Aug. 5, 2008 -- Global warming poses a threat to asthma and allergy patients, according to a new research review.

The review, published in September's edition of the Journal of Allergy and Clinical Immunology, makes these predictions:

Worse allergy seasons. A hotter climate means earlier blooms in spring and a longer season for fall allergens such as ragweed and mugwort. Basically, more warmth means more plants and more pollen, according to the review.

A hotter climate means earlier blooms in spring and a longer season for fall allergens such as ragweed and mugwort. Basically, more warmth means more plants and more pollen, according to the review. Prime conditions for asthma. More air pollution, more ozone, and more wildfires would worsen air quality, aggravating asthma.

People with allergies and/or asthma "are at risk of worsening disease, more symptomatic days, and reduced quality of life as a result of these environmental changes," and a warmer world could make allergies and asthma more common, write the reviewers, who included Katherine Shea, MD, MPH, of the School of Public Health at the University of North Carolina, Chapel Hill.

In July, a report from the Environmental Protection Agency included asthma on a list of possible health risks from global warming.

Shea's team recommends that doctors teach patients how to find and interpret daily air quality reports and pollen counts. "We need champions throughout the world who will work to put protecting human health at the center of the climate change agenda," write Shea and colleagues.

The reviewers also point out that biking, walking, using public transportation, eating locally grown fruits and vegetables, and eating less meat is good for human health as well as for the climate.