There look to be "about 17,700 pages" from Greenpeace spidered on Google according to
this search (
This search finds 17,900 for some reason). I'm not sure how many pages you have and how this compares...
Some posters on WebmasterWorld have suggested that static looking URLs are better indexed by Google, a typical thread goes like this, with WebGuerrilla putting forward the "better as a static page" comment. Point 14 of the Deepbot and Freshbot FAQ covers the point I made above on what Google might find difficult with dynamic URLs ("id=").
On another point, in a past post I pointed out that Google prefers 301 redirects to ad_redirect's 302 redirects.
