Of course the overwhelming majority of scientists agree that global warming exists (those that deny it, are very questionable). However, whilst many biologists, environmental scientists and the like say the cause it human production of CO2, the majority of climatologists completely disagree instead insisting humanity hasn't contributed nearly enough CO2 to cause global climate changes and that the earth is simply moving through a natural cycle. That's the problem with Al Gore's claim that 100% of scientists agree that humanity is causing global warming.
It doesn't really matter if we're the primary cause...we're dumping garbage (generic term for all of those various chemicals and whatnot) into lakes, rivers, oceans and the air. That stuff does environmental damage locally if not everywhere. Its abhorent. We're killing ourselves because we're too greedy and too lazy. Even if we aren't cause number 1 for global warming it doesn't mean that it isn't coming and we shouldn't try and stop from helping it along because we're doing a fantastic job.
All scientists worth their salt know that global warming is occuring. If you talk to those in the far north those people don't care too much for politics and have said that their land has changed over the last 50 years like never before recorded in their peoples histories. Then you have a yahoo politico who has no clue saying "no...no worries...oil companies say its ok!" Towing the party line is right.
Its fortunate that we actually see any traction on this front...I am impressed locally in how well the environment has been turned around. Locally I used to live in steel city industry wasteland where the fish were dying or dead, the rivers and creeks were dying or dead, the habour area was almost completely devoid of the natural species...fortunately some serious work was done and after 25 years of planting trees, diverting water, setting up a fish barrier to let natural species in and larger species out and a bunch of other things...we're starting to see improvement. And its so nice to see.
But this is purely a local thing and its not perfect. A company down the lake has been cited more recently for dumping tons of chemical waste into the lake. Its immoral....but they did it anyways (cheaper that way) and now they are pretty much out of business. The fish are dead in that area...the frogs gone. It'll take time to recover from that sort of thing.