In an effort to curb global warming, the House is considering legislation that calls for:

Reducing greenhouse gases by 17 percent from 2005 levels by 2020 and 83 percent by 2050 through a cap-and-trade program that allows pollution permits to be bought and sold.

Limiting emissions from major industrial sources, including power plants, factories, refineries and electricity and natural gas distributors. Emissions from agriculture would be excluded from the cap.

Controlling carbon dioxide from the burning of fossil fuels and limiting six other greenhouse gases.

Allowing companies to meet emission-limiting targets by investing in offset projects such as tree planting and forest protection.

Requiring electric utilities to produce at least 12 percent of their power from renewable sources such wind and solar energy by 2020, and requiring as much as 8 percent in energy efficiency savings.

Imposing tighter performance standards on new coal-fired power plants and providing $1 billion a year in development money for capturing carbon dioxide from such plants.

Establishing standards that will require new buildings to be 30 percent more energy-efficient by 2012 and 50 percent more efficient by 2016.

Protecting consumers from rising energy costs by giving rebates and credits to low-income households.