News•December 7, 2015

Study Sees Possible Decline in Global CO2 Emissions

The rapid spread of renewable energy and improvements in energy efficiency across the globe may have paid off in a big way this year. Researchers are projecting that for the first time in history, the rate of growth in global carbon dioxide emissions from burning fossil fuels will decline even as the global economy continues to grow.

That decline could eventually lead to a peak in carbon emissions in the next decade or two, according to research led by Stanford University and published Monday in the journal Nature Climate Change.

Emissions from a power plant in China.
Credit: Mingjia Zhou/flickr

“In 2014, global carbon dioxide emissions from burning fossil fuels grew by just 0.6 percent,” lead author Rob Jackson, a professor of Earth system science at Stanford, said. “This year we expect total emissions to flatten or drop slightly, despite strong growth in gross domestic product worldwide.”

That has never happened before, he said.

The results of the study could play a role at the Paris climate negotiations this week, possibly helping to provide additional data that could be used to strengthen countries’ emissions cuts commitments. The central goal of the talks is to reach a legally-binding global agreement to cut greenhouse gases to prevent global warming from becoming widely catastrophic.

“Time will tell whether this surprising interruption in emissions growth is transitory or a first step towards emissions stabilization,” the paper says. “In either case, the trend is a welcome change from the historical coupling of carbon dioxide emissions with economic growth and should be strengthened through efforts at the Paris (climate negotiations) and beyond.”

The study shows that carbon dioxide emissions from fossil fuel burning and cement production in 2014 grew by 0.6 percent compared to 2.4 percent annual growth between 2000 and 2010. The research projects that emissions could drop about 0.6 percent in 2015 even as global GDP continues to climb.

“The slower growth in emissions was attributed largely to a drop in coal consumption in China, with additional contributions from below-average growth in global demand for oil and natural gas and continuing growth in renewables,” the study says.

Since the beginning of the Industrial Revolution, the conventional wisdom has been that economic decline comes with a decline in fossil fuel consumption. The latest data suggest that the global economy is divorcing itself from fossil fuels consumption.

“The hope is we’re on a new trajectory now — the (emissions) growth will be slow and we’ll see peak emissions within a decade or two,” Jackson said.

He warned, however, that a decline in emissions growth doesn’t mean the globe has figured out how to sufficiently curb greenhouse gas emissions to prevent catastrophic global warming.

“Peak emissions and zero emissions are very different,” he said. “When emissions do peak, we have a long road ahead of us to decarbonize the global economy. We’re not saying the hard work is done. The hard work is just beginning.”

One of the biggest challenges is finding a way for India to curb its emissions. India is seeing a rapid growth in emissions, unlike China, the U.S. and the European Union, which are seeing emissions declines, he said.

“India’s emissions are now exactly what China’s were in 1990,” Jackson said. “India has the challenge of producing more energy and yet not just being able to rely on coal to do it.”

Michael Mann, director of the Earth System Science Center at Penn State University who is unaffiliated with the study, said Jackson’s team’s paper is significant.

“What it shows is that we are indeed now turning the corner in transition from a fossil fuel to renewable-driven global economy,” he said. “But we need to turn the corner even faster.”

Air pollution in Paris, the site of the United Nations climate negotiations this week.
Credit: Alberto Hernandez/flickr

He said slower in growth in carbon emissions globally is a reason for cautious optimism, and nations’ emissions commitments ahead of the Paris climate negotiations are helpful, but “we need to go further.”

Other scientists unaffiliated with the study said the paper focuses mainly on good news and ignores the bad news in the data it presents.

Robert Socolow, co-director of the Carbon Mitigation Initiative at the Princeton Environmental Institute at Princeton University, said that while emission growth is declining in China, the U.S. and the EU, India and the dozens of other smaller countries categorized in the paper as the “rest of the world” are seeing their emissions steadily climb. That’s because their economies will develop faster using coal power than with alternative energy sources currently available.

“Large parts of the world are embarking on industrialization a decade or more behind China and are using the same coal-based industrialization that China followed,” Socolow said. “The world is still industrializing around coal.”

No solution has been found yet for that problem, he said. “We haven’t paid enough attention to it. These are the sleepers, and they’re substantial.”

Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research in Boulder, Colo., said the paper doesn’t emphasize the biggest problem that must be overcome to stop global warming — atmospheric carbon dioxide concentrations.

“It is not whether emissions stop growing that matters, it is whether they stop period,” Trenberth said. “It is the concentrations of carbon dioxide in the atmosphere that matter for climate, and those continue to grow as long as emissions are positive. To stabilize concentrations, we first have to stabilize emissions and then decrease them a lot.”