Page 84 - FAO-IPCC Expert meeting on climate change

Appendix 01: Speakers’ summary notes
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Theme 3.
Climate mitigation in agriculture and other land uses and linkages to food security
Trends of GHG emissions resulting from food systems (crops, livestock, land-based aquaculture, processed food)
LOUIS VERCHOT
PLENARY SESSION 5:
EMISSIONS FROM AGRICULTURE AND LAND USING SYSTEMS AND FROM FOOD CONSUMPTION
Over much of the 19th century and the first half of the 20th century land use and land-use change was the dominant source of greenhouse gas emissions to the atmosphere. Near the middle of the 20th century, land based greenhouse gases accounted for about 50 percent of all emissions. The major reason for the decreasing importance of land based emissions was the exponential growth of fossil fuel emissions. In absolute terms, land based emissions have had periods of growth and decline since the beginning of the 20th century. Emissions declined during both of the world wars and during the 1970s. We are now in a new phase of declining emissions that began in the mid-1990s and appears to be accelerating. Today, land use and land-use change is responsible for about 25% of global greenhouse gas emissions and in absolute terms, emissions are declining by around 12 percent per decade.
There are two types of emission associated with crop and livestock production: those associated with land clearing to expand production to new areas; and those associated with production and management practices. Most deforestation and conversion of natural ecosystems is done to facilitate the expansion of agriculture. Emissions associated with these activities are on the order of 8.4 to 10.3 Gt CO2 y-1. FAO reported that the rate of deforestation has been decreasing recently: in the 1990s, deforestation rates were 0.18% annually, but since 2010, this rate has been around 0.08%. It is worth noting that deforestation rates in the Brazilian Amazon region, have been on the rise over the past two years and PRODES data suggest that in 2016 deforestation was about 60 percent higher than in 2014. The continued decline in global land clearing for agriculture depends on reversing this trend. In other regions, subsistence agricultural activities are responsible for about 40 percent of deforestation and as much as 35 percent of forest degradation. Livestock grazing has been responsible for forest degradation and deforestation, particularly in Asia and Latin America.
Emissions related to agricultural production and management practices are predominantly nitrous oxide (N2O) and methane (CH4). The IPCC Fifth Assessment Report reported on data from three sources with global emission estimates between 5.2 and 6.3 Gt CO2e y-1, which is about 12 percent of global emissions. Emissions are from six primary sources: enteric fermentation (CH4); fertilizer application to soils (N2O); manure management (CH4 and N2O) and rice cultivation (CH4), crop residues (N2O), and biomass burning (CH4). Enteric fermentation and emissions from agricultural soils represent about 70 percent of these emissions; paddy rice cultivation are about 10%; biomass burning is about 9% and manure management makes up about 8 percent. Emissions from all categories are increasing. Regional breakdowns of the datasets show that emissions from these sources are increasing mostly in developing regions. Emissions in North America and Western Europe are stable or declining as production becomes more efficient in these regions. In developing regions like South and Southeast Asia, Africa and Latin America, emissions from both enteric fermentation and agricultural soils are increasing rapidly. Rice emissions are also a major contributor to increasing emissions in South and Southeast Asia.
One of the key economic trends that is likely to drive future emissions from agriculture is changing diet preferences. Meat consumption has almost tripled in the last four decades and has increased by over 30% in the last ten years. Dairy consumption is up by over 70 percent in the last four decades. Some of the greatest consumption increases are seen in Asia. While all types of meat consumption are experiencing increases, monogastrics like pork and poultry have seen the strongest increase. Production of these animals in Asia is shifting away from small farms and backyard production to specialized household or local community production and modern intensive farms, especially in areas close to big cities.
FAO-IPCC Expert meeting on climate change, land use and food security