Good News: Global CO2 Emissions Fell Slightly This Year, Study Finds

Have global emissions of carbon dioxide peaked?  It seems hard to believe they might.  But for the past two years, while the global economy has grown by more than 6 percent, the previously inexorable rise in carbon dioxide emissions from burning fossil fuels and industry has stalled. 

CO2 emissions in 2015, at 35.7 billion tons, are likely to be exactly where they were two years ago, according to a study published today in the journal Nature Climate Change.

The flat-lining emissions trajectory is the result of China's recent sharp decline in coal burning and the global surge in renewables like wind and solar power, said Corinne Le Quéré, director of the Tyndall Centre at the University of East Anglia in Norwich, England, who led the analysis.  The study estimates China's emissions have fallen by 3.9 percent this year, said co-author Robert Jackson of Stanford University. 

Le Quéré does not believe the world has yet hit "peak emissions."  Continued rapid industrial expansion by countries such as India that still rely on coal for energy means further rises probably lie ahead, she said.  But the evidence is growing that peak emissions may be closer than previously imagined. 

Of the top three emitters, China is decarbonizing its economy, and the US and European Union have settled into long-term emissions decline.  Meanwhile the Paris climate conference this week is likely to endorse national pledges from more than 180 nations to moderate their own emissions. "The trend of rapid global emissions growth has been broken," said Michael Grubb, an energy economist at University College London unconnected with the study. 

If the US and EU continue on their current track, then an annual 2-per-cent decline in Chinese emissions would be enough to offset emissions growth elsewhere, said report co-author Glen Peters of CICERO, a Norwegian climate research center. 

Of course, this would not solve the climate problem.  Temperatures are driven not by annual emissions but by the accumulated concentration of greenhouse gases such as CO2 in the atmosphere.  So this year's emissions will have added to that accumulation.  In fact, 2015 is set to be the first year for 800,000 years in which average CO2 concentrations in the atmosphere exceed 400 parts per million, says Le Quéré. 

"To stop temperatures rising, net emissions need to be reduced to zero.  But for that, emissions need to peak first," said Myles Allen of Oxford University, commenting on the paper.  "So evidence that it is possible to grow the world economy while reducing emissions is good news." 

The decoupling of trends in global emissions from those of economic activity is sudden and dramatic.  In modern times, emissions have largely followed global GDP.  Since 2000, they have grown by an average of 2.4 percent a year.  The only decline was in 2009, at the height of the global financial crisis. 

But in 2014 emissions bucked the trend by rising just 0.6 percent while global GDP rose 3.4 percent.  And now it appears that 2014 was no freak.  In 2015, the study predicts, emissions will fall by 0.6 percent, despite global economic growth that the International Monetary Fund currently estimates will be 3.1 percent.  This is unprecedented.  On these estimates, the past two years have seen the carbon intensity of the global economy — the tons of CO2 emitted for every dollar of GDP — fall by 6.4 percent.

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