GHG inventory continued (part2).

B)

AGRICULTURE:

With the increasing population and consumption rates the pressure on the agricultural sector has increased tremendously leading to increased use of fertilizers, machines all of which contribute to increase in GHG’s.  The agricultural sector contributes to 8.6 percent of UK’s total emission (UK GHG inventory factsheet, 2010). Unlike other sectors nitrous oxide (N2O) is the dominant GHG emitted with emissions from agricultural soil dominating the agricultural sector.

The agricultural sector is very vast when it comes to calculating the emissions (refer to keynotes to understand terms/processes). Like road transport, emissions from stationary sources are estimated from their activity data (fuel use) and an emissions factor (specified by IPCC and UNECE), this process is used for estimating emissions from most subsectors. Similarly emissions from fermentation are estimated from statistical data (livestock numbers) and emission factors while those from agricultural soils are derived from numerical data (like fertilizer use) and various methods (which follow IPCC guidelines) like waste and manure management systems.

On the other hand mobile machinery are modeled based on specific details of the machine type (eg: population of machines, age profile, lifetime of equipments, annual usage etc). While emissions of breakdown products are estimated from the amount that is stored and the amount released.

There are many uncertainties in an emissions inventory factsheet where each sector needs to follow certain guidelines (if need be shift to more efficient guidelines) and update the inventory regularly (eg: emissions from animal wastes follow the UNFCCC’s recommendations of the inventory). Research in various fields for detailed, specific and accurate outcomes (like tracking sector specific emissions reduction progress) is carried out. Some examples for improvement include: using new parameters, improving resolution, reporting and representation of on farm mitigation measures.

Projected emissions (Updated Energy and Emissions Projections 2011, 2012) of the agriculture sector are expected to decrease by 12 percent from 2010 levels by 2025.

Keynotes:                                                             

·         Stationary source emission includes combustion of fuel (mostly heating).

·         There are various processes going on in the soil like aerobic, anaerobic decay, fermentation (food digestion) and denitrification of waste, manure (releasing gaseous components like methane and nitrous oxide).

·         Mobile machinery relates to emissions from equipments (tractors).

·         Breakdown products of agrochemicals release carbon dioxide.

·         Agricultural soil emissions arise from two sources:

i. Direct (fertilizers, nitrogen fixation, crop residues).

ii. Indirect (atmospheric deposition of nitrogen oxides (NOx) and ammonia, leaching and runoff of nitrate).

References:

·         UK GHG Inventory: http://ghgi.decc.gov.uk/

·        UK GHG National Statistics: http://www.statistics.gov.uk/hub/agriculture-environment/environment/climate-change/index.html

·Projectionsdata: http://www.decc.gov.uk/en/content/cms/about/ec_social_res/analytic_projs/en_emis_projs/en_emis_projs.aspx

·         Defra: http://www.defra.gov.uk/

·         Rothamsted Research: http://www.rothamsted.ac.uk/