CSIR experts in atmospheric science warn of the potential human health risks resulting from exposure to increased temperatures in Africa. This will assist in identifying the geographical areas that may be hot spots for negative impacts to human health, and aid in the development of appropriate preventative measures. The study finds that Johannesburg is projected to have up to 34 days per year whereby maximum apparent temperatures reach over 27 ºC.

A recent CSIR study suggests that 2015 is on its way to being the warmest year ever recorded. Moreover, further warming of 4 – 6 ºC over the subtropics and 3 – 5 ºC over the tropics are projected by the end of the century under low mitigation, relative to the present-day climate.

“These projections of warming suggest that Africa could see an increase in the number of days when health will be adversely affected. Therefore, we decided to research the potential risk to human health by increasing maximum apparent temperatures resulting from climate change,” explained Dr Rebecca Garland, CSIR atmospheric scientist.

Dr Garland explains that the projected increases in temperature have the potential to directly impact human health across the continent.

“High temperatures affect the body’s thermoregulatory system, leading to an inability to maintain thermal balance,” she said, warning that exposure to high temperatures can lead to physical disorders including discomfort, fatigue, heat stroke, and possibly death. Heat exhaustion can occur when human body temperatures rise to above 38ºC.

Climate projections for this study were collected using high-resolution regional climate model simulations over Africa, using the Conformal Cubic Atmospheric Model (CCAM).

“In order to understand the magnitude of the impact of apparent temperature on human health, it would be vital to use locally derived thresholds; however, such thresholds are currently unknown. This is an area where additional research is critical,” said Dr Garland.

The maximum apparent temperature in this study, where heat starts to have the potential to impact human health, is assumed to be 27 ºC. The number of days with maximum apparent temperatures above the defined threshold were modelled and downscaled for Africa per year for 1961 – 2100 by CCAM.

From 1961 – 1990, Johannesburg was modelled to have 34.5 days where apparent temperatures were more or equal to 27 ºC, per year on average. Between the years 2011 – 2040, Johannesburg is projected to have an increase of 35 such days on average per year. Modelling of hot days across the continent indicated that the potential risk to human health from high apparent temperatures is projected to increase.

The majority of Africa is projected to have, on average, over five months of the year, apparent temperatures equal to or more than 27 ºC by the end of the century. Dr Garland advises that future research should focus on developing a comprehensive set of temperature-health impact relationships to use for African populations in order to quantify the impact of increasing temperatures and apparent temperatures on human health.

“Such findings could assist in understanding the magnitude of the health impacts from increasing temperatures in Africa due to both long- and short-term exposure to high temperatures,” she said.

Climate services, such as climate information and projections, can provide the health sector with information to assist in better planning for adaptation to the projected increases in apparent temperature, in order to reduce the associated health impacts.

This study provides one key piece of the puzzle in mitigating the health impacts from climate change in Africa by identifying “hot spot” areas.

The paper, titled Regional projections of extreme apparent temperature days in Africa and the related potential risk to human health, published in the InternationalJournal of Environmental Research and Public Health, can be found on this link: http://www.mdpi.com/1660-4601/12/10/12577/pdf.

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About the CSIR
The CSIR is one of the leading scientific and technology research, development and implementation organisations in Africa. Constituted by an Act of Parliament in 1945 as a science council, the CSIR undertakes directed and multidisciplinary research, technological innovation, as well as industrial and scientific development to improve the quality of life of the country’s people. For more info, visit www.csir.co.za