While globally the impact of climate change on food production may be small, at least until 2050, the distribution of production will have severe consequences on food security: developing countries may experience a decline of between 9 and 21 percent in overall potential agricultural productivity as a result of global warming, the paper estimated.
The paper reported that climate change is among main challenges to agriculture in feeding the world's population, projected to reach 9.1 billion people by 2050.
At the same time, several agriculture-based mitigation options for climate change could generate significant benefits for both food security and climate change adaptation. Increasing soil carbon sequestration through forestry and agro-forestry initiatives and tillage practices, improving efficiency of nutrient management and restoring degraded lands are examples of actions that have large mitigation potential and high co-benefits.
Climate change is expected to affect agriculture and forestry systems through higher temperatures, elevated carbon dioxide concentration, changes in rainfall, increased weeds, pests and diseases. In the short term, the frequency of extreme events such as droughts, heat waves, floods and severe storms is expected to increase.
Emissions from agriculture account for roughly 14 percent of global greenhouse gas emissions. Seventy-four percent of emissions from agriculture and most of the technical and economic mitigation potential from agriculture - some 70 percent - are in developing countries.
The FAO paper notes that a climate change agenda will need to recognize and value agriculture's potential contribution to adaptation and mitigation through options that also safeguard its contribution to food security and development.
Impact on food security
Climate change will affect the four dimensions of food security: availability, accessibility, utilization and stability, notes the FAO paper.
In terms of availability, increased atmospheric CO2 concentrations are expected to have a positive effect on the yield of many crops, even though the nutritional quality of produce may not increase in line with higher yields.
Climate change will increase the variability of agricultural production across all areas, with increased frequency of extreme climate events. The poorest regions will be exposed to the highest degree of instability of food production.
On average, food prices are expected to rise moderately in line with increases in temperature until 2050. After 2050 and with further increases in temperatures, significant decreases in agricultural production potential in developing countries are projected and prices are expected to rise more substantially.
Climate change is likely to alter the conditions for food safety by increasing the disease pressure from vector, water and food-borne diseases. The result could be a substantial decline in agricultural productivity, including labour productivity, leading to increases in poverty and mortality rates.
Africa especially vulnerable
Agricultural and food production in many developing countries are likely to be adversely affected, especially in countries that have low incomes and a high incidence of hunger and poverty and are already highly vulnerable to drought, flooding and cyclone.
In Africa this could lead to an increased dependency in many countries on food imports. It has been estimated that climate change may reduce African potential agricultural output up to the 2080-2100 period by between 15 and 30 percent.
The strongest negative impact of climate change on agriculture is expected in sub-Saharan Africa. This means that the poorest and most food insecure region is also expected to suffer the largest contraction of agricultural incomes.
The climate is right
Adaptation of the agricultural sector to climate change will be costly but vital for food security, poverty reduction and maintaining the ecosystem. The current impetus for investing in improved agricultural policies, institutions and technologies to meet both food security and energy goals, provides a unique opportunity to mainstream climate change related actions into agriculture, the paper notes.
It notes that, until recently, agriculture has largely remained a marginal issue in climate change negotiations, with some exception as regards deforestation and forest degradation mitigation activities. Among the reasons FAO identifies is that the scope of existing financing mechanisms has tended to exclude many agricultural activities, including many soil carbon sequestration activities.