As 2014 gets underway, humanity’s carbon emissions remain on course to catastrophically reshape the global climate over the next century or two.
Global carbon emissions increased 1.4 percent in 2012, hitting an historic high of 31.6 billion metric tons released in a single year, according to a recent assessment by the International Energy Agency (IEA). The Intergovernmental Panel on Climate Change recently pegged the total amount the world can afford to emit at 1,000 billion metric tons of carbon. Beyond that, humanity has little chance of holding the change in global temperatures below 2°C — the threshold after which most scientists agree climate change will become genuinely catastrophic. The world has already blown through 531 billion metric tons of this “carbon budget,” and not using up the rest will require leaving most of the world’s already-proven fossil fuel reserves unused and in the ground.
After several years of decline, America’s total annual carbon emissions ticked back up in 2013, thanks largely to market shifts that left coal once again more economic than natural gas. Meanwhile, the developing world is coming up fast as its economies build up, and it now accounts for 60 percent of global carbon emissions — up from just 45 percent in 2000.
The end result: we’re chewing up that remaining carbon budget at an astonishing — and accelerating — rate, that nothing seems able to slow down:
If this path continues, the IEA estimates we’ll see between 3.6°C and 5.3°C degrees of global warming over pre-industrial levels, most of it within the next hundred years. That’s in line with projections in Nature of 5°C degrees of warming, all of which would be a temperature rise unheard of in human history.
According to the World Bank, a rise of just 4°C would be “marked by extreme heat-waves, declining global food stocks, loss of ecosystems and biodiversity, and life-threatening sea level rise.” A British assessment of climate change’s potential to wreck the world economy put the damage at anywhere from five to twenty percent of global GDP. Meanwhile, the costs of curtailing climate change range between one and four percent. And in case you’re not worried enough already, research in December from climate scientists Michael Mann and others suggests we’re underestimating the damage even at 2°C, and keeping things to 1°C of warming is far preferable in terms of risk management.
There’s also little time left. To hold even to the 2°C threshold, global carbon emissions will have to peak within the decade, after which they’ll have to start falling fast.
The single biggest problem is the world’s two primary carbon emitters — the United States and China — still haven’t established any mechanism for building the economic damage of climate change into fossil fuel use. The result is an effective subsidy for fossil fuel use of hundreds of billions of dollars every year. China is dabbling with some pilot projects, and America is sneaking up on finally regulating carbon emissions through the Environmental Protection Agency. But it’s far from clear that even full implementation of the President’s Climate Action Plan would get us anywhere close to the scale of emission cuts we need. That’s why environmental groups just sent a joint letter to the White House calling President Obama’s “all of the above” energy strategy grossly inadequate given the scale of the threat.
At a bare minimum.