Expansion plans involving a new 14-gate concourse at Mineta San Jose International Airport in California must clear environmental review before moving forward.

If approved, the plan would build a 330-room hotel and 5,000-vehicle parking facility, in addition to the new concourse. The project would result in “significant and unavoidable” amounts of greenhouse gases due to increasing air travel capacity,” said an environmental review report. The expansion would increase the capacity by 50 percent by 2037. Officials must decide if the tradeoff is acceptable.

“If you didn’t take the increase of air traffic into effect, the other work [like increased ground traffic] could be offset with sustainability measures,” said Greg Nudd, deputy air pollution officer for policy, Bay Area Clean Quality Management District. “A lot of people don’t realize how carbon-intensive flying is.”

On the airport’s side, officials said the expansion is necessary to meet demand. If it doesn’t happen, passengers will simply drive further to get to other regional airports.

“The need for air travel and the demand for air travel in San Jose is going to grow regardless of whether we build anything new or not,” said Scott Wintner, deputy director of marketing and communications, Mineta San Jose International Airport. “But these projects will make the airport more efficient, so that planes are spending less time idling and waiting for a gate to open, which would only generate more emissions.”