Trouble viewing? Open in web browser.

Journalist Resources Stanford News Stanford Experts Contact Us
Stanford University homepage

News Service

December 7, 2012

Stanford population biologist calls for realignment of human activity and natural systems

Environmental problems should be treated with as much urgency as solving the debt crisis, says Stanford's Paul Ehrlich.

'Humanity is faced with the most serious crisis in its 200,000-year history,' says Stanford biology Professor Paul Ehrlich. (Photo: Linda A. Cicero / Stanford News Service)

The magnitude and devastation of Hurricane Sandy is the latest example of how Earth systems are reacting to stresses created by human activities. Paul Ehrlich, a biology professor at Stanford University and noted ecologist and demographer, believes that the decoupling of human and natural systems has presented a dire situation, and that realigning these systems should be considered a greater priority.

"Humanity is faced with the most serious crisis in its 200,000-year history," Ehrlich told an audience at the fall meeting of the American Geophysical Union today. "But society remains focused on relatively trivial problems such as the overblown debt 'crisis' and unemployment, rather than attacking the perfect storm of environmental problems that could bring down civilization."

He pointed out that in the environmental science community, much attention has been given recently to the "coupling" of the human (socio-political-economic) system to that of the natural world (Earth system) within which the human system is embedded and upon which it is utterly dependant.

"There is no question about the coupling," Ehrlich said. "Changes in the natural system, such as the development of savannas and the occurrence of ice ages, have had profound effects on human evolution. And changes in the human system, as expected, often generate responses in the natural system."

As an example, Ehrlich cited the hunter-gatherers who invaded the Western Hemisphere and hunted many species of large plant-eating animals to extinction, which in turn completely altered the vegetation of North and South America. Similarly, the adoption of agriculture generated a whole new suite of infectious diseases afflicting Homo sapiens.

"The human system, especially in the last two centuries, has caused profound and – to civilization – dangerous changes in the natural system as a result of its runaway population growth and aggregate consumption," Ehrlich said.

Humanity has significantly altered the gaseous composition of the atmosphere; spread toxic chemicals from pole to pole; altered most of Earth's terrestrial surface through forest clearing, farming, grazing, building and paving; and become a major factor in soil transformation and erosion.

"The list goes on," Ehrlich said. "Human beings have started the most serious episode of population and species extinctions in 65 million years, dramatically reduced the stocks of many oceanic fishes, raised sea level, increased ocean acidity, mined fossil ground water and numerous minerals at rates higher than they are normally recharged or mobilized by natural processes, and in the view of many scientists created a new geological epoch, the Anthropocene."

The human system is so tightly coupled to the biosphere, one might think that humans would be responding urgently to these environmental changes. "But instead it is continuing business as usual, as if the environment were one more political element with which, should it become necessary, it could negotiate. We are decoupling the two systems," Ehrlich warned, "which is like decoupling our metabolism from breathing.

"Greenhouse gases keep pouring into the atmosphere despite disasters related to anthropogenic climate disruption like Hurricane Sandy. Extinction of populations and species is accelerating. Land degradation, aquifer overpumping, mineral resource depletion and global toxification proceed with no serious efforts to control them. And humanity 'plans' to add 2.5 billion more people by mid-century. In short, there is no significant reaction in the human system to the gigantic pernicious changes it has entrained in the natural system."

To see the growing disconnect, Ehrlich said, one only has to consider the attention paid in public discourse to the financial problems currently facing rich nations: "Coverage of these topics in the media is massive compared to, say, the news that Earth's coral reefs are now beyond saving and that civilization may have passed a lethal climatic tipping point and be headed for collapse.

"In the absence of dramatic changes in human behavior relative to Earth's natural systems, gradual population shrinkage, an end to overconsumption by the rich and a redistribution of wealth and opportunity, it is likely the natural system will react in ways that will reduce the scale of the human system in a very unpleasant manner," Ehrlich said. "Debt and employment problems can be solved entirely by negotiation; one cannot negotiate with nature."

Whether mutually beneficial human-nature coupling can be restored in time is an open question, Ehrlich concluded, but it will certainly require action from the grassroots, as well as new institutions/mechanisms for coordinating bottom-up and top-down efforts.

"There are many hopeful small-scale recoupling efforts such as the Natural Capital Project to protect biodiversity and ecosystem services, deployment of renewable energy systems in many countries, and work to unite academics and civil society in developing the necessary foresight intelligence," Ehrlich said. "But time is short, and in my view decoupling is clearly winning."

Ehrlich recommended four organizations for those interested in trying to avoid a collapse of civilization and reach a sustainable society: Occupy Wall Street, Global Movement to Solve the Climate Crisis, GrowthBusters and MAHB: Millennium Alliance for Humanity and the Biosphere.



Paul Ehrlich, Biology: (650) 723-3171,

Bjorn Carey, Stanford News Service: (650) 725-1944,


Update your subscription

More Stanford coverage

Facebook Twitter iTunes YouTube Futurity RSS

Journalist Resources Stanford News Stanford Experts Contact Us

© Stanford University. Stanford, California 94305. (650) 723-2300.