Found a good analogy in response to the "It's happened before" argument.

[Memory Container]

Found this on another site. It's a response to the notion that because CO2 has been high before and there have been temperature changes in the past, that Global Warming is 'no big deal'.

"The very first thing that I can tell you is wrong with this is timeframe. IF the type of Global Warming we were talking about is not just like the ways it happened in the past, It would not be such a serious issue. What we're seeing now is taking place almost instantaneously from a geological perspective. Even from a biological perspective a dramatic increase in atmospheric CO2 levels over a mere hundred years can be devastating. What is devastating to the natural ecology of the planet will become utterly lethal to the Human Race... because we are so VERY dependent upon those ecological systems.

THAT is the problem.

But these nay-sayers leave that bit out at their convenience.

Let's say that geo-climatic change is like driving a car. I know it's not a perfect analogy, but for the purposes of impact I think it will do just fine.

So you're driving your Geo Prism....(LOL! - Ok, we'll go with a Lincoln Navigator).... down a stretch of road. Now your Navigator is the Earth's ecosystem complete with weather, air and ocean currents, and critters of all shapes and sizes. Now we'll consider every off ramp, detour, and speed trap a change in the 'momentum' of your Navigator. All kinds of things happen while driving, so we can assume that while the Navigator (ecosystem) is moving along things will speed up, slow down, and change course quite a bit. So as the ecosystem changes, the passengers (critters) tend to adapt to those changes by slightly shifting position, getting in and out of the vehical at intervals (extinction), and trying very hard not to spill their coffee.

The vast majority of these 'vector changes' are gradual to some degree or another...

But what happens at a 'sudden' change?

Most changes take place over a period greater than a thousand years, this gives the passengers plenty of time to adjust... even if it causes them to spill their coffee on the girl next to them.

But what about the Oort Cloud?
(Yeah, I know... where the hell did that come from?)

-Outer Space.

That's right, there's this thing 'out there' called the 'Oort Cloud' which is comprised of an unimaginable number of asteroids revolving around our solar system... on the outside. Every once in a while, the gravitational forces of the solar system align in just the right way (roughly every 26 million years) to drag a whole bunch of those asteroids into the gravity well of the sun.

And this is a potentially bad thing.

-Just ask the Dinosaurs.

Now back to our analogy-

You are approaching an off-ramp at a very good clip in your Navigator, and all of the sudden a big huge ROCK lands right in front of you. (Can you smell what's cooking now?)

Well, just like a 'Surprise' off-ramp with a dividing wall, that rock was to the ecosystem what that sudden 'dividing wall' is to our Navigator.

Imagine what happens to a Lincoln navigator when it hits that solid concrete blade of dividing wall at say 65 mph...

Let's just say that at the time, the Dinosaurs were the passengers.
(Good thing for eco-toddler seats)

The effects of that particular 'impact' on the ecosphere would have occured in the equivalent of geological microseconds... about a few years. When you go from 65 to '0' in mere microseconds... things are very ugly.

But now imagine, on a geological scale, that the divider has those bright-yellow barrels all aligned like tightly-packed bowling pins right in front of it.
Now drive your Navigator straight into the wall at 65mph.

When we review the video one day, we'll see that the crash can be measured in hundredths of geological seconds due to the progressive resistance of the popping barrels.

Basically what were looking at here is an event which happens just ten times slower than the 'crash' that killed the Dinosaurs.

Now how are the passengers?

(One thing I can't help but notice in the video replay is that baby Stewie seems to have survived unscathed....)

So whether or not Earth's average temperature has been significantly higher or lower relative to the current is not nearly so relevant as they like to make it.
This temporal discrepancy that so many nay-sayers like this guy seem to forget is critical to understanding what this is really about."

This was just a post on another site, do I need to attribute it?

[DS1]

1. Actually that's exactly what I saw on my commute this morning

I was wondering where all the speed-traps were, when I passed about 15 cops on both sides and a half-dozen fire engines and saw the shattered remains of a dividing wall. Didn't see a car, however.

[Odin2005]

2. The GW denialist arguments are hilarious.

Thier arguments almost always consist of saying the earth's climate in past geolgical periods was often warmer than now, which has no fucking relevence to the problem at hand because the Earth's current geography has put it into Ice-house mode for the last 40 million years.