US Energy Secretary Steven Chu said on Thursday he is optimistic that scientific research will help to deal with the current economic and climate challenges.

"As a scientist, I understand the seriousness of the economic and climate challenges we face, but I remain optimistic that scientific research will once again bring us transformative solutions," said Chu before President Barack Obama made a speech at the department.

"Some of these technologies are already within our grasp, while others are yet to come," said Chu.

The Nobel Prize winning physicist acknowledged that the world "face an economic crisis unlike anything since 1930s and a climate crisis that is totally without precedent."

"History and our fellow citizens will judge us on how we respond. We must not miss the rare and remarkable opportunity before us," he said.

He also vowed to support Obama's massive stimulus package, saying it "will put our country back to work."

"It will create new industries. It will begin to transform the way we produce and use energy, recognizing that we must act now to address the global climate crisis," said Chu.

In an address at the Department of Energy, Obama warned that the current economic crisis will "turn into catastrophe" if the congress did not approve his massive stimulus package immediately.

"Crisis could turn into catastrophe for families and businesses across the country, and I refuse to let that happen," said Obama, calling on lawmakers "to rise to this moment."