Earth near point of no return, scientists warn
Effects of civilization on planet threaten collapse of ecosystems in 50 years — with no going back
The Earth’s ecosystems could reach a point of no return resulting in rapid irreversible collapse in as little as 50 years, according to projections by a group of 18 scientists.
Their article in the journal Nature today says that human activities — such as energy use and widespread transformation of the Earth’s surface for habitation and agriculture — are pushing the planet toward a critical threshold for “state shift” not unlike the transition from the last ice age about 12,000 years ago.
Such a shift would create a new normal condition for the entire planet with a new range of temperatures, new ocean levels and widespread species extinctions resulting in an entirely new web of life.
It would not necessarily be a comfortable place for human beings.
“We’ve had a good long run of really benign conditions that have allowed humans to go from cracking rocks together to walking on the moon,” said Simon Fraser University biodiversity professor Arne Mooers, one of the authors of the article.
The transition from the last ice age to the current balmy inter- glacial state that has allowed human beings to flourish took about 1,000 years, he said.
“The change we are undergoing now is much, much faster,” he said. “Orders of magnitude faster.”
The next global state change will be “extremely disruptive to our civilizations,” he said. “Once a thresholdinduced planetary state shift occurs, there’s no going back.”
Such a tipping point is “speculation at this point,” Mooers said. “But it’s one of those things where you say: ‘ Hey, maybe we better find out,’ because if it’s true, it’s pretty serious.”
Even if the human race were to try to reverse the effects of our civilization on the atmosphere, ocean levels and the makeup of the world’s food webs, the Earth wouldn’t revert to the way it used to be.
Human beings have transformed about 43 per cent of the Earth’s land area and increased the concentration of carbon dioxide in the atmosphere by about 30 per cent since pre- industrial times. Humankind will have transformed about 50 per cent of the Earth for our own purposes by 2062.
“In some mathematical models, you can get a tipping point when you swing from slightly less than 50 per cent to slightly more than 50 per cent,” said Mooers, who likened the effect to a flu pandemic that sweeps across the
world when enough people become infected.
“I think that if we want to avoid the most unpleasant surprises, we want to stay away from that 50 per cent mark,” said lead author Anthony Barnosky, professor of integrative biology at the University of California, Berkeley.
The “ultimate effects” of a state shift are unknown, but the researchers suggest it could have severe impact on the world’s fisheries, agriculture, forests and water resources. And they warn that “widespread social unrest, economic instability and loss of human life could result.”
The scholars — from Chile, Canada, Finland, the United Kingdom, Spain the United States — originally met for a two- day brainstorming session at the Berkeley two years ago to discuss ways to cope with the rate of change in the Earth’s ecosystems.
Bringing biological disciplines together with experts on the Earth’s past and mathematicians created a surprising synergy resulting in useful predictive models, Mooers said.
“The paleontologists and the mathematicians teamed up to figure out where the tipping points might be and how to predict them and then figure out from what is happening now whether we are close to one,” said Mooers.
The report notes that the climate is warming so fast that the “mean global temperature by 2070 ( or possibly a few decades earlier) will be higher than it has been since the human species evolved.”
Most disconcerting among evidence under review is that the Earth is not following its normal historical climate cycle of glacial and inter- glacial periods, but veering off in a new direction.
“The drivers of the past for the glacial and inter- glacial pattern — which are external — are not the drivers that are pushing us where we are going today,” Mooers said. “Now we are doing it ourselves by putting all this [ carbon dioxide] into the atmosphere and changing the landscape.”