Image Credit: Lodahln (CC-BY-SA 2.0, flickr)

I woke up in the middle of the night again. Scratchy throat? Insatiably itchy eyes? Just a bit of cough? Oh yeah. Had to be ragweed. Time to start back on the allergy pills.

Admittedly, my fall allergies aren’t nearly as bad as the wave of foggy headedness, poor sleep, and eyeball itching that haunts me every springtime. Still, it’s unpleasant. For many others in eastern and central North America, the sneezing and stuffy noses can be all but debilitating. Unfortunately for people suffering the symptoms of ragweed allergy, the future looks to contain harsher allergy seasons and higher pollen counts thanks to climate change.

To be fair, Ragweed, despite being synonymous with human suffering, is exceptionally important for many bird species. The shrubby little plant produces seeds which are a critical winter food source for native birds. Its pollination abilities are also fairly remarkable; the wind can carry a grain of ragweed pollen as far as 400 miles from its source plant. That kind of wind-based range, and the fact that pollinating in the fall allows a long growing season, means that ragweed is well positioned to benefit (from its own point of view, anyway) in a warmer climate.

Climate change is providing several aspects that make ragweed allergy symptoms worse. At the most basic, a warmer climate with milder winters and earlier springs means that ragweed can start growing earlier. That extra time means plants can grow larger and produce more grains of pollen. Ragweed plants have also been found to respond directly to an increase in atmospheric CO2. In lab tests, higher levels of carbon dioxidecaused ragweed to pack more of the protein responsible for allergy symptoms into each grain of pollen.

It’s not just ragweed pollen that benefits from these shifts in climate. Both oak and hickory trees are anticipated to become more problematic for allergy sufferers as a warmer climate allows for an expansion of their range across eastern North America. A larger range means more trees means more pollen.

Mold allergies, too, are expected to increase as climate change increases flood events. With a greater incidents of building flooding comes an increase in mold development and the detrimental impact its spores can cause. It’s even thought that higher temperatures might increase indoor mold exposure as people crank up their air conditioners more frequently. A greater dependence on these machines means an increase in condensation that lets fungus thrive in poorly maintained units.

The climate and allergy connections don’t stop at just CO2,either. Air pollution, a topic that is inextricably linked to climate change, is also making allergies worse in some interesting ways. Certain pollutants released by burning fossil fuels, such as nitric oxide and nitrogen dioxide, can boost the allergenic ability of pollen by degrading the grain’s cell wall and allowing more symptom-causing proteins to be released once inside the body. There’s also evidence that exposure to airborne pollutants can cause plants to create higher concentrations of allergenic proteins, although it’s not entirely clear why.

Of course, air quality degradation has health consequences more severe than just sniffly noses. Children exposed to higher levels of air pollution are at greater risk of asthma and impaired lung function. Pregnant mothers exposed to air pollution are at higher risk of pre-term birth and fetuses with low birth weight. In older adults, chronic exposure to air pollution carries risk of developing and advancing respiratory conditions like COPD, bronchitis, asthma, and emphysema. These effects are not evenly spread, either. Less affluent populations and communities of color in the United States are bearing the burden of air pollution more heavily than their richer, whiter counterparts.

Climate change also degrades air quality in other ways. As seen recently in western North America and Australia, increasingly severe wildfires and the smoke they generate are disruptive to people’s lives and dangerous to human health. Able to drift on air currents for upwards of 600 miles, the smoke from these fires can cause respiratory distress in even healthy individuals as well as carry dangerous chemical pollutants from facilities caught in the flames.

The ways climate change interacts with allergy and respiratory issues are complex. Increasing greenhouse gas levels from our burning of fossil fuels impacts the health and comfort of allergy suffers today and threatens to be even more of a menace for every year we fail to contain it. Similarly increasing consequences can be found in issues from public health to financial security to social stability. Our failure to adapt our social systems to the reality of climate change is killing us, and I for one am sick of coughing.

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