Nov. 8 (UPI) — Former U.S. President Barack Obama warned Monday that much more needs to done to reduce dangerous carbon emissions and stop global warming.

“We can’t afford to stay where we are,” Obama told the United Nations Climate Change Conference in Glasgow, Scotland. “The world has to step up, and it has to step up now. When it comes to climate, time really is running out.”

Obama said it is going to be hard to keep global warming to 1.5 degrees Celsius, which experts have said is needed.

“Existing political institutions move slowly, even when leaders are well intended,” he said at the conference, known as COP26. “International cooperation has always been difficult. Getting people to work together on a global scale takes time. Right now, that’s time we don’t have. “

He called out Russia and China, in particular, for not attending the conference, which started Oct. 31 and runs through Friday, and for not doing enough to reduce carbon emissions.

Obama, a Democrat, also criticized Republicans in the United States for not taking the issue seriously.

“Saving the planet is not a partisan issue,” he said.

He noted that former President George H.W. Bush, a Republican, was the first president to recognize dangers of climate change.

Obama said that although meaningful progress has been made since the Paris Agreement during his administration and by decisions made in recent weeks by world leaders to reduce emissions, it’s not enough.

“What is also true is that collectively and individually we are still falling short,” he said. “We have not done nearly enough to address this crisis. We are going to have to do more. “

He also acknowledged that the United States is the the world’s second largest emitter of greenhouse gases, saying, “The U.S. has to lead…we have a lot of work to do.”

Obama also said that despite “four years of active hostility toward climate science, coming from the top of the [U.S.] government,” companies and other nations stayed the course on fighting climate change under the Paris Agreement.

“Today, more than one-third of the world’s largest companies have set zero emissions targets,” he said. “More than 700 cities in more than 50 countries have pledged to cut emissions in half.”

He added that, today, more than 3 million people in the United States work in clean energy jobs and more will result from the recently passed infrastructure bill.

Obama urged young people to continue to be active in calling on world and business leaders to act on climate change.

Last week at the conference, more than 40 nations agreed to stop investing in the production of coal power over the next two decades. The United States was not among them.

President Joe Biden pledged at COP26 that the United States will hit its goal of net-zero emissions by 2050, work with the European Union on an aggressive strategy to reduce methane emissions and do more to help developing nations fight climate change.

Britain’s Prince Charles said the world should take a “warlike” approach to climate change.

And Amazon founder Jeff Bezos pledged $2 billion to protect the environment.