Impact-agriculture-climate-pg1

1. Contribution of Agriculture to Climate Change

Industrial agriculture contributes much to the GHG emission. Overall agriculture contributes 32% of the total GHG emission. As agriculture gets more and more mechanized, the Emission of Methane and Emission of Nitrous Oxide also increases.

Currently we are counting emissions either under industrial sector or in energy sector. When we transport agricultural goods from one place to another we count the Emission under Transportation. What about the chemicals and fertilizers produced in the industries? Are we counting it under agricultural emission? Are we counting it at all? Globally Fertilizer Production and Distribution counts only 0.6 to 1.2% to the global GHG emission. This way we are underestimating the contribution of agriculture in GHG emission. For instance the majority of ammonia production takes place in fertilizer manufacturing units in India. The total CO2 released due to ammonia production is 14,395 Gg. But we are considering it under industrial processes. There have been changes in land use. More and more land from forest is being diverted to agriculture. This further contributes to GHGs. Livestock use in agriculture, Use of Energy Intensive Equipment in Agriculture and Using Agriculture for Our Energy Needs lead to GHG emission.

Sources of agricultural greenhouse gases, excluding land use change

Global Statistics
Agriculture directly contributes between 5.1 and 6.1 Pg CO2- eq [1] (10 � 12%) to global greenhouse gas emissions. These emissions are mainly in the form of methane (3.3 Pg CO2-eq yr-1) and nitrous oxide (2.8 Pg CO2-eq yr-1) whereas the net flux of carbon dioxide is very small (0.04 Pg CO2-eq yr-1). Nitrous oxide (N2O) emissions from soils and methane (CH4) from Enteric Fermentation of Cattle constitute the largest sources, 38% and 32% of total non-CO2 emissions from agriculture in 2005, respectively. Nitrous oxide emissions are mainly associated with nitrogen fertilisers and manure applied to soils. Fertilizers are often applied in excess and not fully used by the crop plants, so that some of the surplus is lost as N2O to the atmosphere. Biomass burning (12%), rice production (11%), and manure management (7%) account for the rest.

Clearing of Native Vegetation for Agriculture (i.e. land use change rather than agriculture per se) does release large quantities of ecosystem carbon as carbon dioxide (5.9 - 2.9 Pg CO2-eq yr-1). The magnitude and relative importance of the different sources and emissions vary widely between regions. Globally, agricultural methane (CH4) and nitrous oxide (N2O) emissions have increased by 17% from 1990 to 2005, and are projected to increase by another 35 - 60% by 2030 driven by growing nitrogen fertiliser use and increased livestock production. [2]

[1] 1 Pg (Peta gram) = 1 Gt (Giga tonne) = 1000 million tonnes. To convert Pg CO2-eq to million tonnes multiply by 1000; e.g. 15.5 Pg CO2-eq equals 15.5 Gt CO2-eq or 15500 million tonnes CO2-eq.

[2] Cool farming report, Greenpeace, January 2008 [R.E31d.40]