Japan is now entering the summer season which is always associated with increased risk to heatstroke. The Lancet Planetary Health, published a correspondence article by Longden et al. in May 2020 issue, advocating the need to understand the effects of climate and environmental changes on human health such as heat-related mortality.

Here are some excerpts from the article.

Australia's mortality record shows underestimation of heat-related mortality. Of the 1.7 million deaths from 2006 to 2017, less than 0.1% was attributed directly or indirectly to extreme natural heat.  However, a recent study found that official statistics underestimate the association at least 50 fold. Understanding the extent to which environmental factors affect human health is also important in accurately understanding the impact of climate change.

As severe environmental events become more common, it is necessary to analyze causal relationships in order to provide evidence, and to guide local, national and global adaptation.

The problem of underestimating deaths from heat is similar to the case of death from a lightning accident in which the direct cause, such as collapse of buildings or falling trees, is reported without reference to the indirect cause. Many countries are trying to modernize their death certification system and recording laws to address the issue of systems for reporting causes of death.

It is necessary to design systems to monitor mortality that reflects the impact of large-scale environmental events given the unpredictable, global-scale climate and environmental disasters such as the 2019-20 heatwave and wildfires in Australia.

Monitoring of heat-related mortality should combine death and temperature data sources. However accurate data is not available for more than 2 billion people in the most vulnerable tropical regions. 

Climate change is a concern for many, but it is impossible to understand its impact without recording the effects of extreme temperatures. The death certification system should be modernized and indirect causes of death should be recorded, along with a large-scale environmental datasets.

References

Longden T et al. (2020)  Heat-related mortality: an urgent need to recognise and record. The Lancet Planetary Health. Correspondence Vol 4, Issue 5, E171, May 01, 2020  

Contributor: IIYAMA Miyuki (REsearch Strategy Office)