A chap called Duncan Law responded. He points out that simple measuring of emissions is not enough; as aircraft emit at altitude, their impact is around three times as bad as if it were done on the ground. His most persuasive point is that carbon offsets are a nonsense because the emission is instant whereas the tree's absorption is over many years.
There are, however, many other problems too. It's impossible to say how much carbon a tree will store, so you cannot know how many trees to plant for your emissions. Beyond that, you cannot tell what your emissions are; figures on offset websites for, say, per mile driven usually don't take into account your mpg or how many passengers to divide it among. Figures for a train journey should surely be different if it's a packed rushour train compared to a late afternoon one with only half a dozen of you on board.
Then there's the problem of just counting the number of trees planted. Some offset projects have been buying land that's cheap, clearing existing mixed woodland trees and replacing them with their monoculture plantations.
Whilst all these things are true, they only show why offsets are clumsy and ineffective.
There is a bigger more disturbing truth, that paying for offsets lets us think we can carry on with our unsustainable high consumption, and were we to face the facts that offsets don't really work, we would be forced to concede the reduction on emissions so urgently needed.
Corporate Watch's characteristically excellent article explains:
Not just ineffective or counterproductive but 'a complete fraud'? This is where we hit the biggest and most disturbing truth. You can't offset carbon emissions.
Planting trees and energy efficiency are important things to do in themselves, but the trouble with linking them to offset programmes is that their positive impact is cancelled out by justifying and condoning a negative one, implying that we can consume at current rates guilt free as long as we have the money to salve our consciences, which takes us no further forwards in reducing emissions. If anything, it takes us backwards, as corporations are able to ride on the image boost of appearing greener, whereas the truth of the matter is that they are a complete fraud.
Burning fossil fuels adds CO2 to the carbon cycle. Trees merely store some of it for a while before releasing it once they rot or burn. They're not an offset, merely a delaying device.
As Oliver Rackham said, it's like drinking more water to keep down rising sea levels.
The wish to avoid actually changing the things we've come to rely on is understandable, but it's effectively a blindfold we're putting on to tell ourselves we're not facing what's in front of us as we walk toward the cliff edge.
The reader response to The Independent also featured incredulity at environmentalists wanting to ban damaging activity.
Given that 'the environment' means the single system we have for survival, I'd answer yes.
Do they really expect ordinary people to subscribe to the notion of... "punishing those who damage the environment"?
And it should include mandatory measures. If I saw a line of sick babies in incubators and somebody was trying to inject poison into their oxygen supply, yes I'd want to force them to stop.
The welfare of future generations of people and other species lies in our hands and we're poisoning their fundamental essential prerequisites for survival. If it's not right to poison people and take away their food and water today it's not right to do it to them tomorrow. We should not respect anyone's claim to a right to do so, we should be tackling them head on and if they won't respond to appeals to their common humanity then they should certainly have their toys taken off them.
If only it were their own future they were fucking up. Again I see the curse of our allotted three score years and ten. Were we to live for several centuries then averting the worst effects of climate change would be our top priority.