The global climate is in trouble, worsening faster than experts believed only two years ago, and ambitious international steps to address the problem have been insufficient thus far. In December 2015, nearly every nation on Earth committed to the Paris agreement to reduce greenhouse gas emissions, a concerted effort to limit the rise in global temperature to no more than 2 degrees Celsius above preindustrial levels. But scientists now say the line must be held at 1.5 degrees to prevent the climate change that's already underway from becoming catastrophic.

Representatives of the nations that signed the Paris agreement meet this week at a United Nations climate conference in Bonn, Germany. The United States will have a diplomat there even though President Donald Trump has begun the process of withdrawing from the pact, possibly the single most dangerous step he has taken.

A U.N. Emissions Gap Report released Oct. 31 found that "the gap between the reductions needed and the national pledges made in Paris is alarmingly high," and that emissions must be throttled back even further. Given these findings, attendees at Bonn must come up with a strategy for accelerating global efforts to reduce emissions and ensure that the world reaches net-zero greenhouse gas emissions by 2050.

Even that may not suffice. A new report by the World Meteorological Organization concluded that carbon dioxide increased in the atmosphere at record speed last year and has reached a level not seen in more than 3 million years. Currently, scientists are predicting sea-level rise in terms of feet, not inches, which would inundate coastlines, destroy infrastructure worldwide and displace millions of people. We're already seeing increased storm strength, more frequent flooding and deeper droughts, all ascribed to global warming.

More troubling is that last year's increase came despite a global slowdown in fossil fuel use. Some scientists fear we may be reaching a "feedback loop" in which warmer air in the Arctic thaws permafrost, which releases trapped methane (and carbon dioxide), which in turn feeds the rise in the air temperature. Others think that the risk from tundra emissions might not be significant, but that increased rainfall in the tropics, which leads to microbial processes that release methane, could be. In either scenario, it will be crucial to offset the increases by reducing the amount of methane released from such human activities as drilling, cattle ranching and rice farming.

FROM AN EDITORIAL IN THE LOS ANGELES TIMES