population at risk from hunger (defined as the population with an income
insufficient to produce or procure their food requirements).
The BLS does not incorporate any climate relationships per se. Effects of
changes in climate were introduced to the model as changes in average national
or regional yield per commodity as estimated above. Ten commodities are
included in the model: wheat, rice, coarse grains (e.g. maize, millet, sorghum and
barley), bovine and ovine meat, dairy products, other animal products, protein
feeds, other food, non-food agriculture and non-agriculture. In this context,
however, consideration is limited to the major grain food crops.
The Set of Model Experiments
The results described in this article consider the following scenarios:
The reference scenario. This involved projection of the agricultural system to
the year 2060 with no effects of climate change on yields and with no major
changes in political or economic context of the world food trade. It assumed:
E UN medium population estimates (10.2 billion by 2060).
E 50% trade liberalization in agriculture introduced gradually by 2020.
E Moderate economic growth (ranging for 3.0% per year in 1980—2000 to
1.1% per year in 2040—2060).
E Technology is projected to increase yields over time (cereal yields for world
total, developing countries and developed countries are assumed to increase
annually by 0.7%, 0.9% and 0.6%, respectively).
E No changes in agricultural productivity due to climate change.
Three climate change scenarios. These are projections of the world food trade
system including the effects on agricultural yields under different climate
scenarios (the ‘2 ; CO
scenarios’ for the GISS, GFDL, and UKMO GCMs).
The food trade simulations for these three scenarios were started in 1990 and
assumed a linear change in yields until the double CO
concentration was
reached in 2060. Simulations were made both with and without the physiological
effects of 555 ppmv CO
on crop growth and yield for the equilibrium yield
estimates. In these scenarios, internal adjustments in the model occur, such as
increased agricultural investment, reallocation of agricultural resources according
to economic returns and reclamation of additional arable land as an adjustment
to higher cereal prices, based on shifts in comparative advantage among
countries and regions.
Scenarios including the effect of farm-level adaptations. The food trade model
was first run with yield changes assuming no external adaptation to climate
change and was then re-run with different climate-induced changes in yield,
assuming a range of farm-level adaptations. These included such measures as
altering planting dates and crop varieties and the use of different amounts of
irrigation and fertilizer. Two adaptation levels to cope with potential effects on
United Nations, World Population Prospects 1988, United Nations, New York, 1989.
International Bank for Reconstruction and Development/World Bank, World Bank Population
Projections, Johns Hopkins University Press, Baltimore, 1990.
Climate Change, Global Food Supply and Risk of Hunger
115
insufficient to produce or procure their food requirements).
The BLS does not incorporate any climate relationships per se. Effects of
changes in climate were introduced to the model as changes in average national
or regional yield per commodity as estimated above. Ten commodities are
included in the model: wheat, rice, coarse grains (e.g. maize, millet, sorghum and
barley), bovine and ovine meat, dairy products, other animal products, protein
feeds, other food, non-food agriculture and non-agriculture. In this context,
however, consideration is limited to the major grain food crops.
The Set of Model Experiments
The results described in this article consider the following scenarios:
The reference scenario. This involved projection of the agricultural system to
the year 2060 with no effects of climate change on yields and with no major
changes in political or economic context of the world food trade. It assumed:
E UN medium population estimates (10.2 billion by 2060).
E 50% trade liberalization in agriculture introduced gradually by 2020.
E Moderate economic growth (ranging for 3.0% per year in 1980—2000 to
1.1% per year in 2040—2060).
E Technology is projected to increase yields over time (cereal yields for world
total, developing countries and developed countries are assumed to increase
annually by 0.7%, 0.9% and 0.6%, respectively).
E No changes in agricultural productivity due to climate change.
Three climate change scenarios. These are projections of the world food trade
system including the effects on agricultural yields under different climate
scenarios (the ‘2 ; CO
scenarios’ for the GISS, GFDL, and UKMO GCMs).
The food trade simulations for these three scenarios were started in 1990 and
assumed a linear change in yields until the double CO
concentration was
reached in 2060. Simulations were made both with and without the physiological
effects of 555 ppmv CO
on crop growth and yield for the equilibrium yield
estimates. In these scenarios, internal adjustments in the model occur, such as
increased agricultural investment, reallocation of agricultural resources according
to economic returns and reclamation of additional arable land as an adjustment
to higher cereal prices, based on shifts in comparative advantage among
countries and regions.
Scenarios including the effect of farm-level adaptations. The food trade model
was first run with yield changes assuming no external adaptation to climate
change and was then re-run with different climate-induced changes in yield,
assuming a range of farm-level adaptations. These included such measures as
altering planting dates and crop varieties and the use of different amounts of
irrigation and fertilizer. Two adaptation levels to cope with potential effects on
United Nations, World Population Prospects 1988, United Nations, New York, 1989.
International Bank for Reconstruction and Development/World Bank, World Bank Population
Projections, Johns Hopkins University Press, Baltimore, 1990.
Climate Change, Global Food Supply and Risk of Hunger
115