A world greatly concerned about how the election of Donald Trump as the next U.S. president could stall global climate policy received a major dose of welcome news Sunday, when scientists published a projection suggesting that for the third straight year, global carbon dioxide emissions did not increase much in 2016.
The news comes from the Global Carbon Project, a group of scientists who measure how much carbon dioxide humans emit each year, as well as how much is subsequently absorbed by plants, land surfaces and oceans. The difference between the two determines the amount of carbon dioxide that remains in the atmosphere and drives global warming.
Big news came from this group late last year, when it turned out that emissions in 2014 and 2015 represented a seeming end to a strong growth trend that had appeared unstoppable for some time. And moreover, this flattening had occurred despite steady global economic growth above 3 percent, which has typically been coupled with higher emissions.
And now, the group reports, 2016 appears to be similar to 2014 and 2015, based on early projections. It will be about a 0.2 percent increase above the emissions levels of 2015, the group calculates, or barely a rise at all.
The results were released in the form of a massive study in the journal Earth System Science Data, written by no less than 67 researchers from an army of institutions. That’s what it takes, it seems, to chart the annual flow of carbon throughout the Earth’s systems.
“2016 we estimate to be flat again,” said Glen Peters, one of the contributors to the research and a scientist at the Center for International Climate and Environmental Research-Oslo in Norway. “It’s definitely three years, it’s fairly flat, which is quite a contrast to a decade ago, when it was growing at about 3 percent. It’s really leveled out the last few years.”
Peters said this leveling is attributable to a decline in emissions in China and the United States, the two largest emitters. In both cases, this was in significant part a result of less coal burning.
China saw carbon dioxide emissions decrease by 0.7 percent in 2015 and is forecast to see an additional 0.5 percent decline in 2016. U.S. emissions are falling even faster. They declined by 2.6 percent in 2015 and are expected to fall an additional 1.7 percent this year.
But not all of the world is following suit. By comparison, in 2015 there was strong 5.2 percent emissions growth in India.
The current leveling out still means that slightly more than 36 billion tons of carbon dioxide are expected to have been emitted in 2016 from fossil fuel use and industrial activity. And after the oceans and the land take away their part, the rest of that carbon will stay there for a very long time, steadily warming the planet.
(That 36 billion tons does not include emissions of other greenhouse gases, such as methane, or the releases of additional carbon dioxide from deforestation and other nonindustrial causes. Including these gases and sources only increases our impact on the planet further.)
From a climate policy perspective, the key question is whether these three flat years suggest that the world is beginning to peak its emissions and bring them down again, which will be necessary if there is any hope of limiting warming to widely embraced international targets such as 1.5 or 2 degrees Celsius above preindustrial levels. But Peters said that it’s too soon to know for sure, and that he would want to watch trends in China, in particular, for a bit longer.
“I’d certainly give it five or more years before I’d say it’s a peak,” he said. “But certainly you would say, even leveling out, like we have over the last three years, is a big surprise. If you’d stood back three years ago, we wouldn’t have been expecting this. So it’s certainly good news.”
However, it’s also important to keep things in context. Not only is a cessation of growth very different from a decline. But, as the study notes, emissions today are “still 63% above emissions in 1990.”
What’s more, if global warming is ever to stop — and if we’re ever to cool the planet back down again — eventually emissions have to go to zero. Thirty-six billion tons is very far, indeed, from that. In fact, it’s looking increasingly likely that we may have to find some way to make emissions go negative (pulling more from the air than we put in) in the second half of this century.
The new research also suggests that, starting in 2017, the world will have only 800 billion tons, or gigatons, of carbon dioxide left to emit if it wants to preserve a two-thirds chance of preventing the planet from warming more than 2 degrees Celsius above preindustrial levels. This is the remaining global carbon “budget.” Based on emissions of 36 billion tons per year, we would bust the budget in 22 years.
There are pretty hard-to-miss political implications of the new finding about flat global emissions. The United States, after all, has elected Trump, who has pledged to “cancel” the Paris climate agreement, which seeks to reduce emissions quickly, and to rescue the domestic coal industry, which relies on the mining and the burning of the most carbon-intensive fossil fuel.
“While there are many reasons why the growth in emissions has been halted, a key contribution has been the efforts made by the world’s two biggest emitters, the United States and China, to reduce the consumption of coal,” Bob Ward, policy and communications director at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science, said in a statement. “However, Donald Trump as President could undermine this achievement if he carries through with his threat to scrap the Obama Administration’s Clean Power Plan, and encourages an increase in the use of coal for electricity generation.”
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