University President Peter Salovey reaffirmed Yale’s commitment to protecting the environment in a campus-wide email on Monday, as he and 11 other elite university presidents formed a new coalition pledging to meet the United States’ obligations under the Paris climate accord.

“Yale remains steadfast in its commitment to reduce greenhouse gas emissions and curb climate change—among the gravest challenges our world faces in the 21st century,” Salovey wrote in the email. “We will continue our efforts to build a sustainable, environmentally responsible campus that is a model for other communities.”

He also announced that Yale and the other universities in the coalition, which includes Stanford, the Massachusetts Institute of Technology and all the Ivy League schools except Princeton, have signed a statement pledging to combat the rise in global temperature and to help create a clean-energy economy — goals that are consistent with the Paris Agreement. President Donald Trump withdrew the United States from the climate accord on Thursday.

But so far, Yale has not joined the coalition of companies, cities, states and universities — mobilized by former New York City Mayor Michael Bloomberg and the environmental nonprofit Second Nature — that formally pledged to fulfill the Paris Agreement in an announcement on Monday. Over the weekend, students circulated a series of petitions calling on Yale to join that pact.

Vice President for Communications Eileen O’Connor told the News that Yale chose to form its own coalition because officials are still seeking more information about what joining the Bloomberg group would entail.

“Higher education institutions sign on to different things,” O’Connor said. “We could end up signing on to this other initiative in the future. We just don’t have a lot of details about it.”

Still, there are significant differences between the climate pledge released by the Bloomberg coalition and the statement that Yale signed earlier today.

The Bloomberg pledge — signed by nearly 200 universities, including Northwestern, Wesleyan and George Washington — features pointed criticism of Trump, noting the “absence of leadership” in Washington and criticizing the president by name. By contrast, Salovey, who at times has been reluctant to directly criticize Trump, did not mention the presidential administration in his email to the Yale community. And the Ivy League statement never explicitly acknowledges that Trump withdrew from the Paris Agreement.

“We didn’t find political language necessary because we believe that universities should always have a role in leading in an apolitical way,” O’Connor said. “In trying to improve the world today and for future generations … it’s important to be able to engage all sides.”

Yale unveiled a climate plan last October that aligns with the Paris Agreement and pledges to make campus carbon neutral by 2050. And in his email, Salovey noted that Yale has cut carbon emissions by 24 percent since 2005 and that the solar rooftop on West Campus is the largest installation of its kind in the state.

But Emily Weir FES ’17 — who helped orchestrate one of the student petitions — said Yale should still join forces with the universities in the Bloomberg coalition, despite its previous environmental commitments and the statements released today.

“It’s just a huge list, and having Yale on that list really would add extra weight to that,” Weir said. “It could also further encourage other organizations that may be hesitant to sign on to the pledge to sign on.”

Connecticut is one of just nine states that have joined the Bloomberg coalition.