Maureen Reed, left, Henry Reed, 7, and Ryan Reed pick up trash under a deck at Gardiner Landing along the banks of the Cobbossee Stream in celebration of Earth Day in 2022. Joe Phelan/Kennebec Journal file photo
Earth Day is one of my favorite days of the year.
Established in 1970 thanks to efforts from peace activist John McConnell and former U.S. Sen. Gaylord Nelson of Wisconsin, Earth Day is a time for reflection.
It’s a time for all of us to renew our efforts to take care of our planet and its inhabitants.
Earth Day is well-timed in our corner of the world, as it occurs at the peak of spring. There’s a promise of rebirth and renewal, as plants leaf out and animals return or emerge from hibernation.
Earth Day was born out of an environmental movement. This movement was perhaps given a big boost by Mainer Rachel Carson, whose 1962 book, “Silent Spring,” documented the devastating effect of the use of chemicals on many birds.
There is no shortage of ways we can help improve the health of the earth and all of its creatures. We can recycle, grow native plants in our yards, and turn down the thermostat in our homes a few degrees. We can also pay for voluntary carbon offsets for air and car travel.
The emission of greenhouse gases and its role in environmental protection is often debated.
There is no doubt that air temperatures have consistently increased over the past 100 years, and there does not appear to be any signs of this slowing.
Some people argue that the earth has seen great variation in temperatures over geological history and that climate warming is just not an issue. The assertion that the earth’s temperature has varied greatly is true, but the rate at which global temperatures are changing is unprecedented.
Temperature has a fundamental effect on all organisms. As temperatures rise, organisms must find more optimal temperatures by moving poleward or upward on mountains. For organisms with limited mobility, perishing is the likely outcome.
Warm tropical ocean temperatures are causing widespread coral reef mortality. We expect these corals to move poleward via dispersal of their larvae to find ocean waters below lethal temperatures.
The U.S. Forest Service has released models of the distribution of trees in the northeast in the year 2100, assuming that carbon emissions continue at the same rate. Sugar maples and balsam fir will no longer be able to live in Maine. Nesting birds that depend on balsam fir forests, like Swainson’s thrush, will become less common. So, too, will be winter wren and red-breasted nuthatch.
Some may say that organisms can simply move toward the poles or to higher altitudes to live. The problem is that some organisms will run out of space. Polar bears depend on pack ice to forage for seals. With global warming, polar bears cannot move northward from their arctic habitat. They are in real trouble.
The science of phenology focuses on the timing of biological events. Some examples include: Leaf-out of red maples, first flowering of white elderberry, the first arrival of Yellow Warblers in the spring, first egg-laying of Ovenbirds, the emergence of groundhogs from their hibernation burrows, the first calling of spring peepers, and the emergence or caterpillars from hibernation.
With global warming, we expect phenological events to occur earlier. We have an abundance of evidence of that happening already for many plants, insects, birds, amphibians and mammals.
An insidious effect is a phenomenon called phenological disconnect. When two or more species that depend on each other fall out of sync, disaster can occur.
The pied flycatcher is a common Eurasian bird that winters primarily in Africa. They feed their young caterpillars that feed on oak leaves. In Europe, oak trees are leafing out about two weeks earlier, and the caterpillars are right with them. However, the flycatchers are on their old schedule and are arriving after the caterpillar peak has passed, leading to starvation or slower development of their chicks.
What can we do to prevent such tragedies? Earth Day should inspire us to do all we can to reduce the carbon emissions that are heating our planet.
Herb Wilson taught ornithology and other biology courses at Colby College. He welcomes reader comments and questions at whwilson@colby.edu
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