More intense heat waves. Stronger and more frequent hurricanes. Shrinking glaciers. Rising sea levels. Longer droughts. More frequent wildfires. Shifting flora and fauna. The effects of climate change are and will continue to be felt across the globe. In addition to growing ecological effects, we can expect to experience increased effects on health resulting from climate change. Through a myriad of direct and mediated impacts, climate change is considered to underpin all the social and environmental determinants of health.
The World Health Organization (WHO) projects that climate change will cause 250,000 additional deaths per year between 2030 and 2050. Even accounting for sustained economic growth and health progress, 38,000 additional deaths are expected to be due to heat exposure in elderly people, 48,000 due to diarrhea, 60,000 due to malaria, and 95,000 due to childhood undernutrition. Projections also suggest that children in resource-constrained countries will bear the brunt of adverse health effects attributable to climate change.
HOW DOES CLIMATE CHANGE AFFECT HEALTH?
The Intergovernmental Panel on Climate Change (IPCC), the leading international body for the assessment of climate change, outlined the three main mechanisms by which climate change affects health in its Fifth Assessment Report: (1) direct impacts from extreme weather; (2) impacts mediated through ecological changes; and (3) impacts mediated through changes and disruptions to human-made systems.
Extreme weather events – such as more intense heat waves and frequent, intense tropical storms – directly affect health via death and injury:
There are numerous physiological effects when body temperature exceeds normal, which is elevated risk during heat waves. Some of these effects include: loss of consciousness, impaired cognitive function, physical impairment, organ damage, and potentially death. There are factors that affects one’s ability to survive extreme heat, such as the level of humidity and access to ventilation or air conditioning. However, access to such mitigating resources is highly variable worldwide and even within smaller regional subdivisions.
As the number of devastating tropical storms increases, there is an associated increase in flood risk. Health effects associated with flooding include drowning, hypothermia, and infectious disease, such as diarrhea and cholera. There are also mental health effects, namely psychological distress, anxiety, and depression among those that survive the trauma of the flood event.
800px-Katrina-port-sulphur-la-2005
IN THE PHOTO: EFFECTS OF HURRICANE KATRINA PHOTO CREDIT: WIKIMEDIA / NOAA / COMMANDER MARK MORAN
The health effects of climate change are also mediated through ecological changes and can affect the distribution of disease vectors, pollution, and allergens:
Vector-borne diseases, infections spread by the bite of blood-sucking arthropods (e.g. mosquitoes or ticks), are often influenced by weather and climate. As an example, let us consider dengue fever. Currently, dengue is the most rapidly spreading mosquito-borne viral disease in the world experiencing a 30-fold increase in global incidence in the past 50 years. Each year there are 390 million dengue infections worldwide and roughly 96 million of those infected manifest symptoms. Evidence suggests that increases in temperature, humidity, and rainfall – an effect of extreme tropical storms – are associated with increases in dengue incidence. Drought can also be a cause of dengue spread, if households are storing water in open containers that can provide suitable mosquito breeding sites.
Rising temperatures, along with low rainfall, also increase risk of wildfires, which elevate risk of smoke inhalation injuries, burns, and death. Wildfires also contribute to acute air pollution episodes through release of particulate matter and other toxic substances that may affect large swaths of the population for an extended period. It has been projected that 339,000 deaths per year are attributable to air pollution form forest fires.
Allergies are common and sensitive to the climate. Moreover, warmer temperatures are generally associated with production and release of allergens (e.g. spores and pollen), which may affect rates of asthma and allergic respiratory diseases, conjunctivitis (i.e. pink eye), and dermatitis. Children are especially susceptible.
800px-Zaca3
IN THE PHOTO: 2007 ZACA FIRE, NEAR SANTA BARBARA, CA PHOTO CREDIT: WIKIMEDIA / JOHN NEWMAN
The health effects of climate change on health can also be mediated through human systems affecting nutrition, occupational health, and mental health:
Nutrition is affected by numerous factors, such as agricultural production, food prices, and disease – particularly those affecting appetite and nutrient absorption. The amount and quality of food that is harvested can be negatively impacted by higher temperatures and changes in precipitation. There is also growing evidence that extreme weather events may contribute to higher food prices, which are negatively associated with food consumption. Overall, there is high confidence that, particularly in resource-constrained regions, climate change will reduce per capita calorie availability, exacerbate childhood undernutrition, and worsen undernutrition-related childhood morbidity and mortality.
Around the globe, work performed outside the home, is majorly conducted outdoors, namely in agriculture and construction. Those that are required to work in hot conditions, without sufficient opportunities to rest and/or hydrate, are at increased risk for heat exhaustion and heat stroke. Heat stress is also of concern for those that work in indoor environments lacking ventilation or temperature control. As global temperatures rise, disenfranchised workers in these conditions are at greatest risk of potentially catastrophic health consequences.
Through their multi-faceted impacts on infrastructure, financial systems, land use, and life, extreme weather events, tend to significantly increase stress, exacerbate existing mental illness, or initiate new mental illness. Enduring extreme weather events is an acute exposure to trauma that can manifest in post-traumatic stress disorder, generalized anxiety, or depression. Extended extreme weather events, such as droughts, in addition to adversely affecting agricultural production, can induce or exacerbate psychological distress and suicide incidence. Extreme weather events can also induce “solastalgia” which is known as a distressing sense of loss that people experience when their land is damaged and they lose amenity and opportunity.
RESPONSE TO CLIMATE CHANGE IS “GREATEST GLOBAL HEALTH OPPORTUNITY OF THE 21ST CENTURY”
These findings and projections are understandably concerning, but rather than cause for despair, overcoming these challenges has been couched as an opportunity to be seized by the global community. In fact, the 2015 Lancet Commission on Health and Climate Change reasoned that responding to climate change could be the greatest global health opportunity of the 21st century.
As part of this response, international bodies have made concerted transnational efforts to prioritize understanding the health effects of climate change and develop strategies for curtailing potential adverse health effects.
For example, WHO was instrumental in devising the Ministerial Declaration on Health, Environment and Climate Change regarding the global initiative to drive forward “low carbon, climate resilient, sustainable and inclusive development aimed at ensuring good health and well-being” from the 2016 UN Climate Change Conference (COP-22) in Marrakech. WHO also organized events on climate and health at the 2015 UN Climate Change Conference (COP-21) in Paris. Additionally, WHO convenes its own annual Global Conference on Health and Climate. The 2016 Conference had the express purpose of devising the strategies by which the global public health community would support the implementation of the Paris agreement from COP-21 to help construct healthier and more sustainable societies.
Opening_Ceremony_of_the_Marrakech_Climate_Change_Conference
IN THE PHOTO: OPENING CEREMONY OF THE MARRAKECH CLIMATE CHANGE CONFERENCE PHOTO CREDIT: FLICKR / UNCLIMATECHANGE
There is also the work of The 2015 Lancet Commission on Health and Climate Change, which was formed to map out a comprehensive response to climate change that would ensure positive health outcomes across the globe. The Commission issued this “roadmap” in a free report, with front-lined policy recommendations:
Commit financial resources to improve monitoring, surveillance, and research of the health effects of climate change
Invest in development and implementation of health systems that are resilient against climate change effects
Reduce carbon emissions by rapidly phasing coal out of the global energy mix
Encourage the development of urban environments that promote healthy lifestyles
Create the framework for a robust, predictable, and global carbon pricing mechanism
Expand access to renewable energy sources, especially in resource-constrained countries
Support efforts to estimate the potential health benefits – in terms of prevented disease, reduced healthcare costs, and increased economic productivity – from a low-carbon economy
Facilitate collaborations across government agencies to ensure health and climate considerations are integrated in policy decisions and implementation approaches
Agree on and implement an international agreement that supports countries, especially those that are resource-constrained, in transitioning to a low-carbon economy
The Commission also developed the Countdown to 2030: Global Health and Climate Action, an international, multi-disciplinary research collaboration between academic institutions to monitor progress on the implementation of climate change policies that promote health over the next 15 years.
Furthermore, there are the massive efforts of the IPCC in pulling together all relevant, current evidence on the multi-faceted effects of climate change on not just health, but also on natural and managed resource systems, human settlements, industry, infrastructure, and security for its robust Assessment Reports.
These are just a few of the global entities that have conducted research, issued reports, and convened meetings on climate and health. These efforts have yielded numerous recommendations for changes to policy, governance, infrastructure, and human systems so our societies can adapt to protect human health as the climate changes.
HOW CAN WE ADAPT, IN THE FACE OF CLIMATE CHANGE, TO PROTECT HEALTH?
Climate change, along with its own risks to health, can threaten the progress that has been made to improve health outcomes. The necessary adaptations for health protection in the face of climate change depend on a variety of factors and are extremely place-specific. Some factors include: current burden of illness; current vulnerabilities; feasibility of implementing certain interventions; and the social, economic, and political context for intervention(s).
Current population health status may be the single most important predictor of future climate change-related health effects and potential costs of adaptation. Most health adaptations involve modifications to disease surveillance, exposure monitoring, disaster risk management, and cross-sector collaboration systems. For example, in Benin, a proposed part of the national response to rising sea levels and accompanying flood risk was to expand health insurance arrangements to ensure effective treatments for malaria and enteric infections – infections with increased risk, in flooding conditions – could be deployed quickly.
Adaptation can also include “vulnerability mapping”, which is increasingly being used to understand current and future health risks related to climate change. Vulnerability mapping can involve charting community elements, social and economic resources, infrastructure, and other factors that influence disease transmission and well-being at neighborhood and regional scales. These maps can be used to guide adaptation investments and actions. For example, a map of surface temperatures and urban heat island effects – at the neighborhood level— indicate where urban cooling measures, such as city greening, could be effective, and alert public health officials to populations that may be at the greatest health risk during heat waves.
Early warning systems have also been a critical part of adaptations to protect human health. Early warning systems are increasingly being implemented for heat waves, particularly in high-income countries; evidence has shown fewer deaths during heat waves after implementation of such systems. Such systems have also been developed for vector-borne and food-borne infections – although there is limited evidence of their effectiveness in reducing disease burdens.
Moreover, the factors that influence human health and the health effects associated with climate change are not confined to the health sector. For example, water and sanitation, agriculture, built infrastructure, housing and development, energy and transportation, and land use management are non-health specific sectors, but all conduct work that affects health. Additionally, each of these sectors will be contending with sector-specific effects of climate change. Adaptation strategies in other sectors could yield positive health benefits or increase health risks: for example, improving water quality through re-vegetating watersheds versus designing urban wetlands for flood control that potentially also promote mosquito breeding. Therefore, cross-sector communication and collaboration will be an integral part of any successful adaptation strategy.
So, what can everyday people do? Primarily, two things: (1) learn about the health effects of climate change and how health outcomes can be improved with reduction of carbon emissions and dependence; (2) advocate for policies, strategies, approaches, and adaptations that would mitigate the prevalence and severity of adverse health effects associated with climate change.
Related articles: “HOW CLIMATE CHANGE CONTRIBUTES TO GLOBAL PUBLIC HEALTH CRISES” by Andrew Budsock, (M.A.)
“COMING TOGETHER ON CLIMATE CHANGE” by Annis Pratt