With a historic agreement on carbon reductions forged in Paris last month, the world’s attention is squarely focused on climate change. But could protecting the planet also safeguard our health? From food scarcity and extreme weather events to diseases on the move, climate change is expected to turn up the volume on death and illness, and experts caution that the time to take action is now.
On a global scale, food scarcity and rising sea levels linked with climate change are expected to fuel civil conflict and large-scale migration, explains Ivan Perry, professor of public health at University College Cork.
“In a fragile world where there are many populations that are just hanging on, climate change is a further destabilising factor,” he says.
“In some areas it takes very little to have a negative impact through weather and drought against a backdrop of extreme poverty and a poorly developed public health infrastructure. Add in the gradually increasing effects of climate change on top of that, and it is a fairly potent mix.”
Even in relatively stable regions of the world, severe weather events, such as heatwaves, freezes and floods, can quickly affect health, says Perry. “There can be very significant mortality and morbidity from weather events involving extreme rainfall or heat or cold.”
Climate change may also affect chronic conditions, such as cardiovascular disease, says Dr Blánaid White, a lecturer at Dublin City University’s school of chemistry and chairwoman of DCU’s undergraduate programme in environmental science and health.
“Consider a person who already has cardiovascular disease – increased heat stress could be the straw that breaks the camel’s back,” she says. “If you don’t have cardiovascular disease, then climate change is not going to give it to you, but if you do have it, then climate change could promote and accelerate it.”
A breath of not-so-fresh air
Airway diseases, too, could be exacerbated by air-quality issues linked with climate change, and it’s not just about smog.
For those with hayfever, the misery of symptoms could spread out over time, according to White.
“The growing seasons for plants are changing – we can see that in Ireland already – so you can get different pollen exposures, and from a health point of view this can mean increased or varied pollen exposures,” she says. “It is not going to kill you, but if you have an allergy to it, it will make your life miserable.”
We could also see an increase in airway exposure to fungal moulds that have been associated with respiratory infections, adds White.
“Moulds thrive with more frequent precipitation [rainfall], which is exactly what we are expecting in Ireland,” she says. “So if you have an airway condition like chronic obstructive pulmonary disease, you are going to have a lower resistance or tolerance to such moulds.”
Other potentially dangerous viruses, parasites and their carriers may also carve out new niches in the world, thanks in part to climate change making new areas more habitable for them.
"A competent vector for the dengue fever virus [the mosquito Aedes albopictus] has, in the past 15 years, started to be seen in Europe, and this raises the possibility of dengue outbreaks," says White. "Because northern Europe is predicted to experience increased precipitation, this is going to influence tick distribution, and shift exposure patterns of tick-borne disease. "
Steps to prevention
There are steps we can take to limit the effects of such developments, however. As well as tackling climate change itself, we can intervene to slow chronic diseases and build an infrastructure that allows us to detect and respond rapidly to problems.
To help tackle atmospheric emissions, Ireland will have some tough questions to consider about agriculture, according to Perry.
“As a small country, it is tempting to engage in special pleading in relation to our beef and dairy industry, but we have to look at it very critically,” he says.
“It involves not just carbon dioxide but also methane emissions, and let’s also factor in that there are potentially beneficial health effects from avoiding the overconsumption of meat.”
Another preventive step is research to better understand how chronic conditions such as type 2 diabetes and cardiovascular disease develop, which could point to new ways to address them, according to White.
“We are looking at the molecular mechanisms by which these diseases progress and trying to map those in cells, so that we can see what factors we can change to mitigate against the disease,” she says.
Infrastructure
A properly functioning public health infrastructure is also critical, says Perry. “This is the capacity to detect when things are going wrong and to respond quickly. It is disaster preparedness.
“So that if there is a major outbreak of an infectious disease or a major catastrophic weather event, we have the health intelligence and resources to respond.”
The World Health Organisation estimates that "between 2030 and 2050, climate change is expected to cause approximately 250,000 additional deaths per year, from malnutrition, malaria, diarrhoea and heat stress", and Perry believes the levels could be far higher towards the end of the century.
“As the health impact of climate change really gets going, the mortality rates could take off quite sharply into the 2060s and beyond.
“The time to act is now.”
