The United States has warned inaction by world powers on climate change is tantamount to a “mutual suicide pact” after countries such as China, India, and Russia expressed skepticism on the global security threat it posed.

John Kerry, the US special presidential envoy for climate, described the climate crisis as “a threat multiplier” and “indisputably a Security Council issue” after some nations said it had no place for discussion at the UN body. He added, “In fact, it is among the most complex and compelling security issues that I think we’ve ever faced.”

Experts believe the world must reach net zero carbon emissions by 2050 or sooner to ensure long-term warming is held to no more than 1.5 degrees Celsius (34.7 degrees Fahrenheit) and avoid triggering catastrophic climate tipping points.

The world has already warmed 1.2C (2.2F) since the mid-19th century and the goal now is to prevent an additional 0.3C (0.5F) of warming.

Russia, India and China said climate change should be tackled in other global forums, not at the UN’s main grouping on imminent world threats. Russia was particularly vocal in its opposition to the discussions.