GLOBAL WARMING In-depth: Latest news and graphics | Resources | Overview | Kyoto | IPCC Poll: Climate seen as world's leading threat Vote: Biggest fear of global warming? Reports: Key findings left out | Earth nearing 'tipping points' | Scientists: Act now Endangered?: Birds move northward | High acidity endangers ocean reefs Thawing: Too late for polar areas? | Ice key to life on Earth | It happens like a boat tipping More   HOW THE PROJECT PROGRESSES The plant phases reported by participants in Project BudBurst: Budburst/first leaf: The first leaves are completely unfolded. Full leaf: At least 95% of leaves have completely unfolded. First flower: The first flowers are completely open. Full flower: When 50% of the flowers are fully open. End flower: At least 95% of the flowers have dried up or died.v Seed or fruit dispersal: The first fruits or seeds drop naturally from the plant. Source: Project BudBurst

The flowers and plants in your own backyard or neighborhood park also may have a role in this global drama.

Project BudBurst, a national field campaign for "citizen scientists," is designed to help record how the planet is warming by tracking the dates that 60 plant species leaf and flower this spring and summer.

Students, gardeners and interested residents of the 50 states enter their observations into an online database.

After a trial run in 2007 that included reports from 26 states, the project is in full swing this year with thousands of people signed up.

"You read about climate change all the time, but this project gives people the opportunity to actually participate in climate-change studies," says Sandra Henderson, coordinator of the project, which is operated by the University Corporation for Atmospheric Research in Boulder, Colo. "There aren't enough scientists around. In this project, citizens can be the sentinel eyes on the landscape."

The science involved is known as phenology, an ancient study that measures the timing of life-cycle events of all animals and plants. Phenologists observe the environment to figure out what "calendar" or "clock" plants use to begin to flower, to leaf and to reproduce.

"This is simple observational science," Henderson says. "The project is designed to help both adults and children understand the changing relationship among climate, seasons and plants while giving the participants the tools to communicate their observations to others."

Why now?

Scientists report climate change is affecting plant and animal species throughout the world.

"There's been a dramatic warming in the USA and Europe over the past 30 years," says Paul Alaback, a professor of forest ecology at the University of Montana and a science adviser for Project BudBurst.

"All over the country, people are noticing that they can grow more southerly plants farther north. There's also been a lot of data that shows that plants are flowering earlier in the spring … about one to three days earlier per decade over the past 30 years."

In Japan, for example, cherry trees now bloom four days earlier than they did in the 1950s, according to Japan's meteorological agency.

Other collaborators are the Chicago Botanic Garden and the University of Montana. The project was financed with a grant from the U.S. Bureau of Land Management and the National Fish and Wildlife Foundation.

Project BudBurst began this year on Feb. 15. It's not too late to sign up; data is needed through June. To learn more or to sign up, visit www.budburst.org.

Enlarge By Ross D. Franklin, AP Alysia, a second-grader in Tucson, participates in the project, which sets up an online database.