The document summarizes an economic study on the potential impacts of climate change on global agriculture. It uses an economic model called SWOPSIM to simulate the effects of yield changes in major crop producing regions under different climate change scenarios. The study finds that even with large assumed domestic yield losses, global welfare losses are relatively small, generally less than 1% of GDP for most countries. International trade helps to mitigate the effects of local production changes. The impacts are also reduced if other regions experience offsetting yield increases due to climate change.
Scaling up soil carbon enhancement contributing to mitigate climate changeCIAT
The 4 per 1000 Africa Symposium - Building synergies across Africa to advance on soils for food security and climate, Johannesburg, South Africa 24-26 October 2018
Rolf Sommer, Kristin Piikki, Mats Söderström, Sylvia Nyawira, Mayesse da Silva, Wuletawu Abera and
Job Kihara
Modelling the impact of climate change on cereal yield in MoroccoIJEAB
To assess the impact of climate change different studies were conducted in several regions of Morocco. The assessment of climate change and its impacts involves the simulation of a range of different socio-economic and physical processes. Some of these processes are well known such temperature, rainfall, storms, etc.., others not. Hence for each modeling step researchers need to consider what is known, what is not known, and how climate change can be expressed.This paper is a contribution to research on climate change impact on cereal yield in the last 50 years. The application of the multiple linear regression model to a set of time series of yield, rainfall, temperature and storm has generated significant coefficients that can explain the relation between yield and the three climate variables. The model output confirms the results of the previous studies of yield variability. The positive effect of rainfall and the negative one of storm and temperature ware recorded. Above the three factors, temperature and storms have a negative effect on cereal yield. So more efforts on germplasm, crop management and agricultural policy measures are needed to alleviate the impact of climate change. An estimate coefficient of -4.943 for temperature is very indicating the high impact of temperature on yield. The R² is around 0.45indicates that more than 55% of total yield variability is explained by other factors than rain, temperature and storm.
Scaling up soil carbon enhancement contributing to mitigate climate changeCIAT
The 4 per 1000 Africa Symposium - Building synergies across Africa to advance on soils for food security and climate, Johannesburg, South Africa 24-26 October 2018
Rolf Sommer, Kristin Piikki, Mats Söderström, Sylvia Nyawira, Mayesse da Silva, Wuletawu Abera and
Job Kihara
Modelling the impact of climate change on cereal yield in MoroccoIJEAB
To assess the impact of climate change different studies were conducted in several regions of Morocco. The assessment of climate change and its impacts involves the simulation of a range of different socio-economic and physical processes. Some of these processes are well known such temperature, rainfall, storms, etc.., others not. Hence for each modeling step researchers need to consider what is known, what is not known, and how climate change can be expressed.This paper is a contribution to research on climate change impact on cereal yield in the last 50 years. The application of the multiple linear regression model to a set of time series of yield, rainfall, temperature and storm has generated significant coefficients that can explain the relation between yield and the three climate variables. The model output confirms the results of the previous studies of yield variability. The positive effect of rainfall and the negative one of storm and temperature ware recorded. Above the three factors, temperature and storms have a negative effect on cereal yield. So more efforts on germplasm, crop management and agricultural policy measures are needed to alleviate the impact of climate change. An estimate coefficient of -4.943 for temperature is very indicating the high impact of temperature on yield. The R² is around 0.45indicates that more than 55% of total yield variability is explained by other factors than rain, temperature and storm.
Statistical Model
ii Phonological Model
iii Mechanistic Model
iv Deterministic Model
v Stochastic Model
Dynamic Model
vii Static Model
viii Crop Simulation Models
ix Descriptive Model
x Explanatory Model
contact: dhota3@gmail.com
Climate Information for Mitigation and AdaptationCIFOR-ICRAF
This presentation by Walther E. Baethgen asks and answers some of the most important questions concerning climate change:
Adaptation to What?
What Can We Expect?
What Mitigation options are likely to succeed?
Also it presents many interesting scenarios all related to climate change: for example how it would affect socioeconomics and vice versa.
How can agriculture help achieve the 2°C climate change target? Delivering food security while reducing emissions in the global food system
November 2, 2015
An event co-sponsored by the CGIAR Research Program on Climate Change, Agriculture and Food Security and the World Bank
Presentation
Delivering on a transformed food sector: Frontiers in mitigation
Steven Shafer, Associate Administrator, Agricultural Research Service, United States Department of Agriculture (USDA)
Tracking change in land use and vegetation conditionRichard Thackway
Seminar 'Tracking change in land use and vegetation condition' presented to the Department of Agriculture, Fisheries and Forestry, Canberra on 22 February 2013.
Impacts of climate change on livestock sector and Kenya’s preparedness on the...ILRI
Presented by Robin M. Mbae (Ministry of Agriculture, Livestock and Fisheries, Kenya) at the Expert panel: Sustainable solutions for the livestock sector: the time is ripe! 10th Global Forum for Food and Agriculture, Berlin, 19 January 2018
Climate Change and Future Food Security: The Impacts on root and Tuber CropsACDI/VOCA
Background: Climate Sensitivity of Agriculture
Importance or Root Crops to Jamaican Food Security
Estimating Yields (Manually)- Yield vs. Climate Dilemma
Methodology: Tools and Approaches
Results: Parameterization, Future Production under Climate Change
Conclusions: Climate Smart Implications & Main lessons learnt
Agriculture is one of those activities of man that is greatly affected by climate. Therefore, a change in climate would in no small measure impact on agriculture, location notwithstanding. This work as a result examined the impact of climate change on maize and cassava yields in Southeastern Nigeria. Expost-facto research method in the context of quasi experimental research design was adopted for the study. Data for rainfall and temperature were obtained from Nigerian Meteorological Agency (NIMET); and those for crop yields came from Federal Ministry of Agriculture of Nigeria and Agricultural Development Programme (ADP) of selected states. The data were analyzed using descriptive statistics, multiple linear regressions and analysis of variance. Results showed that, there are evidences of climate change in Southeastern Nigeria, with notable fluctuations in the identified trends. Employing the trend analysis represented by the least square line, Abia State rainfall is increasing at 0.1026mm per annum, while Imo State is decreasing at -1.1255 mm per annum. All the states recorded positive slopes in mean temperature which shows an increase in their trends. The multiple regression model showed R2 values that ranged between 0.25 – 0.29 revealing that only 25 %- 29 % of cassava and maize yields could be explained by rainfall and temperature across the states and the result was significant at p<0.05 revealing that cassava and maize yields significantly depended on rainfall and temperature. Crop yields were also significantly different spatially. As a result of the findings the study strongly advocates, development of better and sustained environmental policies that will be beneficial to climate systems while creating sustainable food security.
Statistical Model
ii Phonological Model
iii Mechanistic Model
iv Deterministic Model
v Stochastic Model
Dynamic Model
vii Static Model
viii Crop Simulation Models
ix Descriptive Model
x Explanatory Model
contact: dhota3@gmail.com
Climate Information for Mitigation and AdaptationCIFOR-ICRAF
This presentation by Walther E. Baethgen asks and answers some of the most important questions concerning climate change:
Adaptation to What?
What Can We Expect?
What Mitigation options are likely to succeed?
Also it presents many interesting scenarios all related to climate change: for example how it would affect socioeconomics and vice versa.
How can agriculture help achieve the 2°C climate change target? Delivering food security while reducing emissions in the global food system
November 2, 2015
An event co-sponsored by the CGIAR Research Program on Climate Change, Agriculture and Food Security and the World Bank
Presentation
Delivering on a transformed food sector: Frontiers in mitigation
Steven Shafer, Associate Administrator, Agricultural Research Service, United States Department of Agriculture (USDA)
Tracking change in land use and vegetation conditionRichard Thackway
Seminar 'Tracking change in land use and vegetation condition' presented to the Department of Agriculture, Fisheries and Forestry, Canberra on 22 February 2013.
Impacts of climate change on livestock sector and Kenya’s preparedness on the...ILRI
Presented by Robin M. Mbae (Ministry of Agriculture, Livestock and Fisheries, Kenya) at the Expert panel: Sustainable solutions for the livestock sector: the time is ripe! 10th Global Forum for Food and Agriculture, Berlin, 19 January 2018
Climate Change and Future Food Security: The Impacts on root and Tuber CropsACDI/VOCA
Background: Climate Sensitivity of Agriculture
Importance or Root Crops to Jamaican Food Security
Estimating Yields (Manually)- Yield vs. Climate Dilemma
Methodology: Tools and Approaches
Results: Parameterization, Future Production under Climate Change
Conclusions: Climate Smart Implications & Main lessons learnt
Agriculture is one of those activities of man that is greatly affected by climate. Therefore, a change in climate would in no small measure impact on agriculture, location notwithstanding. This work as a result examined the impact of climate change on maize and cassava yields in Southeastern Nigeria. Expost-facto research method in the context of quasi experimental research design was adopted for the study. Data for rainfall and temperature were obtained from Nigerian Meteorological Agency (NIMET); and those for crop yields came from Federal Ministry of Agriculture of Nigeria and Agricultural Development Programme (ADP) of selected states. The data were analyzed using descriptive statistics, multiple linear regressions and analysis of variance. Results showed that, there are evidences of climate change in Southeastern Nigeria, with notable fluctuations in the identified trends. Employing the trend analysis represented by the least square line, Abia State rainfall is increasing at 0.1026mm per annum, while Imo State is decreasing at -1.1255 mm per annum. All the states recorded positive slopes in mean temperature which shows an increase in their trends. The multiple regression model showed R2 values that ranged between 0.25 – 0.29 revealing that only 25 %- 29 % of cassava and maize yields could be explained by rainfall and temperature across the states and the result was significant at p<0.05 revealing that cassava and maize yields significantly depended on rainfall and temperature. Crop yields were also significantly different spatially. As a result of the findings the study strongly advocates, development of better and sustained environmental policies that will be beneficial to climate systems while creating sustainable food security.
Agriculture Extension and Advisory Services under the New Normal of Climate ...World Agroforestry (ICRAF)
In the years to come climate change, coupled with population growth, energy and natural resource depletion, will increasingly challenge our continued ability to feed ourselves. As we move forward, persistent problems, past failures and new challenges within Extension change agents and advisory service (EAS) provisioning have the potential to converge in a perfect storm as the scramble to adapt to the new normal of life under climate change intensifies. This presentation outlines the nature of the challenges, identifies past and present points of successful EAS engagement and outlines necessary areas of preparation
Basic Concept of Climate Change and Overview of Ethiopia’s Climate Resilient ...KechaTaye
Climate change and its impact on environment and world economy is the crucial issue of the world today.
The population of the developing world particularly Africa is the most vulnerable to the impacts of climate change.
This is because of their heavy dependence on the natural resource and lack of means to cope up with the impacts of climate change
Running Head COMMITMENT OF USA TO PARIS AGREEMENT1COMMITMENT.docxsusanschei
Running Head: COMMITMENT OF USA TO PARIS AGREEMENT 1
COMMITMENT OF USA TO PARIS AGREEMENT 4
COMMITMENT OF USA TO PARIS AGREEMENT
Danielle Schummer
G328/EVR3410 Human Uses of the Environment
According to my thinking, the United States of America should commit itself to the Paris agreement. It will enable the country to contribute the maximum to environmental conservation. The country should make efforts in committing itself to the Paris agreement as it has brought nations from the entire world into a common cause. Thus undertaking the needed ambitions for combating the climatic change and accordingly adapting the possible effects and challenges experienced by each country and coming up with solutions to help the developing countries to withstand the problems encountered.
The agreement will, therefore, chart a new course in the global climate efforts which will help in safeguarding the welfare of the people's health (Maslin, 2007). The United States of America should, again, commit itself to the agreement as its made to strengthen the global responses to the threats brought by adverse climatic changes by developing favorable global temperature rise in the century, for the world to experience a 2 degrees Celsius decrease in the industrialized areas. According to the Paris agreement, the countries, as a whole, should develop different efforts to ensure that the nations experience a 2 degrees Celsius temperature drop. The deal is significant in that it will strengthen countries’ abilities to deal with the results brought by climatic changes as it is realized that it is changing in every century.
The United States committing itself to the deal will again enable it to oversee more developments in the country as a specific financial flow should be witnessed, new technologies developed, and an enhanced capacity building framework brought into existence which will support the actions of the nation by promoting them invulnerable and reliable nations, thus meeting their set objectives (NSTC, 2008). The Paris deal has again provided enough transparency of the efforts by each state and developed a very clear framework for the nations to fight the effects of climate change within a set period.
According to my understanding, we can experience global warming as a result of continued air pollution and increased industrialization by many countries in the world. As the days go by, many industries are constructed and a mechanism is not put in place to protect the polluted air from entering the atmosphere. On the other hand, the Paris agreement has impacted my stand on global warming as it has enabled me to realize that different countries can come together thus developing mechanisms objectively to reduce the occurrence of global warming.
As a result of global warming water resources have been affected, leading to a decline in irrigation supplies. This occurs due to the loss of the mountain snowpack hence reducing the amounts of water for the ir ...
Animal agriculture adaptation planning guide (climate change)LPE Learning Center
This 44-page publication produced by the AACC project is a planning guide to help guide farmers through the process of future farm planning considering climate change.
Format: Factsheet or Publication - Reference: Schmidt, D., E. Whitefield, D. Smith. 2014. Produced for Animal Agriculture in a Changing Climate Project.
Economic perspectives on the impact of climate change on agricultureharrison manyumwa
The world's climate is changing, and the growing evidence is that the major drivers are anthropogenic, i.e. caused by humans. While humans are contributing to the changing climates the impacts of climate change on other humans range from minor to severe depending on the region one is located. As such, climate change has been viewed as a problem with a negative exernality. The diverse distributionl impacts have resulted in "winners" and "losers". But what is the way forward. I argue that "winners" should support and help the "losers" regain a normal life, by helping them to be resilient. Enjoy.
Climate change and agriculture in Central America and the Andean regionIFPRI-PIM
PIM Webinar, January 29, 2020.
Climate change poses a threat to food security and nutrition, largely through its impacts on agricultural production. To help developing countries identify where adaptation measures are most needed, IFPRI, with support from the CGIAR Research Programs on Policy, Institutions, and Markets (PIM) and Climate Change, Agriculture, and Food Security (CCAFS), conducted a multiyear study to assess the potential impact of climate change on the agriculture sector through 2050, taking into account the likely landscape of political and economic challenges that policy makers will face. The study integrated results from climate and economic models, and included detailed biophysical and bioeconomic analyses of Guatemala, Honduras, El Salvador, Nicaragua, and Costa Rica in Central America and Colombia and Peru in the Andean region of South America.
Presenters and panelists:
Timothy Thomas, Research Fellow, International Food Policy Research Institute (IFPRI)
Deissy Martínez Barón, Regional Program Coordinator for Latin America, CGIAR Research Program on Climate Change, Agriculture, and Food Security (CCAFS)
Ana R. Rios, Natural Resources and Climate Change Senior Specialist, Inter-American Development Bank
More at http://bit.ly/ClimateChangeAgWebinar
Rising to the challenge of establishing a climate smart agriculture - a global context presented as keynote in the Workshop on Climate Smart Agriculture Technologies in Asia workshop, organised by CCAFS, UNEP and IRRI.
Canadian experiences in sustainability in agriculture and climate change Premier Publishers
Agriculture has changed dramatically, with food and fiber productivity soaring due to new technologies, specialization and government policies. These changes allowed fewer farmers with reduced labor demands to produce the majority of the food. It is in this context that the concept of “sustainable agriculture” has come into existence. The severity of climate change has motivated strong scientific inquiry within the past decade. These mysteries have largely to do with the unpredictability of climate change, which varies widely across the globe. Many scientists argue that climate impacts are best understood on a regional scale. Unfortunately, it is often difficult to assess regional impacts of climate change due to various reasons. The tools at the disposal of those interested in building up resilience to climate change are therefore often limited, but some degree of speculation can be achieved through research. This paper aims to: investigate the potential impacts of climate change on Canadian agriculture, and assess the possible effects of these changes on the prevalence of sustainable agriculture. The paper concludes that while few predictions have been made on the specific impacts of climate change on sustainable agriculture, possible scenarios can be speculated based on the multitude of climate change studies.
To Review the Impact and Copping Strategies of Climate Change in Developing C...AI Publications
Rapid change in climate is set to alter the delicate balance that exists between man and nature. The literature to this effect points out that the poorest countries and communities are likely to suffer the most because of their geographic locations, low income and low institutional capacity, as well as their greater reliance on climate-sensitive sectors like agriculture. Even if climate mitigations plans are implemented properly there will be some degree of warming due to inertia of emissions already released. As such, there is a strong consensus about the need of adaptation to changing climatic conditions. Adaptation to climate change is given increasing international attention as the confidence in climate change projections is getting higher. Developing countries have specific needs for adaptation due to high vulnerabilities, and they will in this way carry a great part of the global costs of climate change although the rising atmospheric greenhouse gas concentrations are mainly the responsibility of industrialized countries. Adaptation is believed to enhance the resilience against increasing climate variability. In this backdrop, the objective of the present paper is, therefore, to systematically and critically review the existing literature on the impacts of climate change and choice of adaptations across countries and draw insights for suggesting a comprehensive policy framework particularly for developing countries in this regard. The paper finds that the role of government and civil society is crucial for enabling efficient adaptation methods. Development policies and programs having synergy effect with climate change initiatives help adapt with the changing climate better. However, the availability of clean technology in developing countries will play the decisive role in controlling their growth rate of emission.
Presentation made by Andy Jarvis from the Decision and Policy Analysis Program of the International Centre for Tropical Agriculture (CIAT). Delivered at Supagro in Montpellier, France in November 2009.
204-215 A Review of Potential Adaptation Strategies for Climate Smart Sustain...
Reilly_ag_climate_aer_
1. American Economic Association
Climate Change and Agriculture: The Role of International Trade
Author(s): John Reilly and Neil Hohmann
Source: The American Economic Review, Vol. 83, No. 2, Papers and Proceedings of the
Hundred and Fifth Annual Meeting of the American Economic Association (May, 1993), pp.
306-312
Published by: American Economic Association
Stable URL: http://www.jstor.org/stable/2117682
Accessed: 25/03/2010 15:20
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2. THECONTRIBUTIONSOFECONOMICMODELINGTOANALYSIS
OF THECOSTSANDBENEFITSOFSLOWING
GREENHOUSEWARMINGt
ClimateChange and Agriculture:
The Role of InternationalTrade
By JOHN REILLY AND NEIL HOHMANN *
Economicstudiesof the impactof climate
changeon agriculturehavebeen includedin
Louise Arthur (1988), MartinParryet al.
(1988), RichardAdams et al. (1990), and
Sian Mooney and Arthur(1990).A limita-
tion of these effortswas that they focused
on domestic agriculturalimpacts and did
not consider the effects of climate change
on worldproductionandmarkets.The cen-
tral premiseof this paper is that for open
economies the effect of climatechange on
agriculturein anyindividualcountrycannot
be consideredin isolationfrom the rest of
the world. A small-countryargumentcan
justifyan analysislimitedto that countryif
environmentalchangeoccurswhollywithin
the country.Whereeffectsoccursimultane-
ously throughoutthe world, however, the
only way to justifyconsideringa subglobal
regionis to assumethatthe economyof the
region is closed. There are significant
trade-distortingpolicies in agriculture(the
targetof the recentGATTround),butthese
distortratherthanclose off trade.
Following Sally Kane et al. (1992) and
JamesTobeyet al. (1992),this paperinves-
tigates the agriculturaleffects of climate
changerecognizingthat effectswill simulta-
neously occur worldwide. We summarize
this earlier work and find that, based on
new yield estimates,the broadconclusions
of that work are generallysupported.Sec-
tion I of the paper reviewspredictionsof
future climate and atmosphericconditions,
identifyingthe implicationsfor agriculture
in differentareas of the world. Section II
describesthe SWOPSIM(staticworldpol-
icy simulation)model used to evaluatethe
worldwide economic effects of climate
change. Section III reports an economic
sensitivityanalysisof concurrentyieldlosses
in majorgrain-producingregionsconsider-
ing the possibilityof concurrentchangesin
productionpotentialelsewhereintheworld.
SectionIV, takingadvantageof recentwork
by CynthiaRosenzweiget al. (1993),evalu-
ates agriculturalimpactsof climatechange
based on three general circulationmodels
(GCM's).SectionV offerscaveatsandcon-
clusions.
I. ClimatePredictions
Potentialchangesin climateare summa-
rizedelsewhere(J.T. Houghtonet al.,1990).
The forecastedchangessuggestpotentially
enhanced agriculturalproduction in the
northern regions of the Soviet Union,
Canada, and Europe, where agricultural
productionis limitedby cold temperatures
andshortgrowingseasons,andreducedcrop
tDiscussants:WilliamCline, Institutefor Interna-
tional Economics;CharlesKolstad,Universityof Illi-
nois.
*EconomicResearchService,U.S. Departmentof
Agriculture,1301New YorkAvenue,N.W.,Washing-
ton, DC 20005-4788.Reilly is visiting at the Mas-
sachusetts Institute of Technology.The views ex-
pressedin this paperdo not necessarilyrepresentthe
views of the U.S. Departmentof Agricultureor the
MassachusettsInstituteof Technology.We gratefully
acknowledgethe efforts of Sally Kane and James
Tobey who collaboratedon earlierwork.We thank
JohnSullivanand VernonRoningenfor assistancein
settingup the SWOPSIMmodel.Finally,we aregrate-
ful to CynthiaRosenzweigat the GoddardInstituteof
SpaceStudiesand MartinParryof OxfordUniversity
for providingus with resultsfromtheirstudy.Rosen-
zweig, Kane, David Schimmelpfennig,WilliamNord-
haus,and RichardSchmalenseeprovidedusefulcom-
mentson earlierdrafts.Anyerrorsareours.
306
3. VOL.83 NO. 2 ECONOMICMODELINGOFGREENHOUSEWARMING 307
yields in the United States and most
of Europe due to increased drought(see
Tobeyet al., 1992).
It has sometimesbeen observedthat cli-
mate impactsmaybe less severein equato-
rial regions than in temperateregions be-
cause climate models predict temperature
increasesin the tropicson the orderof 2?C
comparedwith4?C-12?Cfortemperateand
polar regions. However, considerationsof
(i) water use, (ii) adaptationpotential,and
(iii) adaptationcapabilityin these regions
alter this conclusion.(For a lengthier dis-
cussionsee Rosenzweig,et al.,1993).Briefly,
the effectsmaybe summarizedas follows:
Water Use.-Precipitation patterns are
poorly predicted but evapotranspiration
(the plant'sdemandfor water) increases
more than proportionallywith tempera-
ture increase. For example, a 2?C in-
crease in alreadywarmregions(tropical
developingcountries)would increasethe
potentialfor droughtstress more than a
2?Cincreasein coolerregions.
AdaptationPotential.-Tropical regionsare
more likelyto be at the limitsof adapta-
tion measures and thus may have less
potential to adapt. Examplesof adapta-
tionsincludeshiftsfromcool-seasoncrops
to crops that performbetter in warmer
climates; shifts from crops sensitive to
droughtstress;choiceof plantingdatesto
avoidhightemperatures,to avoiddrype-
riods of the year, or to obtain multiple
crops during the year; choice of tillage
practices,seedingrates,row spacing,fal-
low periods;andirrigationas appropriate
for moistureavailability.
AdaptationCapability.-Generally,the ca-
pabilityto adaptmaybe less in develop-
ing countries.Poorly developed markets
for crop inputs(fertilizer,seeds, andma-
chinery)or for outputsmaylimitthe abil-
ity of farmersto obtain inputsuseful for
adaptingto climatechangeor to sell ex-
cess productionof crops favored under
new climates. Infrastructureconsidera-
tions includingeducationof farmersand
the existenceof cropexperimentandtest-
ingstationsapdtransportation,cropstor-
age, and crop processing facilities may
limitdetectionof climatechangeand the
identificationof suitableresponses.
An additionalconsiderationfor agricul-
tureis thatatmosphericCO2actsas a plant
fertilizerand increaseswater-useefficiency
in plants. Higher levels of ambient atmo-
sphericCO2 are thereforeexpected to in-
crease yields. The growthresponse to ele-
vatedCO2isgreaterin C3crops(e.g.,wheat,
rice, barley,root crops, and legumes)than
in C4 crops (e.g., corn, sorghum, millet,
sugar cane); however,water-use efficiency
may be greater in C4 crops. Whether the
full effectsof CO2 fertilizationobservedin
experimentalconditionswill be realized in
the open environmentis an issue of debate.
II. SWOPSIMModelStructure
We used the SWOPSIMmodel of world
food markets,developedby VernonRonin-
gen et al. (1991),to simulateeconomicef-
fect of climate change. Discussion of the
model presented here relies heavily on
Roningenet al. The modelcontains20 agri-
culturalcommodities,includingeight crop,
fourmeat/livestock,fourdairy-product,two
protein-meal, and two oil-product cate-
gories. For the purposesof the sensitivity
studyreportedin SectionIII,the modelwas
constructedto identifyseparatelytheUnited
States, Canada,the EuropeanCommunity
(EC),Australia,Argentina,Thailand,China,
Brazil,the formerSovietUnion, other Eu-
ropean countries (Sweden, Finland, Nor-
way,Austria,and Switzerland),Japan,and
ROW(the restof the world).The commod-
ity supplyand demandequationswere set
to reproduce1986base-perioddataforeach
country'ssupply,demand,prices,andtrade.
For the specificGCMscenariosreportedin
Section IV, the model was updated to a
1989 base and reconstructedinto 33 sepa-
rate countries/regionsto facilitateanalysis
by country-incomeclass.
For each country/regioni and commod-
ity j in the model, constant-elasticityde-
mand and supply functions are specified.
For country i and commodityj quantity
4. 308 AEA PAPERSAND PROCEEDINGS MAY1993
demanded(QD)andsupplied(QS)aregiven
as:
n
(1) QDi= dij(1 +sdi)j l CPik
n
(2) QSi1 = sij (1 +SSj)
I
PPgk
whereCPikandPPikaredomesticconsumer
and producer prices of commodity k =
1,...,n. For k=j, the ak and Pk are the
own-price demand and supply elasticities
(uncompensated)and for k Aj they are
cross-priceelasticities.The dij and si, are
base quantitiessdij and ssij are demand-
andsupply-shiftparameters,whichare zero
underthe base data. In the climate-impact
scenarios,percentageyield changesby crop
and country as developed from crop-
responsemodels are used as a measureof
the ssij. Domestic consumerand producer
prices reflect world prices, governmentin-
terventionsin production(PSW1.),andcon-
sumer subsidiesand interventions(CSWij).
These interventionslead prices in any one
countryto differfrom the worldprice and
cause the consumerprice for a countryto
differfrom the producerprice. The price-
linkageequationsare
(3) PPij= ppij + wijWPI.}ij
+ PSWij+ TPij+ NWij
(4) CPij= cpij+ PPij+ CSWij+ PSWij.
The w11are dummies(1 for tradedor 0 for
nontradedcommodities),and NWijare do-
mestic price changes,which are zero when
w11= 1. The ppij andcp11are constantsand
the TP11aretrade(exportandimport)inter-
ventions. The y11 are price-transmission
elasticities and reflect additional govern-
ment interventionsthat limit the transmis-
sion of world price changes to domestic
prices.
Market equilibriumis characterizedby
excess world demandequal to zero for all
commodities.A numericalsolution is ob-
tainedin the modelthroughiteration.Once
a solution is obtained, producerand con-
sumersurpluschangesaremeasuredaswel-
faretrianglesby calculatingthe valueof the
integralof the supplyanddemandfunctions
betweenthe initialprice and the new equi-
libriumprice.We reporteconomiceffectsin
terms of changesin economicwelfarethat
include changes in consumersurplus,pro-
ducer surplus,and changes in government
payments (revenues) that result implicitly
fromthe worldprice-transmissionelasticity
and explicitlyfromother governmentinter-
ventions.As a caveatwe note that SWOP-
SIMis a partial-equilibriummodel.MaryF.
Kokoskiand V. KerrySmith (1987) show
that the climate-changewelfare effects of
fairly large, single-sectorimpactsare ade-
quately measured in a partial-equilibrium
setting.SWOPSIMtreatsresourceandother
inputs implicitly through specification of
supplyparameters.
III. TheSensitivityofAgriculturetoYield
Lossesin MajorGrainProducingRegions
Among the feared effects of climate
changeareconcurrentproductivitylosses in
the major grain-producingregions in the
United States, the plains of Canada, and
the EuropeanCommunity.In this section,
we examinethe economicimpactof signifi-
cantyieldlosses in these areaswhileinclud-
ing varyingassumptionsof how yields may
change outside these areas. We identify
three types of countries: TEMP (United
States,Canada,and the EC), temperatear-
eas where reducedsoil moistureis usually
predictedto lead to yield declines;COLD
(former Soviet Union, northern Europe,
China, Japan, Australia, Argentina, and
Brazil),areas that some evidence suggests
could see increased yields from warming;
and ROW, the rest of the world.We con-
structed three simulation experiments to
considerthe effect of a rangeof simultane-
ous yield reductions in these regions. In
each experiment,SWOPSIMwas simulated
for concurrentyield reductions in region
TEMP of 10, 20, 30, 40, and 50 percent.
Thus,each experimentis a set of fivemodel
simulations.The three experimentswere as
5. VOL.83 NO. 2 ECONOMICMODELINGOFGREENHOUSEWARMING 309
TABLE 1-GLOBAL WELFARELOSSESAND
YIELD CHANGES(MILLIONSOF 1989
U.S.DOLLARS)
Yieldloss Region
in TEMP _ _ _ _ _ _
(percentage) TEMP COLD ROW
Experiment1:
-10 2,052 8,914 4,797
-30 -1,290 7,513 557
- 50 - 7,497 8,531 -3,146
Experiment2:
-10 - 1,588 -1,699 - 2,052
-30 - 7,878 -4,437 -5,436
-50 - 18,595 -5,551 -7,190
Experiment3:
-10 - 2,873 8,061 - 17,749
-30 - 6,294 8,927 - 21,343
- 50 -16,000 12,891 - 28,138
Notes: Region TEMP= temperate areas (United
States,Canada,EC); regionCOLD= cold areas and
othersthatcouldbenefit(formerSovietUnion,north-
ern Europe, China, Japan, Australia, Argentina,
Brazil);regionROW= rest of the world.The experi-
ments were as follows:
Experiment1.-yield increases of 25 percent in COLD,
no changein ROW,withlossesas givenin tablefor
TEMP;
Experiment2.-no yieldchangein COLDor ROW;
Experiment3.-yield increasesof 25 percentin COLD
withyielddecreasesof 25 percentin ROWandwith
lossesas givenin tableforTEMP.
follows:
Experiment1.-Yield increasesof 25 per-
cent in regionCOLD,with no changein
ROW;
Experiment2.-A neutral effect in COLD
and ROW;
Experiment3.-Yield increasesof 25 per-
cent in COLD and decreasesof 25 per-
cent in ROW.
The welfareeffectsresultingfromthe in-
troduction of climate-inducedchanges in
yieldsspecifiedin the threeexperimentsare
showninTable1.Theresultsillustratethree
interestingfeaturesregardingthe impactof
climate change on agriculture.First, even
underthe assumptionof relativelylargeand
negativedomestic,yield effects,the welfare
losses are small relative to GDP for all
countriesidentifiedin the study.Thelargest
impactsmeasuredas percentagesof GDP
were in China and Argentina in experi-
ments 1 and 3 wherenet economicbenefits
rangedbetween 2 and 6 percent of GDP.
For all other countriesin all other experi-
ments, the effects rangedfrom a few hun-
dredths to a few tenths of a percent of
GDP. Agricultureaccountsfor a smallper-
centageof GDP in mosteconomies,particu-
larlylarge developedeconomies(3 percent
in industrialmarketeconomiesand 19 per-
centindevelopingeconomiesin 1986[World
Bank,1988]).
Experiment 1 illustrates that reduced
productionpotential in the United States,
Canada, and the EC may be more than
balancedbygainsin othergeographicareas,
leading to improvementsin worldwelfare.
The experimentsalso demonstratethat the
pattern of welfare effects amongcountries
dependsnot onlyon domesticyieldchanges,
but also on changes in world commodity
pricesandthe relativestrengthof the coun-
try as a net agriculturalimporter or ex-
porter. Consider the case of Argentina
under experiment2 (in which world agri-
cultural commodity prices rise). Because
Argentinais a largenet exporterof agricul-
turalcommodities,the countrygainedover-
all from an increasein the world price of
agriculturalproducts,even without any in-
crease in crop yields. In contrast, Japan
sufferednet welfare losses over all experi-
ments,despiteyield increasesof 25 percent
in experiments 1 and 3. Japan's welfare
losses were very similaras a percentageof
GDP to the EC'sbecauseof Japan'sdepen-
dence on food imports.As would be ex-
pected,consumereffects(e.g.,welfarelosses
whenworldpricesrose)dominatedin deter-
miningthe signof the net welfareeffectfor
most countries.The exceptionswere very
large agriculturalexportersfor which pro-
ducereffectsdominated.Tobeyet al. (1992)
providegreaterdetail.
These discussions highlight the role of
induced price changes in promotinginter-
regional adjustments in production and
consumption.A comparisonof SWOPSIM
resultswith other models that considercli-
mate-changeeffectson a singlecountryfur-
6. 310 AEA PAPERSAND PROCEEDINGS MAY1993
ther demonstratesthe role of global price
changes.Adams et al. (1990) examine the
economicimpactof climatechangeon U.S.
agricultureusing the GoddardInstitute of
SpaceStudies(GISS)andGeophysicalFluid
DynamicsLaboratory(GFDL)climatemod-
els. Theyfindnet welfarereductionsforthe
United Statesunderthe two scenariosto be
about$6billionand$34billion,respectively
(assumingno growthin technologyor de-
mand and no CO2 fertilization effects).
Yield changesin the GISS and GFDL sce-
narioswere on the orderof 20 percentand
40 percent,respectively.
In contrast,the net welfareimpacton the
UnitedStatesin ourexperiments1, 2, and3
under 40 percent U.S. yield losses were
- $0.5 billion, - $3.0 billion, and - $2.7 bil-
lion. In all experiments,net welfareeffects
for the United States are considerably
smaller than those estimated by Adams
et al. (1990). The differentresultsprovide
an illustrationof the importanceof interna-
tional price changes in promotinginterre-
gional adjustmentsin productionand con-
sumption.
IV. ResultsBasedon GCMSimulations
Rosenzweig et al. (1993) have recently
concluded an assessmentof yield changes
for the entire world under three separate
GCM scenarios. The study used equilib-
rium, doubled-trace-gasclimates as pre-
dictedby the GISS,GFDL, andthe United
Kingdom Meteorological Office (UKMO)
GCM's.The climatescenariosdifferamong
these models in terms of the seasonality,
regionality,and overallmagnitudeof tem-
perature and precipitation change. The
changes between the 2x CO2 equilibrium
andthe controlclimatein globalmean sur-
face temperatureand global precipitation
for the models were: GISS, + 4.2?C and
+ 11 percent;GFDL, + 4.0?Cand + 8 per-
cent; UKMO, + 5.2?C and + 15 percent.
The Rosenzweig et al. (1993) study esti-
matedyieldchangesforeachGCMscenario
usingcrop-responsemodelsrunformultiple
sites in 23 countries.They estimatedyields
withandwithoutadaptation,withandwith-
out the yield-enhancementeffect of in-
creasedambientCO2 levels, and three lev-
els of adaptation(none, moderate,and sig-
nificant).We reporthere only resultswith
no adaptation and moderate adaptation.
They combinedthe new crop studies with
existingestimatesfor other regionsto esti-
mateyield changesworldwidefor all crops.
They simulated economic and production
shiftsusingthe "basiclinkedsystem"(BLS)
model developedat the InternationalInsti-
tute for AppliedSystemsAnalysis(IIASA).
The principaladvantageof the SWOP-
SIM model over the BLS model is that
productionand price changes are summa-
rized as changes in welfare. Welfare mea-
suresaremoredirectlyusefulforcomparing
the benefitsof avoidedclimatechangewith
the costs of emissions reductionsand for
considering,forexample,whatlevelof mon-
etary transfersmight be requiredto com-
pensatecountriessufferingparticularlylarge
losses. Ourfindingswere as follows:
(i) Forthe threeGCM'snet globalwelfare
changes without adaptationand with-
out (with)the carbondioxideeffect in
billionsof 1989U.S. dollarswere:GISS,
-$115.5 (-$.1); GFDL, -$148.6
(- $17.0);UKMO, - $248.1 (-$61.2).
That is, under the GISS climate the
positiveeffectsof carbondioxidefertil-
izationoffset all but $0.1billionof the
losses due to climatechangealone.
(ii) For the three GCM's the net global
welfare changeswith the carbondiox-
ide fertilization effect and without
(with) adaptation were: GISS, -$.1
(+$7.0); GFDL, -$17.0 (-$6.1);
UKMO, - $61.2 ( - $37.6). That is, the
adaptationsconsideredwere worth on
the order between $7 billion and $25
billion.Carbondioxidefertilizationwas
worth on the order of between $115
billionand$190billion.
(iii) Even under the GISS GCM climate
with carbon dioxide fertilization and
adaptation,where the net welfare ef-
fect for the world is positive,all three
developing-countryincome-classgroups
sufferedwelfare losses (Table 2). This
resultstemmedfrom a combinationof
effects.Whilecroppricesgenerallyde-
7. VOL.83 NO. 2 ECONOMICMODELINGOFGREENHOUSEWARMING 311
TABLE 2-WELFARE EFFEcrS BY COUNTRY GROUP
(MILLIONS OF 1989U.S. DOLLARS)
GCM
Countrygroup GISS GFDL UKMO
< $500percapita -210 -2,573 -14,588
$500-$2,000percapita -429 -2,927 -10,669
> $2,000 per capita -603 -534 - 1,021
EasternEurope/former
SovietUnion 2,423 - 125 - 4,875
OECD 5,822 25 -6,470
Total: 7,003 -6,135 -37,623
clined in this scenario, creating con-
sumer surplus gains and producer
surplus losses, many of the tropical
regions suffered yield losses that ex-
acerbatedproducerlossesto the extent
that they were larger than consumer
gains.Thiswastruein mostdeveloping
countries.Economiceffectsin develop-
ing-countryareas where average in-
comes are generallyabove $2,000 per
capitaareparticularlyinteresting.Many
of these countriesarelargeagricultural
producersandexporters.Theysuffered
largeproducersurpluslossesunderthe
GISSclimatebecauseworldcropprice
declined, even though in some cases
yields for some crops increased (e.g.,
crop yields increasedin Argentinaex-
cept for wheat). While the GFDL cli-
mate created global net losses, the
developingcountrieswith average in-
comes of more than $2,000per capita
fared better than they did under the
GISS climate because producers in
these countries benefited from rising
worldcropprices.Under the far more
severe UKMO scenario, this country
groupshowedthe smallestincreasein
net losses amongthe groups,againbe-
cause of producergains. The poorest
regionsare largelyfood importersand
thus showverylargeconsumersurplus
losses relative to producergains. The
principalexception to this was China
whichgenerallyshowedyieldgainsand
net surplusgains across all three cli-
mate scenarios.Underthe UKMOsce-
nario,the net gain for Chinawas $3.2
billion. This means that losses for the
rest of the countrieswith averagein-
comesof less than$500percapitawere
$3.2 billion greater,or nearly$18 bil-
lion.
These three conclusionsconfirmthose of
Rosenzweiget al. (1993).In particular,the
disproportionateimpact in the developing
countriesis emphasizedintheirstudy.Trade
can shiftgainersandlosers,but the pattern
of effects is highlydependenton the origi-
nalyieldestimates.In the futurewe planto
compareSWOPSIMresultsdirectlywiththe
BLS results. Such a comparisonwould be
beneficialbecause the BLS models the dy-
namicadjustmentof agriculturein the con-
textof changingpopulationandtechnology.
V. CaveatsandConclusions
Significantsourcesof errorremaindue to
underlyinguncertaintiesin,forexample,the
climatescenarios,agronomicfactorssuchas
competitionfromweeds and plant and ani-
mal disease, and increasedcompetitionfor
landor waterbecauseof increaseddemand
from other sectors due to climate change.
Further,the modelusedin the analysisdoes
not include technologicalchange, popula-
tion growth, or other changes that may
accompanyeconomic growthand develop-
ment. The yield estimatesfrom GCM'sre-
flect conditionsunderequilibriumclimates.
Givencurrentscientificopinionthat a cen-
tral estimateis a warmingof 3?Cfromcur-
rentglobaltemperaturesby about2100,the
40 -5?C increases in Section IV may be un-
likelyuntil 2125 or 2150. Effects occurring
between now and then may be important
for currentdecisions.
With the above caveats, the findingsof
earlierwork,supportedbynew resultsfrom
GCM scenarios suggest the following.
(a) Interregionaladjustmentsin production
and consumptionwill serve to buffer the
severityof climatechangeimpactson world
agricultureandresultin relativelysmallim-
pacts on domestic economies from a dou-
bled CO2 climate. (b) Evaluation of
climate-changewinnersand losers requires
considerationof global marketchanges as
8. 312 AEAPAPERSANDPROCEEDINGS MAY1993
well as domesticyieldeffects.An important
implicationis that the incentivescountries
have to reduce greenhouse-gasemissions
depend on global price changesas well as
country-specificchangesin yield. Following
fromthe yield resultsof Rosenzweiget al.
(1993)andconfirmingtheireconomicanaly-
sis, (c) developing countries appear at a
greaterdisadvantage,and the beneficialef-
fectsof carbondioxidefertilizationarecriti-
cal in limitingthe economicimpacts.
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