This week, a California state senator will introduce legislation that would replace the state’s troubled cap-and-trade program, and eventually establish one of the highest prices for carbon dioxide in the world. Around 90 percent of the revenue from the program, which would raise several billion dollars annually and climb steadily over time, would go back to California citizens in the form of a "climate dividend rebate."

The proposal, which will be set forth in an amended version of SB 775, marks the latest effort by the world’s sixth-largest economy to step up as a leader in climate policy, highlighting a path to lower greenhouse gas emissions that other states or nations could follow.

"This new post-2020 cap-and-trade program illustrates the California State Senate’s commitment to expanding California’s clean energy economy, protecting [the] health and welfare of Californians, and lowering pollution in all parts of the state," said Sen. Bob Wieckowski, a Democrat representing part of the Bay Area, during a press conference on Monday afternoon.

Cap-and-trade systems are market-based mechanisms that allow companies to bid on a limited number of allowances for producing greenhouse gases, which tick down over time to lower total emissions. Under the program that first went into effect in 2013, California holds quarterly auctions for large power plants, factories, and fuel distributors with a rising price floor, which currently sits at $13.57 per metric ton. Most of those funds are allocated for green projects in the state.

In its current form, Sen. Wieckowski's proposed system would establish a so-called price collar that sets both a floor and ceiling for the price of a metric ton of carbon dioxide. The price collar would start at $20 and $30 in 2021, rise to $20 and $40 in 2022, and then tick up each subsequent year by $5 and $10, respectively, plus inflation adjustments. The ceiling would immediately be higher than the price of carbon in most European nations, and would quickly exceed the roughly $37 tax proposed in Canada starting in 2022. At some point in the 2030s, assuming no other changes, it would also surpass Sweden’s carbon tax of around $150 per metric ton, which is the most expensive in the world.

California’s existing cap-and-trade system was initially seen as a model for other states. But it’s struggled through a series of challenges, including a California Chamber of Commerce lawsuit arguing that it amounts to an illegal tax, an ongoing debate over whether it has the authority to continue operating past 2020, and low demand amid uncertainties about the system’s future.