Whether already an activist or still struggling to sort recyclables, we all have a prime opportunity during the week of April 22 and other days to renew our individual and collective pledge to tread more lightly on the planet.

“Environmentalism touches every part of our lives, from what we eat to what we wear to what we breathe,” says Earth Day Network President Kathleen Rogers. “Learning about where our food comes from or how a product is made can be fun,” she continues, “and awareness is the foundation for action.”

More than a billion citizens have already registered their acts of green through the organization’s website; this year, the campaign seeks to engage a billion more. Suggestions range from the personal, such as pledging to stop using disposable plastic, to the political, in calling our congressional representatives to reestablish a tax credit program for renewable energy.

With an estimated two out of every three people on Earth expected to be living in cities by 2050—straining water, energy and transportation systems—Earth Day Network has chosen Green Cities as this year’s theme. Advocates are calling upon cities to invest in smart grids, overhaul outdated building codes and increase public transportation options.

Visit EarthDay.org to pledge a personal act of green, find a volunteer opportunity or learn more about the re-greening of urban communities around the world. Help Boston celebrate its progress toward sustainability at these local Earth Day 2014 events.

SATURDAY, APRIL 5

2014 Earth Night – 7-10pm. Biggest annual fundraiser for Environmental League of Massachusetts. Drinks, dinner, silent and live auctions, and a night of entertainment featuring Women of the World. Back Bay Events Center, 180 Berkeley St, Boston. 617-742-2553. EnvironmentalLeague.org.

SATURDAY, APRIL 19

6th Annual Race Against Extinction 5K – 11am. We are looking for Cheetahs (experienced and first-time runners), Tortoises (walkers), Gazelles (inline skaters), Kangaroos (parents with strollers), Wolf Packs (runners or walkers with their pets) and Sloths (those who cannot or will not be running, skating, walking or moving in general, but would like to support and help protect their fellow species). $25. Proceeds donated to the World Wildlife Fund. Artesani Park, Brighton. TheRaceAgainstExtinction.org.

TUESDAY, APRIL 22

The Balance of Nature: Ecology’s Enduring Myth – 6:30-8pm. In his lively and thought-provoking book, The Balance of Nature: Ecology’s Enduring Myth, John Kricher demonstrates that nature in fact is not in balance, nor has it ever been at any stage in Earth’s history. He will explain why it is critical that we accept and understand that nature is constantly in flux, and, in effect, quite naturally out of balance. Free/members & students, $10/nonmember. Arnold Arboretum, Hunnewell Building, 125 Arborway, Boston. For students to register free: 617-384-5277. Arboretum.Harvard.edu.

FRIDAY, APRIL 25

Boston Shines – Apr 25-26. West Roxbury, Jamaica Plain, Roxbury, Allston and Brighton residents, as well as local businesses and organizations, are invited to volunteer in a widespread beautification effort. 617-635-4500. CityOfBoston.gov/Ons/BostonShines.

SATURDAY, APRIL 26

Massachusetts Park Serve Day – Annual public service day for residents to clean up area beaches, parks and more. 617-626-1250. web1.env.state.ma.us/DCR/Parkserve.

15th Annual Earth Day Charles River Cleanup – 9am-12pm. In a collaboration led by Charles River Watershed Association, volunteers from over 20 towns will work together to remove litter and debris and beautify the Charles River and its surrounding parklands. 781-788-0007. crwa.org.

Musketaquid Earth Day: River Ceremony, Parade & Festival – 10am-2pm. Includes a morning River Ceremony along the Concord River, a Parade with music and large puppets making its way from the river through Concord Center and ending with a Festival on the grounds of Emerson Umbrella Center for the Arts. Enjoy an abundance of art, entertainment, gastronomic delights and environmental awareness opportunities. Free. Emerson Umbrella Center for the Arts, 40 Stow St, Concord. 978- 371-0820 x 213. EmersonUmbrella.org.

The Greatest Party on Earth – 7:30pm- 1am. Enjoy a dazzling evening of amazing art and design, extraordinary live entertainment, non-stop dancing, and inspired cuisine while raising funds to support empowering jobs in art and design for Boston teens working at Artists for Humanity. Artists for Humanity EpiCenter, 100 W 2nd St, Boston. 617- 268-7620. GreatestPartyOnEarth.com.

SUNDAY, APRIL 27

Earth Rock Run – 8am. Green Stride & Sub 5 have developed a fun and exciting spring option for anyone who loves the challenge of running, postrace party with live music (on and off the course) and the celebration of Earth Day. The course takes you through the beautiful streets of North Andover for a 13.1-mile loop. Double up and run the course twice for a certified 26.2. After the race enjoy beer, food, live music and vendors displaying their sustainable initiatives all in celebration of Earth Day. $70/half; $90/full. 1600 Osgood St, N Andover. Sub5Racing.com/GreenStride262.

Party for the Planet at Franklin Park Zoo – 10am-3pm. Celebrate the animals of Earth with a day at the Franklin Park Zoo, where there will be a variety of Earth Day-themed events. Festivities include opportunities to meet the zookeepers, animal enrichment activities, scavenger hunts, entertainment, ecofriendly exhibitors. One Franklin Park Rd, Boston. 617-541-5466. ZooNewEngland.org.

MONDAY, APRIL 28

Population and The Planet – 5:30pm, reception; 6:30-8pm, panel discussion. How many people are too many? Can conservation and technology innovations support Earth’s ability to provide food, water and other benefits for 9 billion people? How does human population growth affect other species and the planet’s health as a whole? $25. Calderwood Pavilion at the Boston Center for the Arts, Wimberly Theatre, 527 Tremont St. Nature.org/future. 

FRIDAY, MAY 2

Boston Shines – May 2-3. Hyde Park, Roslindale, Dorchester and Mattapan residents, as well as local businesses and organizations, are invited to volunteer in a widespread beautification effort. 617-635-4500. CityOfBoston.gov/Ons/BostonShines.

FRIDAY, MAY 9

Boston Shines – May 9-10. Back Bay, Beacon Hill, Mission Hill, Fenway, South End, Bay Village, North End, West End, Downtown, Charlestown, Chinatown, East Boston and South Boston residents, as well as local businesses and organizations, are invited to volunteer in a widespread beautification effort. 617-635-4500. CityOf Boston.gov/Ons/BostonShines.