Obama met with Stoltenberg before accepting the Nobel Peace Prize in Oslo.
"Today we have discussed the most pressing challenge of our time -- climate change," Stoltenberg said. "We need a strong political agreement" at the U.N.-backed climate change summit in Copenhagen, Denmark.
He said he also briefed Obama on the Norwegian-Mexican initiative concerning financing, "a key issue in Copenhagen. Developed countries must provide more funding for climate action in the developing world."
The prime minister said he and Obama also talked about Afghanistan and Obama's decision to send an additional 30,000 U.S. troops there.
"I welcome the stronger and broader U.S. involvement aimed at ensuring development and stability," Stoltenberg said, adding that Norway was committed to continuing its military and civilian efforts in Afghanistan.
He said Norway will increase its financial contribution to the Afghan national army and police, to a total of $110 million for 2010-2014.
Obama said the U.S.-Norway relationship "thrives on the basis of our common values and our shared aspirations for a better world."
"To that end, our cooperation spans a broad range of issues, as the prime minister indicated, including building stability and security in Afghanistan and the Balkans, confronting nuclear proliferation and climate change, advancing human rights and global health."