sentences:  He also proposed that Norway should become carbon neutral by 2050, and called upon other rich countries to do likewise.This carbon neutrality would be achieved partly by carbon offsetting, a proposal criticised by Greenpeace, who also called on Norway to take responsibility for the 500 m tonnes of emissions caused by its exports of oil and gas.World Wildlife Fund Norway also believes that the purchase of carbon offsets is unacceptable, saying "it is a political stillbirth to believe that China will quietly accept that Norway will buy climate quotas abroad".