There is a better alternative [than cap and trade], one that would be more efficient and less costly than cap and trade: “fee and dividend.” Under this approach, a gradually rising carbon fee would be collected at the mine or port of entry for each fossil fuel (coal, oil and gas). The fee would be uniform, a certain number of dollars per ton of carbon dioxide in the fuel. The public would not directly pay any fee, but the price of goods would rise in proportion to how much carbon-emitting fuel is used in their production.A longer and "saltier" version is available here.
All of the collected fees would then be distributed to the public. Prudent people would use their dividend wisely, adjusting their lifestyle, choice of vehicle and so on. Those who do better than average in choosing less-polluting goods would receive more in the dividend than they pay in added costs.
For example, when the fee reached $115 per ton of carbon dioxide it would add $1 per gallon to the price of gasoline and 5 to 6 cents per kilowatt-hour to the price of electricity. Given the amount of oil, gas and coal used in the United States in 2007, that carbon fee would yield about $600 billion per year. The resulting dividend for each adult American would be as much as $3,000 per year. As the fee rose, tipping points would be reached at which various carbon-free energies and carbon-saving technologies would become cheaper than fossil fuels plus their fees. As time goes on, fossil fuel use would collapse.
On the other hand, Paul Krugman, who had an op-ed piece in the same edition favoring cap and trade, has a blog piece that strongly disagrees with Hansen.