FAYETTEVILLE -- April showers might have brought May flowers 20 years ago, but scientists say global warming is to blame for spring flowers blooming in March.

An early spring is why the allergy season is starting a month earlier. Raleigh and Greensboro were recently listed by Pollen.com as being one of the five worst cities in the U.S. for pollen.

Allergy suffers say they have to stock up on their allergy medications earlier every year. Kimi West and her husband run a lawn and garden business. She says the pollen has gotten so bad this year she now gets allergy shots.

"Actually the strength had to go up on [my shots] because the pollen is coming sooner and sooner,” she said.

Barbara Kacin can tell that pollen is filling the air just by listening to her husband. "Well, my husband sneezes a lot when he does yard work, so I have to assume there is a lot of pollen out there."

John Calhoun is a pharmacist for Cape Fear Discount Drugs. He is already seeing an increase in antihistamine sales.

"We just barely got through the cough, cold, and the flu season and the allergy season is upon us already,” he said.

Often times it is not the pollen you can see, but the pollen you can't that causes the problems.

"If you really need a more potent antihistamine, you can go to Benadryl which is more sedating but is much more potent than the Claritin or the Zyrtec," said Calhoun.

Thirty scientists told the Associated Press that global warming is to blame for the early spring. One study found red maples in Washington, D.C. are now blooming 19 days earlier than in 1970.

West says an early spring has more than an effect on trees. Animals are forced to adapt to a changing environment, "There is no seasons any more. If you notice, we did not have that hard of a winter. Therefore, the bugs and the snakes are unbelievable. I think it is because of global warming, I really do."