Considering that the Earth is about 4 1/2 billion years old, we inhabitants have a lot of catching up to do in terms of celebrating its birthday. This year, more than a billion people around the world are expected to tread lightly and commemorate the 30th Earth Day, which falls this year on Saturday.

Countries, cities, towns and neighborhoods have already started cleaning up, planting new life and trying to find ways to ease up on taxing the planet’s generous but precious bounty. To get involved in local projects, you can call city offices, park organizations or check out www.earthday.net and www.bayareaearthday.net.

As for the parties, only Earth Day lets you dig in the dirt as part of the festivities. So, roll up your sleeves, slap on the sunscreen and find out what’s happening in your neck of the planet. For public transportation, call the event organizers or TRAVINFO at 817-1717 from any area code, or browse www.transitinfo.org.


USS Hornet Museum Alameda Earth Day 2000, 11 a.m.-5 p.m. Saturday. The aircraft-carrier museum ship is out to save the Earth with an environmental idea fair, food booths, skateboard demonstrations, electric go-kart races and a treasure hunt. The Alameda Recycling Company, Museum of Children’s Art and East Bay Depot for Creative Reuse will create crafts from discards. Live entertainment includes Kim Franz and Encinal High School jazz bands, Alameda Children’s Musical Theatre and the Earthcapades. Pier 3, Alameda Point. Details: www.uss-hornet.org; 510-521-8448.


Berkeley Earth Day Festival, 10 a.m.-5 p.m. Saturday. The Berkeley Farmers Market will be the site of wool-spinning, beeswax candle-making and gardening. At 11 a.m., kids and adults go on foot, by stilts and other nonpolluting forms of transport in the Eco-Motion Parade. The noon fair brings out hay rides, a puppet show and guest speakers Julia Butterfly Hill, Ralph Nader and Faith Nolan. Civic Center Park, Allston and Martin Luther King Jr. ways. 510-654-6346, Ext. 2.

Earthweek 2000, April 24-30, UC Berkeley. Environmental education through lectures, workshops, music, dance, a job fair and eco-marketplace. Lecturers include cowboy vegan Howard Lyman, former U.S. poet laureate Robert Hass and San Francisco Grace Cathedral environmental minister Rev. Sally Bingham. www.earthweek2000.org; 510-643-9703; 510-664-1011.

Haas Earth Day Symposium on Business and Environment, 5:15 p.m. April 26. Panel explores “Global Warming: The Science, Policy, and Corporate Response” with speakers John Harte, LBL senior scientist and UCB professor; Janet Yellen, former chief economic policy adviser to President Bill Clinton, and Mark Trexler, president of Trexler and Associates. Arthur Andersen Auditorium, Haas School of Business, UC Berkeley, Gayley Street and Piedmont Avenue. 510-981-0568.


Contra Costa County Earth Day Festival, 10 a.m.-6 p.m. Saturday. In its 10th year, the annual Earth party explores the theme “New Energy for a New Era.” On hand will be large wind turbines, solar displays, solar and electric vehicles, solar cooking demonstrations, an environmental film festival, prayers for the earth wall and the kid-created New Energy Maze made of 100 panels depicting a clean energy future. Former redwood-dweller Julia Butterfly Hill will speak; entertainment includes Pele JuJu. At the Chronicle Pavilion at Concord. Details: www.ccearthday.org; 925-274-3669.


Crockett Earth Day Celebration, 9 a.m.-noon Saturday. Creek Greenhouse. Learn about propagation and visit the butterfly vivarium. Call ahead to reserve a monarch butterfly gardening kit. 1300 Crockett Blvd. 510-787-2265.


Earth Day Celebration at the Oakland Zoo, 11 a.m.-3 p.m. Saturday. Appreciate the Earth amongst its many diverse inhabitants. The zoo explains how global warming affects biodiversity, land, migratory behavior and species distribution, and how using alternative fuel resources can stop the downward spiral. Admission: $6.50 ages 15-60, $3.50 ages 2-14 and 61 and above, and free to ages under 2. 9777 Golf Links Road. Details: www.oaklandzoo.org; 510-632-9525, Ext. 124.

Walnut Creek

Mount Diablo State Park Creek/Trail Restoration, 7 a.m.-2 p.m. Saturday. Preregistration is required for the projects, which include planting native vegetation, removing invasive non-native plants, taking down barbed wire and fence posts, restoring horse stalls and working on trails. Bring gloves, hat, long-sleeved shirt, pants, sturdy shoes, water and a snack. 925-837-5245.


West County Earth Day 2000, 11 a.m.-4 p.m. Saturday. Hosted by the West Contra Costa Integrated Waste Management Authority, the event features a recycling Olympics, treatment plant tours, creek explorations, recycled art and electric vehicles. Bungee Jumpin’ Cows, BLOCO’s Steel Drums, Son de la Tierra, West African Music and Dance Ensemble and the Mien Legends will perform. Call or check the Web site for group bike rides to the event. Integrated Resource Recovery Facility, 101 Pittsburg Ave. Details: www.recyclemore.org; 510-215-3021.

San Francisco

San Francisco Civic Center Earth Day Festival, 10 a.m.-5 p.m. Saturday. A community procession and bike tour lead the festivities, which also feature educational exhibits, demonstrations, activities, environmental art, speakers, live music and food. Exhibitor organizations on hand include Amnesty International, Bay Area Wilderness Training, the Environmental Protection Agency and more. On Van Ness Avenue. 415-701-9864.

California Academy of Sciences, 10 a.m.-5 p.m. Saturday. San Francisco League of Urban Gardeners, Strybing Arboretum and SF Recycles will teach people how to grow full-circle by growing food, then turning leftovers into garden food. Hear storytellers, look at exhibits and visit the live peregrine falcon and rattlesnakes. Free to members, bicyclists and bus riders, $5 nonmembers. Golden Gate Park. Details: www.calacademy.org; 415-750-7145.