If you want to get scared, talk to scientists

I am a subscriber to Science News, and I always learn at least one new cool thing in each issue. The July 21 edition had an article where scientists have uncovered that England was separated from the rest of Europe by a single mega-flood when a huge lake from the melting ice of the last ice age burst its banks. Sorry, you have to be a subscriber to read this, but the New Scientist has a for-free article on this.

There are many examples of sudden massive geologic and ecological change like this. Another megaflood I learned about yesterday from my brother was the one from another ice-age lake bursting that carved out the Channeled Scablands in Washington. This flood came all the way from Montana.

Then there are the super-volcanos that cause mass extinctions and the comet and asteroid hits, including the one that eliminated dinosaurs.

Interesting, but so what, right?

Well, Pa was explaining what is happening with the Greenland Ice Sheet. This sheet is the last remnant of the last Ice Age, and in some areas is many miles deep. And it is melting very rapidly as the melting water lubricates the sheet where it grips the rock. Many of us know this, but what isn't talked about much (at least I couldn't find anything) is how quickly this could actually happen.

According to my father, it's possible that the Greenland Ice Sheet will literally slide off the rock like snow slides off a metal roof once it melts to a certain point, and that sea levels will rise 20 feet not in 100 or 500 years but in just a few years. Moving vast populations of our coastal cities 20 feet uphill in a matter of a few years: doesn't sound like fun.

It's uncomfortable hearing these things from a fairly cynical scientist. He also made me aware of methane hydrates and the methane cycle. Methane is actually a significantly more powerful greenhouse gas than carbon dioxide. And if the oceans get too warm, vast amounts of methane currently frozen up in methane hydrates may be released, increasing global warming and releasing more hydrates and and and...

In a great book called A Short History of Nearly Everything, I read that the situation where we have temperate zones and an ice sheet is a very very rare situation for Earth. It is much more common to have a very frozen planet (at one point it was completely frozen over) or a very hot planet with no ice. It would seem we are tipping a very wobbly seesaw over to a new point of stability, one which our race may not like very much.