Throughout history, every great human civilization has experienced a significant crisis. And although the outcomes of these crises have varied from total eradication (the Classic Maya) to depression and eventual recovery (China), each collapse has been regional in scale. Now, a variety of problems have combined to move the global civilization toward a collapse.
The key drivers of collapse, according to Stanford biologists Paul and Anne Ehrlich, are overpopulation and overconsumption by the wealthy. The side effects of the very practices that have allowed humans to prosper have combined to put incredible strain on the planet's natural systems, and that threatens to negatively impact future generations.
Despite this grim outlook, the Ehrlichs offer a roadmap for avoiding society's total collapse, emphasizing that giving women equal rights worldwide is a critical first step.
The Ehrlichs' commentary – the conclusions of which were reviewed by a panel of renowned biologists and social scientists – is documented by references to more than 150 scientific publications of the state of various Earth systems. It was published online Jan. 8 in Proceedings of the Royal Society B.
Britain's Prince Charles, a vocal environmentalist who has been outspoken about the dangers of climate change, commended the Ehrlichs' report.
"Paul and Anne Ehrlich's report is a timely and urgent reminder of how the collapse of civilizations has, in the past, been caused by the degradation of Nature's services, and how that process is now being repeated on a global scale," the Prince of Wales wrote on his website. "The services provided by Nature underpin all global economic development. … We do, in fact, have all the tools, assets and knowledge to avoid the collapse of which this report warns, but only if we act decisively now. … The alternative hardly bears thinking about."
Studies of the planet's ecological footprint suggest that sustaining today's 7 billion people at current standards will require roughly an additional half planet of resources (or, four to five more Earths if all citizens of the planet were to consume at the level of the United States).
The human population is projected to reach 9.6 billion by the middle of this century. Such growth compounds the consumption problem, because each person added to the planet requires a greater allotment of natural resources than the person who came before. This non-linear trend traces to the start of human civilization: As populations grew from soil-rich river valleys, humans were forced to farm more marginal land, and required more resources – land, fertilizer, energy, etc. – to produce the same quantities of food.
"The next 2.5 billion people will do much more damage than the 2.5 billion added since the 1970s," said Paul Ehrlich, a professor of biology and president of Stanford's Center for Conservation Biology, "because people use the richest, most easily extracted resources first."
There are hopeful signs that technological efforts – such as improving agricultural practices, replacing fossil fuels with innovative energy solutions and reducing greenhouse emissions – could meet the demands of future generations, Ehrlich said, "but you can't save the world on hope alone."
Rather than working to make the planet hospitable for 9.6 billion people, the authors suggest that scientists focus on how to humanely lower birth rates far enough to reduce that number to 8.6 billion, and then moderating consumption to fit within Earth's carrying capacity.
"Anything less is threatening the lives of our grandchildren," Ehrlich said.
The single best step toward avoiding a collapse, Ehrlich said, is to give total equality to women around the world. "This will allow us to include more of their brainpower to help solve these problems," he said. "And studies have shown that when women are given full rights, they have fewer children, which will help slow birth rates. We also need to give every sexually active human free access to modern contraception and emergency abortion."
Modern society has shown some ability to deal with issues that threaten future generations – minimizing the risks of nuclear conflict, for instance – but it will require natural and social scientist, activists and especially politicians to coordinate an international effort to get people to adopt change. Assisting that coordination is a major goal of the developing Millennium Alliance for Humanity and the Biosphere at Stanford.
"One of the saddest things is that the scientific community has described, in detail, the environmental factors leading to the collapse for quite some time, but society has not reacted," Ehrlich said. "After all, the U.S. just had a presidential election in which the crucial issues facing society were not debated. Instead the focus was on financial problems easily solved by negotiation among people. You can't negotiate with nature."
Explore further: Study shows employees become angry when receiving after-hours email, texts