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Assessment of climate change impacts on agriculture and a case study on crop impacts in China Sanai Li APEC Climate Center, Busan, 612-020, Republic of.

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Presentation on theme: "Assessment of climate change impacts on agriculture and a case study on crop impacts in China Sanai Li APEC Climate Center, Busan, 612-020, Republic of."— Presentation transcript:

1 Assessment of climate change impacts on agriculture and a case study on crop impacts in China Sanai Li APEC Climate Center, Busan, , Republic of Korea Erda LIN Chinese Academy of Agriculture Science, Beijing, China Chinese Academy of Agricultural Sciences.

2 Outline Why is climate change such an important issue for agriculture? Introduce the crop models - the response of crop to temperature - the response of crop CO 2 - the response of crop water Assess the impacts of climate change on agriculture –case study in China Adaptation strategies in agriculture

3 Importance of Agriculture 70% of the global land use is for agriculture, rangeland and forestry – 12% for arable and permanent crops – 31% for forest and woodlands – 27% for permanent pasture. Agriculture remains the major source of livelihoods of majority of world’s rural poor. -agriculture accounts for 70 percent of full-time employment in Africa, 33 percent of total GDP, and 40 percent of total export earnings. -Asia-Pacific region 60 percent of the population ( 2.2 billion) is relying on agriculture as a source of livelihood Agriculture is one of the most sensitive sectors to impacts of climate change

4 Climate Change & Agricultural productivity Climates factors directly affect agricultural productivity: -average increase in temperature -change in rainfall amount and patterns -rising atmospheric [CO2] -increase in climatic variability and extreme events -pollution levels such as ozone

5 5 What is the current impact of climate change on agric ulture production ? Source: Lobell et al., 2011 Currently global maize and wheat production declined by 3.8 and 5.5%, respectively relative to without climate trends ( increase in temperature and CO2, changes in rainfall) soybeans and rice, winners and losers largely balanced out changes in maize and wheat production1980–2008

6 6 Current observed impacts of climate change on agriculture in China Climatic regionalization of winter wheat in Liaoning province (Ji et al., 2003) In northeast China winter wheat planted has been extended to north by 2-3 latitude (about 250km) Frequent freezing damages to wheat production in China- for example In 2004 and 2005, the wheat freezing damage area reach 3.33 million hectares in 6 provinces including Henan, Shangdong and Hebei provinces Plant diseases and pests are currently causing a 20%-25% average annual loss to China’s agriculture output value

7 7  We need sustained growth in the agricultural production -to feed the world -to enhance rural livelihoods -to stimulate economic growth  The demand for food will double within the next years,  Food security, remains a challenge, particular in developing countries Future challenges

8 8 Climate and Agriculture  Studies of the effect of weather and climate on agriculture are often limited by the availability of climatological data and experimental results.  The interactions between the plant and its environment cannot be reflected by the simple crop- climate regression  Crop models provide useful tools for analysing crop and its relationship with the climate.

9 9 Crop growth and development Growth-increase in size normal measure in dry weight also Leaf Area Index Leaf area index (LAI) is the total one-sided green leaf area per unit ground surface area LAI= total green leaf area / ground surface area

10 10 Development-progress to maturity  Through different stages-eg: emergency, flowering, graining filling, harvest  The time-span of each development phase depends on genotype, temperature, day-length and sowing date Emergency(9days) Flowering(61-69) graining filling(71-87) harvest (97-110)

11 Outline Why is climate change such an important issue for agriculture? Introduce the crop models - the response of crop to temperature - the response of crop CO2 -the response of crop water Assess the impacts of climate change on agriculture –case study in China Adaptation strategies in agriculture

12 Crop simulation models Site based crop models (e.g DSSAT) : Seek to simulate the complex dynamics of crop growth and development, and its response to environmental variables Large area crop modes (e.g. GLAM): Applied some simple assumptions and empirical relationships to predict the complex crop growth and development

13 13 Site based Crop models High input data requirement Complexity of incorporating the spatial variability of input Climate model output is coarse compared with input to crop model (Yang.P). This method is difficult to apply at a regional level

14 General Large Area Model for annual crops (GLAM; Challinor et al, 2004) Aims to combine: the benefits of more empirical approaches (low input data requirements, validity over large spatial scales) with the benefits of capturing intra-seasonal variability, and so cope with changing climates) Field management -Yield Gap Parameter Groundnut, wheat, maize, soybean general circulation model crop model

15 15 Irrigation Models Irrigation strategies – farm level Irrigation Models Irrigation strategies – farm level CROPWAT (FAO)  Crop water requirements, irrigation requirements based on climate, soil type, rainfall, reference ET, cropping patterns AIMM (Alberta Irrigation Management Model)  Irrigation and scheduling decisions for 52 different crops  Weather, soil moisture, ET, irrigation application methods WaSIM (UK)  Water balance simulation model

16 16 Site based crop models Wageningen models (CSIRO, Australi a)  Simulate potential production under measured climatic conditions  Limitations in simulating cropping systems and dynamics in soil water, nutrients and soil organic matter DSSAT  Include CROPGRO and CERES models, 17 crops  Simulate crop growth, development and yield as well as soil water and nitrogen balances.  Yield limiting factors such as pests, diseases and field management, are not included

17 17 Site based crop models APSIM  Produce accurate yield simulation in response to management and predict the long-term impact of farming practice on the soil resource CropSyst (U. Washington)  Simulate the impact of climate, soils and management on cropping systems productivity and the environment.  Representation of crop rotations

18 18 Risk modelling -NADSS (National Agricultural DSS) USDA and UNL Web-based tools Identify patterns of drought at regional and national level in the USA Drought indices, crop production risk analysis Map and tabular format

19 19 Risk modelling - AgRisk (OSU) PC software Predict farm’s gross revenue at harvest time (corn, soybean, wheat) under different pre-harvest risk management strategies (crop insurance, current and future market information)

20 20 GPFARM (Great Plains Framework for Agr Resource Management) - USDA PC software, farm level use Three components:  Crop growth, animal growth, water balance, water erosion, environmental impacts  Economic analysis tool – estimate costs of rangeland crop production, various cost-benefit analyses  Agricultural information system – web-based links to information on crops, pests, agricultural chemicals

21 21 Whopper Cropper (Australia) PC software Uses both seasonal climate forecasting and crop system modelling to estimate production risks in upcoming season 7 crops in Australia Uses “what if” scenarios to help farmers decide which crops to plant, when to plant, which varieties to plant and how much to invest on various inputs (nitrogen)

22 Outline Why is climate change such an important issue for agriculture? Introduce the crop models - the response of crop to temperature - the response of crop CO2 -the response of crop water Assess the impacts of climate change on agriculture –case study in China Adaptation strategies in agriculture

23 Temperature and crop growth All plants have maximum, optimum and minimum temperature limits. The limits are cardinal temperature points Optimum temperature is required for maximum dry matter accumulation

24 Temperature and crop development The development rate of crop is mainly dominated by temperature

25 25 Cardinal temperature values for selected annual crops under conditions in which temperature is the only limiting variable

26 26 Linear trend in temperature from during rice growing season in Asia In Asia maximum temperatures has increased by roughly o since 1961 in rice growing region minimum temperatures has increased by roughly o

27 27 Correlations between temperature and rice yield from in Asia countries The impact of current warming trend on rice yield in Asian countries for

28 28 What is the current impact of warming trend on rice yield in Asian counties? In Asia rice yield has declined by % due to the warming trend in maximum temperature from 1961 to 2009 In Japan and Srilanka the warming trend has a positive impact on rice yield

29 29 Impact of extreme temperature on rice yield Relation between average daily maximum temperature and spikelet fertility during the flowering period under different CO 2 concentrations(Horie 1993).

30 30 Impact of cooling on rice yield Relation between cooling degree-days and percentage spikelet sterility between the booting and flowering stages (Horie 1988)

31 31 Global mean temperature is increasing Global mean temperature is increasing Effects Shift in vegetational zones Heat stresses on plants Soil moisture Pests and diseases

32 Outline Why is climate change such an important issue for agriculture? Introduce the crop models - the response of crop to temperature - the response of crop CO 2 -the response of crop water Assess the impacts of climate change on agriculture –case study in China Adaptation strategies in agriculture

33 33 Modelling growth: photosynthesis Photosynthesis: A chemical process by which a plant turns light energy from the sun into chemical energy in the form of sugar.

34 34 Crop radiation interception  Regard a crop as a machine that intercepts solar radiation and convert its energy stored in plant material  Incident radiation is intercepted by the crop or transmitted to the soil  Intercepted radiation is then reflected or absorbed Fractions: incident=1 Intercepted=incident -transmitted Intercepted=1- transmitted Absorbed=intercepted-reflected Absorbed=1- transmitted -reflected

35 35 Modelling growth: Radiation Use Efficiency The potential or maximum photosynthesis of a crop canopy can be estimated from a set of parameters describing the photosynthesis-light curve of single leaves.

36 36 Modelling growth: biomass Biomass=RUE* intercepted solar radiation RUE normally increase with more N RUE decreased by significant stress eg. water van Ittersum,2003

37 Increased CO 2 concentration increase the CO2 gradient between the atmosphere and the inside of leaves, Increase rate of photosynthesis increase growth rate and productivity of plants decrease transpiration increase crop water use efficiency and yield

38 38 At a certain level of CO2 photosynthesis will saturate" Photosynthetic response to rising CO 2

39 Free Air CO2 Enrichment (FACE) Long et. all 2006 FACE is the technology by which the environment around growing plants may be modified to realistically simulate future concentrations of atmospheric carbon dioxide (CO2).

40 40 The response of winter wheat to rising CO 2 - FACE experimental results in China at 550 ppm CO 2 Han Xue et al 2012

41 Outline Why is climate change such an important issue for agriculture? Introduce the crop models - the response of crop to temperature - the response of crop to CO 2 -the response of crop to water Assess the impacts of climate change on agriculture –case study in China Adaptation strategies in agriculture

42 Rainfall is especially important for rainfed or dry land agriculture Arid and semi-arid areas account for about 40% the land surface of the world, especially some African countries, where rain-fed agriculture is already limited by water availability (Gamo, 1999). Sufficient Rainfall – Good Crop Low Rainfall – Poor Crop Importance of Rainfall

43 43 Water stress on crop Stress during early growth can stimulate root growth, extreme drought can delay planting and damage seed germination Stress at flowering may be more sensitive (maize) During the grain filling period, water deficit can reduce grain weight by accelerated senescence rate and shortened growth duration

44 44 The response of rice yield to seasonal total rainfall from in Asian countries In india, Laos, Nepal,Thailand and Asia, seaonsal total rainfall has a positive impact on rice yield, viriability of rice yield depends on the amount of rainfall In Japan, rice yield showed a negative response to seasonal total rainfall

45 45 Impact of extremes: rainfall distribution 1975 Total rainfall: 394mm Model: 1059 kg/ha Obs: 1360 kg/ha 1981 Total rainfall 389mm Model: 844 kg/ha Obs: 901 kg/ha

46 Drought mitigation and adaptation Avoid stress at sensitive stages-floral initiation and pollination Adjusting planting structure or sowing date Seed Engineering-choice of cultivar tolerance to drought Rainfall collection based water saving Membrane coverage Protected cultivation ( Less tillage and no tillage )

47 Outline Why is climate change such an import ant issue for agriculture Introduce the crop models - the response of crop to temperature -photosynthesis,CO 2 and crop -the response of crop to water Impact of climate change on Agriculture –case study in China Adaptation strategies in agriculture im

48 48 Integrated impact assessment including socio-economic scenarios Climate Change; CO 2 fertilization effects; Water Availability; Agricultural land conversion; All drivers together Impacts of Climate Change on Chinese Agriculture – Phase II

49 IMPACTS ON CROP YIELDS, WATER AVAILABILITY, AND ARABLE LAND ADAPTATION POLICIES CLIMATE SCENARIOS from PRECIS IMPACTS ON TOTAL PRODUCTION SOCIO-ECONOMIC SCENARIOS CERES crop model GDP, Pop., Water demand, Land use Improvements in Agric. Tech. Land use change policies Water allocation policies VIC hydrological model

50 –Annual change in temperature and rainfall in China: 2020s, 2050s, and 2080s –17 GCMs from IPCC and PRECIS (A2 emissions) Comparison of PRECIS results and GCM output for China

51 Change in total cereal production with different combinations of drivers Only Climate ChangeClimate Change With CO2 Climate Change With Water Climate Change With CO2 and water Climate Change Water & Land All drivers

52 Changes in cereal production per capita in China under combinations of drivers

53 53 Future impacts of climate change on agriculture in China The reduction in crop yield by ℃ temperature increase during 2080s can be offset by elevated CO 2 at ppm and other adaptation, but very high costs may need. An increase in investments of 8 ~ 34.8 billion US dollars per year (in 1990 price) is necessary, otherwise the agriculture will lose 32.3 ~ 80 billion US dollars per year (Lin, & Zhang, 2005)

54 54 How we are responding to climate change Action to address climate change Mitigation: Reducing greenhouse gas emissions Adaptation: A process of adjusting to changes in variables

55 An adaptation framework for China to support national and international adaptation projects 3 Identify adaptation options 1 Assess climate risks 2 Integrate development and adaptation goals 4 Prioritise options New knowledge/ research 6 Monitoring and evaluation 5 Implementation Integrate adaptation into planning and policy framework

56 56 Climate change by 2030 will further aggregate the drought stress in Northeast China 来源: PRECIS 模型;团队分析 crop yield loss due to drought million ton Current climate Future climate +35% Economic loss Billion RMB 1 历史气候:假设 2030 年具有相同的气候条件 ; 气候变化:高二氧化碳浓度的情景( 2050 年 559 ppm ) Percentage of crop production loss due to drought stress in Northeast China 1 ( 2030 ) Factors causing yield loss Decrease in the amount of rainfall Increase in extreme drought stress Less investment in agriculture and infrastructures avoiding drought stress Rainfall in spring (mm) Northeast China * 30% 10% probability

57 * * * * -3.1 * * * * * 3.7 * evitable loss Billion RMB * * * * * * * Pipe delivery water Drip Irrigatio n Rainfall collection based water saving Canal seepage for irrigation Reservoir and pond Protected cultivation ) Seed Engineering Membrane coverage Spray Irrigation evitable loss ~56% inevitable loss ~44% (cost/benefit<1) (cost/benefit>1) inevitable loss Long term economic benefit In northeast China, yield loss due to drought stress can be avoid by 56% by the above adaptive measures 资料来源:麦肯锡分析 the economic costs and benefits of drought adaptation -Case study in Northeast China by 2030

58 Demo. areas Heilong jiang Heihe basin, GS Tailanhe basin, XJ Naqu Tibet Bohai Coast CC Risk Cooling dec. getting dryer Water consuming increase for oasis More water coming now and will decrease Grassland dryer, lake level rise Sea level rise, storm tide Adap. Target Go benef, avoid disaster Water saving & cultivat Saving water and ecolog. protect Protect grassland ecology Build design based on sea level Poten. Adapt. Structure adjusting Low consuming technology Integrated water management pasture animals b. on water Design stand with s.le. rise Adp. Asse Demon. 700 hm2 x 420 hm2 land10 reserv. 60 hm2 land sprinkled Irrigat.12hm2 Project design in costal ar Adaptation Demonstration in China

59 59 How farming can adapt to the changed climate farmers can: change their crop rotation to make the best use of available water, adjust sowing dates according to temperature and rainfall patterns, use crop varieties better suited to new weather conditions (e.g. more resilient to heat and drought) Public policy must support farmers

60 Policy recommendations Improve the capacity of farmers and rural regions to adapt to climate change Develop systems for monitoring regional climate change and provide early warning of disasters adapting options to the farming community providing advisory services and training.

61 Policy recommendations Support the development of low-carbon, high-quality Agriculture Comprehensive, long-term strategy based on local circumstances Long-term subsidies to encourage investment in new technology Market incentives: National Voluntary Carbon trading Mechanism to pay impoverished farmers for reducing pollutants and GHG emissions

62 62 Future work: Integrated impacts assessment around the world the socio- economic environment, world trade, population, technology and the natural resources are likely to undergo significant changes over the next few decades (Nakicenovic and Swart, 2000) Integrated impacts studies including socio-economic scenarios, population and improvements in technology are an important aspect for study.

63 63 Assessing availability of water supplies for irrigation and the costs of adaptation the economic and social costs and benefits of adaptation, and the adaptive capacity Future work: assessing costs and benefits of adaptation Terrace Membrane coverage

64 64 Future work: Sampling uncertainty in impact assessments Possible sources of uncertainty in predicting climate change and its impacts: Scenarios from population, energy,economics models,Coupled climate Models, Impacts models sample the uncertainty in projections of impact by: using > 1 emissions scenario using > 1 climate model using >1 crop model by systematically varying parameters in climate or crop models impact is then given by the ensemble mean, and the variability within the ensemble

65 65 Key Messages Climate change and the extreme events have had an impact on agriculture. Yield potential is likely to decline due to even small rises in global temperature regions that will be more vulnerable --tropical and subtropical, heat and drought stress in summer is likely to increase --in some northern the risk of drought stress would likely increase Prioritisation of adaptation include --adjusting planting systems --increasing water use efficiency --encouraging agroecological sustainable development An increase in investments of agriculture is necessary to secure the food supply --infrastructures against floods and droughts --increasing the support to climate related scientific and technological work Science and technology must spearhead agricultural production in the next 30 years at a pace faster than the Green Revolution’s during the past three decades.” – FAO Director General 2007

66 Thank you for your attention!


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