A study conducted by researchers in one of China’s megacities found that lab estimates of car emissions are way, way off. As Reuters reports, by focusing on data culled from taxis and ridesharing services, scientists were able to expose the huge discrepancy:
The findings from the study in the central city were supported by a research arm of China’s top planning body using data from Uber and taxi firms. It found that standard laboratory estimates of carbon emissions from cars were off by about 6,500 metric tonnes per day, or about 59 percent.“In the (the Chinese government’s most recent) 13th five-year plan, every region and city has the target, but the question is how you meet those targets and how do you verify the target has been met?” said An Feng, head of the Innovation Center for Energy and Transportation, a think-tank that led the study. “You cannot manage if you can’t measure it.”
Measuring emissions from static sources like power plants is relatively easy, but even there China’s self-reported numbers have proven to be unreliable. When you start trying to encapsulate the collective emissions of hundreds of thousands of cars and trucks, the complexity of the task is necessarily going to introduce a larger margin of error. In this sense, it’s not surprising to hear that Chengdu’s car emissions may be more than twice as high as previously estimated.But it’s vitally important to keep the inaccuracy of Chinese statistics in mind when considering global climate efforts. The country is far and away the world’s biggest emitter of greenhouse gases, but its long history of statistical opacity and the strong incentives its local governments have to fudge the numbers they report to Beijing’s central planners make it difficult to get a handle on precisely how much China is emitting, and in the coming years how much it’s doing to curtail those emissions.The Paris climate deal lacks any real enforcement mechanisms, and if ratified will merely require countries to submit national plans for reducing emissions. The only way the UN hopes to keep countries to their word is by naming and shaming them if and when they fail to meet targets, but in China’s case we might not be able to know how committed the country is to mitigated climate change.