On pace to see climate disruption outside the realm of human experience
By Summit Voice
FRISCO — You can almost hear global warming deniers gnashing their teeth and pulling out their hair as staid organizations like the World Bank take a hard look at the economic and environmental realities of climate change.
In a report prepared for the global financial institution, the Berline-based Potsdam Institute for Climate Impact Research and Climate Analytics warned that, without a drastic reduction in greenhouse gases, the world is on a path to warm at least four degrees Celsius, which could result in a “world of risks beyond the experience of our civilization — including heat waves … sea-level rise affecting hundreds of millions of people, and regional yield failures impacting global food security.
“The planetary machinery tends to be jumpy, this is to respond disproportionately to disruptions that come with the manmade greenhouse effect,” PIK’s director Hans Joachim Schellnhuber said. “If we venture far beyond the 2-degree guardrail, towards 4 degrees, we risk crossing tipping points in the Earth system.
“This could be the case with coral reefs which face collapse under unabated global warming, or with the Greenland ice sheet. To melt the ice sheet would take thousands of years, yet this might be an irreversible process that could start soon. “The only way to avoid this is to break with the fossil-fuel-age patterns of production and consumption,” Schellnhuber said.
While some climate researchers are still cautious about linking individual extreme weather events with long-term climate change, the German research group laid it on the line, citing the 2010 heat wave in Russia, which killed several thousand people and reduced harvest yields by 25 percent.
With continued warming, extreme events would become “the new normal” in some parts of the world, according to the report. In the tropics, the coolest months at the end of the century are likely to be substantially warmer than the warmest months today.
Sea level, under this scenario, would rise by 50 to 100 centimeters within this century, and more so in coming centuries. The rate of rise varies from one region to the other, depending on sea currents and other factors. Projections suggest that sea-level rise will be strongest in countries like the Philippines, Mexico, and India.
Within economic sectors, too, tipping effects with rapidly increasing damages can occur, for instance in agriculture. Already, observations showed that important cereals are sensitive to temperature increases passing certain thresholds, resulting in large-scale yield failure. Changes in the water cycle can aggravate this, when droughts occur or flooding affects farmed land.
“The report draws from the current state of science and delivers new analysis of heat waves and regional sea-level rise, so of course there remain some uncertainties,” said William Hare, co-founder of Climate Analytics in Berlin and guest scientist at PIK. “We work with that by defining risk as potential damage multiplied with the probability … a rather improbable event can be a great risk if its impacts are huge.”
“A 4-degree warmer world can, and must be, avoided. We need to hold warming below 2 degrees,” said World Bank President Jim Yong Kim. “Lack of action on climate change threatens to make the world our children inherit a completely different world than we are living in today. Climate change is one of the biggest single challenges facing development, and we need to assume the moral responsibility to take action on behalf of future generations, especially the poorest.”