Roughly a year ago, the International Energy Agency announced a wonky yet nonetheless significant development. Looking at data for the year 2014, the agency found that although the global economy grew - by 3.4 percent that year - greenhouse gas emissions from the use of energy (their largest source) had not. They had stalled at about 32.3 billion metric tons of carbon dioxide, just as in 2013.

The agency called this a "decoupling" of growth from carbon dioxide emissions, and noted that it was "the first time in 40 years in which there was a halt or reduction in emissions of the greenhouse gas that was not tied to an economic downturn." For decades prior to 2014, economic growth had pretty much always meant more pollution of the atmosphere, and a worsening climate problem.

It now seems like 2014 wasn't just a fluke - IEA is saying the same thing about 2015. In a news release Wednesday, the agency said that 2014's hint of decoupling had now been "confirmed," as 2015 also saw flat emissions combined with 3.1 percent global GDP growth. Emissions, the agency said, were just 32.1 billion metric tons in 2015, based on preliminary data - indicating perhaps even a slight downturn from 2014.

"The new figures confirm last year's surprising but welcome news: we now have seen two straight years of greenhouse gas emissions decoupling from economic growth," said IEA Executive Director Fatih Birol in the press statement. "Coming just a few months after the landmark COP21 agreement in Paris, this is yet another boost to the global fight against climate change."


That this decoupling is occurring is certainly a landmark. The relationship between economic growth and carbon dioxide emissions (and other environmental assaults) has been intensively studied, based on the premise that, as one paper put it, "Energy is considered to be the life line of an economy."

When people have more money, they can drive their cars more, take more trips on airplanes, buy new appliances, and much more. Businesses can build new plants and factories. Houses get constructed - and on, and on, and on. And it all takes energy.

"Using GDP and emissions data over multiple countries and time periods, studies consistently find that GDP per capita and emissions per capita move in the same direction among most or all of the sample," noted the U.N.'s Intergovernmental Panel on Climate Change in 2007.

So how do you break this relationship? Simple: Find a new way of getting energy. Sure enough, the IEA attributed the second straight year of decoupled growth and emissions to a greater uptake of renewable energy, particularly wind, and fewer emissions in China and the United States, the two largest emitters by far. The former country is cutting back its coal use deliberately, while in the U.S., market forces have had a similar effect, as cheap natural gas has pushed out a considerable volume of coal in electricity generation.

The finding echoes a late 2015 study, which also said that the year's global carbon emissions appeared to have declined slightly, relative to 2014. However, at that time experts cautioned that it was far from clear that emissions had actually peaked overall - the growth slowdown might be temporary. Many rapidly developing nations, led by India, are actually expected to increase their use of fossil fuels over the coming decade or more, as global populations grow and energy demand increases.

The news comes as global temperatures in early 2016 have spiked to an unprecedented high, and several new studies have called into question whether emissions, even if stalled now, can actually decline fast enough to prevent warming from reaching 2 degrees Celsius, widely considered to represent a "dangerous" level of climate change.

The problem is that once emitted, a significant proportion of carbon dioxide remains in the atmosphere for a very long time, so whether emissions are rising or simply flat, every year is an added accumulation.

For precisely this reason, scientists have said we can only emit a fixed amount of carbon dioxide – sometimes claimed to be 1,000 billion tons from the year 2011 – if we want a good chance of holding warming to 2 degrees C above pre-industrial levels. However, recent research has suggested that the actual carbon "budget" could be even tighter than that.

From this perspective, a decoupling of growth from emissions, while certainly good news, is not enough – emissions need to decline, quickly, to preserve hope of staying within a climate safety zone. Still, the new data suggest that the twin clean energy and natural gas booms are having a global impact – and at least leaving humanity a chance of fixing the carbon problem before it's too late.