Climate Change is the Biggest Global Health Threat of the 21st Century.

Climate Change is the Biggest Global Health Threat of the 21st Century.


Climate change is one of the major environmental threats facing the world today. It is referred to as “any distinct change in measures of climatic condition that could last for a long period of time such as major changes in temperature, rainfall, snow or wind patterns lasting for a decade or longer” (Allen, 2010). Over the past century, there has been a continuous rise in the levels of carbon dioxide (CO2), methane and other green gases (Frumkin et al, 2008) as well as the earth’s surface being warmed by more than 0.8°C and by approximately 0.6°C in the past three decades (NASA, 2007). It has been estimated that by the year 2100, the world’s mean temperature will increase by an additional 1.8 to 4.0°C, sea levels from 0.18 to 0.59m and a significant increase in weather variability (Solomon et al., 2007). The warming of the earth’s surface has brought about severe weather conditions such as torrential rains and flooding, droughts and storms which are as a result of human activities such as the burning of fossil fuels which are rich in carbon and combine with oxygen in the atmosphere to release carbon dioxide that traps heat in the atmosphere (Change, 2007). The annual emissions of CO2 and GHG have increased by 80% and 70% respectively between 1970 and 2004 (Allen, 2010). Deforestation is another human activity that has brought about the continuous change in climatic conditions (Change, 2007).

Global Implications of Climate Change.

It has been estimated that by the year 2015, Global Millennium Development Goals and the assurance of a safe and sustainable future will be harder to obtain due to the changes in the climate (Allen, 2010). Instances of natural disasters that have happened recently are shown below:

The first hurricane ever recorded in the southern Atlantic Ocean in Brazil in 2004 and the Cyclone Nargis which raised a tidal wall 12feet high and forty kilometres long that slammed into Myanmar (Burma) in 2008 are examples of the fact that the earth is changing fast (Epstein et al, 2011 ). In 2003, a heat wave melted 10 percent of the ice in Alps and killed more than fifty two thousand people. One thousand people were killed as a result of a drenching rain in Mumbai which also contaminated water supplies and sickened hundreds. This has led to the spread of “malaria-carrying mosquitoes, the disappearance of mountain glaciers which threatens drinking water supplies on five continents and at least 150,000 additional deaths recorded worldwide each year as well as five million years of healthy life lost to disability” (Epstein et al, 2011).

Health effects of climate change

Climate change affects health in several ways namely: continuous change in disease and mortality patterns, severe weather events, food and water contamination, heat wave, melting permafrost and threats to housing and public infrastructure (Costello et al., 2009, Healey et al, 2011). The major factors affecting human health are “social, political, economic, environmental and technological factors as well as urbanization, affluence, scientific developments, individual behaviour and vulnerability in terms of genetic make up, nutritional status, emotional well being, age gender and economic status” (Allen, 2010).

Other potential health effects of climate change include respiratory and cardiovascular disease related to worsening air pollution, infectious diseases related to changes in vector biology, water and food contamination, nutritional shortages related to changes in food production, allergic symptoms related to increased allergen production (Heinz and Patz, 2004, Heinz et al, 2006). The way pests, parasites and pathogens affect wildlife, livestock, agriculture, forests and coastal marine organisms can also alter ecosystem composition and functions, and changes in these life support systems carry implications for human health” (Epstein, 2005).

The adverse health effects of climate change will also bring about migration from flooded and inhospitable places which will encourage population growth, thereby, resulting in “increased pressure and competition for scarce resources, such as food, water and shelter” (Costello et al., 2009). The demand for more food production will give rise “to high land loss and as a result bring about industrialization, urbanisation, sea level rises and increased flooding” (Costello et al., 2009).

Figure 1 summarises the major pathways through which population health can be affected by climate change. The right hand boxes show an increase in complexity of causal process where the likelihood that health effects may be deferred or protracted while the middle boxes show the main climatic-environmental manifestations of climate change (McMichael et al., 2006).

Climate Change and Health Model

The effect of climate change will be greatest on countries that have made little or no contribution to its cause and those with little resources. The implementation of mitigation and adaptation helps to reduce inequity caused by negative effects on social determinants of health in the poorest countries (Costello et al., 2009).

Mitigation can be described as the true prevention/intervention to lessen adverse health effects (McMichael et al., 2006). One of the most important factors in mitigating the effects of climate change on health is to bring to focus the past, present and the future events which have contributed to the transition of land, environment and the way of life of people (Healey et al, 2011). To avoid dangerous climate change, mitigation is required to “reduce greenhouse gas emissions and increase carbon biosequestration through reforestation and improved agricultural practices as well as to ensure a rapid, sustained and effective coordination of global and regional action” (Costello et al., 2009).


Climate change adaptation is required for an improved coordination and accountability of global governance. Climate change health effects can be managed when all sectors of government, civil society and academic disciplines work together to get to an expected end. It is crucial that the local communities get involved in monitoring, discussing, advocating and assisting with the process of adaptation (Costello et al, 2009). Local action is required for the prevention of local flooding and global action to make funds available as well as the needed cooperation of government and international agencies to reduce health inequalities in communities (Costello et al, 2009). Some examples of adaptation measures to climate change are shown in table 1.

Table 1: Some examples of adaptation measures to climate change. (Sourced from Bulto et al, 2006)

Adaptation optionsCurrent activitiesFuture activities
Strengthening primary health care and the public health systemSpecific health promotion and preventive programs designed to reduce population vulnerability. Educational programs of environmental risks, including climate change and their effects on human health.Continuous development of health promotion and preventive programs, increasing community participation on health issues, increasing the participation of local governments and other sectors in developing the best conditions of life.
Measures to improve health surveillance systemsProviding forecasts of the main climate-sensitive diseases to all levels of the National Public Health System increase number of early warning systems to predict epidemics.Continuous research to improve forecast models using the necessary indices.

Incorporating new diseases and risk factors in the forecast models.

Decreasing uncertainty through improved data and research on climate, epidemic, ecologic and social variables.
Immunization programs, especially for high-risk groupsMaintaining the current vaccination program and prioritizing new programs.Enhancing vaccination programs immunization program and develop a prevention program for diseases.
Improve sanitary conditionsDeveloping responses to increased sanitary demands in all fields (communal, drinking water, garbage, sewage, food, and others). Maintaining contingency plans.Developing educational programs about environmental care with the participation of the community, government, and all sectors. Increasing environment care projects. Improving contingency care projects.
Educational programs on radio and TV and newspapersDevelop educational programs on the health risks associated with climate change Implementing new programs on climate-health associations and communicate results to the population, governments and others.
Exchange information with international researchers working on climate change and health issuesParticipate in international meetings.Develop new projects with participation from other countries.

Other Strategies and Interventions

Public health services are very essential for reducing the challenges brought about by climate change. The services can help to “monitor the health status of the community, investigate and diagnose health problems and hazards, inform and educate people regarding health issues, mobilize partnerships to solve community problems, support policies and plans to achieve health goals, enforce laws and regulations to protect health and safety, connect people to required personal health services, ensure a skilled, competent workforce, evaluate effectiveness, accessibility and quality of health services, research and apply innovative solutions” (Allen, 2010).

The health and well being of humans can be increased by developing a variety of strategies for coping with climate change and reversing its ill effects such as recycling materials. These would greatly help to improve personal choices, enhance sustainability, discourage waste and clean up communities (Healey et al, 2011). Another strategy is to create awareness about the effects of climate change by ensuring individuals are educated and well informed as well as engaging people in political action to strengthen communication and ensure more equitable access to facilities (Healey et al, 2011).

Interventions put in place to reduce the declination of global freshwater resources caused by rising rates of water extraction and contamination are to scale up water and sanitation services which would help to reduce infectious diseases and avoid the health impacts of decreasing water supplies.

Community participation and social mobilization are needed for addressing health concerns and creating healthy environments. The public health community needs a realistic preventive strategy to make sure healthy environments are maintained and developed from local to global needs as well as a sustainable development and protection of ecosystem services which are very important for human health (WHO, 2005).


In conclusion, climate change should be addressed as an integral part of the big challenge towards a sustainable development. This can be achieved by encouraging communities to get more involved in working towards actualizing change at multiple and socio-ecological levels (Healey et al, 2011). Further attention needs to be placed on this issue by the government as well as the maintenance of public health infrastructure by providing adequate funds for environmental and chronic disease surveillance systems and a well trained work force (English et al, 2009).