Alarmists frequently assert that global warming is making allergies and asthma worse. Scientists have documented a substantial greening of the Earth in recent decades as more atmospheric carbon dioxide and warmer temperatures facilitate more plant growth. A side-effect of more plant life is more pollen in the air. More pollen may aggravate allergies and asthma, but few would argue that a world with declining plant life is better than a world with more abundant plant life.
