地球温暖化による水系感染症の健康被害係数の推定

抄録

Objective. According to the IPCC Fourth Assessment Report, it is predicted that the global warming promotes the outbreak of the waterborne disease (diarrhea). However, in the past LCIA studies on damage assessment of human health caused by global warming, heat stress and malaria have been mainly considered and there is little study taking diarrhea into account. Therefore the aim of this study is to quantify the health damage related to diarrhea caused by global warming based on statistical analysis.
Materials and Methods. The procedure of this study is as follows: 1) Four SRES scenarios (A1B, A2, B1 and B2) were used to estimate the marginal temperature rise (2000-2100) by 1 kg-CO₂ emission based on MAGICC (Model for the Assessment of Greenhouse-gas Induced Climate Change) model. 2) Increasing of diarrhea incidence caused by temperature rise was estimated based on the relationship between future temperature rise and future diarrhea incidence calculated by a multiple regression analysis. 3) Cases of diarrhea were calculated by multiplying population data and diarrhea incidence. 4) DALYs were calculated by multiplying the cases of diarrhea and the ratio of DALY and diarrhea case.
Results and Discussion. Damage factors of diarrhea were calculated as 1.1-3.3×10⁻⁷ DALY/kg-CO₂ for four SRES scenarios. The health damage of diarrhea around 2030 was the biggest in all regions and any scenarios. Africa and South East Asia regions showed bigger damage than other regions because their lower ratios of accessing to improved drinking water and large numbers of people. By a comparison of scenarios, A2 scenario showed the biggest damage, because the highest temperature rise and the lowest ratio of accessing to improved drinking water. Moreover, the result indicated that it is important to take diarrhea into account, because the damage of diarrhea caused by global warming is higher than other diseases.
Conclusions. An approach of chronological order was used to quantify the health damage of diarrhea caused by global warming for each region and each scenario. Damage factors of diarrhea for four SRES scenarios were gained in the study.