Is the Paris Climate Agreement Built on Dodgy Math?

Is the Paris Climate Agreement Built on Dodgy Math?

Why you should care

Because every solution starts by understanding the problem.

This article has been updated since its original publication in February 2017.

Since 2007, when China overtook the United States as the world’s largest emitter of carbon dioxide, headlines have gleefully labeled the roaring Asian giant as the “world’s worst polluter,” often accompanied by images of smog-soaked cities.

But before we go wagging our supposedly green fingers at others, it’s worth checking the numbers — and the ruler, for that matter. It turns out that depending on how you measure environmental footprints, you can get very different pictures of where the blame truly lies. As climate negotiators gather this week in Bonn, Germany, for United Nations talks about the future of the 2015 Paris agreement, and with the Trump administration contemplating whether the U.S. should seek to renegotiate its commitments or abandon the pact altogether, it’s worth considering whether we’ve been thinking about global emissions in the wrong way for years.

Specifically, instead of looking at emissions within national territories, some researchers suggest it might be more useful to measure the environmental effects of consumption. According to this “consumption-based accounting,”

Americans are responsible for 10 times as many emissions as the Chinese.

That figure comes from research that breaks down the environmental effects of household consumption — and not just the CO2 emissions but also the land, water and material use that is embodied in everything we do, eat and buy. By this measure, Americans have the world’s largest carbon footprint, at 18.6 tons of CO2 equivalents per person per year.

The environmentally conscious Europeans are also not as innocent as they look, with Luxembourg coming in a close second in carbon emissions and leading the world in terms of material and water footprints. Chinese consumers, meanwhile, have a carbon footprint of just 1.8 tons per year, and are well below the world average by each of the other environmental measures. The overall trend isn’t rocket science: The richer a country, the more it consumes, and the larger its environmental footprint.

With conventional measurements, all countries could meet their emissions reduction targets under the Paris agreement and yet global emissions still rise.

But why use household consumption instead of territorial emissions to measure environmental impact? The answer is twofold, says lead researcher Diana Ivanova, of the Norwegian University of Science and Technology. First, household consumption accounts for the majority of environmental impacts. That’s around two-thirds of all carbon emissions and between 50 and 80 percent of land, water and material footprint (the rest is accounted for by things like government activity and capital formation by businesses). Besides, unlike other sources of emissions, “household consumption is directly under our control,” says Ivanova. Which means we, as consumers, could actually do something about it.

The world economy is far too globalized for territorial production measures to sensibly guide climate policy, says Magnus Jiborn of Lund University in Sweden. For instance, if a steel manufacturer in a nation like Sweden leaves to set up shop in China, Sweden’s production-based stats will show that emissions fell, even though the company will be able to pollute more in China, meaning that global emissions will rise. Several developed countries have shown slowing or declining emissions in recent years, but that trend disappears when looked at from the consumption side. This “carbon leakage” could be hugely consequential: Because of differences in how developed and developing nations defined their emissions reduction targets under the Paris Agreement (absolute reductions for the rich countries; reductions relative to gross domestic product for others), all countries could meet their goals and yet global emissions still rise.

Beyond this, shifting our attitudes about environmental impact from production to consumption could yield better decision-making. Only around 20 percent of emissions that we are responsible for, and less than 5 percent of our water footprint, come from direct usage such as driving a car or running a shower, Ivanova’s research shows. The rest is all hidden in the supply chains of what we buy. So if you want to reduce your environmental footprint, changing what you buy could make a far bigger difference than turning down your house’s thermostat by a degree or two.

Alas, consumption-based accounting is not easy. It’s “much more data demanding” than the traditional approach, meaning that analysis could never be as responsive as current measures, says Jiborn, whose own research advocates for a measure that lies somewhere between the two. So it’s unlikely that this week’s collection of diplomats will perform a 180 on emissions accounting. And with the U.S. sending only seven negotiators to the meeting — fewer than in the Zimbabwean delegation and a fraction of the several dozen from other major economies like China and Germany — it’s unlikely that a united global consensus will be reached this week on any major policy shift.

And for you and me? Until there exists some global product-labeling standard that reports the full environmental footprint of everything we buy, the advice remains pretty general. Shifting your diet from meat to plants or buying more secondhand products can make a big difference, says Ivanova, who has taken both measures herself since starting the research. In the meantime, perhaps we should stop pointing fingers — China may well be the world’s factory, but it’s only making stuff because we’re buying it.

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