If there was one unifying principle as this year's United Nations climate conference started in Marrakesh, Morocco on Monday, it was that the world needs to lift its ambition in fighting global warming.
Unless the world acts quickly, warned Erik Solheim, head of the UN Environment Program (UNEP), "we will grieve over the avoidable human tragedy.
"The growing numbers of climate refugees hit by hunger, poverty, illness and conflict will be a constant reminder of our failure to deliver," he said last week as UNEP unveiled its annual "gap report" describing how far short the promises so far have fallen. "The science shows that we need to move much faster."
"The world is not nearly on track," agreed Patricia Espinosa, executive secretary of the UN climate negotiation body, in an essay co-authored with Morocco's foreign minister and COP22 president, Salaheddine Mezouar.
The problem is simple: temperatures are increasing along with carbon dioxide emissions and its concentration in the atmosphere. Unless this changes in the next few years, the primary goal of the Paris Agreement, negotiated last year and put into effect last week, will drift out of reach in just a few years.
The goal is to limit global warming well below 2 degrees Celsius and as close as possible to 1.5 degrees, to avoid the most severe impacts of global warming.
It has been clear all along that the pledges offered by those joining the Paris agreement are not adequate to achieve that. The first decision of COP21 last year stressed the urgency of accelerating action, and of taking additional steps well before 2020.
A new memorandum of advice for policymakers issued a few weeks ago by Espinosa's science advisers said that even though the promises so far are "woefully short," Paris had provided "significant momentum to build on."
That memo, "Climate Action Now," noted that the costs of clean energy are falling, lower oil prices open an opportunity for carbon taxes and the private sector is beginning to address climate risks.
It would be Pollyannish to think that this is all guaranteed.
"Pretending that these temperature goals are achievable was (and is) essential to the diplomatic process," David Victor of the Brookings Institution wrote in a recent paper for the Harvard Project on Climate Agreements.
"It was politically feasible to agree on such bold, aspirational collective goals—even if they are largely unachievable—because no individual country needed to take responsibility for delivering," he wrote. "Sometime soon the diplomatic community will need to face the reality that we need new, achievable, and more useful long-term goals."
But the United States, China and other major nations continue to talk about increasing their ambition—although not necessarily as quickly or as stringently as the experts say may be required.
Jonathan Pershing, the new U.S. chief negotiator, has said he plans to describe the path the U.S. will follow to new higher ambitions—assuming that Hillary Clinton is elected president. (The initial U.S. pledge was to cut its emissions up to 28 percent by 2025.)
"At the moment, what we have from the world are commitments for 2025 or for 2030, but we know that by 2050 or certainly by the end of the century we've got to have deep de-carbonization," he told reporters last week. "Twenty percent is not enough, 30 percent is not enough. We need to think about an 80 percent reduction or perhaps more."
Industry and institutional investors, too, are going to have to do more. One survey of hundreds of companies found that they have put in place plans to cut 1 trillion tons of emissions, but that to reach the goals of Paris they would have to cut 4 trillion tons.