Raleigh, N.C. — The organizers of the American College and University Presidents Climate Commitment have released guidelines that tackle the purchase of offsets, which is one of the most complicated and controversial issues in the quest for climate neutrality.

The guidelines, released here at the national conference of the Association for the Advancement for Sustainability in Higher Education, will act as a guide for buying offsets, and determining which campus emissions the offsets should mitigate and which they should not.

Anthony Cortese, who is president of the nonprofit group Second Nature and an organizer of the climate commitment, said he hoped that campus administrators would read the guidelines before making decisions about buying offsets. “There are a lot of people who have knee-jerk reactions to offsets,” he said.

David Shi, president of Furman University, noted that the offset market now is unregulated and can involve risky investments. The market “is in what I call its wildcat phase,” said Mr. Shi, who worked on the guidelines. He hopes the participation of higher-education institutions will help develop the market.

Offsets are essentially paying someone to reduce or capture greenhouse-gas emissions somewhere in the world, then claiming those reductions to mitigate the gases spewing out of your own smokestacks, furnaces, and tailpipes. Buy enough offsets, and you can claim to be carbon neutral.

Backers of the American College and University Presidents Climate Commitment have long said that offsets will play some role in reaching climate neutrality, the ultimate goal of the commitment. But among college presidents, offsets have had their share of detractors. Some have regarded offsets as a kind of scam — some institutions have found themselves sending off money for projects that never happen. Others liken offsets to the medieval practice of buying indulgences. And more have been confused about what types of offset programs are most effective — planting trees, setting up green power, sponsoring efficiency projects, and so on.

The new guidelines have some basic principles at their core:

First, offsets should be used only to mitigate emissions that colleges cannot deal with through efficiency measures or on-campus power generation. Such steps should be the first priorities. Emissions known as “Scope 3” emissions, which cover off-campus activities like commuting and air travel, might be mitigated through offsets.

Second, colleges should purchase offsets that provide teaching opportunities or benefits for their local communities. As an example, Mr. Shi pointed to Duke University’s work with hog farms, one of the biggest environmental despoilers in North Carolina. He said the university is paying for projects that capture and utilize methane, a potent greenhouse gas and pollutant, from pig waste. The project not only allows Duke to claim a greenhouse-gas offset, it also helps the local community and provides a research opportunity for students — a “win-win-win,” he said.

Mr. Shi said that Furman, which is in Greenville, S.C., might look for its own win-win-win opportunities by sponsoring mass-transportation projects in its area.