The earth in peril, scientists warn

Posted: 22 January 2004

The earth has entered a new geological era in which humans are a dominating force, and the result could be catastrophic unless precautionary action is taken now.

That is the view of four of the world's leading scientists, who have explained the peril facing the planet in a book, and in a comment article in the International Herald Tribune.

Among the four is Margaret Wallstrom, European Commissioner for the Environment. The others are Bert Bolin, founding chair of the Intergovernmental Panel on Climate Change; Paul Crutzen who was awarded the 1995 Nobel Prize in Chemistry; and Will Steffen, executive director of the International Geosphere-Biosphere Program.

Huge impact

Almost 40% of carbon dioxide emissionsin California comes from passenger vehicles.© US Environmental Protection Agency
Almost 40% of carbon dioxide emissionsin California comes from passenger vehicles.© US Environmental Protection Agency
Almost 40% of carbon dioxide emissions in California comes from passenger vehicles. © US Environmental Protection Agency

The scientists say that "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."

And they warn: "If we cannot develop policies to cope with the uncertainty, complexity and magnitude of global change, the consequences for society may be huge...

"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."

Melting ice

They point out that "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."

Water is another indicator of inter-connected change. "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 situation.

"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.

Maps showing Greenland's melting ice
Maps showing Greenland's melting ice
The Greenland Ice Sheet melt area increased on average by 16 percent from 1979 to 2002. The minimum melt extent was observed after the Mt. Pinatubo eruption in 1992. (Images courtesy of Konrad Steffen and Russell Huff, CIRES, University of Colorado at Boulder)

"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 incognita."

Global co-operation

The scientists say that because the of the uncertainties "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."

So the need is for "large-scale change, technological advances and global co-operation. 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...

"Never before has an effective multilateral system been more necessary.

"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?"

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. For more information, visit: