have had some deviation over the 400,000 years.
  Carbon dioxide levels have gone up and down. But also notice this, 
they have never in the last 400,000 years been as high as they are. 
This is the highest they have ever been, number one. And, number two, 
the rate of increase is now on this graph essentially a vertical line. 
The rate of increase of the amount we are putting of carbon dioxide is 
unprecedented in global history.
  So if we look the projection is that if things remain the same we 
will be 