Impact Of Climate Change On Human Health

Climate change is expected to cause approximately 250,000 additional deaths annually, from malnutrition, malaria, diarrhoea, and heat stress.

Climate change refers to long-term shifts in temperatures and weather patterns. These shifts may be natural, such as through variations in the solar cycle.

The Earth’s temperature today is 1.1 degrees Celsius higher than in the late 1800s. The decade from 2011 to 2020 was the warmest on record.

Since the 1800s, human activities have been the main driver of climate change, mainly due to burning fossil fuels like coal, oil, and gas that generates greenhouse gas emissions which trap the sun’s heat and raise temperatures.

The greenhouse gas emissions include carbon dioxide and methane. The former comes from using gasoline for driving vehicles, coal for heating, and clearing land and forests.

Landfills for garbage are a major source of methane emissions. Energy, industry, transport, buildings, agriculture and land use are among the main emitters of greenhouse gases.

Scientists estimate that greenhouse gases are at their highest levels in two million years.

The impacts of climate change include warming temperatures, changes in precipitation, increases in frequency or intensity of extreme weather events, and rising sea levels.

The severity of these health risks depends on the public health and safety systems that address or prepare for these threats, and factors like individual behaviour, age, gender, and economic status. Impacts will vary depending on a where a person lives, their sensitivity to health threats, their exposure, and how well they and their community adapt to change.

The most vulnerable are those in developing countries and the disadvantaged in all countries.

Temperature Impacts

Warmer temperatures will lead to hotter days, more frequent and longer heat waves, and an increase in heat-related deaths.

Exposure to extreme heat can lead to heat stroke, dehydration, and cardiovascular, respiratory, and cerebrovascular disease. Heat waves are also often accompanied by periods of stagnant air, leading to increases in air pollution and associated health effects

Air Quality Impacts

Climate change affect indoor and outdoor air quality. Warmer temperatures and shifting weather patterns lead to asthma attacks and other respiratory and cardiovascular health effects.

Wildfires, which are expected to continue to increase in number and severity, create smoke and other unhealthy air pollutants. Rising carbon dioxide levels and warmer temperatures also affect airborne allergens like pollen.

Scientists project that warmer temperatures will increase the frequency of unhealthy levels of ground-level ozone, a harmful air pollutant, and a component in smog.

Ground-level ozone can damage lung tissue, reduce lung function, and inflame airways. This can aggravate asthma or other lung diseases, increase hospitalizations and premature deaths.

Particulate matter refers to a category of extremely small particles and liquid droplets suspended in the atmosphere. Some particulate matter like dust, wildfire smoke, and sea spray occurs naturally, while some is created by human activities.

These particles may be emitted directly or may be formed in the atmosphere from chemical reactions of gases like sulphur dioxide, nitrogen dioxide, and volatile organic compounds. Inhaling fine particles can lead to chronic obstructive pulmonary disease (COPD), cardiovascular disease and lung cancer.

Tobacco smoking is a major contributor to air pollution. The toxic products released into the air increases the risk of exposure of everyone in the room.

It has been estimated that second-hand smoking is responsible for 1.2 million premature deaths annually worldwide, in addition to suffering from cardiovascular and respiratory diseases.

An Italian study reported that three cigarettes caused 10 times more pollution than a diesel car exhaust.

Extreme Weather

The increased frequency or severity of some extreme weather events like extreme precipitation, flooding, droughts, and storms, threaten human health during and after the event.

The ways in which human health is affected include a reduction of available safe food and drinking water, damaged roads and bridges which disrupt access to health care facilities, interruption of communication, utility, and health care services, an increase in waterborne diseases and creation or worsening of mental health, and carbon monoxide poisoning following improper usage of portable electric generators. 

Evacuations may impact health care delivery. Those with disabilities may be disproportionately affected because of access to evacuation or limited communication ability.

Waterborne Illnesses

Sickness can follow from exposure to contaminated drinking or recreational water. Climate change increases the risk of water borne illness through increased temperature, frequent heavy rains and runoff, and the effects of storms.

It affects exposure to waterborne pathogens, i.e. bacteria, viruses, and parasites; toxins produced by harmful water organisms; and chemicals that end up in water from human activities.

Extreme weather events and storm surges can damage or exceed water infrastructure capacity and increases the risk of exposure to contaminants.

The health impacts may include gastrointestinal illness, effects on the nervous and respiratory systems, or liver and kidney damage.

Food Safety

Climate change and higher atmospheric carbon dioxide concentrations can affect food safety and nutrition. Extreme weather events can also disrupt or impair food distribution.

Higher air temperatures increase bacterial growth that cause gastrointestinal diseases and in severe cases, death.

There are various impacts that may increase exposure to chemical contamination of food e.g. higher sea temperatures lead to higher mercury levels in seafood, and introduction of food contaminants through storm water runoff.

Higher carbon dioxide concentrations in the air lowers protein and essential mineral levels in crops like rice, wheat and potatoes, thereby reducing its nutritional value. 

Mental Health

Any changes in individuals’ physical health or environment can impact on their mental health, especially with extreme weather events with loss of loved ones or home(s).

Individuals with pre-existing mental illness are vulnerable to extreme heat with thrice the risk of death during heat waves as some medicines they take increases their difficulty in body temperature regulation. 

Some groups are more vulnerable to mental health impacts e.g. children, senior citizens, pregnant women, those with pre-existing mental illness, and emergency staff.

The impact on climate change on mental is complex, differ greatly and can be direct or indirect, short or long-term, with different timings. The link between climatic events and mental health has led to new terms proposed recently, e.g. ecoanxiety, ecoguilt, ecological grief, etc.

New Diseases

A modelling study published in Nature on April 28, 2022 projects that climate change will force new encounters between animals and boost viral outbreaks. It predicts that over the next 50 years, climate change could drive more than 15,000 new cases of mammals transmitting viruses to other mammals.

The increased encounters between species capable of swapping pathogens will occur most often in species-rich ecosystems at high elevations, particularly in Africa and Asia, and in densely populated areas including Africa’s Sahel region, India and Indonesia.

The number of first-time meetings between species will double by 2070, creating virus-transmission hotspots.

This increased likelihood of viruses jumping between species could trigger more outbreaks, posing serious threat to human and animal health, i.e. more pathogens will jump from animals to humans in the coming decades. In short, it will not only be hotter but humans will be sicker.

In summary, the impacts of climate change on human health are varied. According to the World Health Organization, climate change is expected to cause approximately 250,000 additional deaths annually, from malnutrition, malaria, diarrhoea, and heat stress, between 2030 and 2050.

Dr Milton Lum is a Past President of the Federation of Private Medical Associations, Malaysia and the Malaysian Medical Association. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation the writer is associated with.

  • This is the personal opinion of the writer or publication and does not necessarily represent the views of CodeBlue.

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