Climate change, dubbed “the biggest global health threat of the 21st century” by esteemed medical professionals, is not just a distant doomsday prediction. Around the globe, it is already affecting peoples’ physical and mental wellbeing in tangible ways.
According to a report by The Global Climate and Health Alliance, climate change impacts health through multiple pathways. These may include a collapse of infrastructure and essential services, such as water, electricity and health provision; higher levels of death and illness during heat waves; and the breakdown of food systems, particularly in poorer regions.
“Climate change will affect all countries, but will have the greatest impact on those who have the least access to the world’s resources and who have contributed least to carbon emissions,” writes the UCL-Lancet Commission of Managing the Health Effects of Climate Change. “This is a gross injustice – and will prove to be a source of historical shame to our generation if nothing is done to address it. It will also have increasingly adverse health effects on our children and grandchildren, an issue of ‘intergenerational injustice’.”
Changing weather patterns
As our planet gradually warms, we will see more frequent and intense weather events. The direct impacts of extreme heat, drought, storms, flooding and forest fires all have obvious implications for health.
The effects of extreme weather events are particularly severe for people living in slums or informal settlements, as well as women, children and the elderly. There are also important mental health implications to such natural catastrophes, which have, for example, been documented in flood survivors.
The European heat wave of 2003, which came during Europe’s hottest summer in 500 years, led to more than 20,000 excess deaths in a two-week period. While it is difficult to pinpoint the exact causes of such phenomenon, we do know that extreme weather events are becoming more frequent due to global warming.
Changing weather patterns also impact the spread of infectious diseases transmitted by insects, rodents or tainted water supplies. However, the exact mechanisms through which this happens are complex and varied. Increasing temperatures and changing rainfall levels affect sanitation, parasite habitats and pollution levels. This will change who gets sick when.
Insect-borne diseases, like malaria, dengue fever and Lyme disease, are sensitive to changes in climate. Variations in temperature and rainfall create new habitats for disease-spreading insects. Dengue has increased 30-fold in the past 50 years, a change that is associated with climate change.
Various studies have shown that parts of the East African highlands – including Burundi, Kenya, Uganda and Rwanda - that were previously free from malaria now have increased levels of the mosquito-borne disease. This is linked to local warming in recent decades.
Access to the essentials of life
“The carbon footprint of the poorest one billion people is around three per cent of the world’s total footprint,” says the UCL–Lancet Commission of Managing the Health Effects of Climate Change, “yet these communities will be affected most by climate change.”
As global temperatures rise, continued deforestation, soil erosion and pollution will undermine the natural environment’s ability to sustain life as we know it. Scientists are braced for increasing loss of biodiversity, such as the loss of marine and coastal ecosystems and the associated livelihoods on which many people depend. The Amazon and Arctic regions are at high risk of irreversible damage to their sensitive ecosystems.
Currently around 150 million people live in cities affected by chronic water shortages, while one billion people worldwide do not have access to safe drinking water. As the biophysical environment changes, access to clean water, nutritious food and shelter will become increasingly difficult, especially for the world’s poorest communities.
Malnutrition is currently one of the largest health crises worldwide. Climate change looks set to place even more pressure on food supplies, with African food crops predicted to be the hardest hit. Even relatively small changes in temperature can dramatically decrease crop yields.
From 2011 to 2012, a severe drought affected millions of people in East Africa. Tens of thousands of people died in Somalia alone, while refugees were forced to flee across borders into neighbouring countries. While it would be wrong to definitively attribute this drought to global warming, the UK government’s chief scientific adviser said at the time, “events like this have a higher probability of occurring as a result of climate change.”
A rapid rise in the price of staple foods associated with extreme weather events has also caused major social conflict. Food insecurity is cited as a major factor in the Arab Spring, a revolutionary wave of protests and demonstrations that began in 2010. But while people living in parts of Africa or the Middle East may be hardest hit by widespread changes in the food production system, ultimately no one will be immune from it.
Conflict and migration
If even moderate predictions about climate change come true, we can expect to see massive upheaval and social unrest as ecosystems are squeezed and natural resources become scarce. By the middle of next century, some scientists predict more than one billion people could be displaced in environmental mass migration due to rising sea levels.
Perhaps one of the most important mechanisms through which climate change impacts on human health is by making some regions uninhabitable or prone to emergencies, undermining livelihoods and causing displacement. All of these factors can trigger conflict over access to resources. Some regions are already feeling the mounting pressure of a warming climate.
“The Pacific Island countries are internationally regarded as a barometer for the early impacts of climate change,” say policy analysts at US-based think tank the Brookings Institution. “Their geophysical characteristics, demographic patterns and location in the Pacific Ocean make them particularly vulnerable to the effects of global warming.”
In March 2015, Tropical Cyclone Pam ripped through the south Pacific, leaving a path of destruction and death in its wake. The category 5 storm is classed as the worst natural disaster to hit the small island nation of Vanuatu, where 80 percent of homes were damaged or destroyed. Tropical cyclones are occurring with an intensity never seen before in the region as oceans warm.
One native of Kiribati, a nation also affected by cyclone Pam and home to 100,000 people, is seeking to become the world’s first climate change refugee. Teitiota, a farmer and father of three, has applied to the New Zealand government to overturn a pending deportation claim in favour of granting him refugee status. While the odds of success are slim, this highlights the important issue that people affected by climate change will need safe refuge when their homelands are no longer habitable.
How much of a threat climate change is to any country or region depends on: (i) their exposure to climate hazards; (ii) whether they are vulnerable or resilient to threats; and (iii) the extent they can adapt to climate change. In countries that are already insecure or vulnerable, climate change is a ‘threat multiplier’. For example, rural populations in developing countries are especially at risk from climate change, due to the added stressors of having inadequate infrastructure, poor natural resources policies and existing environmental degradation.
In wealthier nations, many of the drivers of climate change, such as poor urban design, over-reliance on cars for transport, overconsumption of meat and burning of fossil fuels, also contribute to health problems. These include obesity, heart disease and respiratory illnesses.
Where to from here?
Understanding climate change is a complex science. The complexity of living systems means multiple factors interact to create outcomes. However, while some areas need further research, there are many opportunities to act now.
We can distinguish between two priority areas for climate change: mitigation and adaptation.
Mitigation efforts focus on limiting the extent of climate change by calling for an urgent reduction of greenhouse gas emissions and a shift to a low-carbon economy. At the same time, it also includes creating ‘carbon sink’ opportunities, which refers to anything that absorbs more carbon than it releases. Reforestation and protecting coastal wetlands are seen as good ways to reduce the amount of carbon in the atmosphere.
Adaptation, on the other hand, aims to lessen the impacts of climate change through making changes to natural or human systems. It can either refer to efforts to avoid potential damage, or ways of dealing with the consequences of climate change once they arise. Under this broad umbrella, we see the creation of climate-resilient cities alongside the development of technologies designed to desalinate sea water or improve water irrigation for crops.
In terms of adaptations that will protect human health, the Intergovernmental Panel on Climate Change recommends “public health policies that recognise climate risk; strengthen health services; [and] regional and international cooperation.” Concretely, the panel calls for better emergency preparedness, with an emphasis on medical services and action plans, improved climate-related disease surveillance and the provision of safe water and good sanitation.
For the poorest communities already facing the health effects of climate change, this could not be more urgent. Governments and international institutions need to act now in order to save lives and improve the quality of life for those affected. As the saying goes, ‘if you do not have your health, nothing else matters’.