Moves to do that have been in play for 14 years, and have resulted in nothing to cap the emission rise.

BBC: US and its airlines: Too much hot air?

In his speech, the Arizona senator proposed capping carbon emissions incrementally, with the goal of returning to 1990 emission levels by the year 2020 using a cap-and-trade program.

CNN: McCain appeals to independents with environment pitch

In his speech Monday, the presumed GOP nominee proposed capping carbon emissions incrementally, with the goal of returning to 1990 emission levels by the year 2020 using a cap-and-trade program.

CNN: McCain: Clean energy a 'national security issue'

Under a cap-and-trade system, a regulatory body allocates CO2 emission allowances to companies, typically by way of auction, but sometimes for no cost.

FORBES: The Climate Change Trap

The great virtue of cap and trade is that the system can be taken directly to the targeted emission reductions.

ECONOMIST: Carbon tax or trade?

One such emerging tool is the voluntary carbon emission market, a place where corporations voluntarily buy emission credits to offset their own carbon emissions without regard for any requirement like a carbon cap.

FORBES: BY DENNIS POSADAS