CNN  — 

Humanity needs to “grow up” and deal with the issue of climate change, British Prime Minister Boris Johnson told world leaders at the United Nations General Assembly in New York on Wednesday.

Johnson, a last-minute addition to the speakers’ list that day, slammed the world’s inadequate response to the climate crisis and urged humanity to “listen to the warnings of the scientists,” pointing to the Covid-19 pandemic as “an example of gloomy scientists being proved right.”

“We still cling with parts of our minds to the infantile belief that the world was made for our gratification and pleasure,” he said. “And we combine this narcissism with an assumption of our own immortality.”

“We believe that someone else will clear up the mess, because that is what someone else has always done,” he added. “We trash our habitats, again and again, with the inductive reasoning that we’ve gotten away with it so far, and therefore, we’ll get away with it again.

“My friends, the adolescence of humanity is coming to an end and must come to an end.”

Johnson highlighted the UN Climate Change Conference – known as COP26 – in Glasgow in November as a “turning point for humanity.”

World leaders need to arrive in Scotland ready to make necessary commitments, he said. It’s already “too late” to stop the rise in global temperatures, but the world can still “restrain that growth” to 1.5 degrees Celsius.

The 1.5-degree marker has been identified by the UN Intergovernmental Panel on Climate Change as a key tipping point beyond which the risk of extreme drought, wildfires, floods and food shortages will increase dramatically. The World Meteorological Organization predicts we now have a roughly 40% chance of reaching that level – even if temporarily – within the next five years.

To prevent crossing that threshold, “we need to pledge collectively to achieve carbon neutrality, net zero, by the middle of the century,” Johnson said on Wednesday. “We need all countries, every single one of you, to step up the commitment to very substantial reductions by 2030.”

The Prime Minister held a closed meeting with UN Secretary-General António Guterres and other world leaders Monday to urge nations to pledge funding to help developing nations move away from fossil fuels.

Climate has been a key pillar of the conference so far, and it seems Johnson’s appeal has resonated with other world leaders concerned about the climate crisis. In a speech to the UNGA on Tuesday, US President Joe Biden announced the US would double its financial commitment to helping developing nations tackle the climate crisis.

In a meeting with Biden on Tuesday, Johnson hailed the US President’s speech as “the most important thing today.”

Chinese President Xi Jinping also made a major new pledge to stop building coal projects overseas, and increase financial support for green and low-carbon energy projects in other developing countries.