BAR HARBOR — If all goes well, Earth Day 1990 will dawn clear and warm for celebrants who will welcome the first rays of sun that morning from the top of Cadillac Mountain.

Even if April 22 is chillingly gray, the organizers of the Mount Desert Islandwide Earth Day weekend expect the music, food, dancing, exhibits and workshops to liven the spirits and warm the hearts of all those who draw together to celebrate the bounty and contemplate the problems of the planet.

Weekend festivities will begin Saturday, April 21, at Mount Desert Island Regional High School, where exhibits and workshops sponsored by College of the Atlantic will be held. Several workshops, which are free and do not require preregistration, are designed for children, such as a natural history walk and a “Please Touch” workshop with American Indian artifacts.

At least 25 workshops are scheduled for Saturday, with topics including air quality in Acadia National Park, energy conservation in the home, responsible consumerism, and environmental ethics.

After a workshop-filled day, which begins at 10 a.m., keynote speaker Steven Katona, a marine biologist at COA, will talk about ecological problems around the world.

COA students are organizing the mountaintop celebration for Sunday morning, which will begin with a predawn torchlit ascent of Cadillac Mountain. At sunrise, 10 American Indian elders, respresenting four Maine tribes, will conduct a pipe ceremony on the summit.

Another islandwide group has organized an afternoon of celebration and workshops for Sunday at the high school. Live music, provided by Salsbury Band, will begin at 1 p.m., followed by a presentation by Sherry Huber of Maine Waste Management, who will speak on Waste Management in Maine: The Next Two Years.

Two panel discussions will be held after Huber’s talk. The first, “Recycling on MDI,” will include Huber and planners for recycling on the island.

The second panel discussion, “Consumers Meet Grocers,” will include representatives from large and small grocery stores to answer questions about packaging and other consumer issues. According to Judith Blank, an islandwide Earth Day organizer, the second panel should focus participants’ concerns on what they can do as consumers.

“We tend to wait for experts to tell us what to do. We’re not tapping into our own mind. We are the consumers, and we can think about it,” Blank said. Those interested in having their questions considered by the grocers at the Sunday discussion should address their inquiries to Steve Alsup, RFD 1, Box 3925, Bar Harbor 04609.

A “Trash Art Gallery” will be displayed in the entryway of the high school during Earth Day weekend. School-aged children on MDI are being encouraged to put together a creative sculpture or mural, using discarded materials, for display at the school.

An afternoon of rock music, games, food and exhibits will complete the Earth Day weekend at the high school.

LaRue Spiker, another organizer of Sunday’s activities, hopes the weekend will “help people become more aware of environmental problems, locally, nationally, and globally. … The emphasis will be on local things people can do,” she said.

“We’re also hoping this will kick off the Environmental Decade,” Spiker said, “with more interest in the topics of global warming, recycling and ozone depletion.”

Blank concurred that the weekend should alert and inform people about environmental issues, “but the weekend will also be a kind of thanksgiving. `We want to look into the future and keep up our hopes.”

“It should be a type of healing. Some people think if you stop and remember the Earth, your consciousness may have something to do with changing the direction. We will be having a moment of standing still, of thinking about the Earth.”