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.
One way to address population growth is to deliver effective family planning services. However, some cultural, moral and religious objections to contraception can pose practical barriers in the development of these services. WHO (2020b) reports that 214 million women of reproductive age in lower-income countries who want to avoid pregnancy are not using a modern contraceptive method. This is for a variety of reasons, such as limited choice, restricted access, fears associated with side-effects, cultural and religious barriers as well as gender-based barriers.
Ageing populations Viewing the population pyramids for Zambia, it is evident that most societies are projected to have higher life expectancy and have larger proportions of the population who live to much older ages. Storey (2018) estimate that in the UK by 2068, there are likely to be an additional 8.6 million people aged 65 years and over. Globally, estimates of the ageing world population are that by 2050, one in six people in the world will be over age 65 (UN 2019). To some degree this should be seen as the success of health improvement programmes and an economically developed world. However, it does require a revision of what may be needed to provide healthy older age. This is influenced by two main factors:
Increasing life expectancy and related ageing of populations poses a significant threat to individual health and health service provision across society.
The changing patterns of illness and disease to conditions associated with fragility,
