International Herald Tribune  [Printer-friendly version]
January 20, 2004


[Rachel's introduction: The European Commissioner for environment and
three other respected scientists say the earth is in danger of
becoming less habitable and that the precautionary principle must be

By Margot Wallstrom, Bert Bolin, Paul Crutzen and Will Steffen

Our planet is changing fast. In recent decades many environmental
indicators have moved outside the range in which they have varied for
the past half-million years. We are altering our life support system
and potentially pushing the planet into a far less hospitable state.

Such large-scale and long-term changes present major policy
challenges. The Kyoto Protocol is important as an international
framework for combating climate change, and yet its targets can only
ever be a small first step. If we cannot develop policies to cope with
the uncertainty, complexity and magnitude of global change, the
consequences for society may be huge.

We have made impressive progress in the last century. Major diseases
have been eradicated and life expectancy and standards of living have
increased for many. But the global population has tripled since 1930
to more than six billion and will continue to grow for several
decades, and the global economy has increased more than 15-fold since
1950. This progress has had a wide-ranging impact on the environment.
Our activities have begun to significantly affect the planet and how
it functions. Atmospheric composition, land cover, marine ecosystems,
coastal zones, freshwater systems and global biological diversity have
all been substantially affected.

Yet it is the magnitude and rate of human-driven change that are most
alarming. For example, the human-driven increase in atmospheric carbon
dioxide is nearly 100 parts per million and still growing -- already
equal to the entire range experienced between an ice age and a warm
period such as the present. And this human-driven increase has
occurred at least 10 times faster than any natural increase in the
last half-million years.

Evidence of our influence extends far beyond atmospheric carbon
dioxide levels and the well-documented increases in global mean
temperature. During the 1990's, the average area of humid tropical
forest cleared each year was equivalent to nearly half the area of
England, and at current extinction rates we may well be on the way to
the Earth's sixth great extinction event.

The Earth is a well-connected system. Carbon dioxide emitted in one
country is rapidly mixed throughout the atmosphere, and pollutants
released into the ocean in one location are transported to distant
parts of the planet. Local and regional emissions create global
environmental problems.

The impacts of global change are equally complex, as they combine with
local and regional environmental stresses in unexpected ways. Coral
reefs, for example, which were already under stress from fishing,
tourism and agricultural pollutants, are now under additional pressure
from changing carbonate chemistry in ocean surface waters, a result of
the increase in atmospheric carbon dioxide.

Similarly, the wildfires that hit southern Europe, western Canada,
California and southeastern Australia last year were a result of many
factors, including land management, ignition sources and extreme local
weather. However, prevailing warm and dry conditions -- probably
linked to climate change -- amplified fire intensity and extent.

Poor access to fresh water means that more than two billion people
currently live under what experts call "severe water stress." With
population growth and economic expansion, this figure is expected to
nearly double by 2025. Climate change would further exacerbate this

Biodiversity losses, currently driven by habitat destruction
associated with land-cover change, will be further exacerbated by
future climate change. Beyond 2050, rapid regional climate change, as
would be caused by changes in ocean circulation in the North Atlantic,
and irreversible changes, such as the melting of the Greenland ice
sheet and the accompanying rise in sea levels of 6 meters, or 20 feet,
could have huge economic and societal consequences.

It is now clear that the Earth has entered the so-called Anthropocene
Era -- the geological era in which humans are a significant and
sometimes dominating environmental force. Records from the geological
past indicate that never before has the Earth experienced the current
suite of simultaneous changes: we are sailing into planetary terra

Global environmental change challenges the political decision-making
process by its uncertainty, its complexity and its magnitudes and
rates of change.

Because of the uncertainties involved, decision-making will have to be
based on risks that particular events will happen, or that possible
scenarios will unfold. A lack of certainty does not justify inaction
-- the precautionary principle must be applied.

Because of its complexity, global environmental change is often
gradual until critical thresholds are passed, and then far more rapid
change ensues, as seen in the growth of the ozone hole. Some rapid
changes -- such as the potential melting of the Greenland ice sheet --
would also be irreversible in any meaningful human timescale, while
other changes may be unstoppable, and indeed may have already been set
in motion.

Because of the magnitudes and rates of change, we are unsure of just
how serious our interference with the dynamics of the Earth's system
will prove to be, but we do know that there are significant risks of
rapid and irreversible changes to which it would be very difficult to

The first step toward meeting the challenge presented by global change
is to appreciate the complex nature of the Earth's system, the ways in
which we are affecting the system, and the economic and societal
consequences. Scientists and policy-makers must establish a dialogue
to communicate current knowledge and to guide future research.

Real policy progress must address the need for large-scale change,
technological advances and global cooperation. Incremental change will
not prevent, or even significantly slow, climate change, water
depletion, deforestation or biodiversity loss. Breakthroughs in
technologies and natural resource management that will affect all
economic sectors and the lifestyles of people are required.

Although action at local, regional and national levels is important,
international frameworks are essential for addressing global change.
We must develop new approaches that consider the diversity of national
circumstances and interests, based on a shared political will for
action. Never before has an effective multilateral system been more

The evidence of our impact on our own life-support system is growing
rapidly. Will we accept the challenge to respond in a precautionary
manner, or wait until a catastrophic, irreversible change is upon us?


Margot Wallstrom is the European Commissioner for the environment.
Bert Bolin is the founding chair of the Intergovernmental Panel on
Climate Change. Paul Crutzen was awarded the 1995 Nobel Prize in
Chemistry. Will Steffen is executive director of the International
Geosphere-Biosphere Program. This comment is based on "Global Change
and the Earth System: A Planet Under Pressure," which looks at the
findings of the International Geosphere-Biosphere Program.