Abnormal weather has a far greater impact on people's health than previously imagined.
Krish Perumal does not look forward to Durban’s summers. A middle-aged supervisor in a rubber-producing company, he was struck by asthma about 25 years ago when he was in his early 30s. “It’s worse when it’s hot and humid,” he says. “When you get bad wheezing, then you can get the flu.”
Perumal believes his condition is caused by industrial pollution—and he may be right. He lives in south Durban, home to two of South Africa’s biggest oil refineries and more than 120 industries, and more than 280 000 people. The area is a notorious pollution hot spot and a study done a few years ago showed that children here were twice as likely to get asthma as those in the northern parts of the city.
But there is reason to believe that global warming may be playing a part in the rise in respiratory disease here and elsewhere (asthma rates have been soaring around the world in the past three decades). Average temperatures in Southern Africa have risen by 1.5°C over the past century as opposed to 0.8°C globally, according to Dr Francois Engelbrecht of the Council for Scientific and Industrial Research (CSIR). The combination of higher temperatures and industrial pollutants is bad news for asthma sufferers like Perumal—and gives him a special interest in the 17th Conference of the Parties of the United Nations Framework Convention on Climate Change (COP17), which will take place in Durban from November 28.
The pollutant by-product of interest here is ozone, which is something most of us connect to the hole in the ozone layer happening in the Antarctic high up in the sky. But ground-level ozone is common in our cities. It forms when nitrogen oxides (NOx, a product of combustion in cars, trucks, industrial processes and coal-fired power plants) react with volatile organic compounds in sunlight, explains Dan Ferber, co-author with Dr Paul Epstein of Changing Planet, Changing Health (University of California Press).
Ground-level ozone irritates the respiratory system, damages lung tissue and reduces lung function. It triggers coughing, chest discomfort, a scratchy feeling in the throat and other symptoms. It makes people more susceptible to respiratory infections and it exacerbates asthma and emphysema.
Effects on health
When he started working on the book, Ferber says, he had no idea what he would discover. “The overall scope of the potential health problems was surprising to me.”
Ferber says that because scientists focus on their own specialities, the public receives information about climate change piecemeal—a study that looks at how crops are being affected; research on expanding ranges for mosquitoes; insight into changing patterns of rainfall. It is only when you step back and try to take in the whole picture that you realise this should be framed “as a public health crisis”, he says.
Consider how all-encompassing the effects on health are. Most of South Africa has been malaria-free hitherto. But it is common cause that climate change will likely increase the range of the Anopheles mosquito that carries malaria. It will also alter—sometimes increasing, sometimes reducing—the range of other insects that carry disease, such as the ticks that carry Congo fever. South Africa needs to be prepared for a possible rise in insect-borne diseases.
Then there is water. “Water is the primary medium through which people in Africa will experience climate change impacts. By 2020, it is estimated that 75-million to 250-million Africans will be exposed to increased water stress,” writes Dr Mary Galvin in a forthcoming publication by the Environmental Monitoring Group, Water and Climate Change: An Exploration for the Concerned and Curious. Projections indicate that South Africa will not benefit from the fact that warmer air holds more moisture: specific climatic features mean that, overall, we will be hotter but not get much increase in useful rainfall.
Some of the rainfall will come in extreme weather events such as the recent floods in the Newcastle and Upington regions, which can damage crops and do not necessarily sink into the underground water table, instead running off and washing away precious topsoil.
What does this mean for our health? Water is, of course, a vital nutrient, but it is also crucial to a secure food supply. A reduced rainfall, combined with changes in times when crops can be planted and harvested because of higher temperatures, will likely add to greater food insecurity. Lester Brown, president of the Earth Policy Institute in Washington, DC, has estimated that for every 1C increase in temperature, yields of staple grains will drop by 10%. This, of course, like all the impacts of climate change, will hit the poor hardest.
“I can say with confidence that there is a link between rising food prices and climate change,” says Ferber. Drought in Australia, wildfires in Russia and other events affect global food supply. In August, for example, China Daily reported that South Korea’s rice harvest was expected to reach a 10-year low next year because of abnormal weather conditions, which we should perhaps be calling the “new normal”.
An absence of fresh, clean water in adequate amounts for drinking and washing, coupled with undernourished people add up to a perfect health storm: water-borne diseases like cholera thrive in such conditions and malnourished people’s immune systems are unable to mount a sufficient defence.
We should be putting thought into adapting to a water-poor future, says Galvin: “Sustainable water usage solutions that could be implemented not simply by ecologically progressive households or municipalities but on a national scale include rainwater-harvesting landscapes for growing food, from commercial agriculture to small-scale farms to homestead gardens; the use of grey water to irrigate agriculture, parks and public sites; ecological treatment of sewage; dry sanitation systems such as compost toilets and pit latrines; and reducing water leaks.
“Adaptation will also require improving river and local wetland health; adjusting farming practice with resilient crops and shifting seasons; expanding the number of households with food gardens; and preparing for drought or floods.”
Heat effects on productivity
We all know about the 2003 heat wave, the hottest on record in more than 450 years, which killed about 40 000 people in Europe. Perhaps we dismiss the significance of this in our minds because the news focus was on the elderly people who died in great numbers. What went largely unnoticed at the time was a significant increase in deaths among those under 65—demonstrating that heat has a substantial effect on younger people too. Interestingly, although far more elderly women than men died, men were about twice as likely to die as women in the younger age group.
Heat waves will be more common in future, but the increase in average temperatures alone is likely to have an impact on human health in ways that will reduce productivity, shorten life spans and decrease wellbeing significantly, as Professor Tord Kjellstrom and his South African colleagues pointed out at a seminar at the University of Johannesburg in August. Kjellstrom is an internationally recognised expert on the health impacts of climate change—he is part-time professor and visiting fellow at the National Centre for Epidemiology and Population Health at the Australian National University in Canberra and is developing a global programme of studies on high occupational temperature health and productivity suppression (Hothaps) that is aimed at quantifying the impacts of heat exposure at work.
In a warming world we will experience the highest temperatures during the day, while we are at work. The majority of workers will not be able to escape the heat in air-conditioned offices. They will be out in the fields harvesting crops, labouring on construction sites or in factories that are inadequately cooled—doing the work that feeds us and gives us the pleasant and useful things in life.
Professor Angela Mathee, head of the Medical Research Council’s Environment and Health Research Unit, and colleagues Joy Oba and Andre Rose have done a pilot study as part of Hothaps. They demonstrated that many outdoor workers were already exposed to alarmingly severe health and productivity impacts from heat exposure.
Focus groups in Johannesburg and Upington spoke of increased thirst, excessive sweating, exhaustion, dry noses, blisters, burning eyes, headaches, nose bleeds and dizziness, among a host of other effects including chronic tiredness: “When it is very hot, sometimes when you wake up in the morning you feel exhausted,” said one Upington participant. As temperatures rise further in the near future, symptoms like these will have to be urgently addressed by employers and the government.
Sweating it out
Excessive perspiration is a serious heat-related health concern that can become a killer. Kjellstrom spoke about South American sugar-cane cutters who sweated several litres of fluid in a day, but only brought two litres of water to work with them because they had to walk and could not carry more. Because the employers did not provide water in the field, each day they would have to wait until knock-off time to replace the deficit, which had led to a spate of life-threatening kidney conditions in relatively young workers.
The imbalance of salts that results from heavy sweating is one reason why heat exposure reduces productivity: it leads to a lessened ability to work intensively and a loss of perceptual and motor performance—even mild dehydration has been shown to decrease mental performance. The brain also sends a signal to decrease muscle tone, which leaves people feeling tired and listless.
People will be working at a slower pace—if you are working in a consistent temperature above 28°C you should work only half your normal hours, says the professor—and their risk of accidents on the job also will increase. There are psychosocial effects as well: aggression rises, for example, increasing the risk of conflict and interpersonal friction in the workplace.
In addition, Kjellstrom points out, heat in many workplaces will interact with chemicals such as solvents and pesticides used on the job; these will evaporate faster, boosting the danger of exposure for workers. And workers who wear protective clothing will be hotter while at the same time being less able to perspire as effectively. In Southeast Asia, innovators are coming up with concepts to tackle this problem. One inventor has developed a vest containing tubes of material that stay frozen solid until about 25°C—when the temperature hits 30°C you stick it in the freezer again.
South African research
“We’ve known about the effects of heat in the workplace for a long time,” says Kjellstrom. But it is only recently that people have begun to link this knowledge with the oncoming juggernaut of climate change.
Interestingly, the original research on heat and labour was done right here in South Africa about 60 years ago. Dr CH Wyndham tested the work capacity of fit young men who came to work in the hot underground of Johannesburg’s mines. He found that although about 64% of men could cope with moderate physical labour in hot conditions, only a few were able to cope with heavy labour. He decided to acclimatise them by having them exercise in a “warm gym” daily for a few weeks, after which the number who could do hard labour jumped to 29%—still less than a third. Wyndham’s concept is still in use to acclimatise and harden new recruits and men who return to the mines after holidays.
Will our future climate be hot enough to trigger these on-the-job health problems? The answer is yes. At the CSIR recently, atmospheric modeller Dr Francois Engelbrecht presented the results of six simulations or models of our future, the largest exercise of its kind ever done here. The news is not good: Southern Africa has an observed temperature increase over the past century of double the global average, and this trend will continue over the decades between now and century’s end. So if—and it’s an unlikely prospect—we manage to keep the global increase down to two degrees, Southern Africa will experience four. This means that whereas a pleasant Gauteng January day between 1960 and 2000 was usually about 25°C, it would in future be about 29°C. If, as many scientists now believe is likely, the increase is three or four degrees globally, we are going to have some stinking hot summers.
The middle class and the wealthy will be able to buy their way out of many of these impacts for the next decade or so—air conditioners and filters will protect us from the heat and pollutants and insect repellents from mozzies and ticks. And we will probably moan at the price of water and food. But climate change will affect the poor the most, worsening the divide between rich and poor and placing serious demands on the public purse.
Few hold out much hope for a meaningful and binding treaty at COP17. But the dark picture experts paint of our future health prospects if we do not act, and act now, provides South Africans with urgent reasons to hope—and lobby—for an outcome that holds some promise.