U.N. Secretary-General Antonio Guterres introduced the 2019 Climate Action Summit in New York City on Monday by saying the time for “talk” and “negotiations” is over.

“This is not a climate talk summit. We have had enough talk. This is not a climate negotiation summit. You don’t negotiate with nature. This is a climate action summit,” Guterres said.

“The best science, according to the Intergovernmental Panel on Climate Change, tells us that any temperature rise above 1.5 degrees will lead to major and irreversible damage to the ecosystems that support us. Science tells us that on our current path, we face at least 3-degrees Celsius of global heating by the end of the century,” he said.

“The climate emergency is a race we are losing, but it is a race we can win,” he declared.

Guterres praised government and business entities for attending the Climate Action Summit to announce major climate-change initiatives.

“Financial actors are here to scale-up action and deploy resources in fundamentally new and meaningful ways. Coalitions are here with partnerships and initiatives to move us closer to a resilient, carbon-neutral world by 2050. And young people are here providing solutions, insisting on accountability, demanding urgent action,” he said.

Guterres acted on his no-talk, no-negotiations stance by stating that only world leaders prepared to make significant commitments to climate change would be welcome at the summit.

“People can only speak if they come with positive steps. That is kind of a ticket. For bad news don’t come,” he said.

Guterres declared climate change is “the defining issue of our time” and claimed it was the first time in history there has been “a serious conflict between people and nature, people and the planet.”

Guterres was mildly supportive of President Donald Trump’s decision to pay a brief visit to the morning session of the summit, even though Trump did not commit to the level of climate-change spending the secretary-general described as a mandatory “ticket” fee for attending. Guterres described Trump’s visit as a “step forward” but declined further comment.