TRENTON - Three scientists who specialize in climate change delivered a message to Gov. Christie on Tuesday: Global warming is real, it is caused mostly by people, and it has already increased the frequency of severe weather in the Garden State.

The Rutgers University scientists came to the Statehouse with reams of documents in the hope of convincing Christie, who has said he is reserving judgment on the issue.

Christie did not meet with the experts. Instead, his representatives sat in on their presentation. Afterward, Christie spokesman Michael Drewniak declined to comment.

Christie told a town-hall meeting last month that he had seen evidence on both sides of the climate change issue and was reserving judgment.

"To be honest with you, I don't know. And that's probably one of the reasons why I became a lawyer and not a doctor, or an engineer, or a scientist - because I can't figure this stuff out," Christie said at the time. "But I would say at this point, that has to be proven, and I'm a little skeptical about it."

Meteorologist Alan Robock of Rutgers' environmental studies department said if he could send one message to the governor, it would be this: "Global warming is real. Humans are causing it, and there's no doubt about that."

Robock, who wondered aloud whether Christie's comments were intended to appeal to conservatives, said he wrote the governor after hearing his comments. In the letter, Robock said, he explained that the only scientifically credible explanation for global warming is that it stems mostly from human activity.

Oceanographer Paul Falkowski, who teaches at Rutgers' Institute of Marine and Coastal Science, faulted the governor for discouraging mass transit by increasing rail fares while encouraging driving by refusing to raise the gasoline tax, which at 14.5 cents is the third lowest in the country.

"While this governor has raised the cost of NJ Transit, he has not yet increased by even one cent the cost of gasoline," Falkowski said.

Jim Miller, a climatologist who also teaches at the Institute of Marine and Coastal Sciences, said the climate is changing, with more floods and droughts in New Jersey, for example.

Overall, the experts rated New Jersey's energy policy as uneven.

Environment New Jersey's executive director, Dena Jaborska, whose group hosted the event, said Christie had been "a real champion" in pursuing wind energy but had not yet affirmed his commitment to the state's renewable-energy goals on solar energy. He also has yet to commit the state to the regional greenhouse-gas reduction initiative known as RGGI.