Reports that Donald Trump is about to quit the Paris accord drew calls on Wednesday for other countries to rally round the climate pact, but warnings from some environmentalists that it would leave the deal badly weakened.
Trump was critical of the deal during his campaign and has been considering whether to remain in the pact.
But Trump's chief White House economic adviser, Gary Cohn, told reporters during the trip overseas that Trump's views on climate change were "evolving" following the president's discussions with European leaders.
U.S. Secretary of State John Kerry, with his two-year-old granddaughter Isabelle Dobbs-Higginson on his lap and United Nations Secretary-General Ban ki-Moon looking on, signs the COP21 Climate Change Agreement on behalf of the United States during a ceremony on Earth Day, April 22, 2016. The United States committed to reducing its own by 26 to 28 percent, compared with 2005 levels, by 2025.
Scientists say Earth is likely to reach more risky levels of warming sooner if the US retreats from its pledge because America contributes so much to rising temperatures.
Last week in Germany, McKenna met with Chinese special envoy for climate change Xie Zhenhua and European Union environment commissioner Karmenu Vella, where they discussed jointly hosting a meeting of environment ministers this fall to chart a path for implementing Paris among the world's major economies.
So far, no other country, not even China or India has said they'd follow the U.S.in pulling out of Paris.
Trump refused to endorse the landmark climate change accord at a summit of the G7 group of wealthy nations, saying he needed more time to decide, and promised an announcement this week.
"If President Trump reads the Pope's writings, I'm confident he will not withdraw from the agreement".
Britain may be heading for hung Parliament
The pollster said the approach was used during the European Union referendum and consistently showed voters backed Leave. Sterling dropped last week , rounding off the worst week this year.
President Donald Trump has only a few main options for dealing with the non-binding climate deal, one of former President Barack Obama's proudest diplomatic achievements.
President Trump has previously dismissed global warming as a "hoax" created by China and has threatened to pull out of the Paris accord. Even fossil fuel companies such as Exxon Mobil, BP and Shell say the United States should abide by the deal.
"Four years of the Trump administration may have only modest consequences, but eight years of bad policy would probably wreck the world's chances of keeping warming below the worldwide target of 2 degrees Celsius", Michael Oppenheimer, professor of geosciences and global affairs at Princeton University, said by email. That hope appears to have been quickly dashed.
On Tuesday, Modi said in Berlin that it would be a "crime" to spoil the environment for future generations as the world awaits a decision on USA climate policy.
Macron had "asked his ministers to take a number of initiatives, with our European partners or directly in France". European Commission Vice President Maros Sefcovic said this would be disappointing.
She says no one government can stop the momentum toward tackling climate change, adding that Canada will continue "marching on".
During his first global tour as president, several European leaders urged him to commit to the agreement seeking, among other things, to keep the temperature rise below two degrees Celsius with respect to pre-industrial levels. "Let's double down on our efforts to make the #ParisAgreement a success". But Trump's statement was clear and direct.
"The U.S.is going from being a global leader to putting itself in a very destructive minority position". But he predicted the deal would survive without Washington.
He said the US could try to re-enter the deal under more favorable terms or work to establish "an entirely new transaction". That means the US would remain in the agreement, at least formally, for another three-and-a-half years, ensuring the issue remains alive in the next presidential election.