Was an asteroid the best excuse the UN could come up with to explain away Antarctica's destruction?
Someone versed in physics could claim that such an event would have wiped out all life on the planet.

It just makes me think back to Abridged Misato laughing at Shinji for believing the cover-up.

Jet fuel can't melt ice caps. 9/13 was an inside job :p

^ Actually, many scientists agree that years of burning fossil fuels are starting to have that exact effect.

Sad to say, but the UN (with an assist from SEELE/Gehirn) probably realized that it would be infinitely easier to get card-carrying members of the Flat Earth Society to buy into fairy tales about rogue asteroids versus expecting them to accept the "junk science" of climate change.

Seele controls information. Information is knowledge. Knowledge is power. They control the information that is fed to the people. They fund the ideas they want to be funded and they silence the ideas that oppose them. The truth is a lie. Two plus two equals five.

Asteroids are pretty much feared that they'll destroy Earth, so what better to play to people's fears then that? Not to mention that after a global disaster like that, the public'll (Most likely/arguably) turn to the government for what the hell they can do.

Given how nonsensical and inconsistent physics are in the series an asteroid isn't that unbelievable of an explanation. Besides the truth would make even less to someone versed in physics. yeah and people were probably more interested in how to fix the problem rather than what caused it.