The European Commission president on Wednesday said that it was the "duty of Europe" to stand up to the USA if President Donald Trump decides to pull his country out of the Paris climate change accord.
If what President Donald Trump, 70, is reportedly planning to do happens, then the United States will join Syria and Nicaragua as being the only other countries on Earth not committed to the Paris Agreement.
One hundred and ninety-five nations have signed the pact, meant to cope with climate change.
Impacts of these catastrophic events, Mr. Guterres noted, would be felt in all corners of the world and in all sectors of the economy.
Leaving the agreement would be a four-year process, unless Trump chose to leave the United Nations Framework Convention on Climate Change completely, according to Article 28 of the agreement.
On Wednesday, as reports of a potential USA exit from the agreement emerged, Trump took to Twitter to assure the public that a decision on whether to leave the deal, struck by President Barack Obama in 2015, was forthcoming.
As president of the United States, the most powerful nation on the planet, Donald Trump should be leading the global effort to avoid the worst effects of climate change.
Trump faced considerable pressure to hold to the deal during visits with European leaders and Pope Francis on his recent trip overseas.
Dozens of other companies have also supported the US involvement in the Paris agreement.
The precise mechanism for withdrawal hasn't yet been determined, but Trump has made clear he plans to fulfill his campaign promise to withdraw.
The legally binding 2017 deal signing would enhance the requirements upon global nations, forcing signatories to limit human economic activity, and rich countries to provide "climate finance" to poor nations, paying for their renewable energy projects.
"Climate change is an unprecedented and growing threat", he warned, announcing that he would host a United Nations climate summit in 2019 to promote global support for the Paris Agreement. "If other countries lose confidence in our commitment to climate change, they may cut back their commitment".
Trump tweeted on Wednesday morning that he will make his decision public within a few days. He said that now 147 parties representing more than 82 percent of greenhouse gas emissions have ratified the Paris agreement.
What's the difference between COP21, the Paris Accord and the Paris Climate Agreement?
Guterres called the Paris agreement, the first global and comprehensive accord to tackle climate change, a "remarkable moment in the history of mankind" that brought the most fractious of countries together under a single cause.
Trump has also been the subject of ferocious worldwide lobbying from leaders across the globe to remain in the agreement.
The U.S.is the world's second largest emitter of carbon, following only China. The agreement allows countries to achieve the emissions goal in whatever manner the country sees fit mainly because every country differs and lives under varying circumstances.