SCENARIOS: Possible changes to House climate bill

WASHINGTON (Reuters) - Climate change legislation that aims to cut U.S. greenhouse gas emissions faces several hurdles before being put to a vote in the House of Representatives and possibly in the Senate later this year.

The legislation, having cleared the House Energy and Commerce Committee, seeks to cut emissions by 17 percent by 2020 and 83 percent by 2050.

* AGRICULTURE - Democrats from farm states are threatening to withhold support unless they win safeguards for ethanol and other biofuels from proposed Environmental Protection Agency regulations. The climate bill could give them leverage: assuming most House Republicans oppose the bill, many in this group of moderate Democrats must be on board in order to pass the measure.

* OIL DRILLING - Democrats on the Natural Resources Committee want to increase the fees industry pays for oil and gas drilling on federal lands. It also wants to cut the duration of those leases. The committee could attach the plan to the climate bill.

Another possible initiative: New planning for offshore oil drilling. If incorporated, that could give some Democrats enough political cover to support the climate bill, as their worries about higher energy prices related to the climate bill could be eased by prospects of more domestic oil production.

* TAXES AND TRADE - The House Ways and Means Committee may leave the bill mostly alone but that is still being weighed. If the panel decides it needs to raise revenues to pay for other initiatives, it could attach new tax provisions. President Barack Obama had hoped the climate legislation would generate hundreds of billions of dollars to finance the continuation of a working-class tax break, but the Energy and Commerce Committee did not go along.

The Ways and Means Committee also oversees trade and it could consider provisions such as further aid to heavy manufacturing firms competing with foreign imports.

* SCIENCE AND RESEARCH - The Science and Technology Committee voted to create a national climate agency within the National Oceanic and Atmospheric Administration. It might try to attach the initiative to the climate bill moving through the House. The idea is to improve scientific knowledge of climate change and provide forecasts and warnings to the public related to changes in the weather and climate.

* OTHER CONCERNS: The House Financial Services Committee and the Agriculture Committee want to have rules in place for trading pollution permits down the road.

When the legislation is debated before the full House, some members might try to set a 14 percent goal, instead of 17 percent, for the reduction in carbon dioxide emissions by 2020. Other lawmakers might try to add provisions to help the U.S. nuclear power industry, which they note emits no greenhouse gases.

(Reporting by Richard Cowan; Editing by Peter Cooney)