Joy Miller of Hallandale Beach asked Gore about carbon credits and offsets — "buying our way out of the problem."

You won’t be surprised to hear that Gore’s answer was wonky and careful and came in parts. He said credits are a “good thing” if the standards and information are in place to validate their quality. "The economy can be an ally," and we know cap-and-trade systems work.

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However, if used irresponsibly, as a substitute for direct reductions, they can be counterproductive. (The same issues face individuals with voluntary offsets.)

That segued into a discussion of the EU trading system and the "rocky start" of its first few years — poor baseline calculations, over-allocation of permits, too-low initial price — which are now being ironed out. Most of the real reductions in the world are coming from this system. "We can make this work."

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He also said trade in carbon credits can serve as a bridge to build relationships between the North and South.