作者：Science Alert 2019-12-04 18:49
Carbon dioxide and methane aren't the only greenhouse gases the world needs to worry about. The rapid rise of nitrous oxide (N2O), colloquially known as 'laughing gas', is no joke either.
This little-known greenhouse gas may not be as prevalent nor as long-lasting as carbon dioxide, but it is hundreds of times more potent and can stick around in the atmosphere for more than a century.
Today, it's released mainly through human agricultural practices, such as using cheap nitrogen fertiliser. And, as you've no doubt guessed, it's also a main contributor to ozone depletion and global warming.
To make matters worse, we've seriously underestimated its use. Since the turn of the century, new measurements reveal atmospheric N2O has risen much faster than experts at the United Nations once predicted.
"We see that the N2O emissions have increased considerably during the past two decades, but especially from 2009 onwards," says climate scientist Rona Thompson from the Norwegian Institute for Air Research (NILU).
"Our estimates show that the emission of N2O has increased faster over the last decade than estimated by the Intergovernmental Panel on Climate Change (IPCC) emission factor approach."
Instead of basing their calculations on human emissions, which are usually gathered from indirect sources, the researchers used a 'top-down' approach, based on dozens of atmospheric measurements from around the world. These data were then used to predict N2O dynamics on land and in the ocean between 1998 and 2016.
研究人员的计算并非基于通常从间接来源收集的人为排放量，而是利用“自上而下”的方法，基于全球数十个大气测量值进行计算。这些数据被用来预测1998 年至 2016年间陆地和海洋的氧化亚氮的动态变化。