Research press release


Nature Geoscience

Developed nations outsource part of nitrogen emissions to developing countries



Manfred Lenzenたちは経済モデルと生産、輸送および日用品の消費から放出される反応性窒素の見積もりを用いて、188か国のおよそ15,000の経済地域にわたるそれぞれの国の消費により生成される窒素放出量を定量化した。彼らは、ブラジル、中国、インドおよび米国の消費が世界の日用品に関連した窒素放出のほぼ半分(47%)の原因となっていることを示している(およそ8900万トン)。最終的に著者たちは、国外で生産された商品の消費が極めて大きい国があり、それらの国々は自らの国よりも他の国でより多くの窒素汚染を起こしていることを発見した。

同時掲載のNews & Views記事で、James GallowayとAllison Leachは、Lenzenたちが「実際、我々が窒素汚染をどの程度他の国に輸出しているか」を明らかにしていると述べている。

Roughly one quarter of global nitrogen emissions come from the production of goods and commodities that are consumed outside their country of origin, reports a paper published online this week in Nature Geoscience. The study quantifies the amount of nitrogen pollution generated for 188 countries and suggests that net importers of these goods and commodities (importing more than they export) are almost exclusively in the developed world, whereas the countries where the related production-and therefore pollution-occurs are often developing economies.

Reactive nitrogen gases produced from combustion and agriculture can contribute to air pollution, climate change and acid rain, and nitrate from fertilizers can pollute groundwater or create dead zones in lakes and coastal regions.

Manfred Lenzen and colleagues used an economic model and estimates of reactive nitrogen emissions from the production, transportation and consumption of commodities to quantify the amount of nitrogen emissions caused by a country’s consumption-for 188 countries, across nearly 15,000 economic sectors. They show that consumption in Brazil, China, India and the United States is responsible for nearly half (47%) of the world’s commodity-related nitrogen emissions (approximately 89 million tonnes). Finally, the authors find that consumption of foreign-produced goods is so great in some countries that they cause more nitrogen pollution in other nations than they do in their own.

In an accompanying News & Views article, James Galloway and Allison Leach write that Lenzen and colleagues reveal “the degree to which we may be, in effect, exporting our nitrogen pollution to other countries”.

doi: 10.1038/ngeo2635


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