Will we have enough food for the growing world population? How will we serve more people in the next pandemic? What will heat do for millions of hypertensives? Will countries start water wars because of increasing drought?
All these risks have three things in common: health, climate change, and a growing population that will reach 8 billion people around November 15, 2022, according to the United Nations estimates, that is, twice the population of just 48 years ago.
In my 40-year career working first in the Amazon rainforest and the Centers for Disease Control and Prevention, then in academia, I have faced many public health threats, but none as resilient and pervasive as climate change.
Of the many adverse health effects associated with the weather, the following four represent the greatest public health concerns for a growing population.
1. Infectious diseases
Researchers have found that more than half of human infectious diseases may worsen with climate change.
For example, floods can affect water quality and habitats where dangerous bacteria and vectors such as mosquitoes can breed and transmit infectious diseases to humans.
Dengue fever, a painful mosquito-borne viral disease that sickens about 100 million people a year, is more common in warm, humid environments. An indication of how quickly it spread, the R0, or baseline reproduction number, increased by about 12% from the 1950s to the 2012-2021 average. As temperatures rose during the same period, the malaria season expanded by 31% in the highlands of Latin America and by almost 14% in the highlands of Africa.
Floods can also spread waterborne organisms that cause hepatitis and diarrheal diseases such as cholera, particularly when large numbers of people are displaced by disasters and living in areas with poor quality water for drinking or bathing.
Drought can also reduce the quality of drinking water. As a result, more rodent populations are entering human communities in search of food, increasing the potential for hantavirus spread.
2. Excessive heat
Another serious health risk is rising temperatures.
Extreme heat can exacerbate existing health problems such as cardiovascular and respiratory diseases. When heat stress turns into heat stroke, it can damage the heart, brain, and kidneys and can be fatal.
Currently, approximately 30% of the world’s population suffers from life-threatening heat stress each year. The Intergovernmental Panel on Climate Change predicts that this proportion will rise to at least 48% and 76% by the end of this century.
Where climate change impacts human health. Centers for Disease Control and Prevention
In addition to the lives lost, exposure to heat is estimated to potentially cause 470 billion working hours worldwide in 2021, with a corresponding loss of $669 billion in revenue. As the population increases and the temperature rises, more people will rely on fossil fuel-powered air conditioners, which will further contribute to climate change.
3. Food and water security
Heat also affects the food and water security of a growing population.
A review by The Lancet found that high temperatures in 2021 shortened the growing season by an average of 9.3 days for corn and six days for wheat, compared to the 1981-2020 average.
Meanwhile, ocean warming could kill shellfish and replace the fisheries that coastal communities depend on. Heatwaves in 2020 alone caused 98 million more people to face food insecurity than the 1981-2010 average.
Rising temperatures also affect freshwater supplies through evaporation and shrinking of mountain glaciers and snowdrifts, which historically allowed water to run off during the summer months.
According to UN estimates, water scarcity and drought have the potential to displace around 700 million people by 2030. Combined with population growth and rising energy needs, they can also fuel geopolitical conflicts as countries face food shortages and compete for water.
4. Poor air quality
Air pollution can be exacerbated by climate change factors. Hot air and the same gases from fossil fuels that warm the planet contribute to ground-level ozone, a major component of pollution. This can exacerbate allergies, asthma and other respiratory problems, as well as cardiovascular disease.
Forest fires fueled by hot, dry environments increase the risk of air pollution damaging health. Smoke from wildfires is loaded with tiny particles that can reach the lungs and cause heart and respiratory problems.
What can we do about it?
Many medical groups and experts are working to counter these adverse climate consequences on human health.
Addressing the health burden in low- and middle-income countries is critical. Often the most vulnerable people in these countries suffer the most from climate change, without the necessary resources to protect their health and the environment. Population growth can exacerbate these inequalities.
Adaptation assessments can help high-risk countries prepare for the impacts of climate change. Development groups are also spearheading projects to expand crops that can thrive in drought conditions. Focusing on the Caribbean, the Pan American Health Organization is an example of how countries are working to reduce communicable diseases and build regional capacity to respond to the impacts of climate change.
Consequently, reducing health risks will require reducing greenhouse gas emissions that cause climate change.
Countries around the world made a commitment to reduce greenhouse gas emissions in 1992. Thirty years later, global emissions are only beginning to slow and communities around the world are increasingly experiencing extreme heat waves, devastating floods and droughts.
The 27th United Nations Conference on Climate Change – and I think that does not focus enough on health – can help to draw attention to the significant climate impacts that are detrimental to health. As UN Secretary-General António Guterres put it: While celebrating our progress, “it is also a reminder of our shared responsibility to care for our planet and a time to reflect on where we are failing to deliver on our commitments.” ”
Samantha Totoni, PhD candidate in the University of Pittsburgh School of Public Health, contributed to this article. 
Maureen Lichtveld, Dean of the School of Public Health, University of Pittsburgh
This article was originally published at: Speech. Read the original.
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