http://gristmill.grist.org/story/2008/3/10/21649/9673#6

The tax that is not a tax, and the carbon trade that does not trade carbon.

Sound impossible?  Well...

It's not.  By cutting subsidies for carbon emmision intense energy, the cost of that energy will rise.   The corporate right will call it a tax.  We will call it cutting corrupt corporate welfare voted in by bribed politicians.

A direct subsidy for each carbon free kwh and each conserved kwh is not carbon trading.  But it does have an effect on currently skewed, manipulated markets.  It has the effect of shorting carbon intense energy across the markets.  Oil, gas, coal, ethanol.  By putting money into carbon free energy.

Going to cash, in the form of diverting carbon energy subsidy, is in effect, shorting carbon based energy.

How so?  Well that subsidy diverted from carbon energy is cash withdrawn, cash that impelled oil and gas exploration, for example. Betting that the value of carbon energy, and investment in it,will go down compared to cash.  Instead that cash would be going long on renewables and conservation.

As carbon energy is abandoned, the value of that cash withdrawn and reinvested in renewables and conservation goes up.  When do we cover the short position?  Never.  The lower cost of carbon free energy covers it for us.  In the form of a stronger currency, bolstered by dropping energy prices and dropping inflation.

This is a different kind of trading, it invests in solar panels on people's homes and smart grids and plugin hybrids.  That's where regulation comes in, determining clean kwh generated and saved.   Rating different systems for acomplishing this.  The better the system the more the kwh generated or saved, the bigger the investment.  

Determining which solutions are actually GHG free and actually save kwh would be part of the regulation process.  So it's government examining and verifying specific solutions, but not really choosing which ones to endorse.