Figure . Global satellite-based (panel A) and inventory (panel B) annual NH3 emissions derived over the period of 2013-2020. The four insets in each subplot show enlarged and aggregated totals at county/provincial level for four hot-spot regions around the globe.
Global ammonia emissions underestimated
Satellite observations show that global ammonia emissions are higher than reported by bottom-up inventories. The study is a first attempt to use remote sensing to quantify county-level annual rates of ammonia emissions and was published in a pre-print article in June.
The new observations show that already known anthropogenic sources are around 80 per cent higher than indicated by data from inventories. When new anthropogenic sources and natural sources are included, ammonia emissions are a staggering four times as high as previously believed.
The latter include small but detectable emissions over large areas, such as the Russian taiga, that have previously been assumed to be zero. The researchers note that the observed emissions tend to deviate less from the reported emissions in countries with ammonia regulations in place, such as the European Union.
Despite the differences in the reported size of emissions, satellite-based methodology shows a familiar geographical pattern of global hotspots, with the central United States, north-western Europe, the Po Valley in northern Italy, the Nile Delta, Indo-Gangetic-Plain and eastern China having the largest emissions.
Source: Dammers, et al. (2022). County-level ammonia emissions monitored worldwide. 10.21203/ rs.3.rs-1752718/v1.