Supporters of the climate bill passed by the House and the similar bill under consideration in the Senate — including President Obama — say that the cap-and-trade approach would guarantee greenhouse-gas reductions. But this claim ignores flaws in both bills that would undermine even their weak emissions-reduction targets.

Cap-and-trade means a declining “cap” on total emissions, while allowing trading of pollution permits. Confidence in the certainty of declining caps is based on the mistaken assumption that cap-and-trade was proven in the Environmental Protection Agency’s acid rain program. In fact, acid rain reductions were accomplished primarily by a fuel switch to readily available, affordable, low-sulfur coal, along with some additional scrubbing.

The issues presented by climate change cannot be solved by tweaks to facilities; it requires a clean-energy revolution. The biggest obstacle to this revolution is that uncontrolled fossil fuel energy remains much cheaper than clean energy.

What guarantees failure of the proposed climate bills, however, are their provisions for carbon offsets. Both bills allow all required greenhouse-gas reductions for almost 20 years to be met with carbon offsets rather than actual reductions in use of the capped sources. But experience in Europe and California has shown the flaws with offsets.

Suppose, for example, that a landowner is paid not to cut his forest so that it can continue capturing carbon dioxide from the atmosphere. Purchasing this offset allows owners of a coal-fired power plant to burn extra coal, above the cap.

But if the landowner wasn’t planning to cut his forest, he just received a bonus for doing what he would have done anyway. Meanwhile, demand for wood isn’t reduced. A different forest will be cut. There is no net reduction in greenhouse gases, and coal burning above the cap continues at the power plant.

Or consider the refrigerant HCFC-22, the manufacture of which creates an extremely powerful greenhouse gas as a byproduct. This byproduct is relatively easy and cheap to destroy, and governments could require refrigerant manufacturers to do just that. But offset investors have persuaded regulators to approve destruction of the byproduct as a carbon offset, making it twice as profitable to sell byproduct destruction as it was to sell the refrigerant. This also creates incentive to make unneeded refrigerant to profit from byproduct offsets.

The House and Senate climate bills are not a first step in the right direction. The illusion of greenhouse-gas reductions and the creation of powerful lobbies seeking to protect newly created profits in permits and offsets would lock in climate degradation for a decade or more.

(Williams and Zabel are lawyers with the Environmental Protection Agency. The views expressed here are their own and not those of the EPA. This essay first appeared in the Washington Post.)