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.
Booming London Property a ‘Haven for Dirty Money’i
X
July 29, 2015 9:34 PM
Billions of dollars of so-called ‘dirty money’ from the proceeds of crime - especially from Russia - are being laundered through the London property market, according to anti-corruption activists. As Henry Ridgwell reports from the British capital, the government has pledged to crack down on the practice.
Video

Video Booming London Property a ‘Haven for Dirty Money’

Billions of dollars of so-called ‘dirty money’ from the proceeds of crime - especially from Russia - are being laundered through the London property market, according to anti-corruption activists. As Henry Ridgwell reports from the British capital, the government has pledged to crack down on the practice.
Video

Video Hometown of Boy Scouts of America Founder Reacts to Gay Leader Decision

Ottawa, Illinois, is the hometown of W.D. Boyce, who founded the Boy Scouts of America in 1910. In Ottawa, where Scouting remains an important part of the legacy of the community, the end of the organization's ban on openly gay adult leaders was seen as inevitable. VOA's Kane Farabaugh reports.
Video

Video 'Metal Muscles' Flex a New Bionic Hand

Artificial limbs, including the most complex of them – the human hand – are getting more life-like and useful due to constant advances in tiny hydraulic, pneumatic and electric motors called actuators. But now, as VOA’s George Putic reports, scientists in Germany say the future of the prosthetic hand may lie not in motors but in wires that can ‘remember’ their shape.
Video

Video Russia Accused of Abusing Interpol to Pursue Opponents

A British pro-democracy group has accused Russia of abusing the global law enforcement agency Interpol by requesting the arrest and extradition of political opponents. A new report by the group notes such requests can mean the accused are unable to travel and are often unable to open bank accounts. VOA's Henry Ridgwell reports.
Video

Video 'Positive Atmosphere' Points Toward TPP Trade Deal in Hawaii

Talks on a major new trade agreement among 12 Pacific Rim nations are said to be nearing completion in Hawaii. Some trade experts say the "positive atmosphere" at the discussions could mean a deal is within reach, but there is still hard bargaining to be done over many issues and products, including U.S. drugs and Japanese rice. VOA's Jim Randle reports.
Video

Video Genome Initiative Urgently Moves to Freeze DNA Before Species Go Extinct

Earth is in the midst of its sixth mass extinction. The last such event was caused by an asteroid 66 million years ago. It killed off the dinosaurs and practically everything else. So scientists are in a race against time to classify the estimated 11 million species alive today. So far only 2 million are described by science, and researchers are worried many will disappear before they even have a name. VOA’s Rosanne Skirble reports.
Video

Video Scientists: One-Dose Malaria Cure is Possible

Scientists have long been trying to develop an effective protection and cure for malaria - one of the deadliest diseases that affects people in tropical areas, especially children. As the World Health Organization announces plans to begin clinical trials of a promising new vaccine, scientists in South Africa report that they too are at an important threshold. George Putic reports, they are testing a compound that could be a single-dose cure for malaria.
Video

Video 'New York' Magazine Features 35 Cosby Accusers

The latest issue of 'New York' magazine features 35 women who say they were drugged and raped by film and television celebrity Bill Cosby. The women are aged from 44 to 80 and come from different walks of life and races. The magazine interviewed each of them separately, but Zlatica Hoke reports their stories are similar.
Video

Video US Calls Fight Against Human Trafficking a Must Win

The United States is promising not to give up its fight against what Secretary of State John Kerry calls the “scourge” of modern slavery. Officials released the country’s annual human trafficking report Monday – a report that’s being met with some criticism. VOA’s National Security correspondent Jeff Seldin has more from the State Department.
Video

Video Washington DC Underground Streetcar Station to Become Arts Venue

Abandoned more than 50 years ago, the underground streetcar station in Washington D.C.’s historic DuPont Circle district is about to be reborn. The plan calls for turning the spacious underground platforms - once meant to be a transportation hub, - into a unique space for art exhibitions, presentations, concerts and even a film set. Roman Mamonov has more from beneath the streets of the U.S. capital. Joy Wagner narrates his report.
Video

Video Europe’s Twin Crises Collide in Greece as Migrant Numbers Soar

Greece has replaced Italy as the main gateway for migrants into Europe, with more than 100,000 arrivals in the first six months of 2015. Many want to move further into Europe and escape Greece’s economic crisis, but they face widespread dangers on the journey overland through the Balkans. VOA's Henry Ridgwell reports.
Video

Video Stink Intensifies as Lebanon’s Trash Crisis Continues

After the closure of a major rubbish dump a week ago, the streets of Beirut are filling up with trash. Having failed to draw up a plan B, politicians are struggling to deal with the problem. John Owens has more for VOA from Beirut.
Video

Video Paris Rolls Out Blueprint to Fight Climate Change

A U.N. climate conference in December aims to produce an ambitious agreement to fight heat-trapping greenhouse gases. But many local governments are not waiting, and have drafted their own climate action plans. That’s the case with Paris — which is getting special attention, since it’s hosting the climate summit. Lisa Bryant takes a look for VOA at the transformation of the French capital into an eco-city.
Video

Video Racially Diverse Spider-Man Takes Center Stage

Whether it’s in a comic book or on the big screen, fans have always known the man behind the Spider-Man mask as Peter Parker. But that is changing, at least in the comic book world. Marvel Comics announced that a character called Miles Morales will replace Peter Parker as Spider-Man in a new comic book series. He is half Latino, half African American, and he is quite popular among comic book fans. Correspondent Elizabeth Lee reports from Los Angeles.
Video

Video Historic Symbol Is Theme of Vibrant New Show

A new exhibit in Washington is paying tribute to the American flag with a wide and eclectic selection of artwork that uses the historic symbol as its central theme. VOA’s Julie Taboh was at the DC Chamber of Commerce for the show’s opening.

VOA Blogs