As millions around the world mark Earth Day, imagine what Acadia National Park would be like without the banning of DDT, the Clean Air and Endangered Species Acts, or any of the other changes since that first massive showing of environmental activism in 1970:

• – No peregrine falcons nesting on the Precipice of Champlain
• – Hazy views atop Cadillac
• – Declining loon populations
• – Acidified ponds that can’t support certain aquatic life
• – A silent spring in Acadia, with no birdsong

On this Earth Day and beyond, whether you’re marching for science in Washington on April 22 or for climate change action in Bar Harbor on April 29, or you’re volunteering for the Friends of Acadia’s annual roadside clean-up later this month, just imagine what a silent spring in Acadia would be like.

And imagine, too, what rising sea levels could mean to Acadia, as climate change worries join the ranks of environmental concerns like pesticides, mercury contamination, acid rain and acid fog, and air pollution.

As our way of marking Earth Day, of science’s contribution to protecting the environment of Acadia for people, plants and wildlife, and of the challenges like climate change still to be faced, we gather here some resources to remind us of how far we have come, and how much further we have to go.

May this listing, although not exhaustive, help spur reflection, respect, and action, in honor of Earth Day and Acadia.

Resources and activities to mark Earth Day in and around Acadia

Peregrine falcon comeback – With the banning of DDT in 1972, the Endangered Species Act of 1973, and park efforts to reintroduce peregrine falcons, the first successful nest in 35 years occurred in 1991. Last year, 11 chicks fledged, or took their first flight, at the park’s three main nesting sites, on the Precipice of Champlain, Jordan Cliffs and Valley Cove. That represents more than a 55 percent increase over the year before of fledged chicks at those three sites. The Precipice, Jordan Cliffs and Valley Cove Trails typically stay closed through late July, early August, to protect peregrines and people. Rangers or volunteers with spotting scopes at the base of the Precipice Trail allow visitors a peek in the late spring, early summer, during Peregrine Watch. DDT and other pesticides’ impact on birds, bees, plants, people and other forms of life was the focus of Rachel Carson’s best-selling 1962 book, “Silent Spring.” (NOTE: Please see sidebar about Amazon.com links)

Air quality monitoring – As part of air quality monitoring, the park has a webcam on McFarland Hill across from park headquarters that tracks visibility and other variables. On good visibility days, you can see as far as 153 miles in Acadia. On poor visibility days, 23 miles. The McFarland Hill monitoring station also collects data on nitrogen and sulfur, contributors to acid rain and acid fog; mercury, which can affect the reproductive cycle of loons; and ozone, which can cause respiratory problems in people and damage plants. The Environmental Protection Agency, in its overview of progress made under the Clean Air Act, particularly since major amendments in 1990, specifically includes improvement in national park vistas as being among the act’s accomplishments.

Ozone- and climate-change-sensitive plants in Acadia – Twenty plants in Acadia – ranging from bigleaf aster, with its large heart-shaped leaves and purple or white flowers, to dogbane, which is poisonous to dogs – appear on a 70-page list of ozone-sensitive plants found throughout national parks, compiled by the National Park Service. Plants of Acadia are also being looked to as indicators of climate change, since it’s suspected that plants of northern climes, like rhodora, may be more at risk of disappearance or decline with warming temperatures.

Climate change research – Early in the Trump administration, with concerns about changes that could affect climate research and the National Park Service, we gathered in one place links to such research and other resources available through Acadia and the rest of the National Park Service. We’ve periodically been checking the links, to make sure they continue to be live, and list other ways to access the information if the Web sites are changed. Among the resources that can be accessed via the blog post: A carbon dioxide calculator showing how much you can help the planet by taking such steps as reducing how much you drive by 25 miles a week, or changing to more energy efficient light bulbs.

Acadia natural resource assessments – From a 2008 natural resource report identifying areas of significant concern or caution, in lakes and ponds, on land, or in air quality; to current lists of species and their status in the park; to annual reports of visitation, there have been many efforts to gauge human impacts on Acadia’s environment, and to hopefully allow for better planning. A major reason there isn’t a silent spring in Acadia: More than 300 species of birds, many of them songbirds.

Earth Day activities in and around Acadia – While April 22 is officially Earth Day, with the March for Science in Washington and elsewhere, local groups are marking the occasion on April 29: The Downeast Climate March at 1 p.m. in Bar Harbor, and the Friends of Acadia Earth Day roadside cleanup at 8:30 a.m.

May there never be a silent spring in Acadia National Park

As Acadia enters its second century, and as the 50^th anniversary of Earth Day approaches in 2020, may these visions of where we’ve been and where we could be heading, and this sampling of the many resources out there, help in some small way to prevent a silent spring in Acadia, or an Acadia besieged by climate change and rising sea levels.

In honor of Earth Day, we leave you with these visions of Spaceship Earth, a metaphor for us all being on the same planet – or island – with limited resources, and the need to work together.