Climate Change Impact on Rice Insurance Payouts in Japan

Abstract

The authors constructed the framework for a preliminary assessment of climate change impact on the rice insurance payout in Japan. The framework consisted of various models ranging from climate projection downscaling, rice yield estimation, yield loss assessment, and rice insurance payout estimation. In this study, a simulation was conducted based on the dynamically downscaled regional climate projection with a lateral boundary condition given by the global climate projection of the Meteorological Research Institute Coupled General Circulation Model, version 2 (MRI CGCM2), under the A2 scenario of the Special Report on Emission Scenarios (SRES). Results indicated that rice yield in the 2070s will decrease slightly in central and western Japan and increase in northern Japan. The increase in yield was derived from a significant reduction in yield loss caused by cool-summer damage; on the other hand, the decrease in yield was caused by the increase in yield loss caused by heat stress and the shortening of the growth period induced by the temperature rise. The increase in the atmospheric CO 2 concentration resulted in an increase in paddy rice biomass because of the fertilization effect; however, the increase in biomass was not enhanced much as a result of shortening of the growth period if early planting was not considered as an adaptation practice. Reflecting such changes in yield, the rice insurance payout significantly decreased in northern Japan but only slightly increased in the areas of central and western Japan. In total, the 9-yr mean payout in Japan in the 2070s decreased to 120.2 billion yen; the value corresponded to 87% of the payout averaged over 9 yr in the 1990s .

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“…Those yields will be higher in the 2070s in Hokkaido and Tokai, where average yields also will increase, but lower in all other areas. The resulting simulated insurance payouts are smaller in the 2070s than in the 1990s, in six of the nine regions defined by Iizumi et al [152] in their analysis. In sum, the annual payout for the national rice insurance program is 13% smaller in the 2070s than in the 1990s (104.4 billion yen vs. 120.2 billion yen).…”

“…The Government of Japan has provided compulsory crop insurance for all of the country's rice farmers for many years [152]. Payments are made to farmers in years when average rice yields are smaller than pre-determined standard yields, which vary by prefecture.…”

“…Payments are made to farmers in years when average rice yields are smaller than pre-determined standard yields, which vary by prefecture. Iizumi et al [152] examined the likely impact of climate change on rice yields and insurance payments in Japan, using downscaled climate change projections for each prefecture to simulate temperature effects, while also accounting for the likely impacts of storms, diseases, and pests. The authors project a 10% increase in rice yields in the 2070s in Hokkaido, in Northern Japan, due to a significant reduction in damage from cool summer temperatures.…”

“…The authors project a 10% increase in rice yields in the 2070s in Hokkaido, in Northern Japan, due to a significant reduction in damage from cool summer temperatures. Rice yields will decline in the 2070s in Central and Western Japan, due to an increase in heat stress and a reduction in biomass, due to a shortening of the growth period [152]. The authors also project changes in the standard yields that determine the insurance payment benchmarks.…”

“…In sum, the annual payout for the national rice insurance program is 13% smaller in the 2070s than in the 1990s (104.4 billion yen vs. 120.2 billion yen). The authors suggest that adaptation measures, such as changing the planting date or adopting new cultivars, might further reduce the average annual insurance payout [152].…”