Agriculture

estimated that conversion to organic agriculture could sequester additional 3 tonnes of carbon per hectare per year (LaSalle et al. 2008). The carbon sequestration efficiency of organic systems in temperate climates is almost double (575-700 kg carbon per ha per year) that of conventional treatment of soils, mainly owing to the use of grass clovers for feed and of cover crops in organic rotations. German organic farms annually sequester 402 kg carbon/ha, while conventional farms experience losses of 637 kg (Küstermann et al. 2008; Niggli et al. 2009). From such studies, it is possible to approximate that if only all the small farms on the planet employed sustainable practices, they might sequester a total of 2.5 billion tonnes of carbon annually. Such verifiable carbon sequestration levels could be equivalent to US$ 49 billion in carbon credits per year, assuming a carbon price of US$ 20/tonne. The FAO has documented that a widespread conversion to organic farming could mitigate 40 per cent (2.4 Gt CO2

-eq/yr) of the world’s

agriculture greenhouse gas emissions in a minimum implementation scenario; and up to 65 per cent (4 Gt CO2

-eq/yr) of agriculture GHG emissions in a maximum

carbon sequestration scenario (Scialabba and Muller- Lindenlauf 2010).

Furthermore, emissions of nitrous oxides and methane could be reduced if farmers use nitrogen and other fertilisers more efficiently, including through precision applications and introducing improved crop varieties that more effectively access and use available nitrogen in the soil. Greening agriculture also has the potential to eventually become self-sufficient in producing nitrogen through the recycling of manures from livestock and crop residues via composting; and by increased intercropping rotations with leguminous, nitrogen-fixing crops (Ensor 2009; ITC and FiBL 2007).

Additional ecosystem benefits resulting from greening of agriculture include better soil quality18

with more

organic matter, increased water supply, better nutrient recycling, wildlife and storm protection and flood control (Pretty et al. 2001; OECD 1997). Systems that use natural predators for pest control also promote on-farm and off- farm biodiversity and pollination services.

3.4 Modelling: Future scenarios for green agriculture

In this section we assess a scenario in which an additional 0.16 per cent of the global GDP is invested in green agriculture per year (equalling US$ 198 billion) between 2011 and 2050. This is as part of a green investment scenario in which an additional 2 per cent of global GDP is allocated to a range of key sectors. More details are available in the Modelling chapter of this report. In the part of the modelling exercise, which focused on

The green scenario19 is compared with a BAU2 scenario,

where the same amount of additional investment is made in conventional and traditional agriculture over the 40-year period.

The results are stark. Overall, the green investments lead to improved soil quality, increased agricultural yield and reduced land and water requirements. They also increase GDP growth and employment, improve

nutrition and reduce energy consumption and CO2 emissions (Table 7).

■ Agricultural production and value added: In the green scenario, total agricultural production (including agricultural products, livestock, fishery and forestry) increases significantly compared to other scenarios.20 This change is driven by increased crop production, which is able to satisfy a growing population that is projected to reach 9 billion by 2050. Similarly value added in agricultural production increases by 9 per cent compared with the BAU2 scenario. It is important to note that despite an increase in agricultural production and value added, there is no increase in area harvested. This suggests positive synergies between ecological agriculture investments and forest management. Similarly, improved water-efficiency reduces water demand by almost one-third by 2050, compared with the BAU2 scenario. On the other hand, energy consumption

18. Such soils are better quality, contain greater organic matter and microbial activity, more earthworms, have a better structure, lower bulk density, easier penetrability and a thicker topsoil (Reganold et al. 1992).

19. Here we have presented results of scenarios that are referred to as G2 and BAU2 in the Modelling chapter.

20. Detailed information about these results can be found in the Modelling chapter.

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agriculture sector, these additional green investments are undertaken equally in the following four activities:

■ Agricultural management practices: one-fourth of the investment is assumed to be invested in environmentally sound practices;

■ Pre-harvest losses: another one-fourth of the additional budget is invested in preventing pre-harvest losses, training activities and pest control activities;

■ Food processing: one-fourth of the investment is assumed to be spent on preventing post-harvest losses, better storage and improved processing in rural areas.

■ Research and Development: the remaining one- fourth amount is assumed to be spent on research and development especially in the areas of photosynthesis efficiencies, soil microbial productivity, climate adaptation biological processes, and improvements of energy and water-use efficiency.