Quantifying greenhouse gas emissions from global aquaculture

Abstract

Global aquaculture makes an important contribution to food security directly (by increasing food availability and accessibility) and indirectly (as a driver of economic development). In order to enable sustainable expansion of aquaculture, we need to understand aquaculture's contribution to global greenhouse gas (GHG) emissions and how it can be mitigated. This study quantifies the global GHG emissions from aquaculture (excluding the farming of aquatic plants), with a focus on using modern, commercial feed formulations for the main species groups and geographic regions. Here we show that global aquaculture accounted for approximately 0.49% of anthropogenic GHG emissions in 2017, which is similar in magnitude to the emissions from sheep production. The modest emissions reflect the low emissions intensity of aquaculture, compared to terrestrial livestock (in particular cattle, sheep and goats), which is due largely to the absence of enteric CH₄ in aquaculture, combined with the high fertility and low feed conversion ratios of finfish and shellfish.

Figure 1

World production of capture fisheries, aquaculture and pig, chicken and cattle meat from 1961 to 2017. Data sources^,.

Figure 2

Emissions intensity of the main aquaculture groups, 2017. Source calculated in this study. IMC Indian Major Carps, E. Eur, Eastern Europe, LAC Latin America and the Caribbean, N. Am. North America, NZ and Aus. New Zealand and Australia, SSA Sub-Saharan Africa, W. Eur. Western Europe, WANA West Asia and North Africa.

Figure 3

Total global emissions and emissions intensity of aquaculture (2010), terrestrial meat (2010) and marine fisheries (2011). Sources: Aquaculture—calculated in this study. Marine fisheries. Cattle, pig, chicken, buffalo, sheep and goat meat.

Figure 4

Schematic diagram of the method used to quantify the total emissions and emissions intensity. SG species-group; FCR feed conversion ratio; EI emissions intensity.