WASHINGTON – Environmental groups hailed President Barack Obama's warning Monday about climate change, but said the president's words will soon be tested as he decides whether to approve the Keystone XL oil pipeline from Canada to the Gulf Coast.

Obama pledged in his inaugural speech to respond to what he called the threat of climate change, saying, "Failure to do so would betray our children and future generations."

By singling out climate change, Obama indicated a willingness to take on an issue that he acknowledges was often overlooked during his first term. He also was setting up a likely confrontation with congressional Republicans who have opposed legislative efforts to curb global warming.