California’s pioneering climate legislation, the Global Warming Solutions Act, or AB 32, caps the state’s emissions at 1990 levels by 2020. That’s the headline, anyway.

But the bill contains other interesting statutory language. For one thing, 1990-levels-by-2020 is referred throughout the bill as a limit, not a target. The implication would seem to be that it’s a floor on emissions reductions, not a ceiling. What’s more, Sec. 38560 says this (my emphasis):

The state board shall adopt rules and regulations in an open public process to achieve the maximum technologically feasible and cost-effective greenhouse gas emission reductions from sources or categories of sources, subject to the criteria and schedules set forth in this part.

Hm, “maximum technologically feasible and cost-effective” reductions. What’s that mean? The obvious interpretation is that the cap is a floor, and if emissions reductions beyond the cap can be achieved cost effectively (even if at greater cost), they should be pursued.

But then, in Sec. 38562b1, the bill mandates that regulations be developed in such a way that they “minimize costs and maximize the total benefits to California.”

So which is it? Maximize reductions or minimize costs? Cost-effective and lowest-cost are not the same. If you’re minimizing costs, you reach the cap and stop. If you’re maximizing reductions, you might spend considerably more (within the bill’s definition of “cost-effective”).

How this statutory language is interpreted will have a huge effect on the implementation of the law. If interpreted as requiring maximum (technologically feasible blah blah) reductions, it opens up the possibility of all sorts of policies that might not meet the narrower requirements of the cap. The result would be a stronger and more potent bill. Conversely, if it’s interpreted as requiring only what’s necessary to meet the cap and no more, the bill will be fairly weak in light of the current science.

This all came to my attention via Grist reader Ken Johnson, who’s had an interesting exchange of letters with Schwarzenegger and members of CARB about it. The entire exchange can be read here.

Johnson was told at one of the public workshops that the Cali Air Resources Board (CARB) is interpreting the maximum reductions language as effectively identical to the cap. But that doesn’t make much sense. For one thing, that would make the language completely redundant. Why’s it in there? For another, it seems to disregard the plain language of the statute.

Johnson aptly summarizes the relevant points in his final letter (my emphasis):

An AB 32 implementation strategy that not only satisfies the letter of the law, but which could also significantly influence the odds of averting severe and irreversible climate change, must be based on a recognition the following realities:

(1) Current science, empirical evidence, and paleoclimate data provide no evidence that the AB 32 emission cap in 2020, or even the Governor’s longer-range 2050 target, will be sufficient to assure avoidance of severe climate change.

(2) In view of the risks and uncertainties inherent in climate change, AB 32 mandates “the maximum technologically feasible and cost-effective greenhouse gas emission reductions” as a statutory requirement that is distinct from, and additional to, the 2020 cap. In this context “cost-effective” is clearly intended to mean something other than “sufficient only to achieve the cap”.

(3) This mandate authorizes and requires a regulatory strategy that creates incentives for maximum technologically feasible and cost-effective emission reductions irrespective of whether such reductions exceed the minimal compliance requirement of the cap.

(4) Pursuant to this mandate, the regulations to be proposed in the Scoping Plan by Jan. 1, 2009 and enacted by Jan. 1, 2011 should create incentives for overcompliance to the extent that such overcompliance would be feasible and cost-effective.

Worth reading the whole exchange and, if you live in California, contacting CARB or going to one of the public meetings about it.