The Health Effects of Global Warming

Infectious Diseases and Death Rates Rise Along With Global Temperatures

Global Health
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Climate change driven by global warming is a reality; the health effects which can be attributed to the changes are measurable and increasing in severity. The World Health Organization reports that between 2030 and 2050, climate change is likely to cause approximately 250,000 additional deaths per year, from malnutrition, malaria, diarrhea, and heat stress.

Key Takeaways: The Health Effects of Global Warming

  • Health effects of climate change have been recorded and are being actively studied in five areas
  • Climate change indicators include sea level rise of 7 inches since 1918, global temperature of 1.9 degrees F higher than in 1880 
  • More than 4,400 people have already been displaced by climate changes
  • Heat waves and other weather-related events are increasing

Climate Change and Health

According to the United States NASA, in 2019, the global temperature was 1.9 degrees Fahrenheit higher than it was in 1880: 18 of the 19 warmest years since then have occurred since 2001. The global sea level has risen 7 inches in since 1910, a fact which is directly attributable to the rise in ambient and sea surface temperature leading to the shrinking of glacial ice at the poles and in the tops of the highest mountains. 

In 2016, the British scientific/medical journal The Lancet announced the Lancet Countdown, an ongoing study to be written by an international team of researchers tracking climate change and its health impacts, as well as supporting efforts to ease the associated problems. In 2018, the Countdown's groups of scientists were focused (in part) on five health-related aspects: health effects of heat waves; change in labor capacity; the lethality of weather-related disasters; climate-sensitive diseases; and food insecurity. 

Health Effects of Heat Waves 

Heat waves are defined as a period of more than three days during which the minimum temperature is greater than the minimum recorded between 1986 and 2008. The minimum temperatures were chosen as measures because coolness in the overnight hours is a vital component helping vulnerable people recover from the heat of the day.

Four billion people live in hot areas worldwide and are expected to experience significantly reduced work capacity as a result of global warming. Health impacts of heat waves range from a direct increase in heat stress and heat stroke to impacts on pre-existing heart failure and acute kidney injury from dehydration. Elderly people, children younger than 12 months, and people with chronic cardiovascular and renal disease are particularly sensitive to these changes. Between 2000 and 2015, the number of vulnerable people exposed to heatwaves increased from 125 million to 175 million.

Changes in Labor Capacity 

Higher temperatures pose profound threats to occupational health and labor productivity, particularly for people undertaking manual, outdoor labor in hot areas.

Increased temperature makes it more difficult to work outside: the global labor capacity in rural populations decreased by 5.3 percent from 2000 to 2016. The level of heat impacts health as a side effect of the damage incurred to people's economic well-being and livelihoods, particularly on those who rely on subsistence farming.

Lethality of Weather-Related Disasters 

A disaster is defined as either 10 or more people killed; 100 or more people affected; a state of emergency is called, or a call for international assistance is made.

Between 2007 and 2016, the frequency of weather-related disasters such as floods and droughts has increased by 46 percent, compared to the average between 1990 and 1999. Fortunately, mortality of these events has not increased, due to better reporting times and better-prepared support systems. 

Climate-Sensitive Diseases 

There are several diseases which are considered sensitive to climate change, falling into the categories of vector-borne (diseases transmitted by insects such as malaria, dengue fever, Lyme disease, and plague); water-borne (such as cholera and giardia); and airborne (such as meningitis and influenza).

Not all of these are currently on the rise: many are being effectively treated by available drugs and health services, although that may not continue as things evolve. However, the cases of dengue fever have doubled every decade since 1990, and there were 58.4 million apparent cases in 2013, accounting for 10,000 deaths. Malignant melanoma, the least common but most lethal of cancers, has also been steadily rising over the past 50 years—annual rates have risen as rapidly as 4–6 percent in fair-skinned people. 

Food Security 

Food security, defined as the availability and access to food, has decreased in many countries, particularly those in East Africa and Southern Asia. Global wheat production drops 6 percent for every 1.8 degree Fahrenheit rise in growing season temperatures. Rice yields are sensitive to overnight minimums during the growing season: an increase in 1.8 degrees means a decrease of 10 percent of rice yield. 

There are one billion people on earth who rely on fish as their principal source of protein. Fish stocks are declining in some regions as a result of sea surface temperature rise, salinity increases, and harmful algal blooms. 

Migration and Population Displacement 

As of 2018, 4,400 people have been displaced from their homes solely as a result of climate change. Those include Alaska, where over 3,500 people had to abandon their villages because of coastal erosion, and in the Carteret Islands of Papua New Guinea, where 1,200 people left because of sea level rise. That has health impacts on mental and physical health of individuals within those communities, and in the communities where the refugees end up. 

That is expected to increase, as the sea level rises. In 1990, 450 million people lived in regions that were below 70 feet above sea level. In 2010, 634 million people (about 10% of the global population) lived in areas that are less than 35 feet about current sea level. 

Health Effects of Global Warming Hardest on Poor Nations

Climate change and global warming are impacting the entire world, but it is particularly hard on people in poor countries, which is ironic because the places that have contributed the least to global warming are most vulnerable to the death and disease higher temperatures can bring.

Regions at the highest risk for enduring the health effects of climate change include coastlines along the Pacific and Indian oceans and sub-Saharan Africa. Large sprawling cities, with their urban "heat island" effect, are also prone to temperature-related health problems. Africa has some of the lowest per-capita emissions of greenhouse gases. Yet, regions of the continent are gravely at risk for diseases related to global warming.

Global Warming is Getting Worse

Scientists believe that greenhouse gases will increase the global average temperature by approximately 6 degrees Fahrenheit by the end of the century. Extreme floods, droughts and heat waves are likely to strike with increasing frequency. Other factors such as irrigation and deforestation can also affect local temperatures and humidity.

Model-based forecasts of health risks from global climate change project that:

  • Climate-related disease risks of the various health outcomes assessed by WHO will more than double by 2030.
  • Flooding as a result of coastal storm surges will affect the lives of up to 200 million people by the 2080s.
  • Heat-related deaths in California could more than double by 2100.
  • Hazardous ozone pollution days in the Eastern U.S. could increase 60 percent by 2050.

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