Climate change will adversely affect agricultural productivity
and human well-being. Overall, it is projected that crop
productivity will decline, particularly at lower latitudes,
especially in the seasonally dry and tropical regions. This
would increase the risk of hunger. Moreover, it is the majority
of the world's rural poor who live in areas that are
resource-poor, highly heterogeneous and risk-prone, who will be
hardest hit by climate change.
On the other hand, agriculture releases a significant amount of
carbon dioxide, methane and nitrous oxide into the atmosphere,
amounting to around 10-12 percent of global anthropogenic
greenhouse gas emissions annually. If indirect contributions
(e.g. land conversion, fertilizer production and distribution
and farm operations) are factored in, the contribution of
agriculture could be as high as 17-32 percent of global
anthropogenic emissions.
The challenge is therefore to design an agriculture that adapts
and responds to the changes in climate experienced, as well as
reduces greenhouse gas emissions. This challenge could be met
through biodiverse, agroecologically-based farming.
This was acknowledged by the International Assessment on
Agricultural Knowledge, Science and Technology for Development (IAASTD),
which is the most comprehensive assessment of agriculture to
date. Some key findings of the IAASTD were that:
· The future of agriculture lies in biodiverse, agroecologically
based farming (including organic agriculture) that can meet
social, economic and environmental goals
· Reliance on resource-extractive industrial agriculture is
unsustainable, particularly in the face of worsening climate,
energy and water crises
· Short-term technical fixes, including genetically engineered
crops, cannot adequately address the complex challenges facing
agriculture, and often exacerbate social and environmental harms
· Achieving food security and sustainable livelihoods requires
ensuring access to and control of resources by smallscale
farmers, especially women
· Indigenous knowledge and community-based innovations are an
invaluable part of the solution
Why agroecology is climate friendly
By increasing resilience within the agroecosystem, agroecology
increases its ability to continue functioning when faced with
unexpected events such as climate change. Resiliency to climate
disasters is closely linked to farm biodiversity; practices that
enhance biodiversity allow farms to mimic natural ecological
processes, enabling them to better respond to change and reduce
risk. Thus, farmers who increase interspecific diversity suffer
less damage compared to conventional farmers planting
monocultures. Moreover, the use of intraspecific diversity
(different cultivars of the same crop) is insurance against
future environmental change.
Agroecological practices that preserve soil fertility and
maintain or increase organic matter can reduce the negative
effects of drought while increasing productivity. Water holding
capacity of soil is enhanced by practices that build organic
matter, helping farmers withstand drought. In addition,
water-harvesting practices allow farmers to rely on stored water
during droughts. Other practices such as crop residue retention,
mulching, and agroforestry, conserve soil moisture and protect
crops against microclimate extremes. Conversely, organic matter
also enhances water capture in soils, significantly reducing the
risk of floods.
Indigenous and traditional knowledge are a key source of
information on adaptive capacity, centered on the selective,
experimental and resilient capabilities of farmers. Many farmers
cope with climate change, in different ways: by minimizing crop
failure through increased use of drought-tolerant local
varieties, water-harvesting, extensive planting, mixed cropping,
agroforestry, opportunistic weeding and wild plant gathering.
Traditional knowledge, coupled with the right investments in
plant breeding, could yield new varieties with climate
adaptation potential.
On the other hand, agriculture has the potential to change from
being one of the largest greenhouse gas emitters to a much
smaller emitter and even a net carbon sink, while offering
options for mitigation by reducing emissions and by sequestering
carbon dioxide from the atmosphere in the soil. The solutions
call for a shift to more sustainable farming practices that
build up carbon in the soil and use less chemical fertilizers
and pesticides.
There are a variety of practices that can reduce agriculture's
contribution to climate change. These include crop rotations and
improved farming system design, improved cropland management,
improved nutrient and manure management, improved grazing-land
and livestock management, maintaining fertile soils and
restoration of degraded land, improved water and rice
management, fertilizer management, land use change and
agroforestry.
It has been estimated that a conversion to organic agriculture
would considerably enhance the sequestration of carbon dioxide
through the use of techniques that build up soil organic matter,
as well as diminish nitrous oxide emissions by two-thirds due to
no external mineral nitrogen input and more efficient nitrogen
use. Organic systems have been found to sequester more carbon
dioxide than conventional farms, while techniques that reduce
soil erosion convert carbon losses into gains. Organic
agriculture is also self-sufficient in nitrogen due to recycling
of manures from livestock and crop residues via composting, as
well as planting of leguminous crops.