News

    Climate Change: Good for Weeds, Bad for Allergies

    An allergy sufferer sneezes, and scientists say rising average temperatures and elevated levels of carbon dioxide are spurring the growth of many weedy, allergenic plants, and extending the season of suffering for pollen-sensitive people across the countr
    An allergy sufferer sneezes, and scientists say rising average temperatures and elevated levels of carbon dioxide are spurring the growth of many weedy, allergenic plants, and extending the season of suffering for pollen-sensitive people across the countr

    Multimedia

    Zulima Palacio

    More than 50 million people in the United States suffer from allergies, and their numbers are growing. New studies suggest that climate change may be at least partly to blame. Scientists say rising average temperatures and elevated levels of carbon dioxide are spurring the growth of many weedy, allergenic plants - such as ragweed - and extending the season of suffering for pollen-sensitive people across the country.

    At the U.S. Department of Agriculture's research center near Washington, D.C., plant physiologist Lewis Ziska said weeds - defined as any unwanted plant - appear to be thriving in today's atmosphere, which is richer in carbon dioxide, or CO2. And Ziska said agricultural research studies show that if climate trends continue, allergy sufferers will have to endure longer and more intense pollen seasons in the decades ahead.

    "The average ragweed plant growing in the year 1900, for that CO2 concentration was producing about 5 grams of pollen," he said. "If you go forward in time to the 1990s and look at the CO2 concentration at that time, the average ragweed produced about 10 grams of pollen. If you go into the future 50 years from now, at the [expected] CO2 concentration, that ragweed will produce 20 grams of pollen."

    Ziska began studying allergenic weeds and pollen 10 years ago. He said the more pollen a weed puts out, the more potential harm there is to public health and to agriculture, where weeds can steal water, soil nutrients and light from commercial crops. Ziska said one of the most common and most allergenic weeds is the fast-growing plant called ragweed.

    “This is common ragweed coming up in the spring," he said. "It can get up anywhere from four to six feet (1.5 to 2 meters) tall.”

    Dr. Darryl Zeldin is a senior investigator and acting clinical director at the National Institute for Environmental Health Science in North Carolina. He said common allergies have been on the rise for the past 10 to 15 years. And he said that if there's going to be more pollen from weeds in the years ahead, he's certain the number of allergy sufferers - now estimated at 50 million people - will continue to rise, as well.

    Zeldin said asthma and allergies are closely related. Most people with asthma also suffer from allergies.

    “Allergies are thought to cost the public somewhere in excess of $8 billion to $10 billion every year, in both direct and indirect costs," said Zeldin. "Asthma is also a major issue and costs billions of dollars a year, not just in doctor's office visits, in hospitalizations, and emergency department visits.”

    Zeldin also said there are many causes for allergies, and people with allergies often are sensitive to more than one weed. His latest research on the subject has shown that environmental and genetic factors play a role as well. And there is evidence of a connection between a pre-disposition to asthma and allergies, and obesity and cardiovascular disease.

    “Asthma and allergies are a major health problem in the U.S.," he said. "(They) cost a lot of money, major cost of symptoms and hospitalizations and doctor’s office visits and there are not real cures.”  

    Among the thousands of known weed species, only eight or 10 are known to induce allergies. Many species of weeds, however, have become resistant to herbicides. And that means more money will be needed for health and agricultural research, including new and safer methods of controlling weeds.

    This forum has been closed.
    Comments
         
    There are no comments in this forum. Be first and add one

    Featured Videos

    Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
    As Refugees Perish, Greek Graveyards Filli
    X
    Hamada Elsaram
    February 11, 2016 8:01 PM
    Aid workers on the Greek island of Lesbos say they are struggling to bury the increasing number of bodies of refugees that have been recovered or washed up ashore in recent months.  The graveyards are all full, they say, yet as tens of thousands of people clamor to get out of Syria, it is clear refugees will still be coming in record numbers. For VOA, Hamada Elrasam reports from Lesbos, Greece.
    Video

    Video As Refugees Perish, Greek Graveyards Fill

    Aid workers on the Greek island of Lesbos say they are struggling to bury the increasing number of bodies of refugees that have been recovered or washed up ashore in recent months.  The graveyards are all full, they say, yet as tens of thousands of people clamor to get out of Syria, it is clear refugees will still be coming in record numbers. For VOA, Hamada Elrasam reports from Lesbos, Greece.
    Video

    Video To Fight Zika, Scientists Target Mosquitoes

    Mosquitoes strike again. The Zika virus outbreak is just the latest headline-grabbing epidemic carried by these biting pests, but researchers are fighting back with new ways to control them. VOA's Steve Baragona takes a look.
    Video

    Video Mosul Refugees Talk About Life Under IS

    A top U.S. intelligence official told Congress this week that a planned Iraqi-led operation to re-take the city of Mosul from Islamic State militants is unlikely to take place this year. IS took over the city in June 2014, and for the past year and a half, Mosul residents have been held captive under its rule. VOA's Zana Omar talked to some families who managed to escape. Bronwyn Benito narrates his report.
    Video

    Video Scientists Make Progress Toward Better Diabetes Treatment, Cure

    Scientists at two of the top U.S. universities say they have made significant advances in their quest to find a more efficient treatment for diabetes and eventually a cure. According to the International Diabetes Federation, the disease affects more than 370 million people worldwide. VOA’s George Putic reports.
    Video

    Video NATO to Target Migrant Smugglers

    NATO has announced plans to send warships to the Aegean Sea to target migrant smugglers in the alliance's most direct intervention so far since a wave of people began trying to reach European shores.
    Video

    Video Russia's Catholics, Orthodox Hopeful on Historic Pope-Patriarch Meeting

    Russia's Catholic minority has welcomed an historic first meeting Friday in Cuba between the Pope and the Patriarch of Russia's dominant Orthodox Church. The Orthodox Church split with Rome in 1054 and analysts say politics, both church and state, have been driving the relationship in the centuries since. VOA's Daniel Schearf reports from Moscow.
    Video

    Video Used Books Get a New Life on the Streets of Lagos

    Used booksellers are importing books from abroad and selling them on the streets of Africa's largest city. What‘s popular with readers may surprise you. Chris Stein reports from Lagos.
    Video

    Video After NH Primaries All Eyes on South Carolina

    After Tuesday's primary in New Hampshire, US presidential candidates swiftly turned to the next election coming up in South Carolina. The so-called “first-in-the-South” poll may help further narrow down the field of candidates. Zlatica Hoke reports.
    Video

    Video US Co-ed Selective Service Plan Stirs Controversy

    Young women may soon be required to register with the U.S. Selective Service System, the U.S. government agency charged with implementing a draft in a national emergency. Top Army and Marine Corps commanders told the Senate Armed Services Committee recently that women should register, and a bill has been introduced in Congress requiring eligible women to sign up for the military draft. The issue is stirring some controversy, as VOA’s Bernard Shusman reports from New York.
    Video

    Video Lessons Learned From Ebola Might Help Fight Zika

    Now that the Ebola epidemic has ended in West Africa, Zika has the world's focus. And, as Carol Pearson reports, health experts and governments are applying some of the lessons learned during the Ebola crisis in Africa to fight the Zika virus in Latin America and the Caribbean.
    Video

    Video Smartphone Helps Grow Vegetables

    One day, you may be using your smartphone to grow your vegetables. A Taipei-based company has developed a farm cube — a small, enclosed ecosystem designed to grow plants indoors. The environment inside is automatically adjusted by the cube, but it can also be controlled through an app. VOA's Deborah Block has more on the gardening system.
    Video

    Video Illinois Voters Have Mixed Emotions on Obama’s Return to Springfield

    On the ninth anniversary of the launch of his quest for national office, President Barack Obama returned to Springfield, Illinois, to speak to the Illinois General Assembly, where he once served as state senator. His visit was met with mixed emotions by those with a front-row seat on his journey to the White House. VOA's Kane Farabaugh reports.
    Video

    Video Exhibit Turns da Vinci’s Drawings Into Real Objects

    In addition to being a successful artist, Renaissance genius Leonardo da Vinci designed many practical machines, some of which are still in use today, although in different forms. But a number of his projects were never realized — until today. VOA’s George Putic reports.
    Video

    Video Heated Immigration Debate Limits Britain’s Refugee Response

    Compared to many other European states, Britain has agreed to accept a relatively small number of Syrian refugees. Just over a thousand have arrived so far -- and some are being resettled in remote corners of the country. Henry Ridgwell reports on why Britain’s response has lagged behind its neighbors.
    Video

    Video Russia's Car Sales Shrink Overall, But Luxury and Economy Models See Growth

    Car sales in Russia dropped by more than a third in 2015 because of the country's economic woes. But, at the extreme ends of the car market, luxury vehicles and some economy brands are actually experiencing growth. VOA's Daniel Schearf reports from Moscow.