FREEPORT, Maine — Mainers from a number of organizations including the Sierra Club and students from the College of the Atlantic will join President Barack Obama and thousands of others in Paris next week, all carrying different perspectives on a proposed agreement aiming to protect the planet from the most devastating effects of climate change.

Nearly 140 world leaders have confirmed their attendance at the opening day of the two-week U.N. Climate Change conference, even after the Nov. 13 attacks by Islamic State militants in Paris, Reuters reported.

Mike Williams of Cumberland will leave Tuesday for his fifth climate conference. Williams is vice president of strategic development at the BlueGreen Alliance, a national partnership of labor unions and environmental organizations.

“I’m optimistic for a comprehensive agreement [and] that we can globally come together around a structure that puts us on a path to, at most, 2 degrees of climate change,” Williams said Tuesday.

Scientists have said the 2-degree rise will prevent the most devastating effects of climate change.

The BlueGreen Alliance is focused on five key components of any agreement, including “strong, science-based targets,” a “just transition” for workers around the world as economies shift to comply with an agreement, and creating a “more even playing field” for U.S. manufacturing industries such as Maine’s paper mills.

Three paper mills in the state closed in 2014, including Old Town Fuel & Fiber, which competed with cheap, fast-growing eucalyptus pulp from South America.

Lincoln Paper and Tissue announced indefinite layoffs for hundreds of employees, citing the loss of a major customer to a mill in Indonesia. The company did not identify a specific mill, but the Jakarta, Indonesia-based Asia Pulp and Paper announced in 2012 that it planned to build 42 new tissue machines at mills in China and another 15 at mills in Indonesia.

“Bringing China’s environmental and climate commitment up to standard and making sure they’re compliant and transparent will go a long way toward keeping America’s manufacturing competitive,” Williams said.

Williams, who serves on the Natural Resources Council of Maine’s rising leadership team, said the United States is “closer than we’ve ever been before” to taking strong action toward climate change. He credited the Obama administration for “a lot of great work in forging bilateral agreements and targets with very important countries like China and India, to really work over the last year to set out a common framework.”

Seventeen students from the College of the Atlantic in Bar Harbor will carry a different message, however.

During the two-week conference, eight of the students will join negotiations to track policy, write blog posts and attend gatherings throughout the city, including civil protest actions such as a human chain scheduled for Saturday.

Among the students from Doreen Stabinsky’s course Practicing Climate Politics, Sara Velander of Stockholm, Sweden, hopes to see “ambitious, legally-binding mitigation commitments requiring major emitters like the United States, the European Union, Russia, Australia and others to reduce emissions by at least forty percent by 2030,” she said in an email.

The students hope to highlight key issues “that are preventing an equitable deal from coming out of Paris,” according to the college.

The needs of developing countries and indigenous communities are being blocked by developed countries, according to the group, which hopes to expose “inequities caused by the unjust, capitalistic systems currently in power” and apply pressure on developed countries to agree to large-scale reductions in greenhouse gas emissions.

“People in Maine should be interested because, even if international agreements like these are so distant and their outcomes aren’t immediately tangible, the results of these negotiations will have an impact of our socio-economic system in the long-run by either completely changing the energy sector or influencing local politics with priority shifting,” Velander said.