The U.S. and Canada are responsible to a great degree for causing the Earth's temperature to rise and spurring climate change, President Obama said Thursday.

"In some ways, as wealthier countries, we can probably adapt and manage better," Obama said in a joint press conference with Canadian Prime Minister Justin Trudeau. "On the other hand, we're also those responsible for a lot of the carbon pollution that is causing climate change."

He added that if the U.S. and Canada are not strong leaders on addressing the issue of climate change, nothing will get done.

"If we don't agree, if we're not aggressive, if we're not farsighted, if we don't pool our resources around the research and development and the clean energy agenda that's required to solve this problem, then other countries won't step up and it wont get solved," Obama said.

Obama and Trudeau agreed to a list of actions to increase their leadership on the issue. They will be taking a landmark step to cut methane emissions in half from the oil and gas sector, with first-ever standards for existing oil and gas wells. Methane is a potent greenhouse gas that is far more damaging to the climate than more prevalent carbon dioxide emissions. Many scientists blame such greenhouse gas emissions from burning fossil fuels for spurring manmade global warming.

The two leaders also will harmonize greenhouse gas and fuel-efficiency standards for big rig trucks and will work to craft a system to cut carbon dioxide from the commercial airline industry. The two countries also will take steps to reduce emissions in the Arctic by creating standards to limit carbon emission from ships moving freight through the icy waters, while also putting in place measures to preserve the region's fisheries and biodiversity.