Assessment of climate change impacts on agriculture and a case study on crop impacts in China

1. Chinese Academy of Agricultural Sciences. Chinese Academy of Agricultural Sciences. Chinese Academy of Agricultural Sciences. 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 Korea Erda LIN Chinese Academy of Agriculture Science, Beijing, China

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 CO2 - the response of crop water Assess theimpacts 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 & Agriculturalproductivity 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. What is the current impact of climate change on agriculture production ? changes in maize and wheat production1980–2008 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 Source: Lobell et al., 2011

6. Current observed impacts of climate change on agriculture in China 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 Climatic regionalization of winter wheat in Liaoning province (Ji et al., 2003)

7. Future challenges • 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 25-50 years, • Food security, remains a challenge, particular in developing countries

8. Climate and Agriculture • Studies of the effect of weather and climateon 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. 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 areaper unit ground surface area LAI= total green leaf area / ground surface area

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 graining filling(71-87) Flowering(61-69) Emergency(9days) 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 theimpacts of climate change on agriculture –case study in China Adaptation strategies in agriculture

12. Crop simulation models Site based crop models (e.gDSSAT) : 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. 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 This method is difficult to apply at a regional level (Yang.P).

14. general circulation model crop model General Large Area Model for annual crops (GLAM; Challinoret 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

15. 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. Site based crop models • Wageningen models (CSIRO, Australia) • 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. 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. 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. 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. 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. 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 theimpacts 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. Cardinal temperature valuesfor selected annual crops underconditions in which temperature is the only limiting variable

26. Linear trend in temperature from 1961-2009 during rice growing season in Asia In Asia maximum temperatures has increased by roughly 0.5-1o since 1961 in rice growing region minimum temperatures has increased by roughly 0.5-1.5o

27. Correlations betweentemperature and rice yield from 1961-2009 in Asia countries The impact of current warming trend on rice yield in Asian countries for 1961-2009

28. What is the current impact of warming trend on rice yield in Asian counties? In Asia rice yield has declined by 2.3-10.8% 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. Impact of extreme temperature on rice yield Relation between average daily maximum temperature and spikelet fertility during the flowering period under different CO2 concentrations(Horie 1993) .

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. 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 CO2 -the response of crop water Assess theimpacts of climate change on agriculture –case study in China Adaptation strategies in agriculture

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

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. 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. 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 CO2 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. Photosynthetic response to rising CO2 At a certain level of CO2 photosynthesis will saturate"

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

40. The response of winter wheat to rising CO2-FACE experimental results in China at 550 ppm CO2 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 CO2 -the response of crop to water Assess theimpacts 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). Importance of Rainfall Low Rainfall – Poor Crop Sufficient Rainfall – Good Crop

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. The response of rice yield to seasonal total rainfall from 1961-2009 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. 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 important issue for agriculture Introduce the crop models - the response of crop to temperature -photosynthesis,CO2 and crop -the response of crop to water Impact of climate change on Agriculture –case study in China Adaptation strategies in agriculture im

48. Impacts of Climate Change on Chinese Agriculture – Phase II Integrated impact assessment including socio-economic scenarios • Climate Change; • CO2 fertilization effects; • Water Availability; • Agricultural land conversion; • All drivers together

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

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