Contemporary Health Studies. Louise Warwick-Booth

Table 2.1 Changing patterns of disease, illness and health

Notes

      1 Office of Health Economics, http://www.ohe.org/page/knowledge/schools/appendix/life_expectancy.cfm

      2 World Bank Indicators

      3 Hicks & Allen, 1999

      4 United Nations Statistics Division

      5 World Health Organization

Contemporary threats

      It is not possible to consider all health risks within the scope of this chapter; therefore, in this next section we aim to give a sense of the threats drawing on the conceptual framework outlined earlier, rather than producing a definitive list of the major threats to health. More comprehensive reading about risk factors and diseases can be found in the suggestions for further reading at the end of this chapter. This section is organized into a discussion of key global threats to health starting with a description of broader threats and then moving to a focus upon more direct health issues.

Climate change Climate change is now receiving both media and political attention and is certainly a health threat, based upon the evidence that has been gathered about how potential changes in the climate might impact upon health. Table 2.2 outlines different categories of the different key impacts on health.

Table 2.2 Effects of climate change upon health

      Source: adapted from Summerhayes (2010); Donkersley (2019); Haines and Ebi (2019)

Elements of climate change	Impacts of climate change	Effects on health
Extreme weather events	Increased:typhoonscyclonic eventstorrential rainsextended hot dry periods (and associated wild-fires)high windshailstorms.	Increasing burden from malnutrition, diarrhoeal, cardio-respiratory and infectious diseases. Increased morbidity and mortality from heat waves, floods and droughts. Changed distribution of some disease vectors. e.g. mosquitoes transmitting malaria. Risks from populations on the move resulting in homelessness and overcrowded conditions, associated conflicts over land and borders. Substantial burden on health services. Negative impacts upon mental health – exposure to floods and other extreme events can lead to depression and anxiety.
Water	Increased water insecurity and drought in mid and low latitudes.
Food	Food production reduced or entirely lost in some regions. Negative impacts on small holders, subsistence farmers and fishers.
Coasts	Increased damage from floods and storms. Increased costal erosion.
Ecosystems	Increasing species shifts and extinctions may lead to collapse of food chains. Pollution leading to declining insect populations and related decline in pollinators.

Rao (2009) suggests that impacts within the UK may include increased deaths, injuries and disease (because of heat waves; for example, vector-borne diseases), floods and storms, poorer air quality, increased pollens and reduced food safety. Haines and Ebi (2019) highlight several areas of health-related risks, such as direct effects from higher temperatures and indirect effects such as poverty. Extreme weather events are certainly happening more often and when these do occur they result in deaths, disease and injuries because people drown, and sanitation and clean water supplies become a problem. Heavy rains and more flooding may lead to the further spread of diseases carried by rodents. The depletion of the ozone layer is also a related health issue because of increased exposure to ultra-violet radiation (UVR), although this is slowly repairing, following international action (World Meteorological Organization et al., 2018). This is not specifically associated with climate change, rather with air pollution, but too much exposure to UVR can result in many detrimental health effects: sunburn, heatstroke, skin cancers, cataracts and weakened responses to immunizations. The environment is also likely to be affected negatively by climate change and the health impact may again be detrimental.

      Our health is linked to the environment, and the destruction of the natural environment is therefore a threat to our health. In destroying our environment, we threaten our basic needs, such as food, shelter, clean air and water (Stone, 2009; Le Roux et al., 2019). Degraded environments are associated with health problems, and high levels of mortality. Hawkes (2019) highlights that air pollution arising from traffic is responsible for four million new cases of childhood asthma worldwide every year. These numbers are likely to increase as current damage to our environment continues. In 2018, WHO held its first ever Global Conference on Air Pollution and Health in Geneva, reflecting increasing concern with this issue. All of these physical health problems certainly may impact upon mental health too, and the effects of climate change upon mental health have not yet been estimated. For example, post-traumatic stress rates are likely to soar after events like flash floods, typhoons and torrential rains.

      WHO (2014) estimate that approximately 250,000 deaths annually between 2030 and 2050 will be due to climate change, but Haines and Ebi (2019) suggest that this is a conservative assessment. So, even if we begin to tackle some aspects of climate change, and its effects are stopped or even reversed, the impact upon our health still remains a threat. Hence, climate change remains a risk to health for the immediate, as well as the long-term future.

      Population growth An issue intrinsically linked to climate change is the growing population of the world and movements of people from rural to urban areas in search of better and more affluent lives, or to escape war. The Syrian refugee crisis led to the estimated movement (outwards from Syria) of 4.2 million persons in 2010–2015 (UN, 2017). All continents are predicted to increase in population size in the twenty-first century and globally, while the rate of population growth has slowed over the past few decades, the absolute number of people continues to increase. The UN (2019) estimates that the world population is expected to grow to around 8.5 billion in 2030, 9.7 billion in 2050, and 10.9 billion in 2100.

Figure 2.1 illustrates two population pyramids from Zambia in sub-Saharan Africa, indicating the population structure by sex and age categories. The second pyramid is an estimate for 2050, which shows projected increases in total population size, as people live longer.

      Figure 2.1 Population pyramids – Zambia

      Source: data from US Census Bureau

      Population growth is generally argued to be problematic for health because of increased demands for scarce resources including food, shelter, fuel, water and all types of service provision (for example education and health care). These factors will not only impact on physical health but will also threaten social and mental health as a consequence of overcrowded living conditions.