How can a warming planet support 8 billion people?

There are questions 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 hypertension? Will countries wage water wars due to increased droughts?

All of these risks have three things in common: health, climate change, and a growing population that
United Nations forecast
it would exceed 8 billion people on November 15, 2022, double the population of just 48 years ago.

In Myself
40 year careerfirst working in the Amazon rainforest and the Centers for Disease Control and Prevention, and later in academia, I have come across many threats to public health, but none as intransigent and pervasive as climate change.

Of the multitude of weather-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
It may get worse with climate change.

Flooding, 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 makes sick
about 100 million
people per year, it becomes more common in warm and humid environments. Its R0, or basic reproduction number, an indicator of how fast it spreads,
increased by 12 percent
from the 1950s to the average in 2012-2021, according to the 2022 Lancet Countdown report. Malaria season expanded by 31 percent in highland Latin America and nearly 14 percent in highland Africa as temperatures rose over the same period.

Extreme heat

Another serious health risk is rising temperatures.

Excessive heat can
exacerbate existing health problemsWhat
cardiovascular
and respiratory diseases. And when heat stress turns
heatstrokecan
damage the heart, brain, and kidneys
and become lethal.

Today, about 30 percent 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 percent and as high as 76 percent
at the end of this century.

Food and water safety

The heat also affects food and water security for a growing population.

The Lancet review found that high temperatures in 2021
shortened the growing season
at about 9.3 days on average for corn and six days for wheat compared to the 1981-2020 average. Meanwhile, warming oceans may kill shellfish and change
fisheries on which coastal communities depend. In 2020 alone, heat waves caused
98 million more
people facing food insecurity compared to the 1981-2010 average.

Rising temperatures also affect freshwater supplies through evaporation and reduced
mountain glaciers
Y
blanket of snow
which have historically kept the water flowing during the summer months.

poor air quality

Air pollution can be
exacerbated by drivers of climate change. Hot weather and the same gases from fossil fuels that warm the planet
contribute to tropospheric ozone, a key component of smog. That can exacerbate allergies, asthma and other respiratory problems, as well as cardiovascular disease.

Wildfires Fueled by Hot, Dry Landscapes
increase the health risk of air pollution. Wildfire smoke is loaded with tiny particles that can travel deep into the lungs,
causing heart and breathing problems.

What can we do about it?

Many medical groups and experts are working to counter this cascade of negative climate consequences for human health.

Addressing the health burden in low- and middle-income countries is critical. Often the
most vulnerable
people in these countries
cope with the further damage of climate change
without having the resources to protect their health and the environment. Population growth can
deepen these iniquities.

Adaptive Assessments
it can help high-risk countries prepare for the effects of climate change. Development groups are also leading projects to
expand crop cultivation
which can thrive in dry conditions. the
Pan American Health OrganizationFocusing on the Caribbean, it is an example of how countries are working to reduce communicable diseases and promote regional capacity to counteract the impact of climate change.

Ultimately, reducing health risks will require
reduce greenhouse gas emissions
that are driving climate change.

Countries around the world
committed in 1992
to reduce greenhouse gas emissions. Thirty years later, global emissions are
just beginning to flattenand communities around the world are increasingly experiencing extreme heat waves and devastating floods and droughts.

the
UN Climate Change Talks, which are, in my opinion, not sufficiently focused on health, can help draw attention to key climate impacts that harm health. As UN Secretary General António Guterres noted: While 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 of our commitments to one. other.”

Maureen Lichtveld is the dean of the University of Pittsburgh School of Public Health.
Samantha Totoni, Ph.D. candidate there, contributed to this article, which was first published by Conversation.

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