The Health Impacts of Climate Change

Carbon dioxide is the perfect killer. Invisible and odourless, it exerts its mal-effects insidiously and so surreptitiously that they have managed to avoid registering on most peoples’ daily list of concerns. Indeed this has allowed its continued production to be regarded by many as essential to maintaining the quality of life that most of us currently enjoy.

Unfortunately it has overstepped the mark. The global community is becoming increasingly aware of the consequences of decades of unfettered release of carbon dioxide and other greenhouse gases into the atmosphere. Much has been publicised with regards to the changing climate and its impact on extreme weather patterns and the stresses placed upon the most vulnerable humans and animals, as a result of dramatic changes to their fragile environments. Far less has been mentioned about the effect of climate change on the health of the world’s population and it has been acknowledged by the World Health Organisation (WHO) that “discussions on climate and health have been divided” for too long.1

Climate change and its causes affect us individually, locally and globally and have detrimental health effects in the immediate-, medium- and long-term.

Increased episodes of high rainfall, and the ensuing floods, have huge impacts on peoples’ livelihoods, as well as providing optimal conditions for the spread of water-borne disease. When coupled with frequent annual droughts, extreme pressure is placed on food production and the supply of potable water. Eventually this will have the effect of displacing millions of people, with massive implications for food and water security, increasing the potential for armed conflicts and the resultant public health disasters they cause. This mass displacement brings with it health consequences of its own, both for the migrants and for the host population, as living conditions and access to healthcare are inevitably compromised, and both populations are exposed to unfamiliar diseases.

The gradual warming of the world as a whole also allows disease-carrying insects which were previously confined to the warmer tropics, such as mosquitoes , to survive at higher altitudes and latitudes. This places significantly greater numbers of people at risk of acquiring diseases which were previously unheard-of in certain countries. The European Centre for Disease Prevention and Control cites sporadic outbreaks of dengue, West Nile virus and chikungunya virus in Europe and warns of an increased risk of future local spread due to more favourable climatic conditions for the insects that harbour these diseases.2

Climate change will serve to further exacerbate existing global inequalities, as the brunt of the effects on sea level and extreme weather patterns will be felt by the lower-income countries, while the high-income countries continue to produce the lion’s share of emissions. The lack of a daily reminder of the consequences of our actions, ensures that there is no strong incentive to expedite the mitigation of our consumption of carbon-rich fuels. The continued combustion of fossil fuels, mainly for the production of energy and for agricultural and transport purposes, releases a cocktail of harmful, cancer-producing chemicals, as well as greenhouse gases and fine particles, into the thin layer of our atmosphere. The western world appears to only now be waking up to the health impacts of these emissions. And it is a rude awakening.

As well as carbon dioxide, the main pollutants released from the combustion of petrol, diesel and coal are:

1. Nitrogen oxides – act as irritants, causing airway inflammation and exacerbating asthma and other respiratory conditions. They contribute to the formation of fine particulate matter (PM) and react in sunlight to form ground-level ozone, which are both potent lung irritants.
2. Sulphur dioxides – another potent airway irritant, which may have longer-term effects on respiratory function.
3. Carbon monoxide - enters the bloodstream and reduces the ability to transport oxygen to the tissues of the body, which may exacerbate pre-existing cardiovascular disease.
4. Benzene – classed as a human carcinogen, benzene is linked predominantly to the development of leukaemia.
5. Benzo[a]pyrene – also classed as a carcinogen, its exposure is linked to numerous different types of cancer in the human body.
6. Toxic metals, such as arsenic, cadmium, nickel, lead and mercury are also released.
7. Particulate matter (PM) is produced both directly by the combustion of solid fuel, and indirectly by the reaction of the sulphates and nitrogen oxides produced. They consist of a complex mixture of solid and liquid particles which are carried in the air. They are classed as ‘coarse’, ‘fine’ or ‘ultrafine’ according to their size in microns (>10, 2.5-10 and <2.5, respectively). Fine PM can penetrate into the small airways of the lung, cross into the bloodstream, and are the cause of significant illness and death due to both respiratory and cardiovascular disease. More recently, smaller particles have been found to penetrated into human brain tissue, the clinical significance of which is now under investigation.3 

The autumn of 2016 saw the publication, in quick succession, of a World Health Organisation publication on global Air Pollution,4 the European Environment Agency’s 2016 report on Air Quality in Europe5 and the Irish Environmental Protection Agency’s report on Ireland’s Environment.6 These make for sobering reading.

The WHO estimates that 3 million premature deaths in 2012 were attributable to ambient (outside) air pollution.4 In Europe, the numbers of premature deaths attributed to fine particulate matter, nitrogen dioxides and ground-level ozone are 436 000, 68 000 and 16 000, respectively.5 Closer to home, an estimated 14,400 years of life are lost due to 1200 premature deaths caused annually in Ireland by air pollution.6,7 Cardiovascular disease and stroke are the most common causes of premature death attributed to air pollution, followed by respiratory disease and lung cancer.8

There is also evidence to suggest an association between air pollution and negative health impacts during pregnancy, in new-borns and children, and on later fertility.9,10 These manifest as negative effects on neural development and cognitive capacity, which may be detrimental to performance at school and later in life. Recent evidence also suggests an association between air pollution and the development of type 2 diabetes, obesity and dementia.11

Fortunately, there are health and environmental co-benefits to mitigating emissions by moving away from the car as the main mode of transport.

The health benefits to physical activity are well-documented and the WHO guidelines recommend that each adult undertake at least 30 minutes of moderate physical activity on 5 days of the week. This amount of physical activity is demonstrated to significantly reduce the risk of developing cardiovascular and respiratory disease, diabetes, hypertension (abnormally high blood pressure) and a number of other chronic conditions. Currently only around 31% of Irish adults and 12-19% of children are sufficiently active.12 The 30 minutes may be accumulated in short bouts of activity, no more strenuous than a brisk walk or a light cycle, and may be incorporated into the daily commute.

Using a bicycle for short distances would also significantly reduce pollutant emissions, while simultaneously conferring health benefits. The 2006 Irish census revealed that 205,000 people drove less than 4km to work and that there has been a startling 83% reduction in the number of children cycling to school between 1986 and 2006. For a variety of reasons, cycling is no longer considered a normal means by which to get from A to B.
In a Japanese study of nearly 6000 workers, those who commuted by public transport were significantly less likely to be overweight, and to have hypertension or diabetes than those who drove to work.13 There is, unsurprisingly, a positive association between cycling, walking or skateboarding to school and childrens’ cardiovascular fitness.14 Changing from ‘non-cycling’ modes of school transport to cycling is also a significant predictor of increased cardiovascular fitness.14

It is clear that fundamental changes in the manner in which we produce energy and food, and in which we travel, need to be made if we are to address the current situation. As our population ages, and the prevalence of chronic disease increases, creating an environment which is conducive to exacerbating the impacts of these diseases will only serve to further overwhelm our stretched healthcare system. By transitioning to sustainable methods of energy production and by adopting less carbon-reliant means of transport, Ireland may begin to move towards fulfilling its commitment to the 2015 Paris Agreement and to reduce air pollution.

To make these changes on a population level requires the political will and bravery to commit to funding new infrastructure that will facilitate the increased use of public transport, walking and cycling. This has been achieved successfully in cities around the world and communities have benefitted from the reduced pollution, noise and congestion, as well as from the health benefits.

In its proposal to increase the number of air quality monitoring stations around Ireland, the EPA states the intention to provide real-time information to the general public, so that they may “plan, and make in advance, informed decisions about their (outdoor) activities”.7 It is a sorry situation that we on the Emerald Isle find ourselves in when we need to consider checking the quality of the air outside before we decide to plan our activities! It is my hope that by identifying and addressing the critical enablers that would allow a transition to a completely ‘electrified’ society, with energy produced solely through sustainable means, our government will ensure the long-term health of the country’s population, environment and economy.

Dr Matt Robinson
Consultant Sports & Exercise Physician
@ValleyboyMatt

References

• http://www.who.int/mediacentre/commentaries/climate-change/en/ [Accessed 24th November 2016]
• http://ecdc.europa.eu/en/healthtopics/climate_change/health_effects/Pages/vector_borne_diseases.aspx [Accessed 24th November 2016]
• Maher BA et al. Magnetite pollution nanoparticles in the human brain. Proc Natl Acad Sci USA. 2016 ;113(39):10797-801
• Ambient air pollution: A global assessment of exposure and burden of disease. WHO publication 2016 (http://apps.who.int/iris/bitstream/10665/250141/1/9789241511353-eng.pdf) [Accessed 24th November 2016]
• Air quality in Europe – 2016 report. European Environment Agency publication. (http://www.eea.europa.eu/publications/air-quality-in-europe-2016) [Accessed 24th November 2016]
• Ireland’s Environment. An Assessment 2016. Environmental Protection Agency publication. (http://www.epa.ie/pubs/reports/indicators/SoE_Report_2016.pdf) [Accessed 24th November 2016]
• Environmental Protection Agency (Ireland). National Ambient Air Quality Monitoring Programme 2017-2022. Consultation paper (http://www.epa.ie/pubs/consultation/files/Consultation%20Paper.pdf) [Accessed 24th November 2016]
• World Health Organisation. Burden of disease from Ambient Air Pollution for 2012 — Summary of results
• Effects of air pollution on children's health and development — a review of the evidence. World Health Organisation 2005
• Review of evidence on health aspects of air pollution — REVIHAAP Project, Technical Report. World Health Organisation 2013
• Every breath we take: the lifelong impact of air pollution Report of a working party, Royal College of Physicians London 2016
• National Physical Activity Plan, Ireland 2016. (http://www.getirelandactive.ie/Professionals/National-PA-Plan.pdf) [Accessed 24th November 2016]
• Tsuji H. AHA Scientific sessions 2015
• Lubans DR et al. The relationship between active travel to school and health-related fitness in children and adolescents: a systematic review. International Journal of Behavioral Nutrition and Physical Activity 2011;8:5