The “twin global challenges of climate change and sea level rise” will dramatically alter critical habitat for migrating birds, insects and fish along our Connecticut shorelines.

That’s the assessment of this year’s “Connecticut State of the Birds” report, released by the Connecticut Audubon Society on Dec. 5.

Here are some findings.

Computer models are now predicting a six-foot sea level rise along parts of our Connecticut coastline within the next 80 years. This will almost certainly cause the extinction of some birds like the saltmarsh sparrow, who nest in the high marsh areas, the report said.

And this caught my eye:

“Since coastal marshes store more carbon than do other ecosystems, such as forests, they play an important role in mitigating the effects of climate change,” writes David Kozak, senior coastal planner in the Land and Water Resources Division of state DEEP.

He adds, “They are also hotspots for nitrogen removal via plant uptake … helping to control hypoxia or oxygen depletion in the Sound.”

Changes in the marshes could reduce those benefits, Kozak writes.

When I read that, I had no idea how important marshes are to our livelihoods.

Kozak further notes that as sea levels rise, marshes will migrate, moving to higher ground, and warns that we must protect these sensitive shoreline areas from further residential and commercial land development.

Elsewhere, Jenny Dickson, director of DEEP’s Wildlife Division writes, “Overall population trends for great and snowy egrets have declined, but black-crowned night-herons have increased.

Ana Paula Tavares, executive director of Audubon Connecticut and Audubon New York, writes that forage fish may be heading into deeper, colder waters.

These are small fish, like shad, river herring and sand lances that provide critical food for ospreys, northern gannets, loons, gulls and cormorants.

“The scientific consensus is that shifting ocean temperatures and increasing acidification, both the result of climate change, will alter the distribution of fish species,” Tavares writes in the report.

She adds, “Movement of forage fish to deeper or cooler waters outside the Sound equates to an uncertain future for our birds – terns especially.”

In the 2019 report, I also learned there are 50,000 acres of salt marsh in Long Island Sound. The Sound is 110 miles long, from New York City’s East River to the Race inlet between Fishers Island and Little Gull Island. It is 21 miles across, at its widest point, and has some 10 million people living around it.

“It is critical that we understand the Sound’s natural environments if we are to protect and defend our wild shores in a time of rapid change,” writes Patrick Lynch, board member of the Connecticut Audubon Society.

The annual “Bird” report is in its 14th year, and vitally important to local and state organizations. It helps them with their management plans, environmental reviews, species status assessments, and with public awareness.

I salute CT Audubon Society’s efforts.

Bill Hobbs lives in Stonington. He can be reached by email at whobbs246@gmail.com.