services available to humans, and they can also imply the possibility of unprecedented events or growing adverse impacts.

This section will explain the impacts that global warming-caused changes in ecosystems have on human beings.

### 1. Impact on the Agricultural and Stock-Raising Industries

Humans depend on animals and plants for food as energy source which means that changes in the status of inhabitation of those life could affect our food-security status enormously.

It is known that rice plants would be damaged if the daily mean temperature were to exceed 27 or $ 28^{\circ} $ C during the ripening period from the time ears are formed to the full maturity stage, and that it would result in the increase of immature milky white rice kernels, including white-back kernels. It is also known that a rise of $ CO_{2} $ concentration could help increase rice yields, but that the higher the temperature, the lower the yield-increasing effect (“Data on the recent climate change and its impact on the growth of farm produce” by the Ministry of Agriculture, Forestry and Fisheries). According to a simulative future estimate of rice yields, based on climate change models and atmospheric circulation models, the yield in the southern part of Japan is estimated to be reduced by nearly 40% when an atmospheric circulation model developed in Canada is applied. It is also estimated that global warming could increase the population of insects harmful to rice, such as Chilo suppressalis (rice stem borer moths), Nephotettix cincticeps and Laodelphax striatella, and also could change their habitats or activity season. Therefore, there is a concern that rice quality will be degraded in extensive areas nationwide. Actually in Kochi Prefecture, the ratio of the first-grade (top quality) rice to the entire yield, that had been maintained around 60% to 80% traditionally in this region, has already dropped to 30% to 40% (“For overcoming high-temperature damage on deepwater rice” a report by the Ministry of Agriculture, Forestry and Fisheries). Cultivation of rice requires a lot of water in the preparation stage (at the time of planting). As the recent climate change has damaged the integrity of the water cycle, leading to changes in the river flow and seasonal natural characteristics as well as reduced-irrigation water supply, those changes are likely to affect conventional cropping seasons and production patterns.

It is known that fruit trees are particularly susceptible to climate change. This is because of the low adaptability of fruit trees to adjust their cropping period to climate conditions, while on the other hand annual plants are relatively adaptable due to their adjustable seeding time, which makes it possible to obtain optimal temperatures every year regardless of climate fluctuations. Citrus unshiu (Japanese tangerine), which occupies the largest share over all Japan-grown fruit trees in terms of production, has actually been found, by a survey, to be affected by the recent global warming, resulting in the northward shifting of its optimal growing zone (having a yearly mean temperature of $ 15^{\circ} $ C or higher but less than $ 18^{\circ} $ C). Traditional growing regions for Citrus unshiu, which currently range over coastal regions along the Pacific Coast, the Seto Inland Sea or in Kyushu, will be most possibly found as outside the optimal growing zone by 2060s, because their temperatures will be higher.

Europe had a severe record-breaking heat wave in 2003, suffering heavy casualties mainly in Western Europe. In addition, it caused significant damage to farm produce due to high temperatures and dried weather. This year, grain production in the EU dropped by as much as about 23 million tons from the previous year. Although it is too early to conclude that global warming was a direct cause of this devastated heat wave, it can be estimated that accelerated global warming could increase similar heat waves, possibly resulting in chronic and expanded damage.

Stock farming also receives serious damage from global warming. For example, a study conducted by the National Agriculture and Food Research Organization (NARO) based on climate models shows that accelerated global warming would invite serious damage to broiler-meat production. NARO reports that it could significantly reduce chicken-meat production especially in the

Basal-white rice

Immature white rice kernels

White-back rice

Milky white rice

Photo: courtesy of Hideki Nagahata of Ishikawa Prefectural University