"Meat free Monday, it's a fun day, and it's happenin', all around the world." - former Beatle Paul McCartney.

You have only to watch singer Paul McCartney's Meat Free Monday song on YouTube (see below) to be convinced of his commitment and sincerity when it comes to getting the world to adopt Meat Free Monday. McCartney believes cutting back on meat and dairy consumption would have a significant environmental impact. But a UC Davis researcher says science is raining on McCartney's parade.

Author of the Fresno Bee Earth Blog, Mark Grossi, picked up on a UC Davis news release distributed this week that says meat shouldn't be blamed for climate change.

Grossi wrote that McCartney believes meat-free Mondays would empower individuals to fight global warming, basing his assertion on a report from the United Nations Food and Agriculture Organization called "Livestock's Long Shadow."

UC Davis Cooperative Extension Specialist Frank Mitloeher did his own study, however, and came up with a different conclusion. He said only 3 percent of the global warming contribution comes from livestock. Cutting back the use of fossil fuels will have a much greater impact.

"Smarter animal farming, not less farming, will equal less heat," Mitloehner was quoted in the release. "Producing less meat and milk will only mean more hunger in poor countries."