Sorry to be digging this old chestnut up again. Some time after I posted the first item, a documentary programme on this very subject appeared on TV. Entitled "The Great Green Smoke Screen", shown on Dispatches and broadcast on Channel Four, the programme was able to investigate all the suspicions related to carbon offsetting and follow the whole story right through to the painful end. In short, it effectively blew the validity of carbon offsetting, and the integrity of the companies investigated off the face of the earth. From the underlying principles of offsetting through to the execution of carbon transactions, one malpractice after another was exposed to daylight, discrediting the whole business as a money generating scam. The most telling picture was of 6 saplings, each about 12 inches tall, said by one company to offset the air pollution attributed to the investigator during a year of flying.