The 2010 Cancún agreements include voluntary pledges made by 76 developed and developing countries to control their emissions of greenhouse gases.

But while some countries want to see action to address the "emissions gap", the US wants to stick with voluntary pledges until 2020.

The voluntary pledges, made by some 80 nations, will - at best - achieve only half the needed emission cuts by 2020.

But Japan has rejected a demand that its manufacturers renew a "voluntary" pledge to use more American parts in their new models.

But something more than a voluntary pledge may be needed to protect the integrity of the market and the interests of unsuspecting investors.

Are we moving to a legal agreement committing major economies to emission targets, or merely to a framework for voluntary national pledges?

There was an immediate fuss about how voluntary this pledge was.

The voluntary pledges made in the Accord (at that date) would, according to his projection, be above this, nearer to 50 gigatons.

The Cancún agreement, agreed in 2010, includes voluntary pledges made by 76 countries to control emissions.

The voluntary pledge has obvious pitfalls of its own.