U.S. Secretary of State John Kerry said Thursday that the world is “on a course leading to tragedy” because countries are failing to tackle climate change. The diplomat arrived today in Lima, Peru, to urge negotiators at an annual summit to reach a plan that will dramatically reduce global greenhouse gas emissions and avoid the most calamitous effects of global warming.

“Measured against the array of global threats that we face today, and there are many – terrorism, extremism, epidemics, poverty, nuclear proliferation --- climate change absolutely ranks up there equal with all of them,” he told the group of delegates from 196 countries. He listed as proof the 2013 monsoon floods that killed nearly 6,000 people in India, and devastating droughts in Brazil and New Zealand. He noted that 2014 is on track to be the warmest year on record.

“There is still a window of time for us to change course and avoid the worst consequences. But the window is approaching closely. We have to approach this global threat with the urgency that it warrants,” Kerry said.

The United Nations climate conference kicked off Dec. 1 with a rare surge of optimism. The United States and China, which have long bumped heads over emissions, last month unveiled joint commitments to reduce their respective carbon pollution. A global green fund, paid for by rich countries to help poorer nations cope with climate change, reached its initial target of $10 billion.

But over the past few days, familiar snags have surfaced, threatening to stall progress on a deal once again. Developing and industrializing countries, such as India, have argued that richer nations like the United States should be saddled with the largest climate commitments, since those countries are responsible for the bulk of the world’s historic emissions. European nations, which have some of the world’s most aggressive climate policies, are fighting for a plan that includes legally binding emissions cuts.

By Thursday morning, the text of a draft agreement had swelled from six to 50 pages, of which only a single paragraph had been agreed upon by diplomats, the Guardian reported. In most successful negotiations, officials would only be polishing the text, observers say. Countries have agreed to sign a final version of the Lima framework at next year’s conference in Paris.

Kerry chastised delegates during his talk, saying that all nations -- not just the biggest polluters -- must commit to deep emissions cuts under a global plan. “It’s everyone’s responsibility, because it’s the net amount of carbon that matters, not each country’s share,” he said in his speech, which was also attended by former U.S. Vice President Al Gore.

He added, “No one here believes a global climate agreement is going to be the silver bullet that eliminates this threat, but I think everyone believes that we certainly won’t eliminate it without a global agreement.”