Still, an ominous trend threatens to undermine this progress: Global reliance on coal, the highest-carbon fuel of all, is rapidly growing. Another July study found that cheap coal exports from the U.S., Australia and elsewhere are driving a “coal renaissance” in dozens of developing countries. Those nations are expected to build hundreds of new coal-fired power plants by 2030. Once up and running, “those coal capacities will stand there for the next 30 to 40 years,” contributing billions of tons of carbon emissions, says Jan Steckel, an economist at the Potsdam Institute for Climate Impact Research in Germany, who led the study.
If these economies could be persuaded to shift to renewable energy, that scenario could be averted, but the window of opportunity is closing, says Steckel. Negotiators at the Paris talks, which had not begun by press time, hope to figure out how to make that transition to renewables more affordable.
The benefits of making these hard choices are clear. Some researchers say cutting carbon emissions enough to limit warming to 3.6 F (2 degrees Celsius) above pre-industrial levels could avert the worst impacts of climate change. The Amazon forest, which stores vast amounts of carbon, would survive, and according to a study published in September, staying within this threshold could stop sea level rise at 5 or 10 feet. While much of Florida would be sacrificed, many other coastal areas would remain intact.
Meeting this goal would require capping humanity’s cumulative carbon emissions at about a trillion tons, and we’ve already burned through about two-thirds of that “allowed” carbon budget. We must choose wisely how we spend the rest.