Its a little long but its a very descriptive dotcom with great keywords! This name is excellent for a website. Develop it with pertinent content and it should be worth at least lower to mid 4 figures....maybe more.
While seperately the words are good keywords, together they are non-sensical.
Never heard of a 'Global Warming Greenhouse' before (but I've heard of 'Global Warming Greenhouse Gases' (which obviously would be an even longer name, and begit you simply get GreenhouseGases.com (as it's already inferred that they are related to Global Warming anyways)).
Developed, the name itself only incures a marginal improvement to it's value, as the value of the Website added to the name will just parallel the investment you put into it.
The thin layer atmosphere of co2 and other greenhouse gases surrounding our planet are the outer shell of the GlobalWarmingGreenhouse. Its much the same as a common greenhouse but on a global scale. Its a GlobalGreenhouse with the word "warming" included in it....makes sense to me.