Climate Change, Ragweed and Allergies

Recent warming by latitude associated with increased length of ragweed pollen season in central North America (Abstract, Lewis Ziskaa,, Kim Knowlton, Christine Rogers, Dan Dalan, Nicole Tierney, Mary Ann Elder, Warren Filley, Jeanne Shropshire, Linda B. Ford, Curtis Hedberg, Pamela Fleetwood, Kim T. Hovanky, Tony Kavanaugh, George Fulford, Rose F. Vrtis, Jonathan A. Patz, Jay Portnoy, Frances Coates, Leonard Bielory, and David Frenz, Proceedings of the National Academy of Sciences of the USA(PNAS), Feb. 22, 2011)

Also discussed here: Links Between Longer Ragweed Season and Climate Change Confirmed (Science Daily, Feb. 25, 2011)

And here: Ragweek Research Is Nothing To Sneeze At (Science Daily, Sep. 25, 2007)

And here: Nothing To Sneeze At: Real-Time Pollen Forecasts (Science Daily, Jan. 2, 2009)

Climate change brings with it longer and warmer summers as well as shorter and milder winters. Today’s article looks at the effect that a longer growing season for vegetation has on ragweed, one of the most common allergies known and the main cause of asthma in northern USA and Canada.


Key Quotes
“Ragweed pollen in some parts of the northern United States and Canada now lingers almost a month longer than it did in 1995.. from 1995 to 2009, the number of frost-free days at higher-latitude study sites had increased, and so had the length of the ragweed pollen season. During that period, the pollen season lasted from 13 to 27 days longer than in 1995.”

“15 million people with ragweed allergies in the United States and Canada alone.”

“a longer ragweed pollen season was strongly correlated with a delay in the onset of the first fall frost.”

“one small plant is capable of releasing 1 billion grains of pollen per season,”

"Concentrations of fewer than 10 pollen grains per cubic meter can cause an allergic reaction in people who are sensitive to ragweed.. During our field research, we found concentrations of 10,000 grains per cubic meter in the air above the plants. My clothes were stained yellow with pollen."

"One of the biggest challenges in studying climate change is finding out how the plant kingdom is adapting to increases in air temperature and other meteorological phenomena,"

"Studies like this also show us that these ecological shifts don't stop at crop production. They can also have a significant impact on public health."

“Researchers in Germany are reporting an advance toward development of technology that could make life easier for millions of people allergic to plant pollen. It could underpin the first automated, real-time systems for identifying specific kinds of allergy-inducing plant pollen circulating in the air.”

Related articles

• Climate change has made ragweed season longer (ctv.ca)
• Climate Change Extending Ragweed Season in Colder Climes: Study (healthscout.com)
• Climate Change Extending Ragweed Season in Colder Climes (nlm.nih.gov)
• Climate change creates longer ragweed season (reuters.com)
• Trouble In The Air: Warmer Temperatures Lengthen Midwest Ragweed Pollen Season (switchboard.nrdc.org)
• Suffer From Allergies? Blame Climate Change (doyourpart.com)
• Fighting Fall Allergies? (everydayhealth.com)
• Climate Change Is Already Making Your Hayfever Worse - Ragweed Season Now Up To 1 Month Longer (treehugger.com)
• Climate Change Means Longer Allergy Season, Study Says (ecoworld.com)
• Canadian allergy season getting longer (theglobeandmail.com)
• Climate change lengthens allergy season (dedever10.wordpress.com)
• The Most Common Fall Allergies (everydayhealth.com)