双视角下中国畜牧业甲烷排放的温室效应

准确评价甲烷（CH₄）的温室效应是制定有效减排路径的基础.首次采用新提出的、针对短寿命气候污染物（SLCP）设计的气候指标GWP-star （GWP^*）对中国畜牧业CH₄排放的温室效应进行定量评价，并与常用的GWP指标评价结果相比较.结果表明，GWP的视角下我国畜牧业CH₄排放的温室效应持续增加.因此，畜牧业实现碳中和需要完全消除排放，或以增加碳汇、增加资源化利用的形式抵消每年稳定的CH₄排放.在GWP^*的视角下，2015~2019年间畜牧业CH₄排放的温室效应较20年前有所减少，降低的热量相当于从20年前的大气中减少2.1×10⁴万t CO₂的热量，畜牧业只需每年有效降低0.3%的CH₄排放则可在短期内实现自身碳中和.在中国畜牧业持续采取有效减排措施的情况下，采用GWP^*的标准制定减排目标比用GWP制定的减排目标更早达到，但选择GWP还是GWP^*需要综合考虑评价的目的、评价的时间尺度和实际可操作性.

Dual-Perspective Analysis of the Warming Effect of the Methane Emissions from Animal Husbandry in China

Accurate quantitative evaluation of the greenhouse effects of methane(CH₄) is the foundation for developing effective mitigation strategies. This study was the first to quantitatively evaluate the warming effects of the CH₄ emissions from animal husbandry in China using the recently proposed climate metric GWP-star(GWP^*), which is designed for short-lived climate pollutants(SLCP), and to compare the results with the commonly used climate metric global warming potential(GWP). The results showed:CH₄emissions from animal husbandry in China decreased from 957.0×10⁵ t in 2000 to 764.0×10⁵ t. The GWP results showed that the greenhouse effect of CH₄ emissions from animal husbandry in China was increasing between 2015 and 2019, and the GWP^* results showed that it decreased compared to that 20 years ago. The amount of reduction was equivalent to removing the warming of 2.1×10⁸ t of carbon dioxide. Under the GWP evaluation system, achieving carbon neutrality in the livestock industry in China requires eliminating or offsetting stable annual CH₄ emissions from increased carbon sinks. Instead, under the GWP^* evaluation system, China''s livestock industry could achieve its carbon neutrality in the short term by effectively reducing CH₄ emissions by only 0.3% per year. In the case that the livestock industry in China continues to take effective emission reduction measures, the reduction target under the GWP^* metric will be reached earlier than that under GWP. Still, the choice of GWP or GWP^* requires careful consideration of the objectives of evaluation, the time scale of assessment, and practical operability.