'The decisive decade': Biden climate envoy John Kerry sounds alarm as US rejoins Paris climate accord

The United States formally rejoined the Paris climate accord on Friday, 30 days after President Joe Biden signed the mechanism to reenter the historic agreement.

While climate advocates cheered the decision, Biden's special presidential envoy for climate change, John Kerry, sounded the alarm about the need for urgent and ambitious action.

Kerry attacked former President Donald Trump, blaming his administration for being "inexcusably absent for four years."

"A lot of us thought that the failure of this enterprise might rest on one word. The word was Trump," he said Friday morning to members of America Is All In, a coalition of states, cities, private businesses and other groups led by Mike Bloomberg to keep the U.S. on track to meet its Paris climate goals.

The U.S. withdrawal lasted just over 100 days. While Trump announced he would exit the non-binding deal in June 2017, that withdrawal wasn't effective until Nov. 4, 2020, one day after the U.S. presidential election. But his administration dismantled several environmental protections during his tenure, including protections for clean water and air and fuel efficiency standards.

At the Munich Security Conference Friday, Kerry lamented that the world is "not close to where we need to be" in part because the U.S. wasn't leading.

"Three years later, three years wasted," he said. "Around 2030 is the date in which we have to get the world now on the right path in order to cap the warming at that level of 1.5 [degrees Celsius]. So we are absolutely, clearly, without question inside the decisive decade ... it's what people will do in the next 10 years that matter."

Those warnings come as world leaders urge the Biden administration to implement an ambitious agenda to reduce America's emissions, which compromise about 13% of the world's total.

Kerry did not announce any new steps as the administration continues to review its climate policies. But the former secretary of state and presidential nominee pointed to Biden's plan for a Leaders' Climate Summit on Earth Day, as well as to COP26, the United Nations climate summit in Glasgow, Scotland, this November.

In stark terms, he told conference attendees that climate change is a "threat multiplier" already causing displacement and mass migration, conflict and humanitarian crises.

"When tensions are already high somewhere and resources are increasingly scarce, the embers of conflict just burn brighter," he said. "And when farmers can no longer make a living because the weather is so extreme and unpredictable, they become increasingly desperate. Many, according to some studies, hundreds of millions, will be forced from their homes ... if it is not managed well, it can literally begin to undermine countries, homes, peace, and stability."

In fact, Kerry tied the crisis in Texas to climate change, saying, "This week in the state of Texas, we've seen unprecedented extreme cold related to climate because the polar vortex penetrates further south because of the weakening of the jet stream related to warming."

That link between climate change and cold weather is not definitive, but scientists say climate change may be making warm and cold seasons more extreme.

Not every country will be invited to Biden's Earth Day summit, Kerry confirmed, but it will include many developing countries like Bangladesh and Pacific states like Palau that are already facing the climate crisis in tangible ways. The world's 17 major economies and biggest emitting countries must take note of "the plight of the people who are the victims," Kerry said.

He added, "There's simply no faking it at this moment. Failure is really not an option if we expect to pass the Earth on in the shape that it needs to be to future generations."