The UN chief summons world leaders to action. But, he says, they seem ‘incapable of coming together’

UNITED NATIONS (AP) — Insisting that international cooperation is critical, the United Nations chief delivered a dire warning to leaders from across the world Tuesday, declaring that the planet is becoming unhinged with mounting global challenges and geopolitical tensions — and warning that "we seem incapable of coming together to respond." Addressing presidents and prime ministers, monarchs and ministers at the opening of the U.N. General Assembly's high-level meeting, Secretary-General Antonio Guterres ticked off a list of "existential threats" the world is facing, from climate change to disruptive technologies like artificial intelligence. "Our world is becoming unhinged. Geopolitical tensions are…