Next time local land conservation advocates seek support for saving a nearby forest from development, they’ll have a “big extra arrow in the quiver” of reasons why people should pitch in to help.

The historic international agreement reached in Paris on Dec. 12, which set ambitious goals for reducing heat-trapping carbon dioxide emissions to slow climate change, recognizes that keeping and increasing forestland worldwide will be an important part of the solution.

“Deforestation at a global scale amounts to about 12 percent of the carbon dioxide emissions, second to burning fossil fuels,” said Adam Whelchel, director of science for The Nature Conservancy’s Connecticut chapter. “This is a big extra arrow in the quiver of strong arguments about the benefits of land conservation.”

Transitioning away from fossil fuels remains the key strategy for meeting the agreed target of keeping global average temperatures below 2 degrees Celsius (about 3.5 degrees Fahrenheit) above pre-industrial levels.

However, the agreement also emphasizes that the planet also needs more carbon sequestration.

That could mean designing elaborate new and expensive technologies to take carbon out of the atmosphere and inject it underground. Or, it could simply mean more trees.

One acre of 20- to 40-year-old Connecticut hardwood forest annually captures about one ton of carbon dioxide from the atmosphere.

“Trees have been doing this job longer than humans have been on the planet,” Whelchel said.

At local land trusts, the value of forest preservation in stemming global warming hasn’t been strongly emphasized thus far. But that could change.

“We’ve been protecting and saving forest blocks mainly to preserve habitat, not in terms of climate change,” said Anthony Irving, preservation committee chairman for the Lyme Land Conservation Trust.

But with the agreement bringing the public’s attention to the looming crisis of climate change, he said, the land trust could be reminding potential donors that contributing toward the next land purchase — an 80-acre parcel off Brush Hill and Joshuatown roads is on the horizon — would mean they’re doing good for the entire planet.

“It is certainly an important aspect of it, in terms of killing two birds with one stone,” said Irving.

Michelle Fitzpatrick, president of the Avalonia Land Conservancy, agreed that her organization should stress the climate change aspect of forest conservation when it embarks on its next campaign.

A 500-acre parcel in Preston is under consideration, she said. Her group has preserves in six local towns — Griswold, Groton, Ledyard, North Stonington, Preston and Stonington.

“That would certainly be a good angle to work with,” she said.

Already, groups like the Lyme and Avalonia land trusts and the Friends of Oswegatchie Hills in East Lyme can make a case for land protection for wildlife, clean water, clean air, erosion control and recreational values.

Now, said Mike Dunn, co-founder and chairman of the Legal Defense and Land Acquisition Committee of the friends group, people can be invited to join their efforts as a way of doing their part to reduce climate change.

Reducing personal fossil fuel and overall energy use will remain important individual efforts, he said, but participating in a land conservation drive is a chance to become part of a communitywide initiative.

His group currently preserves 455 acres, and is hoping to add another 236 now owned by Landmark Development Group.

“Every little bit helps,” he said.

That phrase was also used by Sarah Ganong, media coordinator for the Connecticut Fund for the Environment/Save the Sound, in describing the role of local forests as “carbon sinks.”

Her group recently participated in the successful preservation of the 1,000-acre Preserve in Old Saybrook, and is currently supporting the Oswegatchie friends group in its efforts.

“While nowhere near the scale of something like the Amazon, every little bit helps,” said Ganong, who grew up in Ledyard and now lives in New Haven.

Sponsored by her alma mater, Dickinson College, Ganong attended the Paris conference, coming away pleased that an international agreement on climate change was reached for the first time.

While falling short of what many environmentalists say is needed, it was at least a positive start toward the challenging task ahead to end the age of fossil fuels, she said.

Statewide, about 58 percent of Connecticut is tree-covered, meaning “we have a lot of carbon currently stored in our forests,” said Eric Hammerling, executive director of the Connecticut Forest & Park Association.

But that doesn’t mean the state should be complacent, given the need for more natural landscapes worldwide to sequester carbon.

He cited a newly released report from the Forest Climate Working Group, "Forest Carbon Solutions for Mitigating Climate Change."

“Our big challenge for the future is to stem the loss and better manage our existing forests,” he said. “We need a mindset that when we trim or remove trees, we offset that by planting a tree for the future.”

About half of the forestland in the state is owned by families rather than the state, land trusts, water companies or conservation organizations, and is considered vulnerable to development, said Tom Worthley, associate extension professor of the University of Connecticut Extension Center.

Along with working to protect those lands, he said, more effort also needs to be focused on keeping forests healthy through responsible thinning, removing invasive species and other actions.

Selective harvesting of trees for wood products, he added, also sequesters carbon in the furniture, flooring or salad bowl it becomes, and gives the landowner income to help maintain the forest.

“If trees are grown to good quality, they will sequester more carbon,” he said. “Let’s grow the best trees we possibly can.”

Many forest owners whom he works with, he said, are motivated by concerns about climate change to keep their lands in a natural state, and he expects that sentiment will continue to strengthen.

“Carbon sequestration is becoming a more important reason for people with a land conservation ethic,” he said.

Allison Morrill Chatrchyan, director of the Cornell Institute for Climate Change and Agriculture, noted that while there are incentives through the United Nations for developing countries to prevent deforestation, there are no equivalent programs available in the United States.

Voluntary efforts by private landowners and joint efforts of individuals, private nonprofit groups and local, state and federal government will be key to increasing this country’s contribution to achieving the Paris goals through sequestration, she said.

“We need public-private partnerships,” she said.

She emphasized that the public can further the Paris agreement’s goals by keeping pressure on local, state and federal officials.

“There are climate impacts in the Northeast already, and it’s going to increase,” she said. “It’s up to us to keep the pressure on our own government and globally."

Currently, U.S. forests absorb about 1 billion tons of carbon dioxide out of the atmosphere annually, but the country has an obligation to do even more, according to Doug Boucher, director of research and analysis at the Union of Concerned Scientists.

The Paris agreement, he noted, calls for all carbon emissions to be offset by sequestration by the second half of this century.

“That means forests,” he said. “That’s the only practical way. Preserving the ones we have, and regenerating new ones. It’s something the U.S. can take the lead on.”

While forests in Connecticut and the entire Northeast are “pretty good” at sequestering carbon, Boucher said, the volume is restricted by seasonal growing cycles. Not so the forests in tropical regions.

That’s where Reforest the Tropics, a nonprofit group based in Mystic, comes in.

Founded by Herster Barres, an environmental scientist who lives in Mystic, the group raises funds to pay farmers in Costa Rica to convert parts of their farms back into forests.

Donors contribute as a way of offsetting their own carbon footprint, said Greg Powell, the group’s director.

“Our farmers sign a 25-year contract, and over that 25 years our forests extract 500 metric tons of carbon per hectacre (2.5 acres) per year,” he said. “We are accumulating and storing carbon for the long term, and trying to do it in a way that is environmentally responsible and economically sustainable.”

The group is supported by 63 major donors and about 100 smaller ones, many from southeastern Connecticut. It has enlisted 14 farmers in Costa Rica to reforest about 460 acres thus far.

"Our best technology for sequestration is an ancient one. It’s tropical reforestation,” Powell said. “We hope the attention given to the issue in Paris will stimulate interest in our program. We still have to educate the public about the potential of tropical reforestation. It’s something we know how to do, and it can be economically sustainable. Because it’s so simple and straightforward, reforestation has been overlooked at times.”

j.benson@theday.com

Twitter: @BensonJudy