Extreme Allergies and Global Warming - Natural Resources Council ...

Extreme Allergies and Global WarmingN A T I O N A L W I L D L I F E F E D E R A T I O N 2 0 1 0Unchecked global warming will worsen respiratory allergies forapproximately 25 million Americans. Ragweed—–the primary allergentrigger of fall hay fever—–grows faster, produces more pollen perplant, and has higher allergenic content under increased carbondioxide levels. Longer growing seasons under a warmer climate allowfor bigger ragweed plants that produce more pollen later into the fall.Springtime allergies to tree pollens also could get worse. Warmertemperatures could allow significant expansion of the habitatsuitable for oaks and hickories, which are two highly allergenic treespecies. Changing climate conditions may even affect the amount offungal allergens in the air.More airborne allergens could mean more asthma attacks for theapproximately 10 million Americans with allergic asthma. Globalwarming may also exacerbate air pollution, which interacts withallergens to trigger more severe asthma attacks. Cities pose thebiggest health threats for asthmatics because the urban heat islandeffect can exacerbate both pollen production and air pollution. Thesepotential impacts of global warming could have a significanteconomic impact: allergies and asthma already cost the UnitedStates more than $32 billion annually in direct health care costs andlost productivity.Ragweed Pollen: American Academy of Allergy, Asthma and ImmunologyPoison ivy also grows faster and is more toxic when carbon dioxideincreases in the atmosphere. More than 350,000 cases of contactdermatitis from exposure to poison ivy are already reported in theUnited States each year. These numbers are likely to increase ifpoison ivy grows faster and becomes more abundant. The reactionsmay also become more severe because poison ivy produces a morepotent form of urushiol, the allergenic substance, when carbondioxide levels are higher.We must act now to reduce risks for allergy and asthma sufferers.An essential first step is to reduce global warming pollution to avoidthe worst impacts, and enable allergy sufferers to continue enjoyingthe great outdoors. At the same time, states, communities, andhomeowners should undertake smart community planning andlandscaping, with attention to allergenic plants and urban heat islandeffects, to limit the amount of pollen and other allergens thatbecome airborne.C O N F R O N T I N GReportG L O B A L W A R M I N G

Nature Is Noticing the Changing ClimateThe evidence that climate is changingdue to human activities is stronger thanever. 1 The average global temperature in2009 tied for the second highest yearon record and the decade from 2000-2009 is the hottest on record. 2 Duelargely to the burning of fossil fuels, thiswarming is expected to continue for theforeseeable future. By the 2080saverage annual temperatures in theUnited States could be another 3 to 10degrees Fahrenheit warmer than today,depending upon how aggressively wemove to reduce emissions of carbondioxide and other greenhouse gases tothe atmosphere. 3Many aspects of nature are sensitiveto the changes in atmosphericcomposition and climate. Impacts onnature will vary regionally. Individualplant and animal species will responddifferently, sometimes causingecosystem processes to get out ofsynch. At the same time, ecosystemswill continue to be under threat fromchanging land use, urbanization,transportation, and energy production. 4For example, trees and other plantsare beginning to respond to the muchhigher levels of carbon dioxide to whichthey are being exposed. Carbon dioxidelevels in the atmosphere have increasedby about 40 percent since the 1700s. 5They are now at their highest level in800,000 years 6 and perhaps as long as15 million years. 7 Because carbondioxide is essential for plant survival,many plants can grow faster and largeras carbon dioxide levels increase.However, not all plants are respondingthe same way, sometimes reflectinginherently different abilities to use theincreased carbon dioxide, or otherlimitations such as the availability ofwater or other nutrients. 8Longer growing seasons and warmertemperatures are also shifting whereand when plants can grow. Across thecountry, spring arrives an average of 10to 14 days earlier than it did just 20years ago. 9 The preferred ranges formany species are shifting northwardand to higher elevations as trees andother plants are unable to toleratehotter summer conditions. In 2006, theNational Arbor Day Foundation revisedmaps of plant hardiness zones to reflecta distinct northward shift (see below).Precipitation and storm patterns willalso be affected. As warmer air is able toevaporate and hold more moisture, thetrend will be toward more and longerdry periods punctuated by heavierstorms. More heavy rainfall events havealready been observed during the last50 years, during which the amount ofrain falling in the heaviest events hasincrease by 20 percent on averageacross the United States. 10 Climatechange is also expected to shift stormtracks and to bring more extremethunderstorms and wind events. 111990 Map 2006 MapAfter USDA Plant Hardiness Zone Map, USDA MiscellaneousPublication No. 1475, Issued January 1990ZoneNational Arbor Day Foundation Plant Hardiness Zone Mappublished in 20062 3 4 5 6 7 8 9 10©2006 The National Arbor Day FoundationPlant hardiness zone maps are used by gardeners to decide what to plant where. Most areas of the countryshifted to a warmer hardiness zone when the National Arbor Day Foundation revised these maps in 2006to account for recent climate conditions. This shift means that plants that used to thrive in a certain placeare now more suitable for farther north locations. Each zone represents an average of 10 degreesFahrenheit temperature difference.

Ragweed Pollen: More FallHay Fever on the WayHay fever symptoms are familiar tomany: eye irritation, runny nose, stuffynose, puffy eyes, sneezing, andinflamed, itchy nose and throat. Theoffending allergen for about 75percent of people suffering from hayfever is ragweed. An herbaceousrelative of the sunflower, ragweedproduces highly allergenic pollen thatis readily dispersed by the wind. 12Native ragweed plants are foundacross the country, surviving under arange of habitat conditions, and arerenowned for colonizing disturbedareas. Ragweed provides importantwildlife habitat, even though it can be anuisance for people. The plants flowerin late summer and fall. With eachplant able to produce about a billiongrains of pollen each season―pollenthat can be carried up to 400 miles bythe wind―it is no surprise thatragweed allergies already affect somany Americans. 13As atmospheric carbon dioxidelevels and temperatures continue torise, ragweed pollen loads will increaseand possibly become more potent.Global warming is expected to affectragweed in several ways:• Ragweed growth rates increase andthe plants produce more pollen whencarbon dioxide in the atmosphereincreases. If fossil fuel emissionscontinue unabated, pollen productionis projected to increase by 60 to 100percent by around 2085 from thiscarbon dioxide effect alone. 14• Ragweed pollen itself may becomemore allergenic if carbon dioxideincreases. One study found thatproduction of Amb a 1, the allergenicprotein in ragweed, increased by 70percent when carbon dioxide levelswere increased from current levelsPollen production (grams per plant)RAGWEED POLLEN COUNTS RISE WITHINCREASING CARBON DIOXIDE252015105BY THE NUMBERS:ALLERGIES IN THEUNITED STATES■ 18.0 million adults suffer from hayfever allergies 20■ 7.1 million children suffer from hayfever allergies 20■ 13.1 million doctor’s visits for hayfever each year 20■ $11.2 billion in medical costs to treatallergic rhinitis each year 21■ 4 million missed or low productivityworkdays each year due to hay feverallergies 22■ $700 million in lost productivity dueto hay fever allergies each year 22Kim the imaginary friend on flickr0CO2 280 ppm 370 ppm 720 ppmYear ~1900 ~2000 ~2075Scientists have grown ragweed in chambers where theycan control the atmospheric carbon dioxide levels. Thesestudies have found that ragweed plants produce muchmore pollen when carbon dioxide levels are increased.SOURCE: Ziska and Caulfield (2000)Page 3

Tree Pollen on the MoveA.Y.Jackson on flickrRagweed is for the birds.Although its pollen causes muchhuman suffering from allergies,ragweed seeds are an importantwinter food source for manybirds and the larvae of manybutterflies and moths feed onthe plants themselves. Finding agood balance between the needsof wildlife and humans will be achallenge in managing allergies.of about 385 ppm to 600 ppm, 15 thelevels expected by mid-century ifemissions are not reduced. 16From the majestic to the showy, treesare integral to the fabric of theAmerican landscape and invaluable forwildlife. Yet, some tree species thatrely upon the wind for pollination andhave highly allergenic pollen, canbring misery to people who getspringtime hay fever allergies. 23Unfortunately, it appears that climatechange may favor the growth of treeswith more allergenic pollen. Inparticular, habitat suitable for highlyallergenic oak and hickory speciesmay expand at the expense of habitatwhere much less allergenic pine,spruce, and fir trees currentlydominate. 24 These shifts might bemost dramatic along the AppalachianMountains, Northeastern states fromPennsylvania to Maine, in the UpperMidwest, and along the lowerMississippi River (see maps).The earlier start to spring could alsoaffect the timing of tree pollinationand allergy symptoms. Satelliteimages of land cover have shown anadvancement of spring by 10 to 14days over the past 20 years in theNorthern Hemisphere. Some of thebest direct observations of spring budbursts come from Europe. Forexample, birch trees in severalEuropean locations show a trendtoward earlier flowering and pollenrelease correlated with warmingtrends over the last 35 years. 25 Arecent study in one region of Italyfound that increases in pollen seasonlength since the 1980s for several treespecies are correlated with increasingnumbers of patients allergic to thosetypes of pollen. 26The more intense thunderstormsand stronger winds expected withclimate change could further expandthe reach of tree and other pollen. Thewinds and precipitation associatedwith severe thunderstorms can cause• The earlier arrival of spring couldallow for a longer growing season,resulting in a significant increase inpollen production. In one study,allowing spring to arrive 30 daysearlier resulted in a 54.8 percentincrease in ragweed pollenproduction. 17HOW POLLEN MAKES US SNEEZE AND WHEEZEClimate change impacts on ragweedare amplified in urban areas. Buildings,roads, and other infrastructure canmake cities several degrees warmerthan surrounding rural areas, creatingwhat are known as urban heat islands.At the same time, the large number ofpolluting vehicles, power plants, andindustry in cities increases carbondioxide levels in the immediatevicinity. 18 One study found thatragweed production could be seventimes higher than surrounding ruralregions for a city that averaged 3.6degrees Fahrenheit warmer and had30 percent more carbon dioxide. 19SOURCE: American Academy of Allergy, Asthma and ImmunologyPage 4

Current Tree Habitat DistributionANNUAL ALLERGENIC TREE POLLEN POTENTIALPage 5Allergenic LevelVery lowLowModerateHighVery high2100 Tree Habitat Distribution—–Low Emissions ScenarioAllergen HotspotsStates with a risk oflarge increases inallergenic tree pollen:IowaStates with a risk ofmoderate increases inallergenic tree pollen:IllinoisMinnesotaWisconsin2100 Tree Habitat Distribution—–High Emissions ScenarioAllergen HotspotsStates with a risk oflarge increases inallergenic tree pollen:ArkansasIowaMaineMinnesotaNew HampshireNew YorkPennsylvaniaVermontWest VirginiaStates with a risk ofmoderate increases inallergenic tree pollen:ConnecticutIllinoisKentuckyMassachusettsMississippiTennesseeWisconsinChoices we make now aboutglobal warming pollution canmake a big difference in thefuture potential for allergenictree pollen. These maps showthe annual allergenic potentialfrom tree pollen for the currentdistribution of tree specieshabitat and for projecteddistributions of tree specieshabitat under two future climatescenarios—–one in whichgreenhouse gas emissions arehigher and one with loweremissions. Following the loweremissions pathway will help curbthe possibility of expanding therange of trees, like oaks andhickories, that are known toproduce highly allergenic pollen.How the Maps Were Made:The potential tree habitat distributionsfor 134 species are from the USDAForest Service’s Climate Change TreeAtlas, available athttp://www.nrs.fs.fed.us/atlas/tree.Future distributions based on theaverage of three global climate models,each run for two emissions scenarios(low: carbon dioxide increases to 550ppm by 2100; high: carbon dioxideincreases to 970 ppm by 2100). TheTree Atlas calculates Importance Values(IV) for each species for each 20 km by20 km gridbox in the Eastern half of theUnited States. We scaled theseImportance Values by how allergenicthe pollen from each species is, asindicated in the Researchers Allergyand Botany Library available athttp://www.pollenlibrary.com (highlyallergenic= IV*3, moderately allergenic= IV*2, low allergenic = IV*1, notallergenic = IV*0). Then, we summedthe contributions from all 134 speciesto calculate the total annual allergenicpotential for each grid box. Note thatthe actual future distribution of treesand annual allergenic potential will alsodepend on many factors that thismodel does not consider, such asfragmentation of landscapes andcompetition with other species.Page 5

pollen grains to burst, releasing muchsmaller allergen particles, granulesthat are less than 2.5 micrograms,which can reach the small airways ofthe lung. 27 Indeed, emergencydepartment visits for asthma inAtlanta, Georgia are significantlycorrelated with intensethunderstorms. 28 Changing stormtracks could also affect the dispersionof pollen.It is important to note that mostnative tree species, even those thatcause human allergies, have significantvalue as sources of food and shelterfor wildlife, and generally are desirableto retain. In fact, global warming willmake these trees even more valuableas places to store carbon, for providingshade that can help reduce coolingcosts, and for helping naturallymanage our water supply. A majorchallenge for future urban design willbe to weigh the pros and cons ofplanting strategies to address thesemultiple different utilities.NON-NATIVE SPECIES AND ALLERGIES: HOW POLLENIN TUCSON, ARIZONA INCREASED 10-FOLDAfter World War II, thousands of allergy and asthma sufferers flocked toTucson, Arizona, where they found relief from their symptoms.Relatively few allergenic species were native to the region, so pollenlevels were extremely low. As Gregg Mitman, a medical historian,recounts in his book Breathing Space, Tucson aggressively marketeditself as a place where those with asthma and allergies could find reliefand healthy air. Roughly 30 percent of people who moved to Tucson inthe two decades following World War II did so for health reasons. 29IMC on WikipediaYet, by the 1970s, pollen levels in Tucsonhad increased by a factor of 10. Why? Manyof the people who moved to the city plantednon-native trees and grasses thatreminded them of their former homes.Some of these were the same tree andgrass species that caused their allergy andasthma symptoms in the first place. Theworst offenders were mulberry trees,Russian olive trees, and Bermuda grasses.At the same time, the rapid urbanization ofthe area created an urban heat islandeffect that further exacerbated pollenproduction, not to mention led to unhealthylevels of air pollution. 30Tucson was not the only Western citywhere allergenic pollen levels increasedsignificantly since the mid 20th century.Similar stories can be told for Phoenix,Arizona; Albuquerque, New Mexico; El Paso, Texas; and Las Vegas,Nevada. These cities now prohibit the sale or require labeling of certainspecies known to produce significant windborne and allergenic pollen. 31UGArdener on flickr

More Fungal Spores in Storefor the United States?Pollen is not the only natural allergenthat global warming might intensify.Fungal spores, which can cause allergicand asthmatic reactions in bothoutdoor and indoor air, 32 could alsobecome more abundant as carbondioxide and temperatures increase. 33One experimental study found thatdoubling atmospheric carbon dioxidelevels led to a 4-fold increase inairborne fungal spores released fromleaf litter. 34 Increases in plant growthassociated with higher carbon dioxidelevels could also accelerate fungalactivity, for example, if more plantbiomass is available for decomposition. 35It is likely that more fungus will resultin more spore production, however,improved observations are needed toconfirm this assumption.Changes in temperature andprecipitation regimes due to globalwarming may also affect theabundance of fungal spores in indoorair following extreme floods ordroughts, 36 both of which are expectedto become more common in thecoming decades. 37 For example, heavyrainfall and flooding events often arefollowed by a proliferation of indoorfungal spores due to the increaseddampness. The aftermath ofhurricanes, which are also projected tobecome more severe and have about22 percent more rainfall by the end ofthe century, 38 provide a strikingillustration of how flooding canincrease mold and affect respiratoryhealth. Following Hurricane Katrina,mold problems were widespread andhospitals in New Orleans reported anincrease in patients with allergysymptoms, nagging cough, andchildhood asthma. 39Extremely hot and dry conditionsmight also exacerbate fungal allergies,especially as more people rely on airconditioning. Improper installation ormanagement of air conditioningsystems can create conditions ripe forgrowing mold (a type of fungus).Fortunately, this problem can beaddressed through proper managementof air conditioning systems.Reggie Rachuba on flickrBY THE NUMBERS: ASTHMAIN THE UNITED STATES 46Double Threat for Asthmatics:Allergies and Air Pollution■ 16.4 million adults have asthma■ 7.0 million children have asthma■ 3,600 deaths from asthma each year■ 3 black people die from asthma forevery 1 white person■ 14.2 million days of work missedeach year■ 14.4 million days of school missedeach year■ $15.6 billion a year in hospitalizationcosts due to asthma■ $5.1 billion a year in lost earningsdue to asthmaAbout 10 million Americans have“allergic asthma,” in which theirasthma attacks are triggered by areaction to pollen or other airborneallergens. 40 Thus, the risk of asthmaattacks is likely to go up if globalwarming increases these allergens.Air pollution also increases the riskand severity of asthma attacks. If airpollution gets worse because of globalwarming, as several studies indicate, 41asthmatics may have to deal with thedouble threat of more allergens andmore air pollution. 42To make matters worse, airpollutants and allergens can interactin ways that amplify their individualeffects. For example, when groundlevelozone pollution levels are high, ittakes much less ragweed pollen totrigger an asthmatic or allergicresponse. In effect, the ozone primesthe bronchial airways to be moresensitive to the allergen. Particlesemitted from diesel exhaust alsoincrease allergic responses byextending how long the allergens stayin the body. The airborne allergens inpollen grains can stick to the tinyexhaust particles, which thenpenetrate deep in the lungs andremain their a long time. Some studieshave even found that plants grown inplaces with more air pollution producepollen with increased levels ofallergenic proteins. 43Page 7

Global warming will likely make iteven harder to reduce ozone in citiesWORST CITIES IN THE UNITED STATES FOR ASTHMATICSAND FOR SPRING AND FALL ALLERGIESthat already have problems with airpollution. Warmer temperaturesaccelerate the chemical reactions inthe atmosphere that create unhealthyAsthma2010 47 Spring AllergyCapitals 2010 48 Fall Allergy2009 49Environmental Protection Agency is14 Allentown, PA Providence, RI New Orleans, LAnow considering lowering tosomewhere between 60 and 70 ppb. 45 15 Scranton, PA Birmingham, AL Baton Rouge, LAozone. At the same time, warmer1 Richmond, VA Knoxville, TN McAllen, TXconditions increase emissions of ozoneprecursors. One study found that2 St. Louis, MO Louisville, KY Wichita, KSglobal warming could increases the 3 Chattanooga, TN Chattanooga, TN Louisville, KYdaily maximum 8-hour average4 Knoxville, TN Dayton, OH Oklahoma City, OKconcentration of ground-level ozone 3to 5 parts per billion (ppb) by 2050 in 5 Milwaukee, WI Charlotte, NC Jackson, MSthe Midwest and Northeast, even if 6 Memphis, TN Philadelphia, PA Dayton, OHozone precursor emissions aredecreased as required by the Clean Air7 Tulsa, OK Greensboro, NC Augusta, GAAct. During heat waves, higher8 Philadelphia, PA Jackson, MS Tulsa, OKtemperatures and increased9 Augusta, GA St. Louis, MO Knoxville, TNstagnation could lead to increasesexceeding 10 ppb. 44 This climate10 Atlanta, GA Wichita, KS Little Rock, ARpenalty will require some cities to take 11 Little Rock, AR Madison, WI Madison, WIeven more aggressive steps to meetthe ozone standard, which is currently12 Springfield, MA Columbia, SC San Antonio, TX75 ppb and which the U.S.13 Dayton, OH Richmond, VA Dallas, TX16 Birmingham, AL Memphis, TN Charlotte, NC17 Madison, WI Oklahoma City, OK St. Louis, MO18 Detroit, MI Baton Rouge, LA Birmingham, AL19 Pittsburgh, PA Allentown, PA El Paso, TX20 Nashville, TN New Orleans, LA Virginia Beach, VAEach year, the Asthma and Allergy Foundation of America ranksthe 100 most populated cities in the United States to identifywhich are the most challenging places to live for people who haveasthma, spring allergies, or fall allergies. The asthma rankings arederived from 12 factors measuring the prevalence of asthma,environmental and other risks, and access to medical treatment.The allergy rankings are based on observed pollen levels andaccess to medical treatment.SOURCE: Asthma and Allergy Foundation of America.Andrew Bain on flickrPage 8

Poison Ivy: More Toxic andMore of ItPoison ivy already ranks among thetop ten “medically problematic”plants in the United States, with morethan 350,000 cases of contactdermatitis reported each year. 50About half to two-thirds of peoplehave an allergic reaction to urushiolpresent in oils found in the leaves,stems, and roots of poison ivy, oak,and sumac. The rash, known asallergic contact dermatitis, consists ofitchy red bumps and blisters, and insevere cases can be debilitating. 51A landmark study by DukeUniversity examined the response ofpoison ivy to increasingconcentrations of carbon dioxide inthe atmosphere to about 570 ppm,levels that are expected bymidcentury if fossil fuel emissionscontinue unabated. Poison ivy plantsexposed to more carbon dioxideproduced a more allergenic form ofurushiol, the substance responsiblefor the itchy response. 52 To makematters worse, increasing carbondioxide also caused the poison ivyvines to grow even faster. Moreabundant vines will likely mean moreopportunities for people to come incontact with them in places wherepoison ivy already grows naturally. 53While many animal species rely onpoison ivy berries as a food source,larger poison ivy vines could have anegative impact on forest ecosystems,reducing tree regeneration andincreasing tree mortality becausevines tend to respond more vigorouslyto elevated carbon dioxide thantrees. 54 In fact, more abundant growthof vines has been documented aroundthe world. 55 Poison ivy joins a list ofother aggressive vines that will likelybenefit from global warming, includingJapanese honeysuckle, English ivy,and kudzu. 56A STINGING TREND FOR ALASKANSPeople in Alaska are seeing increased incidence of allergicreactions to insect stings in recent years. This trend—–includingtwo unprecedented cases of fatalanaphylaxis due to yellow jacket stingsin Fairbanks in 2006—–has ledscientists to investigate whetherglobal warming may be playing a role. 57Research suggests that higher averagewinter temperatures and a decrease inthe frequency and intensity of coldsnaps in the region can allow moreyellow jacket queens to survive overthe winter. 58 In fact, a significantincrease in the number of insect stingsacross the state has occurred inregions where the average annualtemperature increase is 3.4 degreesFahrenheit or average wintertemperature has risen at least 6degrees Fahrenheit during the past50 years. 59Alpert, Harvard University, www.forestryimages.orgiStockphoto, www.istockphoto.comPage 9

Actions We Can Take Now to ReduceAllergy RisksAlthough the future for allergysufferers may appear grim, it is nottoo late to change course. We need toimmediately start reducing the airpollution that contributes to globalwarming. At the same time, we canbegin preparing for some climatechanges that have already been putinto motion. Through smart urbanplanning and attention to allergenicplants, communities may be able tolimit how much their residents areexposed to allergens.Reduce global warming pollutionto minimize future allergy risk. Tolimit the magnitude of changes to theclimate and the impacts on those whosuffer from allergies, we must curbglobal warming pollution as much andas quickly as possible. It is importantthat policy makers, industry, andindividuals work together to reduceglobal warming pollution from today’slevels by at least 80 percent by 2050.This target is achievable withtechnologies either available or underdevelopment, but we must takeaggressive action now to avoid themost worrisome impacts.Some emission reductions offer awin-win in terms of both limitingglobal warming and improving airquality. Shifting from reliance onburning fossil fuels to solar energysources has the combined benefits ofreducing air pollution and producingplentiful energy when electricitydemand for air conditioning peaksduring hot summer days. Methane isboth an ozone precursor and a potentgreenhouse gas, which makes a strongcase for reducing its emissions. 60Curbing emissions of tiny particles,which include black carbon thatdirectly absorbs incoming solar heat,would have similar benefits. Theseparticles can exert a strong localwarming effect and have significantimpacts on respiratory andcardiovascular health. 61Minimize exposure to dangerousairborne allergen levels using smartcommunity, regional, and stateplanning as well as landscaping byhomeowners. 62 As trees and otherplants begin producing more pollenthere may be increased pressure toplace restrictions on planting ofcertain pollen-producing species. Suchstrategies may be workable, but mustbe considered a long-term solutionbecause trees have long life spans.Any such restrictions would need tobe carefully weighed against the valueof the plants for wildlife, providingshade that reduces cooling costs,storing carbon, storm water reduction,and other natural benefits. A goodfirst step will be for qualified arboristsand foresters to conduct citywide treeinventories and evaluate surroundingpollen and climate conditions todetermine whether regulations canactually influence pollen levels. 63Well-designed urban areas can alsoreduce the urban heat island effectthat accelerates pollen production andincreases air pollution levels. Roofcoatings and other materials that aremore reflective absorb less heat andthe use of green space—–parks, trees,and “green” roofs—–can greatly reducethe urban heat island effect. Urbanvegetation absorbs less incomingsunlight than pavement, concrete, andother building materials, and alsoprovides some cooling throughevapotranspiration.The Udall Legacy Bus Tour: Views from the Road on flickrSupport research of the allergyclimateconnection. Much is stillunknown about the incidence ofasthma and allergies, trends inairborne allergens, the relationshipbetween allergies and climate, and theinterconnections between airborneallergens and both climate and nonclimaterisk factors. 64 With millions ofAmericans already suffering someallergy symptoms, many would benefitfrom investing in research to betterunderstand how global warming isaffecting allergies and what we can doto minimize the impacts.

ALLERGIES WON’T STOP ME FROM GETTING OUTAND GARDENINGWhile many know me as lover of the outdoors, it’s less well known thatI also suffer from severe allergies to pollen and poison ivy. While I canappreciate the humor of a “naturalist that’s allergic to nature”, thepotential that global warming will make my allergies even worse is nolaughing matter. Even so, I don’t let my allergies keep me inside now,and don’t plan to let them do so in the future. Here are some tips tomake your time outdoors more enjoyable, even during allergy season.■ Get an allergy test. Knowing which plants trigger your allergies andwhen they are in bloom will help you decide the best times to be outdoors.■ Ask your medical practitioner about air pollutants and allergens, how tominimize exposure, and what synergistic effects to look out for. Allergymedications can minimize your symptoms.■ Check daily pollen counts and plan your outdoor time when pollen levels arelow. Wear a pollen-filtering mask when you’re outside on days with high pollencounts to minimize exposure.■ Pollen gets trapped in hair and clothing, so shower after spending timeoutdoors, wash bedding and clothing frequently, and vacuum regularly. Usesaline spray or a neti pot to flush pollen from your nasal passages.■ Choose plants for your garden that don’t produce airborne pollen. Luckily,most plants with large, showy blooms have heavy pollen grains designed tostick to insects rather than blow in the wind and aren’t big allergy triggers.■ Plant female trees and shrubs. Male plants don’t produce fruit or seeds, whichsome consider messy, but female plants don’t produce pollen and the fruitsand seeds they do produce will help attract birds.While these steps can minimize your personal exposure to allergens, it’simportant to realize that pollen can be carried long distances by the wind andyou will always be exposed to some level of allergens in the environment.Ultimately, we’ll all need to work together to slow global warming and minimizethe potential increases in allergies.David MizejewskiNaturalistNational Wildlife FederationThomas StukasReport prepared by National WildlifeFederation staff:Amanda Staudt, Ph.D., Climate ScientistPatty Glick, Senior Global Warming SpecialistDavid Mizejewski, NaturalistDouglas Inkley, Ph.D., Senior ScientistWe gratefully acknowledge the followingexperts for helpful input and reviewcomments:Jeffrey Demain, Allergy, Asthma, andImmunology Center of AlaskaPaul Epstein, Center for Health in the GlobalEnvironment, Harvard UniversityJanet Gamble, U.S. EnvironmentalProtection AgencyNicholas Kuhn, ISA Certified Arborist /Municipal Specialist, Albuquerque, NewMexicoAnantha Prasad, USDA Forest Service,Northern Research StationMike Tringale, Asthma and AllergyFoundation of AmericaIn addition, we would like to extend specialthanks to:Doug Tosa, Alaska Center for theEnvironmentMatthew P. Peters, USDA Forest Service,Northern Research StationMax Greenberg, George Ho, Tony Iallonardo,Felice Stadler, Bruce Stein, Tim Warman, andAileo Weinmann from National WildlifeFederationBarbara Raab Sgouros, who skillfullyhandled the design and layout of the reportEndnotes1McMullen, C.P., and J. Jabbour, 2009. Climate Change Science Compendium2009. United Nations Environment Programme, Nairobi, EarthPrint.2NASA Goddard Institute of Space Studies, 2010. 2009: Second Warmest Yearon Record; End of Warmest Decade. Available at http://www.giss.nasa.gov/research/news/20100121/(Accessed March 22, 2010).3U.S. Global Change Research Program (USGCRP), 2009. Global ClimateChange Impacts in the United States, T.R. Karl, J.M. Melillo, and T.C. Peterson,(eds.). Cambridge University Press, 191 pp.4Climate Change Science Program (CCSP), 2008. Preliminary review ofadaptation options for climate-sensitive ecosystems and resources. A Reportby the U.S. Climate Change Science Program and the Subcommittee on GlobalChange Research. [Julius, S.H., J.M. West (eds.), J.S. Baron, B. Griffith, L.A.Joyce, P. Kareiva, B.D. Keller, M.A. Palmer, C.H. Peterson, and J.M. Scott (Authors)].U.S. Environmental Protection Agency, Washington, DC, USA: 873 pp.5Le Quéré, C., et al., 2009. Trends in the sources and sinks of carbon dioxide.Nature Geoscience. Published online Nov. 17. 2009.6Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, et al., 2008. High-resolutioncarbon dioxide concentration record 650,000–800,000 years before present.Nature 453: 379-382.7Tripati, A.K., C.D. Roberts, and R.A. Eagle, 2009. Coupling of CO2 and IceSheet Stability over Major Climate Transitions of the Last 20 Million Years.Science Express. October 8, 2009.8USGCRP, 2009.9USGCRP, 2009.Page 11

10USGCRP, 2009.11USGCRP, 2009.12Asthma and Allergy Foundation of America (AAFA), 2005a. Ragweed allergy.Available at: http://aafa.org/display.cfm?id=9&sub=19&cont=267 (AccessedMarch 23, 2010).13Rees, A.M., 1997. Consumer Health USA: Essential Information from theFederal Health Network, 2nd ed. Westwood, Connecticut: Greenwood, vol. 2.14Ziska, L.H., and F.A. Caulfield, 2000. Rising CO2 and pollen production ofcommon ragweed (Ambrosia artemisiifolia L.), a known allergy-inducingspecies: implications for public health. Australian Journal of Plant Physiology,27(10): 893-898.Wayne, P., S. Foster, J. Connolly, F. Bazzaz, and P. Epstein, 2002. Production ofallergenic pollen by ragweed (Ambrosia artemisiifolia L.) is increased in CO2-enriched atmospheres. Annals of Allergy, Asthma and Immunology 8: 279-282.15Singer, B.D., L.H. Ziska, D.A. Frenz, et al., 2005. Increasing Amb a 1 content incommon ragweed (Ambrosia artemisiifolia) pollen as a function of risingatmospheric CO2 concentration. Functional Plant Biology 32: 667–670.16USGCRP, 2009.17Rogers, C.A., P.M. Wayne, E.A. Macklin, et al. 2006. Interaction of the onset ofspring and elevated atmospheric CO2 on ragweed (Ambrosia artemisiifolia L.)pollen production. Environmental Health Perspectives 114: 865–869.18Jacobson, M.Z., 2010. Enhancement of Local Air Pollution by Urban CO2Domes. Environmental Science and Technology, in press.19Ziska, L.H., D.E. Gebhard, D.A. Frenz, et al., 2003. Cities as harbingers ofclimate change: common ragweed, urbanization, and public health. Journal ofAllergy and Clinical Immunology 111: 290–295.20Centers for Disease Control and Prevention, 2009. FastStats A to Z.Available at: http://www.cdc.gov/nchs/fastats/allergies.htm (Accessed March22, 2010).21Soni A., 2008. Allergic rhinitis: Trends in use and expenditures, 2000 to2005. Statistical Brief #204, Agency for Healthcare Research and Quality.22AAFA, Allergy Facts and Figures. Available at:http://www.aafa.org/display.cfm?id=9&sub=30 (Accessed March 22, 2010).23SDI Health, LLC, 2010. Researchers Allergy and Botany Library. Available at:http://www.pollenlibrary.com (Accessed March 11, 2010).24Prasad, A.M., L.R. Iverson, S. Matthews, M. Peters, 2007-ongoing. A ClimateChange Atlas for 134 Forest Tree Species of the Eastern United States[database]. http://www.nrs.fs.fed.us/atlas/tree, Northern Research Station,USDA Forest Service, Delaware, Ohio.25Emberlin, J., M. Detandt, R. Gehrig, S. Jaeger, N. Nolard, A. Rantio-Lehtimäki,2002. Responses in the start of Betula (birch) pollen seasons to recentchanges in spring temperatures across Europe. International Journal ofBiometeorology 46: 159–170.26Ariano, R., G.W. Canonica, and G. Passalacqua, 2010. Possible role of climatechanges in variations in pollen seasons and allergic sensitizations during 27years. Annals of Allergy, Asthma, and Immunology 104: 215-222.27D’Amato, G., G. Liccardi, and G. Frenguelli, 2007. Thunderstorm asthma andpollen allergy. Allergy 62(1): 11–16.28Grundstein, A., S.E. Sarnat, M. Klein, M. Shepherd, L. Naeher, T. Mote, et al.,2008. Thunderstorm associated asthma in Atlanta, Georgia. Thorax 63(7):659–660.29Mitman, G., 2007. Breathing Space: How Allergies Shape Our Lives andLandscapes. New Haven, Connecticut: Yale University Press: 312 pp.30Mitman, G., 2007.31Albuquerque Official City Website, 2010. Restricted Trees. Available at:http://www.cabq.gov/airquality/treeflyer.html (Accessed March 22, 2010).Brooke, J., December 22, 1996. Pollen Police vs. Wheeze- and Sneeze-MakingLeafy Outlaws. New York Times.32Institute of Medicine (IOM), 2004. Damp Indoor Spaces and Health. NationalAcademy Press,Washington, DC.33Ziska, L.H., P.R. Epstein, and W.H. Schlesinger, 2009. Rising CO2, ClimateChange, and Public Health: Exploring the Links to Plant Biology. EnvironmentalHealth Perspectives 117(2): 155-158.34Klironomos, J.N., M.C. Rillig, M.F. Allen, D.R. Zak, K.S. Pregitzer, and M.E. Kubiske,1997. Increased levels of airborne fungal spores in response to populustremuloides grown under elevated atmospheric CO2, Canadian Journal ofBotany - Revue Canadienne de Botanique 75(10): 1,670-1,673.35Ziska, L.H., P.R. Epstein, and C.A. Rogers, 2008. Climate change, aerobiology,and public health in the Northeast United States. Mitigation and AdaptationStrategies for Global Change 13: 607–613.36Ziska, Epstein, and Rogers, 2008.37USGCRP, 2009.38Knutson, T.R., J.L. McBride, J. Chan, K. Emanuel, et al., 2010. Tropicalcyclones and climate change. Nature Geoscience, published online February 21,2010 (doi: 10.1038/ngeo779).39Reid, C.E., and J.L. Gamble, 2009. Aeroallergens, Allergic Disease, andClimate Change: Impacts and Adaptation. EcoHealth, (doi: 10.1007/s10393-009-0261-x).40AAFA, 2005b. Allergic Asthma. Available athttp://www.aafa.org/display.cfm?id=8&sub=16 (Accessed March 9, 2010).41Wu, S., L.J. Mickley, E.M. Leibensperger, D.J. Jacob, D. Rind, and D.G. Streets,2008. Effects of 2000–2050 global change on ozone air quality in the UnitedStates, Journal of Geophysical Research 113: D06302.42Knowlton, K., M. Rotkin-Ellman, and G. Solomon, 2007. Sneezing and wheezing:how global warming could increase ragweed allergies, air pollution, andasthma. Natural Resources Defense Council. Available at: http://www.nrdc.org/globalWarming/sneezing/sneezing.pdf. (Accessed April 8, 2010).43D’Amato, G., G. Liccardi, M. D’Amato, and M. Cazzola. 2002. Outdoor airpollution, climatic changes and allergic bronchial asthma. The EuropeanRespiratory Journal 20(3): 763–776.44Wu, et al., 2008.45Soos, A., January 11, 2010. EPA to Improve Ozone Standards. EnvironmentalNews Network. Available at: http://www.enn.com/pollution/article/40914(Accessed April 5, 2010).46American Lung Association. 2010, Trends in Asthma Morbidity and Mortality.Available at: http://www.lungusa.org/finding-cures/for-professionals/asthmatrend-report.pdf(Accessed March 22, 2010).47AAFA, 2010. Asthma Capitals 2010. Available at: http://www.aafa.org/pdfs/2010_AC_FinalPublicList.pdf (Accessed March 22, 2010).48AAFA, 2010. Spring Allergy Capitals 2010. Available at: http://www.aafa.org49AAFA, 2009. Fall Allergy Capitals 2009. Available at: http://aafa.org/pdfs/FINAL%20Public%20Fall%20List%202009_final.pdf(Accessed March 22, 2010).50Bronstein, A.C., et al. 2009. 2008 annual report of the American Associationof Poison Control Centers’ National Poison Data System (NPDS): 26 th annualreport. Clinical Toxicology 47: 911-1,084.51AAFA, 2005c. Poison Plants. Available at: http://aafa.org/display.cfm?id=9&sub=23&cont=333 (Accessed March 23, 2010).52Mohan, J.E., et al. 2006. Biomass and toxicity responses of poison ivy(Toxicodendron radicans) to elevated atmospheric CO2. Proceedings of theNational Academy of Sciences 103: 9,086-9,089.53Ziska, L.H., et al. 2007. Rising atmospheric carbon dioxide and potentialimpacts on the growth and toxicity of poison ivy (Toxicodendron radicans).Weed Science 55: 288-292.54Belote, R.T., J.F. Weltzin, and R.J. Norby, 2003. Response of an understoryplant community to elevated CO2 depends on differential responses ofdominant invasive species and is mediated by soil water availability. NewPhytologist 161: 827-835.55Mohan et al., 2006.56Middleton, B.A. 2006. Invasive species and climate change. U.S. GeologicalSurvey Open-File Report 2006-1153. U.S. Department of the Interior, Washington,D.C.57Oswalt, M.L., J.T. Foote, and S.F. Kemp, 2007. Anaphylaxis: Report of two fatalyellowjacket stings in Alaska. Journal of Allergy and Clinical Immunology 119:S34.58Akre, R.D., and H.C. Reed, 1981. Population cycles of yellowjackets(Hymenoptera: Vespidae) in the Pacific Northwest. Environmental Entomology.10: 267-274.59Demain, J.G., et al., 2009. Increasing insect reactions in Alaska: is thisrelated to changing climate? Allergy and Asthma Proceedings 30: 238-243.60Fiore, A.M., J.J. West, L. Horowitz, V. Naik, and M.D. Schwarzkopf, 2008.Characterizing the tropospheric ozone response to methane emission controlsand the benefits to climate and air quality. Journal of Geophysical Research113: D08307.61Ramanathan, V., and G. Carmichael, 2008. Global and regional climatechanges due to black carbon. Nature Geoscience 1: 221–227.62Shea, K.M., R.T. Truckner, R.W. Weber, and D.B. Peden, 2008. Climate changeand allergic disease. Journal of Allergy and Clinical Immunology, 122(3): 443-453.63Nicholas Kuhn, Albuquerque City Forester, March 17, 2010, Personalcommunication.64Reid and Gamble, 2009.Page 12THIS REPORT AND OTHERS IN NWF’S SERIES ON GLOBAL WARMING AND EXTREMEWEATHER ARE AVAILABLE AT WWW.NWF.ORG/EXTREMEWEATHER