Climate change isn’t just contributing to rising sea levels and warmer temperature. It can also leave people suffering from allergies further into the year.

A United States Department of Agriculture study with collaborators including Agricultural Research Service, allergy and asthma clinics, University of Massachusetts assistant professor of public health, Christine Rogers and other contributing universities found that over a period of 15 years,  ragweed season lasts longer and ends later due to climate change.

The study published in Proceedings of the Natural Academy of Sciences suggest ragweed season is ending up to a month later and can be a result of higher temperatures in northern latitudes and the delay of frosts.

According to Webmd.com Allergies Health Center, at least one in five Americans suffers from allergies. The Allergies Health Center also said more common allergies are seasonal allergies related to pollen, weeds and grass.

Ragweed is classified as a severe allergen by Pollen.com with unpleasant and harmful effects beginning its season in late August and ending with the first frosts of the year.

Dr. Dan Dalan, owner and allergy doctor of Allergy and Asthma Care and associate professor of medicine at the University of North Dakota said Allergy and Asthma Care was a location providing data for the study.

Dalan said the information included in the study displays how the probability of people being exposed to more allergens is increased. He described the findings as “amazing” in that several years of information was summarized and it was an opportunity to learn how the environment affects allergies.

Dr. Fred Mudawwar a physician at Hampden County Physicians and a consultant for University Health Services said seasonal allergies greatly bring down public health because they affect so many people at the same time.

“With climate change, allergies will definitely be affected,” Mudawwar said. “They’re miserable, they can’t focus as well, they become less efficient”

Allergies are on a gradual increase for the population overall, according to Mudawwar.

The study authors indicate the recent projections of Intergovernmental Panel on Climate are consistent with their research. According to the IPCC Fourth Assessment Report, annual warming is projected to be two to three degrees Celsius warmer across western, southern and eastern continental edges, and over five degrees Celsius at higher latitudes. The report also projected warm temperature extremes are likely to become more frequent and last longer in North America.

Charlie Walthall, national program leader for climate change at Agricultural Research Service said weeds, vines and poison ivy are experiencing the enhanced fertilization effect.

Walthall explained, when plants are exposed to excessive nutrients, it can produce stronger plant growth. He also mentioned how some plants are highly receptive to carbon dioxide. With excess carbon dioxide in the atmosphere, he said plants can become more competitive and resistant to herbicides.

Walthall explained if the conditions for the plants to survive are lasting longer, such as warm temperatures and access to sunlight, the plants will linger longer into the year.

He described the study’s findings as “something we need to plan for and adapt to.” Walthall also mentioned the northern latitudes see more effects of climate change and gave examples of wide swings in temperature, precipitation and vegetation patterns as well as melting of glaciers and permafrost.

Walthall talked about changes in the environment such as seasonal shifts being a consequence of climate change and what made the allergy season last longer. He also noted plant life cycles changing and noted a change in types of species as well as the actual ecosystems in which they live.

Nancy Pierce can be reached at [email protected].