Human
Pressure on Earth's
Carrying Capacity Rises
OAKLAND, California, November 28,
2002 (ENS) - Humanity is putting increasing pressure on global ecosystems, with
consumption exceeding the Earth’s biological capacity by 20 percent, according
to a new report from the Sustainability Program of Redefining Progress, a
nonprofit, nonpartisan public policy organization.
The biosphere needs about one year
and three months to renew what humanity consumes in a year, the report found.
The organization’s latest
“Ecological Footprint of Nations” report analyzes the ecological impact of
146 of the world’s nations, demonstrating to what extent a nation can support
its resource consumption with its available ecological capacity.
The report uses ecological footprint
accounts to provide a measurable estimate of humanity’s pressure on global
ecosystems.
“The ‘Ecological Footprint’
accounts show us that humanity’s consumption and waste production today exceed
the Earth’s capacity to create new resources and absorb waste,” the report
says. “We are, as a result, liquidating certain natural capital to support
current resource use, thereby reducing the Earth’s capacity to support future
life.”
The Redefining Progress report
expresses ecological footprint in terms of global acres. Each global acre, the
report explains, corresponds to one acre of biologically productive space with
world average productivity.
The “Ecological Footprint”
measures the biologically productive area required to produce the food and wood
people consume, to supply space for infrastructure, and to absorb the greenhouse
gas carbon dioxide emitted from burning fossil fuels.
The global ecological footprint in
1999 was 5.6 global acres per capita, while the Earth’s biocapacity was 4.7
global acres. In metric terms, these measurements are 2.3 global hectares per
capita and 1.9 global hectares per capita.
According to the report, “The
bottom line for sustainability thus becomes - how can each person have a
satisfying life within the average of 4.7 global acres per person or less? This
is the most significant challenge for research, business and politics.”
The analysis is primarily based on
data published by the United Nations and the Intergovernmental Panel on Climate
Change. The data from 1999 is the most recent available to scientists.
“Humanity’s Ecological Footprint
exceeds the Earth’s biological capacity by 20 percent,” said Sustainability
program director Mathis Wackernagel, one of the report’s three authors.
“Many nations, including the United States, are running even larger ecological
deficits. As a consequence of this overuse, the human economy is liquidating the
Earth’s natural capital.”
The United States recorded an
ecological footprint of 24.0 global acres (9.7 hectares) per capita, nearly
doubling its national biocapacity of 13.0 global acres (5.3 hectares) per
capita.
The U.S. deficit of 10.9 global
acres (4.4 hectares) per capita is among the highest, only exceeded by Belgium
and Luxembourg taken as a unit, which has a deficit of 14 global acres (5.6
hectares) per capita.
New Zealand had by far the largest
surplus at 35 global acres (14 hectares) per capita, with Australia second on
the list with a surplus at 17 global acres (7 hectares)per capita.
The report details these individual
measurements, but emphasizes the need to take a global perspective on this
issue. In 1999, there were 28.2 billion acres, or 11.4 billion hectares, of
biologically productive land on Earth, covering some 25 percent of the
planet’s surface.
This consists of 22.5 billion acres
(9.1 billion hectares) of usable land, and 5.7 billion acres (2.3 billion
hectares)of water that provide economically useful resources that can be
considered biologically productive. The world population in 1999 was 5.9
billion.
Based on the assumption that 12
percent of all biologically productive space should be left undisturbed for
other species, the report found that the available space per person worldwide
shrinks from 4.7 global acres (1.9 hectares) to 4.1 (1.7 hectares). This measure
of 4.1 global acres, or 1.9 global hectares, is then the “ecological
benchmark” for comparing peoples’ ecological footprints.
Reaching this ecological benchmark
will get more difficult in the future as the global population increases and
further resource degradation occurs, the report found.
“Assuming on further ecological
degradation, the amount of biologically available space will drop to 2.8 global
acres (1.1 hectares) per capita once the world population reaches its predicted
10 billion. If current growth trends continue, this will happen in about 30
years.”
“Sustainability talk is
meaningless unless it is backed up by specific measurable commitments and
timetables for implementation,” said Wackernagel. “We will achieve
sustainability only when every person can lead a satisfying life within the
Earth’s biological capacity. People can use the ecological footprint to hold
individuals, organizations, businesses, and governments accountable for their
sustainability performance.”
Calculations for these accounts make
five assumptions. First, that it is possible to keep track of most of the
resources people consume and the wastes they generate. Redefining Progress also
assumes that resource and waste flows can be “converted into the biologically
productive area required to maintain these flows.”
The third assumption is that
different types of biologically productive areas can be expressed in the same
unit “once they are scaled proportionally to their productivity.”
In addition, the calculations assume
that since these areas represent mutually exclusive uses and are standardized to
represent the same amount of productivity, they can be added to a total that
measures humanity’s demand.
The fifth core assumption in
calculating an ecological footprint is that the area of total human demand can
be compared with nature’s supply of ecological services, “which may also be
expressed in standardized units of productivity.”
The authors say the footprint
calculations are conservative measures. The report underestimates human impact
and overestimates the available biological capacity in several ways, its authors
wrote.
First, it counts each area only
once, even if the area provides two or more ecological services. In addition,
the authors choose the conservative estimates when in doubt and include current
agricultural practices as if current industrial yields would not caused any
significant long term damage to soil productivity.
Some human activities for which the
authors have insufficient data are left out, and they have excluded activities
that systemically erode nature’s capacity to regenerate, such as plutonium,
polychlorinated biphenyls (PCBs) and other materials for which the Earth has no
significant assimilation capacity.
Nonrenewable resources from the
Earth’s crust are included in these accounts only to the extent that their use
damages the biosphere, such as through mining and burning of fossil fuels. These
assets appear in the carbon dioxide component of the ecological footprint
accounts.
Neither fresh water nor the release
of solid, liquid and gaseous waste other than carbon dioxide are included in the
accounts.
The calculations include six types
of bioproductive areas used to support the human economy - cropland, grazing
land, forests for harvesting timber and fuelwood, fisheries, built up areas for
accommodating human infrastructure, and forests to sequester carbon dioxide from
fossil fuels or to replace fossil fuels with biomass.
Improvements have been made to their
measuring techniques, the authors said, largely thanks to better data and
databases. In earlier accounts, agricultural production statistics were separate
from trade statistics. Units for production, generally measured in metric tons,
were difficult to equate with trade figures reported in dollars. The United
Nations Food and Agriculture Organization now has all of its statistics
available in tons.
“These accounts show the
importance of addressing the current population dynamic to avoid future human
suffering,” the report says. “If the lack of affordable, safe, and effective
family planning leads to a human population of 10 billion people, we implicitly
condemn large segments of future generations to harsh lives.”
Home