used as a reason to delay action. At age
41, he is one of the youngest scientists in the IPCC network trying
to reformulate climate-change projections that can cope better with
uncertainty by accounting for “future learning.” O’Neill hopes the
strategy will make it clear that, even with gaps in understanding, it
pays to act now.

His work is gaining notice. Although an American, O’Neill has scooped
up one of the coveted European Young Investigator Awards (EURYI), a
$1.5 million grant meant in part to keep Europe’s most promising
scientists at home. “He is one of the brightest young scientists out
there, and we’re all watching to see what he does,” says Simon Levin,
an ecologist at Princeton University.

A winding path

O’Neill’s job is to predict the future, but his own career path has
been unpredictable. With 3 years’ training in engineering and a
degree in journalism, he became passionately involved in the 1980s in
efforts to prevent ozone depletion, working for Greenpeace in
California. After collecting a Ph.D. in earth-system sciences from
New York University, he did research stints at Brown University and
the Environmental Defense Fund in New York City. In 2002, he moved to
IIASA, a center for multidisciplinary research founded in 1972. Here,
O’Neill has built up a new program focusing on population and climate
change. The treatment of demographics in most climate-change
analyses, he says, is “simplistic at best.” With the EURYI money,
he’s assembled a team of a half- dozen demographers, economists,
statisticians, and physical scientists to sharpen the models.

A long-limbed basketball player who looks like he could be fresh out
of graduate school, O’Neill seems to peel away layers of uncertainty
as he speaks. His slow-paced answers to questions often begin with a
detailed preamble of assumptions, conditions, and footnotes. But as
the father of two daughters, he says, “thinking about how the world
will be in 50 years is not so abstract for me anymore.”

At IIASA, his work focuses on building realistic demographic
projections, and China has become his main beat. Different
predictions of how the country’s population will age and urbanize —
and how carbon-emission policies will shape Chinese consumption —
have an enormous effect on global climate change scenarios. But
obtaining accurate demographic data has been difficult. With the help
of a Chinese member of his new team, O’Neill has done an analysis
revealing that the IPCC assumptions about China’s rate of
urbanization and energy consumption could be off by a factor of 2.

Learning about learning

Earlier this year, O’Neill organized a unique meeting at IIASA,
bringing together experts from different areas of climate science,
economics, and demography to think about how they generate knowledge.
One of the most important questions that emerged, says Klaus Keller,
a climate scientist at Pennsylvania State University in State
College, is how do you avoid “the Wile E. Coyote effect?” The cartoon
coyote often doesn’t realize he’s falling off a cliff until he looks
down, too late to turn back. One of the potential cliffs in climate
change involves the ocean’s conveyer-belt system — known as the
meridional overturning circulation (MOC) — which prevents a Siberian
chill from spreading across western Europe by carrying warm water
north from the equator. Scientists worry that global warming could
abruptly change or even shut down the MOC. “These are the kind of
climate thresholds that we need to identify,” says Keller.

Scientists need to know more about the natural variability in MOC
behavior, says O’Neill. But they don’t even know “how precise your
measurements have to be” or how large an area must be studied before
uncertainty could be sufficiently reduced to spot “the edge of the
cliff.” He argues that the only way to attack such complex
uncertainties with limited time and resources is to have scientists
from different fields work together, assessing observations over many
years to learn which approaches pay off the most. O’Neill and others
did exactly this with 2 decades of research on the carbon cycle,
finding that some kinds of observations narrowed uncertainty in model
parameters far better than others. Such big-picture,
multidisciplinary studies are low on the priority scaleof funding
agencies, but this is exactly what’s needed if you want “to learn
about the potential of an MOC shutdown,” he says.

The second big question to emerge from the IIASA sessions is how can
we tell if mainstream research is headed in the wrong direction?
O’Neill, Michael Oppenheimer, and Mort Webster, climate scientists at
Princeton and the Massachusetts Institute of Technology in Cambridge,
respectively, use the term “negative learning” to describe cases in
which scientific consensus builds around the wrong model. “This is
what happened with ozone,” says Oppenheimer. People believed that
ozone’s key interactions are with other gases, until scientists
realized that the critical reactions driving ozone depletion occur on
the surfaces of airborne particles. With revised reaction rates, it
was suddenly clear that the planet’s protective ozonelayer was in
much bigger trouble than had been thought. Oppenheimer proposes that
scientists team up with philosophers and historians to find common
signs of negative scientific learning. A search for such red flags
could be built into climate science’s regular review process.

And O’Neill says more funds should be set aside to explore hypotheses
outside the mainstream. Researchers desperately need a strategy for
tackling climate uncertainties, O’Neill says. Michael Schlesinger, a
climate scientist at the University of Illinois, Urbana-Champaign,
points to another example. Polar ice sheets are melting more rapidly
than anticipated, and some observers fear that this could lead to a
catastrophic sea-level increase ( Science , 24 March, p. 1698).
“Things are happening right now with the ice sheets that were not
predicted to happen until 2100,” Schlesinger says. “My worry is that
we may have passed the window of opportunity where learning is still

Whether a catastrophe can be averted using some form of scientific
introspection — or learning about learning, as O’Neill calls it —
remains unclear. The concept, like O’Neill’s career, is still at an
early stage of development.