The NFL meterological department has issued an official statement on global warming, according to the Onion:
"The phenomenon of weather-related African-American supracranial vaporous emission, or ‘Steaming Black-Guy Heads,’ as it is colloquially known, occurs when cold dry winter air comes into contact with hot, humid, shaven heads of football players, causing their personal water vapor to condense and rise on a column of heated air," the statement read in part. "It is then observed by network cameramen, who overwhelmingly choose to film African-American players due to the dramatic contrasts that result—especially when the player in question is backlit—and beamed to millions of households during time-outs, replay reviews, and other stoppages of play. The viewers then realize that winter has come to America."
"However, film review reveals that steaming black-guy heads, which during the 1970s were commonplace in mid-September, have in recent years not been sighted until the weeks after Thanksgiving," the statement continued. "Although further study is definitely called for, we conclude that the pronounced trend for steaming black-guy heads to occur progressively later every year—coupled with the phenomenon of giant triangles of ass-sweat persisting well into November—is a possible indication of a slowly warming climate across the entire NFL."