There are issues that concern me deeply as a population and environmental health scientist. Will we have enough food for a growing world population? How will we care for more people in the next pandemic? What will the heat do to millions of people with high blood pressure? Will countries fight water wars due to increased droughts?
All these risks have three things in common: health, climate change and a growing population that, according to the United Nations, will reach 8 billion people around November 15, 2022, double the population of just 48 years old.
In my 40-year career, first working in the Amazon jungle and the Centers for the Control and Prevention of Diseases, and living in the academic world, I found myself with many threats to public health, but no one as intransigent and widespread as climate change.
Of the multitude of climate-related adverse health effects, the following four represent the greatest public health concerns for a growing population.
Infectious diseases
Researchers have found that more than half of all human infectious diseases could be made worse by climate change.
Floods, for example, can affect water quality and habitats where dangerous bacteria and vectors, such as mosquitoes, can breed and transmit infectious diseases to people.
Dengue, a painful, mosquito-borne viral disease that sickens about 100 million people a year, is more common in hot, humid environments. Its R0, or basic reproduction number, an indicator of how quickly it spreads, has increased by about 12% since the 1950s to average in 2012-2021, according to the 2022 Lancet Countdown report. % in the mountainous areas of Latin America and almost 14% in the highlands of Africa when temperatures increased during the same period.
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 live in areas with poor-quality water for drinking or washing.
Droughts can also degrade the quality of drinking water. As a result, more rodent populations are entering human communities in search of food, increasing the potential for hantavirus to spread.
extreme heat
Another serious health risk is rising temperatures.
Excessive heat can aggravate existing health problems, such as cardiovascular and respiratory diseases. And when heat stress turns into heatstroke, it can damage the heart, brain and kidneys and become fatal.
Today, around 30% of the world’s population is exposed to life-threatening heat stress each year. The Intergovernmental Panel on Climate Change estimates that the percentage will increase to at least 48% and up to 76% by the end of this century.
In addition to lost lives, heat exposure is projected to result in 470 billion potential lost work hours globally in 2021, with associated revenue losses totaling up to $669 billion. As the population grows and the heat rises, more people rely on fossil fuel-powered air conditioning, further contributing to climate change.
Food and water security
Heat also affects the food safety and water for a growing population.
The Lancet review found that high temperatures in 2021 shortened the growing season by about 9.3 days on average for corn and six days for wheat compared to the 1981-2020 average. Meanwhile, warming oceans could kill shellfish and alter the fisheries coastal communities depend on. In 2020 alone, heat waves caused 98 million more people to face food insecurity compared to the 1981-2010 average.
Rising temperatures also affect freshwater supplies through evaporation and shrinkage from mountain glaciers and snow cover that historically kept water flowing during the summer months.
Water scarcity and drought have the potential to displace nearly 700 million people by 2030, according to UN estimates. Combined with population growth and rising energy needs, they can also fuel geopolitical conflicts as countries face food shortages and compete for water.
bad air quality
Air pollution can be exacerbated by the drivers of climate change. Hot weather and the same fossil fuel gases that warm the planet contribute to tropospheric ozone, a key component of air pollution. This can exacerbate allergies, asthma and other breathing problems, as well as cardiovascular disease.
Wildfires fueled by hot and dry landscapes increase health risk due to air pollution. Smoke from wildfires is loaded with tiny particles that can penetrate deep into the lungs and cause heart and breathing problems.
What can we do?
Many medical and expert groups are working to combat this cascade of negative climate consequences for human health.
The US National Academy of Medicine has embarked on a grand and ambitious challenge on climate change, human health and equity to advance research. At many academic institutions, including the University of Pittsburgh School of Public Health, of which I am dean, climate and health are being integrated into research, teaching and service.
Addressing the health burden in low- and middle-income countries is critical. Often, the most vulnerable people in these countries face the greatest damage from climate change without the resources to protect their health and the environment. Population growth can deepen these inequalities.
Adaptation assessments can help high-risk countries prepare for the effects of climate change. Development groups are also spearheading projects to expand the cultivation of crops that can thrive in drought conditions. The Pan American Health Organization, which focuses on the Caribbean, is an example of how countries are working to reduce communicable diseases and increase regional capacity to counteract the impact of climate change.
Ultimately, reducing health risks will require reducing the greenhouse gas emissions that are driving climate change.
Countries around the world committed in 1992 to reducing greenhouse gas emissions. Thirty years later, global emissions are just starting to decline, and communities around the world are increasingly facing extreme heat waves and devastating floods and droughts.
The United Nations Climate Change Conference to be held in November 2022, which is not sufficiently focused on health, in my opinion, can help to draw attention to the main climate impacts that harm health. As UN Secretary-General António Guterres noted: As we celebrate our progress, “at the same time, it is a reminder of our shared responsibility to care for our planet and a time to reflect on where we still fall short in our commitments to one another. . 🇧🇷 🇧🇷
This article was written by Maureen Lichtveld, Dean of the School of Public Health at the University of Pittsburgh. Republished from The Conversation under a Creative Commons license. Article in English
