Aluminum mining company Alcoa bases some of its employees' salaries on whether they achieve specific environmental goals. Will the strategy pay off?

An Alcoa production plant in Goose Creek, South Carolina.

FORTUNE -- There's no easy way to run a green mine. Harvesting metal from the ground disrupts the environment, even when that metal is gathered relatively close to the surface, which is the case with aluminum.

Yet Alcoa (AA), one of the world's biggest miners of aluminum ore bauxite, has set ambitious green goals for itself. In 2010, the company said that it would cut its carbon emissions from its refining and smelting businesses by 35% over the following 20 years, compared to the amount it emitted in 2005. Also in 2010, Alcoa created a new chief sustainability officer position for Kevin Anton, who was formerly CFO of one of the company's business units. Alcoa connects 20% of Anton's pay to his progress in advancing the company's green goals.

Most companies don't tie employee compensation directly to environmental goals. That's including the firms that tend to be ahead of the curve on corporate responsibility, says Jennifer Wagner, a principal at consulting firm Mercer's Human Capital business.

Part of the trouble, perhaps, with moving green initiatives off of the backburner and into people's salaries is in nailing down specific, measurable targets for sustainability. "It's not like financial reporting," says Wagner. When it comes to sustainability, "There really aren't standards about the best way to track things."

MORE: An exuberantly sunny Broadway director? Really?

Green goals aside, companies must set very specific goals for incentive-based pay to work at all. According to a 2006 U.S. Merit Systems Protection Board report to Congress about how to implement incentive-based pay, "Organizations must be very careful when deciding what to measure and reward, because they are quite likely to get what they measure -- which may or may not be what they really want."

Alcoa doesn't have a numbers problem, Anton insists. "We've got mature processes and we've got a great historical database of performance, so we have the confidence to know that our metrics work." Every year, Anton and other Alcoa employees are evaluated on their ability to reach their carbon footprint, greenhouse gas emissions, and other environmental goals they have set for 2020 and 2030.

Anton and other C-Suite members aren't the only Alcoa employees whose salaries are tied to sustainability. In fact, the practice goes fairly deep into the organization, Anton says. Even staffers in charge of medium-sized departments have part of their salaries tied to green goals, as well as goals involving workplace safety and diversity. More