Health impacts of climate change
Regardless of the causes for the warming of our environment, public health officials are very aware of how environmental changes lead to catastrophic health problems for a population because of drought or flooding, starvation from crop failures, or effects of increasing environmental pollution leading to a rise in respiratory problems, such as asthma.
Most of the dramatic changes that are occurring are in our northern and southern regions of the earth. Clear examples are the record melting of ice fields and glaciers in southern Alaska, large shelves of ice breaking off Antarctica, and record-high summer temperatures at the North and South poles. There are also subtle changes occurring that have the potential of effecting our long-term health, especially in terms of air and water quality, food supply and risks from increased vector-borne diseases.
According to the National Climate Assessment, there is an increase in the amount of ground-level ozone (a key part of smog) in many of our larger cities. This is associated with many respiratory problems, including decreased lung function, increased hospital admissions and visits to emergency departments especially for asthma, along with an associated increase in premature deaths.
Because of increases in the number of forest fires this year due to changing rain patterns and droughts, the air quality in many communities is adversely affected. Persons with pre-existing pulmonary and cardiovascular conditions are impacted the most because of sudden onset of respiratory and heart problems. The risk for acute onset of breathing problems also increases with exposure to heightened pollen and mold counts, related to warmer, damper weather. In areas of flash floods or drought, there are either increased levels of mold or dust due to lack of rainfall that will complicate asthma, COPD and emphysema.
Warmer water and floods can cause a great deal of human disease. Certain marine bacteria will proliferate in warmer ocean causing diarrheal illnesses, especially when consumed in raw and undercooked shellfish, especially oysters.
The same problems can occur in freshwater streams and lakes when the temperature of the water increases. Amoebae, parasites and viruses can proliferate when temperatures increase. With heavy rains and floods, sewer plants can spill raw human waste into these bodies of water, causing diseases if people use this water for drinking or recreational activities.
In some coastal areas, algal blooms are more common with warmer water temperatures. The organisms responsible for these blooms release neurotoxins that infect fresh and marine seafood sources that in extreme cases can cause brain damage, respiratory problems and even death.
Climate change can affect crop production directly and indirectly. In cases of decreased rain or drought in some areas of the country, crops are being attacked by infestations of aphids, locusts, white flies, molds and other pests. This often leads to increased use of pesticides, herbicides and fungicides. These chemicals, however, can enter our food supply and can cause a wide range of serious health problems with chronic exposure.
Heat-related health problems
Weather patterns are changing worldwide and are associated with alterations in wind, rain, moisture and heat circulation patterns. These changes do lead to extreme heat events.
As discussed last month in The River Reporter, higher ambient temperatures can lead to life-threatening heat stress conditions such as heat stroke. Small children, older adults and persons with chronic respiratory and neurological conditions and outdoor workers are at high risk for heat-related illnesses. Many cities across the U.S. are experiencing increases in death rates with heat waves.
Vector-borne and zoonotic diseases (VBZD)
Vector-borne diseases usually involve insects, ticks and/or mites to spread diseases. Zoonotic diseases are spread from animals to humans by direct contact. Examples of these types of diseases include malaria, yellow fever, dengue fever and Lyme disease and West Nile virus. Changes in precipitation and temperature affect VBZD spread by allowing insects and other vectors to extend to new geographical areas. A perfect example is the recent surge in tick-borne diseases in our area, due to better survival of ticks resulting from milder winters, earlier springs and hotter summers.
What we need to know
The above information is just a sampling of public health issues confronting medical practitioners today. It is important that all of us remain knowledgeable about environmental changes that are occurring locally, nationally and internationally.
Our healthcare system will need to adapt to future epidemics and address health problems related to air, food and water changes as climate warming progresses. There needs to be a vigorous national dialogue about ways of reducing the trend of global warming and its impact on current and future health issues.