FACTBOX: Presidential candidates on environment, energy

(Reuters) - With crude oil prices hovering near a record $125 a barrel, energy and environmental issues like global warming have moved to the forefront of the U.S. presidential campaign.

Here is what the candidates are saying about energy and the environment:

* CLIMATE CHANGE

NEW YORK SEN. HILLARY CLINTON, DEMOCRAT - Cut U.S. greenhouse gas emissions to 80 percent below 1990 levels by 2050 through a cap-and-trade system; require all publicly traded U.S. companies to file report on climate change risks with the Securities and Exchange Commission.

ILLINOIS SEN. BARACK OBAMA, DEMOCRAT - Cut carbon dioxide (CO2) emissions to 80 percent below 1990 levels by 2050; reduce emissions to 1990 levels by 2020; require fuel suppliers to cut carbon content by 10 percent by 2020.

ARIZONA SEN. JOHN MCCAIN, REPUBLICAN - Favors a cap-and-trade CO2 approach; sponsored legislation in 2007 to cut emissions by 30 percent by 2050.

* GASOLINE PRICES

CLINTON - Investigate oil companies and energy traders to see if market manipulation is occurring; take pressure off pump prices by releasing emergency crude oil stockpiles; suspend 18.4-cents-per-gallon federal tax on gasoline during the summer.

OBAMA - Probe energy industry activities, stop filling emergency oil reserve.