Physiologist

At the U.S. Department of Agriculture's research center near Washington, D.C., plant physiologist Lewis Ziska said weeds — defined as any unwanted plant — appear to be thriving in today's atmosphere, which is richer in carbon dioxide, or CO₂. And Ziska said agricultural research studies show that if climate trends continue, allergy sufferers will have to endure longer and more intense pollen seasons in the decades ahead.

Plant physiologist Christina Walters is proud of her work at the National Center for Genetic Resources Preservation, where she studies ways to extend the longevity of the Center's massive seed collections. She leads me down long, echoey hallways to the heart of the seed storage lab. I'm soon to discover, it's a frigid heart.