Global warming, global cooling, it's been going on for a while!
People didn't know what was going on in 1816 because the telegraph had not been invented, and most people still don't know what happened.
How a
Volcano Eruption Wiped Away Summer : NPR Weather People and History Go down to "Eighteen hundred and froze to death".
I'm not going to debate this, just thought you might find it interesting.
