Innovations in food production and land use that are ready to be scaled-up today could reduce greenhouse gas emissions equivalent to roughly 25% of global fossil fuel emissions and present the best opportunity to remove greenhouse gases already in the atmosphere, according to a new report by the Worldwatch Institute and Ecoagriculture Partners.
As the price of carbon rises with new caps on emissions and expanding markets for carbon offsets, the contribution of land-based, or "terrestrial," carbon to climate change mitigation efforts could increase even further.
Carbon capture and sequestration technologies, which remain unproven and will not be ready for implementation for a decade at best, promise only to sequester greenhouse gases that have yet to be released into the atmosphere. Agricultural and other land use management practices, in contrast, are the only innovations available today to sequester greenhouse gases that are already in the atmosphere-pulling in carbon dioxide through photosynthesis to grow and sustain more plants.
Mobilizing agricultural carbon sequestration is therefore an essential tool in the effort to reduce the atmospheric concentration of greenhouse gases to the 350 parts-per-million level that many scientists argue we must achieve to avoid catastrophic climate change. A recent assessment published by Worldwatch in State of the World 2009: Into a Warming World found that emissions of carbon dioxide will have to "go negative"-with more being absorbed than emitted-by 2050 to achieve this goal.
"The science and policy communities in Europe and beyond have focused most of their attention to date on improving energy efficiency and scaling up renewables," said Ecoagriculture Partners' Sara Scherr, co-author of Mitigating Climate Change Through Food and Land Use with Sajal Sthapit. "While these initiatives are integral in the transition to a low-carbon economy, any strategy that seeks to mitigate global climate change without reducing emissions from agriculture, forestry, and other land uses is doomed to fail."
More than 30% of all human-caused greenhouse gas emissions are linked to agriculture and land use, rivaling the combined emissions of the transportation and industry sectors. The report outlines five major strategies for reducing and sequestering greenhouse gas emissions through farming and land use:
- Enriching soil carbon. Soil, the third largest carbon pool on Earth's surface, can be managed to reduce greenhouse gas emissions by minimizing tillage, cutting use of nitrogen fertilizers, and preventing erosion. Soils can store a vast amount of additional carbon by building up organic matter and by burying carbon in the form of biochar (biomass burned in a low-oxygen environment).
- Farming with perennials. Two-thirds of all arable land is used to grow annual grains, but there is large potential to substitute these with perennial trees, shrubs, palms, and grasses that produce food, livestock feed, and fuel. These perennials maintain and develop their roots and branches over many years, storing carbon in the vegetation and soil.
- Climate-friendly livestock production. Livestock accounts for nearly half of all greenhouse gas emissions from agriculture and land use. Innovations such as rotational grazing, manure management, methane capture for biogas production, and improved feeds and feed additives can reduce livestock-related emissions.
- Protecting natural habitat. Deforestation, land clearing, and forest and grassland fires are major sources of greenhouse gas emissions. Incentives are needed to encourage farmers, ranchers, and foresters to maintain natural forest and grassland habitats through product certification, payments for climate services, securing tenure rights, and community fire control.
- Restoring degraded watersheds and rangelands. Restoring vegetation on vast areas of degraded land can reduce greenhouse gas emissions while making land productive again, protecting critical watersheds, and alleviating rural poverty.
The report also responds to several key issues that have constrained the use of terrestrial carbon solutions and highlights six principles for tapping the full potential of land use mitigation. These include: incorporating the full range of terrestrial emission options, including cap-and-trade systems, in climate investment and policy; promoting voluntary markets for greenhouse gas emission offsets from agriculture and land use while working out rules for regulated markets; and linking terrestrial climate mitigation with climate adaptation, rural development, and conservation strategies to generate widespread benefits beyond climate-helping to mobilize a worldwide-networked movement for climate-friendly food, forest, and other land-based production.
Although the climate conversation has long focused on developing enduring solutions in the energy sector, Worldwatch President Christopher Flavin says that land use is equally important. "The bottom line is that innovations in agriculture provide the best opportunity to remove carbon from the atmosphere. We cannot reach 350 ppm without changing the way we grow our food and use our land."