Page 33 - FAO-IPCC Expert meeting on climate change

Human-directed impacts on food and land-based ecosystems and their implications for food security
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Certain intensive lowland technologies extract resources from upland agriculture and thus preserve forests.18 A recent review by Byerlee and colleagues19 demonstrates a marked difference in impact according to whether intensification
is driven by technology or market-driven. On the one hand, technology-driven intensification generally deploys better technologies that are able to reduce cropland areas and, therefore, deforestation. Market-driven intensification, on the other hand, can justify land expansion and the loss of forests. In Viet Nam, for example, the commercial production of coffee has expanded to meet export demand at the expense of forested areas.20
Ultimately, changes in technology and the intensification of agriculture may or may not have an effect on deforestation. Nevertheless, where afforestation has succeeded, there is evidence of a combination of factors that include technical, economic and active policy engagement. The issue of agriculture intensification should thus be considered within the context of agricultural practices and not in isolation. It will significantly contribute to and complement other forest conservation measures, adding to their effectiveness and political feasibility. Some of the complementarities include: land use zoning; economic instruments such as those proposed by the previously mentioned TEEB/UNEP study; spatial targeting; and standards and certification. In particular, a comprehensive land based accounting for GHG emissions would take into consideration the potential synergy between agricultural intensification for food production and the offsets provided by forest ecosystem services, contributing to a better understanding of how much productivity can be increased without raising global level GHG emissions.
2.6 Mangroves: a severely threatened high biodiversity biome21
Mangroves are immensely important ecosystems and harbour a unique assemblage of aquatic terrestrial biodiversity. Mangroves are a major source of carbon stock with a net primary production among the highest compared with any terrestrial ecosystem. With more than 50 mangrove species and a multitude of fish and shellfish species these unique tidally influenced vegetation systems are biologically diverse. Their multiple ecosystem services are well documented and range from provisioning (fish habitat, wood, fuel, and food), supporting (nutrient cycling and land building) and regulating (pollution, salinity, carbon storage, wave, storm surges, and tsunami) services. With their unique root system and tidal range mangroves can also protect against soil erosion upstream and capture sediments downstream.
The large capacity of mangroves and other blue carbon ecosystems22 in sequestering atmospheric carbon is due to their high carbon burial rates, which are around 20 times higher than any terrestrial ecosystems. Therefore, the carbon stocks in the mangrove ecosystem is as much as four times higher compared to other terrestrial ecosystem.23
Globally mangroves cover an area of around 14 million hectares in more than 30 countries, mainly in the tropics. Mangroves and other coastal ecosystems are facing tremendous pressure due to land use change for aquaculture, agriculture and infrastructure development. The world’s mangrove has lost more than 40 percent in the past 30 years.24 Mangrove deforestation potentially costs up to US$40 billion per annum.
The implications of mangrove deforestation are multiple. The most immediate one is GHG emissions. The rate is staggering as it is estimated to range between 0.02 and 0.21 Pg annually. This amount represents 10 percent of emissions from deforestation globally, even though mangroves account for just 0.7 percent of tropical forest area. Mangrove deforestation with regeneration has another disadvantage: the potential re-introduction of mono-species and substantial reduction of species diversity in all coastal settings. As a result, aquatic biota will be tremendously affected as the nutrient cycling is altered.
18 Mayfroidt (2013).
19 Byerlee et al. (2014).
20 Meyfroidt, Vu, and Hoang. (2013).
21 Forest carbon dynamics from deforestation and afforestation are not addressed in detail at this expert meeting given the limited time and the broad agenda.
22 UNEP. (2014).
23 Alongi. (2014); Donato et al. (2011).
24 FAO. (2007).
FAO-IPCC Expert meeting on climate change, land use and food security