No pediatrician will doubt the importance of adequate food, clean air and water, and freedom from disease to the health of a child. In fact, the greatest improvements to children's health over the last century can be linked to improvements in each of these areas.
Unfortunately, climate change puts all of these achievements at risk. Because of the increased risks for heat waves, droughts, and floods, as well as sea level rise more greenhouse gases in the atmosphere make food shortages more likely, lessen air quality, diminish freshwater supplies, and may create conditions favorable the spread of certain infectious diseases.
Here are a few areas in which recent research has deepened our understanding of how climate change has influenced and will continue to influence the health of children.
As cold-blooded creatures, insects, including those mosquitos and ticks that may transmit infections to humans, must adapt to a changing climate. Studies of recent climate change have established that while average minimum temperatures have risen, nighttime minimum temperatures have risen faster. In addition, higher latitudes are warming faster than the tropics. These findings lend credence to predictions of wider distribution of insects, and with them, raise the possibility of more vector-borne disease, as more land area falls into a temperature range conducive for their survival.
The most common vector borne disease in North America and Europe, for example, is Lyme disease, with 25,000-30,000 cases reported to the U.S. CDC annually. In the United States, children ages 5-9 have the highest annual incidence of Lyme disease. The primary vector here is the blacklegged tick, which has been expanding its northward range into Canada as annual temperatures warm.
However, even with warming since the Industrial Revolution, the distribution of many infections transmitted by mosquitoes has declined dramatically due to draining of mosquito wetland habitats, pesticides and other measures.
Air quality, allergies and asthma
Climate change, and the greenhouse gases that are causing it, matter for those who have seasonal allergies and asthma. Carbon dioxide itself fuels greater pollen production from plants such as ragweed, a well-known cause of seasonal allergies. In addition, warming has led to earlier springs and longer growing seasons for many plants, and evidence indicates that the pollen season in parts of the United States may have grown by two weeks, or more, since the 1990s.
Warmer temperatures, and heat waves in particular, promote the production of ground level ozone. Ozone high in our atmosphere protects us from harmful ultraviolet radiation. However, at ground level, inhaling ozone harms lungs. Ozone is produced when several chemical byproducts of burning fossil fuels are exposed to sunlight. More ozone tends to get produced when temperatures are higher (although if temperatures get well above 100°F or 39°C this is no longer the case). This potent air pollutant is a known trigger for asthma attacks in children as well as breathing troubles for adults with chronic lung diseases.
For those who rely upon lakes, rivers and streams for their drinking water, and even more so for those who rely upon snow melt, a warming climate may endangers the supply of this vital resource. Warming temperatures are causing glaciers to melt around the globe. Their retreat puts at risk the water supply to some 200 million people.
Warming also causes sea levels to rise, in part from melting sea ice, but largely due to water expanding as it warms (the world’s oceans have absorbed roughly 90% of the warming that has happened on Earth over the past 50 years). Rising seas may intrude into coastal groundwater supplies making them unsuitable for drinking or irrigation.
Today, about 80% or 5.6 billion people live in areas of water scarcity. Climate change adds to the challenge of providing adequate and safe fresh water to meet our needs.
For the first time since the Industrial Revolution, we are on the cusp of transforming the energy sources that supplies our lives. The decisions made today about where our energy will come from and how it will be used will have longstanding effects upon our health, just as the choice to exploit fossil fuels two centuries ago affects our health today. We have a remarkable opportunity, as this energy shift unfolds, to find energy sources that provide for the healthiest possible future for all.