Post written by C.Will
Our
recent blogs have been discussing food security, and the role agricultural
production has to play in ensuring a sustainable future. Below are two recently
published papers that incorporate the effects of climate change into this
discussion.
“Climate change
effects on agriculture: Economic responses to biophysical shocks”. By Nelson et al.
2013. Published in Proceedings of the National Academy of Sciences (PNAS).
Abstract:
“Agricultural
production is sensitive to weather and thus directly affected by climate
change. Plausible estimates of these climate change impacts require combined
use of climate, crop, and economic models. Results from previous studies vary
substantially due to differences in models, scenarios, and data. This paper is
part of a collective effort to systematically integrate these three types of models.
We focus on the economic component of the assessment, investigating how nine
global economic models of agriculture represent endogenous responses to seven
standardized climate change scenarios produced by two climate and five crop
models. These responses include adjustments in yields, area, consumption, and
international trade. We apply biophysical shocks derived from the
Intergovernmental Panel on Climate Change’s representative concentration
pathway with end-of-century radiative forcing of 8.5 W/m2. The mean biophysical
yield effect with no incremental CO2 fertilization is a 17% reduction globally
by 2050 relative to a scenario with unchanging climate. Endogenous economic
responses reduce yield loss to 11%, increase area of major crops by 11%, and reduce
consumption by 3%. Agricultural production, cropland area, trade, and prices
show the greatest degree of variability in response to climate change, and
consumption the lowest. The sources of these differences include model
structure and specification; in particular, model assumptions about ease of
land use conversion, intensification, and trade. This study identifies where
models disagree on the relative responses to climate shocks and highlights
research activities needed to improve the representation of agricultural
adaptation responses to climate change.”
“The future of food
demand: understanding differences in global economic models”. By Valin et al.
2013. Published in Agricultural Economics.
Abstract:
“Understanding
the capacity of agricultural systems to feed the world population under climate
change requires projecting future food demand. This article reviews demand
modeling approaches from 10 global economic models participating in the
Agricultural Model Intercomparison and Improvement Project (AgMIP). We compare
food demand projections in 2050 for various regions and agricultural products
under harmonized scenarios of socioeconomic development, climate change, and
bioenergy expansion. In the reference scenario (SSP2), food demand increases by
59–98% between 2005 and 2050, slightly higher than the most recent FAO
projection of 54% from 2005/2007. The range of results is large, in particular
for animal calories (between 61% and 144%), caused by differences in demand
systems specifications, and in income and price elasticities. The results are
more sensitive to socioeconomic assumptions than to climate change or bio-energy
scenarios. When considering a world with higher population and lower economic
growth (SSP3), consumption per capita drops on average by 9% for crops and 18%
for livestock. The maximum effect of climate change on calorie availability is −6%
at the global level, and the effect of bio-fuel production on calorie
availability is even smaller.”
