Those who suffer from allergies may have noticed it seems as if allergy season is lasting longer and longer – and they would be right.

Allergy season used to last just a few weeks into the spring. But now it seems to last throughout the entire season. Meteorologists say that there are several reasons for this.

“The plants tend to be a little more active, is how you could imagine it,” says Sean Sublette with Climate Central. “The pollen that is released is more allergenic. There are certain proteins in the pollen that are ratcheted up in a higher carbon dioxide atmosphere.”

Sublette says that research has shown that plants will produce more pollen as carbon dioxide levels rise. Carbon dioxide traps heat, and as a result warmer seasons like spring are starting earlier than in previous years. This means a longer spring allergy season.

"In New Jersey specifically, we've seen more of it coming earlier. It’s extended on both sides of the calendar. But it's extended a little bit more towards the beginning,” says Sublette. “We're getting the final freeze of the season, earlier in the season, and as a result the pollen is starting to show up earlier in the year.”

A changing climate will mean that allergy sufferers will need to prepare for the season earlier. It also will mean an increase in asthma cases directly related to pollen. Health officials say that it is wise to see a doctor if allergies become more than just a nuisance. People who have allergies should also keep doors and windows closed throughout the spring.

The worst of this allergy season is expected to continue through early May.