Suchergebnisse

Cropland ammonia (NH3) emission is a critical driver triggering haze pollution. Many agricultural policies were enforced in past four decades to improve nitrogen (N) use efficiency while maintaining crop yield. Inadvertant reductions of NH3 emissions, which may be induced by such policies, are not well evaluated. Here, we quantify the China's cropland-NH3 emission change from 1980 to 2050 and its response to policy interventions, using a data-driven model and a survey-based dataset of the fertilization scheme. Cropland-NH3 emission in China doubled from 1.93 to 4.02 Tg NH3-N in period 1980-1996, and then decreased to 3.50 Tg NH3-N in 2017. The prevalence of four agricultural policies may avoid ~3.0 Tg NH3-N in 2017, mainly located in highly-fertilized areas. Optimization of fertilizer management and food consumption could mitigate three quarters of NH3 emission in 2050 and lower NH3 emission intensity (emission divided by crop production) close to the European Union and the United States. Our findings provide an evidence on the decoupling of cropland-NH3 from crop production in China, and suggest the need to achieve cropland-NH3 mitigation while sustaining crop yields in other developing economies.

Cropland ammonia (NH3) emission is a critical driver triggering haze pollution. Many agricultural policies were enforced in past four decades to improve nitrogen (N) use efficiency while maintaining crop yield. Inadvertant reductions of NH3 emissions, which may be induced by such policies, are not well evaluated. Here, we quantify the China's cropland-NH3 emission change from 1980 to 2050 and its response to policy interventions, using a data-driven model and a survey-based dataset of the fertilization scheme. Cropland-NH3 emission in China doubled from 1.93 to 4.02 Tg NH3-N in period 1980-1996, and then decreased to 3.50 Tg NH3-N in 2017. The prevalence of four agricultural policies may avoid ~3.0 Tg NH3-N in 2017, mainly located in highly-fertilized areas. Optimization of fertilizer management and food consumption could mitigate three quarters of NH3 emission in 2050 and lower NH3 emission intensity (emission divided by crop production) close to the European Union and the United States. Our findings provide an evidence on the decoupling of cropland-NH3 from crop production in China, and suggest the need to achieve cropland-NH3 mitigation while sustaining crop yields in other developing economies.

© 2018 Elsevier Ltd Ecosystem services (the benefits to humans from ecosystems) are estimated globally at $125 trillion/year [1, 2]. Similar assessments at national and regional scales show how these services support our lives [3]. All valuations recognize the role of biodiversity, which continues to decrease around the world in maintaining these services [4, 5]. The giant panda epitomizes the flagship species [6]. Its unrivalled public appeal translates into support for conservation funding and policy, including a tax on foreign visitors to support its conservation [7]. The Chinese government has established a panda reserve system, which today numbers 67 reserves [8, 9]. The biodiversity of these reserves is among the highest in the temperate world [10], covering many of China's endemic species [11]. The panda is thus also an umbrella species [12]—protecting panda habitat also protects other species. Despite the benefits derived from pandas, some journalists have suggested that it would be best to let the panda go extinct. With the recent downlisting of the panda from Endangered to Vulnerable, it is clear that society's investment has started to pay off in terms of panda population recovery [13, 14]. Here, we estimate the value of ecosystem services of the panda and its reserves at between US$2.6 and US$6.9 billion/year in 2010. Protecting the panda as an umbrella species and the habitat that supports it yields roughly 10–27 times the cost of maintaining the current reserves, potentially further motivating expansion of the reserves and other investments in natural capital in China. Wei et al. estimate that the value of ecosystem services of the giant panda and its nature reserves was US$2.6–US$6.9 billion/year in 2010. Protecting the panda and its habitat yields roughly 10–27 times the cost of maintaining the current reserves, potentially motivating expansion of the reserves and other investments in natural capital in China.