Yasushi Honda

Climate change and health: on the latest IPCC report

www.thelancet.com Vol 383 April 5, 2014 1185 The Intergovernmental Panel on Climate Change (IPCC) released its latest report on March 31, 2014. This report was the second instalment of the Fifth Assessment Report, prepared by Working Group 2, on impacts, vulnerability, and adaptation to climate change. In this Comment, we, as contributors to the chapter on human health, explain how the IPCC report was prepared and highlight important fi ndings. The IPCC reviews and assesses the scientifi c published work on climate change. As an intergovernmental body composed of members of the UN, the IPCC does not undertake research itself; instead it appoints Working Groups who assess the work. This assessment means more than simply to summarise the state of knowledge: Working Groups are asked to weigh what has been written (in both peer-reviewed publications and grey literature), to make judgments about likelihood and uncertainty, and to fl ag important emerging issues. The focus for Working Group 2 was mainly, but not exclusively, on what had been written since the previous assessment in 2007; papers were eligible for inclusion if they were published, or accepted for publication, before Aug 31, 2013. The Working Groups were required to highlight what might be relevant to policy, but did not recommend policies. The Fifth Assessment Report Working Group 1 reported on the physical science of climate change in September, 2013 (appendix). Working Group 3, concerned with mitigation (ie, reduction of greenhouse gas emissions), will release its report in April, 2014. The scale of the enterprise is remarkable—indeed, reports by the IPCC together probably represent the largest scientifi c assessment exercise in history. There are 310 authors and review editors in Working Group 2, and an even greater number of contributing authors who have added to the report from their areas of special expertise. In addition to health, Working Group 2 examined natural and managed resources (eg, fresh water, coastal systems, and food production), human settlements, and other aspects of wellbeing such as security and livelihoods. The report (30 chapters) will be published in two volumes, and includes integrated assessments of impacts and adaptation in nine geographic regions and an overarching summary for policy makers. Work on the Fifth Assessment Report began 5 years ago (appendix) and aspects of the IPCC process distinguish its assessments from other reviews and scientifi c publications. One diff erence is the substantial role of member states in determination of, in the initial stages, the scope of the reports and the membership of writing groups. At the beginning of each round of assessment, meetings organised by the IPCC decide on the structure of the reports, including the number of chapters and the topics to be covered, and then member states nominate potential authors. The fi nal decision about authors is made by a subgroup from the IPCC, the Bureau, on the basis of scientifi c merit and the necessary institutional and disciplinary perspectives for each chapter, seeking, at the same time, to achieve a balance of representation by gender and region. Once appointed, the IPCC authors work independently; government input occurs as part of the peer review process. However, the member states must approve and sign off on the fi nal report. Thus, the IPCC assessments are the outputs of many iterative interactions between scientists and policy makers. Another feature of the IPCC process is the intensity of peer review. There were four rounds of review for the Fifth Assessment Report, two of which involved hundreds of self-nominated experts and scientists appointed by member-state governments. Each round generated an enormous number of comments, questions, and requests for change. For instance, the IPCC received 1009 reviewer comments just on the second-order draft of chapter 11 (human health). Two dedicated review editors per chapter are charged with ensuring that the authors consider each comment seriously and, if they reject it, that they do so with good reasons. Both the comments and the chapter authors’ responses will be published on the IPCC website. The IPCC does not prescribe how chapter groups should gather and interpret the scientifi c work, partly because conventions and practice diff er among disciplines. Contributors to the health chapter used many strategies to identify relevant published work. Due to the breadth of the topic, including the range of health outcomes and exposure pathways, the chapter team decided that one systematic review would not be possible. Climate change and health: on the latest IPCC report

Heat-related mortality risk model for climate change impact projection

ObjectivesWe previously developed a model for projection of heat-related mortality attributable to climate change. The objective of this paper is to improve the fit and precision of and examine the robustness of the model.MethodsWe obtained daily data for number of deaths and maximum temperature from respective governmental organizations of Japan, Korea, Taiwan, the USA, and European countries. For future projection, we used the Bergen climate modelxa02 (BCM2) general circulation model, the Special Report on Emissions Scenarios (SRES) A1B socioeconomic scenario, and the mortality projection for the 65+-year-old age group developed by the World Health Organization (WHO). The heat-related excess mortality was defined as follows: The temperature–mortality relation forms a V-shaped curve, and the temperature at which mortality becomes lowest is called the optimum temperature (OT). The difference in mortality between the OT and a temperature beyond the OT is the excess mortality. To develop the model for projection, we used Japanese 47-prefecture data from 1972 to 2008. Using a distributed lag nonlinear model (two-dimensional nonparametric regression of temperature and its lag effect), we included the lag effect of temperature up to 15xa0days, and created a risk function curve on which the projection is based. As an example, we perform a future projection using the above-mentioned risk function. In the projection, we used 1961–1990 temperature as the baseline, and temperatures in the 2030s and 2050s were projected using the BCM2 global circulation model, SRES A1B scenario, and WHO-provided annual mortality. Here, we used the “counterfactual method” to evaluate the climate change impact; For example, baseline temperature and 2030 mortality were used to determine the baseline excess, and compared with the 2030 excess, for which we used 2030 temperature and 2030 mortality. In terms of adaptation to warmer climate, we assumed 0xa0% adaptation when the OT as of the current climate is used and 100xa0% adaptation when the OT as of the future climate is used. The midpoint of the OTs of the two types of adaptation was set to be the OT for 50xa0% adaptation.ResultsWe calculated heat-related excess mortality for 2030 and 2050.ConclusionsOur new model is considered to be better fit, and more precise and robust compared with the previous model.

Relation between temperature and suicide mortality in Japan in the presence of other confounding factors using time-series analysis with a semiparametric approach

ObjectivesThe objective of this study was to assess the relation between temperature and suicide mortality in Japan using time series analysis with a semiparametric approach.MethodsWe analyzed the relation between daily fluctuations in suicide mortality and maximum temperatures for all regions in Japan over the period of time from 1972 to 1995 using a generalized additive model. The model controls for the time trend, season, selected meteorological parameters, day of the week, and holiday. Adjustment was based using penalized splines and the decision on the amount of smoothness was based on minimizing the unbiased risk estimation criterion.ResultsThe results show that suicide mortality in Japan has a seasonal character and it varies from year to year, with the highest occurrence in April, as well as in the first part of the week, especially on Mondays and Tuesdays. As for the day of the week, there were only few suicide cases on Saturdays and holidays. We found that for all regions in Japan when temperature increased the suicide mortality increased on the same day (lagxa0=xa00). Analysis by method of suicide showed that when temperature increased mortality significantly increased only for suicide by a violent method. The pattern of the relation for other methods remained unclear.ConclusionsThis study suggests that an increase in temperature has a short-term effect on suicide mortality in Japan.

Short-term exercise-heat acclimation enhances skin vasodilation but not hyperthermic hyperpnea in humans exercising in a hot environment.

We tested the hypothesis that short-term exercise-heat acclimation (EHA) attenuates hyperthermia-induced hyperventilation in humans exercising in a hot environment. Twenty-one male subjects were divided into the two groups: control (C, nxa0=xa011) and EHA (nxa0=xa010). Subjects in C performed exercise-heat tests [cycle exercise for ~75xa0min at 58%

Comparison of hyperthermic hyperventilation during passive heating and prolonged light and moderate exercise in the heat

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Effect of initial core temperature on hyperthermic hyperventilation during prolonged submaximal exercise in the heat

(37°C, 50% relative humidity)] before and after a 6-day interval with no training, while subjects in EHA performed the tests before and after exercise training in a hot environment (37°C). The training entailed four 20-min bouts of exercise at 50%

Population at high-risk of indoor heatstroke: the usage of cooling appliances among urban elderlies in Japan

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