Tony Blair has promised to offset emissions from his holiday flights after opposition parties and green groups questioned his leadership on climate change. But offsetting emissions is not a solution to the problem. It is a great idea to pay for plating trees but it won't change our behaviour. Carbon offsetting only allows us to believe we can carry on polluting. Also, the timing is critical: "emissions saved today are far more valuable, in terms of reducing climate change, than emissions saved in 10 years' time, yet the trees you plant start absorbing carbon long after your factories released it (Guardian)."