I think however its been put by the politicians/journalists, HD is somewhat missing the point of the statement that is made, Holding regardless of where it occurrs, even if it was in the middle of the atlantic does have negative enviromental effects. Quite simply because the aircraft is burning more fuel than it would if it took off flew direct and then landed. More fuel=more pollution, more fuel=less fuel left, more fuel=greater cost to pax, more fuel=airline going bust. The highest proportion of the cost of operation to most flights is fuel, not crew, a/c maintenance or the like.
ATC may think they are the "skygods" but keeping them apart isnt the only thing to consider because increased holding, delays, could actually mean that a few more airlines go bust and then there be less to worry about to actually keep apart! So wherever they hold for heathrow, holding does need to be reduced for more than just enviromental reasons, quite simply to keep ATC in a job!
regards PETER47's post and computers to calculate and plot flightplans, sorry but too late to patent your idea, its already being worked on now, NATS and various parts of europe are already working on tools, to do just this, parts of IFACTs and other tools, will help control profiles. There is also whats been around for years, Flow control (or Network Management). But just as peter mentions thunder storm cells dont fit into computer models so well, as they tend to not obey their slots! There will never be a perfect system, as like as also been mentioned all business men want to fly at the same time to get to or back from their meeting, but thats where management of non-business flights get pushed away from these times helps.
Its interesting point to look at though, one argument could be go the airbus way, bigger planes, less flights, yet enviromentalists, then argue they use more fuel, are noisy blah blah blah. So go the boeing way and develop a smaller 787 that is "greener" to operate, but then you fly more of them, and end up with holding again so end up using more fuel. Its all gettin a bit distorted this green thinking, its like buying some far eastern made electric car, the government will say how great you are for driving one, it doesnt pollute the atmosphere, use fuel blah blah blah....Ummm apart from the toxic substances in the batteries that damaged the enviroment to produce them, the fact that it cost massive amounts of Carbon emmisions to manufacture and then ship it half way across the world in a oil burning ship, the batteries made somewhere else and shipped in....and then finally, the electric you power it with, was yes you guessed it, generated from a coal burning power station! lol
So I suppose to summarise bugger the enviroment, reduce holding at EGLL for far better reasons, to keep those that are alive now in jobs, save us time so we can enjoy the planet while its still here, because as history as shown dominant species get wipped out everynow and then anyway and more likely to be because of something else other than just a bit of natural global warming/cooling. We are due a reversal of the poles, yellowstone park should errupt soon, some erruption is due in the atlantic which will release massive amounts of frozen methane, oh and there some trillion trillion amounts of rock hurtling around space thats got our name on it. Or more likely Bacteria will finally see us off due to overuse of Anti-biotics.
