Apples unibody macboom pros may sing their own environmental praises from the point of view of materials used, but its actually their design that makes them less environmentally friendly than older laptop as their lifespan will be less because of the following design flaws, and that has to be a good measure of a laptops environmental menace.

PROBLEM A : UNITARY PART DESIGN: The totally unitary design apple has created means the unibodys consist mainly of three replaceable parts when it comes to repair, nearly all of which are three quarters the price of the laptop itself when it comes to replacing them and keeping the laptop running :
part 1:
logic board has its expensive processor and graphics and every other port controller surface mounted on mainly in BGA packages, meaning everything thats expensive about the guts of the computer must be replaced as well when the logic board fails in one hit, 2 years from purchase the cost of this component alone will outweigh having it repaired versus buying a new computer, this shortens its lifespan.
part 2:
the screen casing and lcd are glued together, to such an extent that taking the screen apart is actually quite difficult these units will tend to be replaced as one unit in allot of situations, this part is a little bit less expensive than the logic board, again 2 years down the line most will probably consider buying a new laptop before paying for this parts replacement.
Part 3:
Upper case because it is a unibody and milled from a single peice of aluminium is very expensive, but what makes it more expensive is that the keyboard and other parts are glued and screwed into it, making it cost even more $279.00 from what i could see.

PROBLEM B : THE SEALED IN BATTERY : Battery screwed into place not considered a user replaceable part ? even more un-environmentally friendly, apple have placed the battery behind a 10 screw backplate and then secured in place with 2 tri-wing security screws which are about as non standard as you can get, so if you ever … like one of my clients … spill some liquid onto your laptop, then the combination of sealed in battery and liquid will make sure your laptop is utterly fried and becomes uselless, unless Part 1 above is replaced which will cost 3/4 the price of a new laptop ? In the old days a drink spilt on a laptop keyboard could be remedied with fast action by doing these moves as fast as possible :
Remove Power cable
Remove battery
invert laptop

then mopup all visible liquid, place in a towel in a dry cupboard using gravity to draw any liquid that ingressed out, then you would carefully open the laptop clean out any signs of water ingress, if sticky residue is there (coffee) then remove with 90% alchohol or distilled water, then again wait for 24/48 hours for laptop to be thoroughly dry resting in a dry cupboard, re-assemble and turn on, 80% of the time most laptops could be rescued by this method.

Apples unibody laptop seems to be designed to guarantee that liquid ingress will kill your laptop every time, as getting the source of power out of the equation ie the internal sealed in battery, seems impossible in any timescale that is usefull, therefore these unibody macbook pros are designed to die with the slightest of water ingress.

Its the combination of water and electricity in this situation that kills the logic board, not one or the other, and apples design has guaranteed the presence of electricity at all times.

and then when its taken to those “Genius’s” in the apple store, whats the first button these buggers will press after its brought in ? the power button, oh it doesnt seem to be working sir ? really … well now you given another huge jolt from the battery, by turning it on again with remnant water in it youve certainly guaranteed to have killed it cheers “Apple Genius !”.

etc etc you get the idea .