An update on the health effects from climate change
Climate changes that affect our health
Most of us are becoming increasingly aware of changing weather patterns, reports of droughts and flooding, larger and stronger hurricanes and cyclones, rapid melting of ice fields and changes in our air and water quality. Most of the dramatic changes we read about today are occurring in the earth’s northern and southern regions. These dramatic changes, along with many subtle environmental changes closer to home, ultimately can lead to diseases or exacerbate pre-existing chronic conditions.
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 increased visits to emergency departments for asthma, along with an associated increase in premature deaths.
Because of increases in the number of wildfires due to changing rain patterns and droughts, the air quality in many communities on the West Coast were adversely affected. The cardiovascular and pulmonary systems are over stressed when breathing in air pollutants, leading to shortness of breath, coughing and asthma symptoms. For individuals with chronic obstructive disease and emphysema, this exposure can lead to respiratory failure and severe strain on cardiac functioning.
Persons with lung and breathing conditions are also at high risk for acute onset of breathing problems when exposure to pollen, molds and dust particles in areas of flooding or draught.
Warmer water and floods can cause a great deal of human disease. Certain marine bacteria will proliferate in warmer oceans, causing diarrheal illnesses, especially when consumed in raw and undercooked shell fish, especially oysters.
The same problems can occur in fresh waterstreams and lakes when the temperature of the water increases. Ameba, parasites and other 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 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 associated with alterations in wind, rain, moisture and heat circulation are changing worldwide. These changes can lead to extreme heat events.
Small children, the elderly, people with chronic respiratory and neurological conditions and outside workers are at high risk for heat-related illnesses. Many cities across the country are experiencing increases in death rates from heat waves.
Vectorborne and zoonotic diseases (VBZD)
Vector-borne diseases usually involve insects like mosquitoes, ticks and mites to spread. Zoonotic diseases are spread from insects and animals to humans by direct contact. Examples of these types of diseases include malaria, yellow fever, dengue fever, Lyme disease, West Nile virus and Zika-associated conditions. Changes in precipitation and temperature affect the spread of VBZD by allowing insects and other vectors to expand or spread to new areas. This includes extending diseases to other countries by travelers.
In our area, we are experiencing more tick-borne diseases due to milder winters, earlier springs and hotter summers benefiting the survival of ticks.
Although not directly connected to local climate changes, many of us are potentially exposed when we travel to areas that have endemic diseases. Many times, the local weather and rain patterns increase the population of mosquitoes that carry the diseases listed above.
It is now a relatively common experience for people on returning home to begin to show signs of a vector-borne infection and consult with their physician. It is important for the primary-care physician to take a travel history that can provide clues to a potentially serious infection that needs to be accurately diagnosed and treated.
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 health problems related to air, food and water changes, as climate warming progresses. There is a urgent need for a national dialog about ways of reducing the trend of global warming and its impact on current and future health issues.