About 28 percent of U.K. Catholics abstain from meat on all Fridays, reducing greenhouse gas emissions .012 percent. A similar level of compliance in the U.S. would have a 20 times greater impact.
The practice dates back to the first century CE, when Pope Nicholas I declared that Catholics were required to abstain from eating meat on Fridays in memory of the death and crucifixion of Christ.
In 2011, the Catholic bishops of England and Wales called on congregations to return to foregoing meat on Fridays. Only around a quarter of Catholics changed
Millions of tonnes of carbon emissions could be mitigated every year if the tradition of meat-free Fridays is revived by the Pope, a study by University of Cambridge has found.