Sneezing, Wheezing, Wising Up

Wondering how climate change is affecting you or your loved ones personally, in the here and now? Take a deep breath — if you’re able to — and read on.

The poets like to herald spring as the season when the world is reborn: Love blooms, hope blossoms, and the full-blown flower of humanity bows gracefully toward the nurturing rays of the sun.

For 50 million Americans, though, it can’t be over soon enough. To be perfectly clear, these people aren’t sniveling cynics: They’re sniffling allergy sufferers. And if you’re unfortunate enough to count yourself among their ranks, I know I don’t have to describe for you the ambivalence that comes with seeing the first brilliantly colored crocuses popping out of the half-frozen soil in March, or with inhaling the fragrance of freshly cut lilacs just a few weeks into April. Because as you already know, these unmistakable harbingers of spring are also unmistakable harbingers of the bloodshot eyes, scratchy throats, runny noses, and inflamed sinuses to come as allergy season gets fully underway.

It’s enough to make many of us nostalgic for winter snow-shoveling. Not all of us, though: The 26 million Americans who suffer from chronic asthma have already learned to be extra cautious about overtaxing their lungs. This treatable but incurable respiratory disease can make the simple, involuntary act of breathing into a laborious — and frequently terrifying — task. As bad as both of these conditions can be by themselves, they’re even worse when they team up — which they do more often than you might suspect. About 70 percent of asthmatics worldwide also suffer from some form of allergic rhinitis, which is the scientific term for nasal allergies and hay fever. And episodes of allergic rhinitis, as it happens, are surefire triggers for asthma attacks.

When my colleagues at NRDC and I began looking into the statistics for these two maladies, we were struck by several things. One was the basic and easy-to-spot increase in the prevalence of both afflictions over the last several years. In the United States, asthma prevalence has increased from about 20 million sufferers in 2001 (7 percent of the population) to almost 26 million sufferers in 2010 (8.4 percent of the population). Meanwhile, in the States and other industrialized countries, there’s ample evidence to indicate that respiratory allergic diseases are also increasing in both prevalence and severity.

When we began cross-referencing these data sets with certain others, what we discovered strongly suggested a causal relationship between both respiratory ailments with the rising levels of climate change–related atmospheric carbon dioxide. Our conclusions, published in this just-released update of our 2007 report exploring the roots of this relationship, add to the ever-lengthening list of indictments that can fairly be leveled against climate change for crimes against public health. If you’ve ever wondered exactly how global warming is affecting you and your loved ones in the here and now, here’s Exhibit A.

The most powerful triggers for an episode of allergic rhinitis or an asthma attack are, respectively, ragweed pollen and ground-level ozone. With regard to the former, studies have shown that as temperatures and atmospheric CO2 levels rise, the production of allergenic ragweed pollen rises along with them. To add insult to injury, not only do ragweed plants grow larger and generate more sneeze-worthy stuff in the presence of higher concentrations of CO2, they also generate it for longer stretches of time — effectively extending allergy season at both ends of its seasonal window.

The relationship between climate change and ozone, for its part, is as multifaceted as it is nefarious. At ground level, ozone is generally formed when two types of pollutants, nitrogen oxides and volatile organic compounds (VOCs), chemically react in the presence of sunlight and warm temperatures. Emissions from vehicles, power plants, and industrial facilities just happen to contain both of these pollutants in high concentrations. In addition, VOCs can and often do emanate from certain types of vegetation — vegetation whose growth, of course, is only enhanced by the higher temperatures that climate change is already responsible for. Perversely, increased ozone thus has the distinction of being both a cause of climate change and an effect of it.

Our research also led us to two more inescapable conclusions regarding the allergy/asthma/climate change nexus. First: For the millions of Americans who suffer from both asthma and allergies, it’s much harder to live in the city than it is to live in the country, despite the fact that so much more vegetation can be found in the latter than in the former. The reason is that asthma-triggering ozone is inevitably found at higher levels in urban and suburban areas — as is ragweed, which thrives wherever emissions and disturbed soils combine. (An appendix to our report ranks 35 of America’s “Sneeziest and Wheeziest” cities for 2014, in order from worst to best, for people in this unlucky crossover category.)

The second conclusion, while equally inescapable, is far less surprising to anyone whose research area is the intersection of climate change and public health. Unless we act immediately to reduce emissions, every last one of the major problems attributable to climate change is going to get worse — much worse. Our planet has recently hit a pair of ominous milestones. Last year was the hottest year on earth since recordkeeping began in 1880, and March of 2015 was the first month in recorded history in which global CO2 levels didn’t fall below 400 parts per million. If we don’t reverse these trends, respiratory allergies and asthma symptoms will get worse for those who suffer them, making daily life an exercise in gasping, wheezing anxiety. Although by that point, allergies and asthma won’t be our biggest problems. Not by a long shot.