Regional Variability Analysis for Pear Scab by Risk Forecast Model and Suitable Area Map of Pear Based on RCP 8.5 & 4.5 Scenario

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1 POSTER 05 Regional Variability Analysis for Pear Scab by Risk Forecast Model and Suitable Area Map of Pear Based on RCP 8.5 & 4.5 Scenario M. I. Ahn 1,2 *, S. K. Kim 1, W. S. Kang 1, J. S. Park 1, Y. K. Han 1, S. C. Yun 2, and E. W. Park 3 1 R&D Center, EPINET Co., Ltd, Anyang 14056, Korea, 2 Department of Biomedical Science, Sun Moon University, Asan 31460, Korea, 3 Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea I. Introduction According to a report on analysis of temperature data observed in South Korea from 1904 to 2000 by the National institute of Meteorological Sciences, the average temperature increased by 1.5 C, which was more than 2 times of the average increase in global temperature (0.74 ± 0.18 C). According to a climate change scenario report (2011) by the Korea Meteorological Administration, there would be a definite increasing trend in temperature of the Korean Peninsula in the future, and it was predicted to increase by 6 C in the end of the 21st century compared to normal in the RCP 8.5 scenario that greenhouse gas would be emitted in the current trend, and also by 3.4 C in the RCP 4.5 scenario that efforts to reduce greenhouse gas would become effective. Climate change has substantial effects on industries. In particular, meteorology is closely related with agriculture such as growth and yield of crops, pests and diseases and meteorological disasters. For fruit trees, once their cultivation have begun, production at the same spots continues more than 10 years, so that future climate change and its risks for pests and diseases are highly significant. Pear, one of the 5 major fruits in South Korea, accounted for about 50% of the total fruit exports in However, its yield decreased by 14% in 2015 compared to that of 2014 due to reduction of cultivation area, abnormal weather and pear scab (Korea Rural Economic Institute, 2016). In addition, it was reported that Pyres pyrifolia cv. Niitaka that accounts for 80% of pear varieties in South Korea is susceptible to pear scab (Shin et al., 2004). Pear scab significantly affecting to reduce the yield of pears is caused by Venturia nachicola Tanaka & Yamamoto, and its incidence is different greatly depending on meteorological environment. Climate change has been studied in various fields of agriculture. Although experts predicted that there would be growing numbers of semitropical pests and diseases and unpredictable pests and diseases due to global warming, few studies have been conducted in response to them. Thus, we conducted regional variability analysis on risk of pear scab that causes continuous reduction of pear yield in South Korea since 2000, using the RCP climate change scenario (model: HadGEM3RA) provided by * Correspondence to: ahnmi@epinet.kr

2 the Korea Meteorological Administration considering changes in pear cultivation area. II. Materials and Methods 2.1. Analysis of variation in the RCP 8.5 & 4.5 climate change scenarios The RCP (Representative Concentration Pathway) climate change scenario provided by the Climate Change Information Center (CCIC, of the Korea Meteorological Administration was divided into the past and the future, and then applied to climate change analysis. The future scenario was subdivided into RCP 8.5 and 4.5 by carbon dioxide level; data with a resolution as high as 1 km for maximum temperature, minimum temperature, average temperature and precipitation were used; and data for relative humidity was 1 km interpolation -estimated from data with 12.5 km resolution. Data of reference years to compare with the future scenario were resulted from the same HadGEM3RA regional climate model, in which mean values from 2001 to 2010 were used. In addition, resolution data by climate element and data for relative humidity of reference years were produced using the same method for the future scenario (Table 1). Table 1. Description about the RCP climate change scenarios and data of reference years Tense Model Elements Years Future Past HadGEM3RA HadGEM3RA Spatial res. Temporal res. Max.Temp km Daily Min.Temp km Daily Avg.Temp km Daily Precipitation km Daily Relative humidity km Daily Max.Temp km Daily Min.Temp km Daily Avg.Temp km Daily Precipitation km Daily Relative humidity km Daily Since temperature and precipitation are important environmental factors for occurrence of plant diseases, maps showing regional changes were produced using past and future scenarios. Raster data of temperature and precipitation in 1 km resolution were used to calculate mean values by city/gun in 2020s, 2050s, 2070s and 2090s using a South Korea administrative

3 district map. Amount of variation for temperature and variation rate for precipitation were calculated in comparison to the past scenario, by which maps of temperature variation and precipitation variation by administrative district were made finally, and then used for analysis Operation of pear scab forecast model using the RCP climate change scenarios Using daily data of reference years ( ) and the RCP 8.5 & 4.5 climate change scenarios ( ), daily pear scab forecast model was operated. The pear scab forecast model used in the present study utilized daily meteorological data-based forecast model that estimates daily maximum infection risk in the pear scab infection forecast model by time developed by Kang et al. in 2007 (Ahn et al., 2015). For regional analysis, regional mean values were calculated from grid data calculated by daily pear scab forecast model in 1 km resolution based on the administrative district map by city/gun of South Korea Regional analysis of pear scab risk depending on variation of possible cultivation area of pears For regional analysis of pear scab risk depending on variation of pear possible cultivation area by climate change, variation maps of pear cultivation areas in 2020s, 2050s, 2070s and 2090s were made using data of the RCP 8.5 & 4.5 climate change scenarios as input values. Legends were divided into optimal cultivation area, possible cultivation area and low productive & not suitable area, and average temperature in growth period, annual average temperature, average temperature in germination period and extreme minimum temperature were utilized. Standards determined by experts of pears in the National Institute of Horticultural and Herbal Science were applied as the standards for each climate element Variability analysis of pear scab risk in main production areas of pears Regional variability of pear scab risk by the future climate change scenario was analyzed with current main production areas of pears in South Korea. Based on data from the Statistics Korea in 2014, 6 regions with large cultivation areas were selected, which included Naju (1,896 ha), Cheonan (1,064 ha), Anseong (946 ha), Sangju (592 ha), Pyeongtaek (412 ha) and Jinju (549 ha). Increase rates of pear scab risk following RCP 8.5 & 4.5 climate change scenarios compared to 2000s, the reference years, were calculated for 2020s, 2050s, 2070s and 2090s, from which data for main producing areas were extracted and presented as a box plot

4 III. Results and Discussion 3.1. Analysis of climate variability in the past and future scenarios Annual average temperatures and annual cumulative precipitations were compared based on the RCP 8.5 & 4.5 climate change scenarios from 2021 to 2100 of the HadGEM3RA regional climate model provided by the Korea Meteorological Administration and mean values from 2001 to In the RCP 4.5 scenario, temperature was elevated by 0~1 C in 2020s, 1~2 C in 2050s and 2070s and 2~3 C in 2090s, compared to 2000s, reference years. Temperature became higher within a similar range throughout the nation regardless of regions (Fig. 1). RCP s RCP s RCP s RCP s Fig. 1. Temperature elevation compared to reference years ( ) based on the RCP 4.5 climate change scenario. In the RCP 8.5 scenario, temperature was elevated by 0~1 C in 2020s, 2~3 C in 2050s, 3~4 C in 2070s and 4~5 C in 2090s compared to 2000s. The RCP 8.5 scenario, similar to the RCP 4.5, had no significant difference in elevation level of temperature by region. Temperatures in 2050s of the RCP 8.5 and 2090s of the RCP 4.5 increased to a similar level (Fig. 2)

5 RCP s RCP s RCP s RCP s Fig. 2. Temperature elevation compared to reference years ( ) based on the RCP 8.5 climate change scenario. In the RCP 4.5 scenario, precipitation increased in the East coast area of Gangwon-do in 2020s, 2050s, 2070s and 2090s compared to 2000s, reference years, whereas it was predicted to decrease by 10~20% nationwide in 2090s. RCP s RCP s RCP s RCP s Fig. 3. Rate of precipitation increase compared to reference years ( ) based on the RCP 4.5 climate change scenario

6 The RCP 8.5 scenario was predicted to have obviously higher precipitation than the RCP 4.5 scenario. Gyeonggi-do and Chungcheongnam-do was predicted to have lower precipitation by about 10% in 2020s compared to that in 2000s; however, overall precipitation was higher in 2090s, and in particular, the South coast region had about 30~40% of elevated precipitation. Precipitation, unlike temperature, showed a large regional variation for increase. RCP s RCP s RCP s RCP s Fig. 4. Rate of precipitation increase compared to reference years ( ) based on the RCP 8.5 climate change scenario Regional analysis of pear scab risk depending on possible cultivation area of pears Increase rates of pear scab risk alert in possible cultivation areas of pears compared to 2000s were presented in log scale based on the RCP 8.5 & 4.5 climate change scenarios. Regions in white color indicate low productive & not suitable areas for pears. In the RCP 4.5 scenario, possible cultivation areas of pears were Gyeonggi-do, Chungcheong-do, Jeolla-do and Gyeongsangnam-do in 2020s, which shifted to the eastern Gyeonggi-do, the western Gangwon-do, Chungcheongbuk-do, the southern Jeolla-do and a part of the southern Gyeongsang-do in 2090s. Increase rates of pear scab risk were 100% ~ 1700% in 2020s, 300% ~ 3500% in 2050s, 260% ~ 3400% in 2070s and 300% ~ 3300% in 2090s, showing that pear scab risk markedly grew higher compared to 2000s. While overall increase rates of pear scab risk were high, of which Yeongdong-gun and Gyeongju-si in 2020s and Muju-gun and Cheongsong-gun from 2050s to 2090s were found to be the most risky areas for pear scab compared to 2000s, if climate would be similar to the simulation by the RCP 4.5 scenario

7 Fig. 5. Variations of pear scab risks in future possible cultivation areas of pears compared to reference years based on the RCP 4.5 climate change scenario (model: HadGEM3RA). In the RCP 8.5 scenario, it was predicted that possible cultivation areas of pears would rapidly be diminished after 2050s and then only possible cultivation area in 2090s would be near the Taebaek Mountains of Gangwon-do. When the RCP 4.5 and RCP 8.5 scenarios were compared, the RCP 8.5 scenario generally had higher pear scab risks compared to 2000s. In addition, possible cultivation areas were similar between 2090s in the RCP 4.5 scenario and 2050s in the RCP 8.5 scenario. In 2020s, the region near Pohang-si had the highest increase rate of pear scab risk compared to 2000s, and Inje-gun and Pyeongchang-gun showed the highest rates in 2090s

8 Fig. 6. Variations of pear scab risks in future possible cultivation areas of pears compared to reference years Variability analysis of future pear scab risks in current main producing areas Annual variations of pear scab risk alerts in main producing areas of pears in South Korea were presented in a box plot in comparison to the average of the reference years from 2001 to In the RCP 4.5 scenario, it was forecasted that pear scab risk increased by 2050 and gradually declined thereafter, whereas predictions in the RCP 8.5 scenario showed rapid increases from 2020s to 2050s, followed by gradual elevation of risk. Of the 6 main producing areas, Anseong had the highest risk. In variation pattern, Anseong, Cheonan and Pyeongtaek were similar; and Jinju and Naju appeared similar

9 Fig. 7. Variation of pear scab risks by RCP scenario in main producing areas of pears in South Korea. Acknowledgements This work was carried out with the support of Prediction of occurrence and distribution of crop diseases, insect pests and weeds under climate and their impact assessment (Project No.PJ ) Rural Development Administration, Republic of Korea

10 References Ahn, M. I., W. S. Kang, S. K. Kim, Y. K. Han, and E. W. Park, 2015: Impact assessment of climate change on the major pear growing area based on the forecasting model of daily infection risks of pear scab, The Korean Society of Plant Pathology. Kang, W. S., Y. K. Han, and E. W. Park, 2007: PearScab : software for forecasting pear development on the real-time basis. The Korean Society of Plant Pathology. Shin, I. S., I. H Hyeon, H. S. Hwang, S. S. Hong, K. H. Cho, and H. M. Cho, 2004: Screening of scab (Venturia nashicola) resistance germplasms in Pyrus species. Korean Journal of Horticultural Science & Technoloy 22, Korea Rural Economic Institute, 2016: Agricultural Outlook Report, Korea Rural Economic Institute