Hold the applause. The climate-change accord reached in Paris in December was signed at a leader-studded ceremony on Friday at the United Nations in New York. But that does not mean the agreement is in force; nor does it mean that planet-warming carbon dioxide emissions will fall any time soon even if it does come into force.
There is no doubt that the Paris Agreement marked a grand political victory, in the sense that 195 countries agreed that global warming – now undeniable except among Luddite U.S. Republicans and a few fossil-fuel companies – is a clear and present danger that has to be slowed, then stopped, if Earth is to avoid BBQ status.
As if on cue, the first three months of this year broke high-temperature measures by the biggest margin yet recorded. The Arctic and Greenland ice sheets continue to melt at alarming rates and coral bleaching, caused by warmer than usual water, is devastating Australia's Great Barrier Reef. Some of the warming probably can be attributed to El Nino, the periodic warming in the central equatorial Pacific Ocean, although record amounts of man-made carbon dioxide emissions cannot be ignored.
In Paris, the agreed goal was to limit global temperature increases to 2 C over preindustrial levels; beyond that all bets are off. The aspirational goal was 1.5 degrees, although many scientists think achieving that limit is impossible given the relentless carbon output. Even 2 degrees may prove elusive. Based on the carbon-reduction plans submitted by most countries at the Paris meetings, the Climate Action Tracker project estimates that a 2.7-degree increase is the best that can be hoped for. Before the Paris Agreement, its warming estimate was 3.1 degrees. Even the lower warming figure would make life somewhere between miserable and impossible for some or much of humanity.
To keep warming to 2 degrees or less, industrialized countries will have to launch Apollo moonshot-style renewable-energy innovation programs combined with rigorous environmental regulations over the next couple of decades. Coal plants everywhere would have to be eliminated along with the internal combustion engine. The bill could easily come to tens of trillions of dollars.
The omens are not encouraging. "Climate change" and "global warming" have been part of the everyday lexicon since the 1980s – German reinsurance giant Munich Re first warned about global warming in 1973 – but emissions have only gone up since then. Every United Nations environmental summit since 1992's Earth Summit in Rio de Janeiro has kicked the can down the road. The ambitious 1997 Kyoto Protocol was never ratified by the United States and was abandoned by Canada in 2012, after then prime minister Stephen Harper decided that carbon reduction was incompatible with allowing his cherished oil sands development to munch its way through northern Alberta. The Copenhagen climate summit in 2009 collapsed in acrimony.
The sad reality is that tackling climate change has yet to capture the imagination and resources of governments, voters and corporations. Maybe it's because the problem is so big that it seems impossible to fix, or maybe it's because climate change happens so slowly that it's easy to ignore – there has yet to be a climate-change "Pearl Harbor" moment that demanded the accelerated end of the fossil-fuel era.
Or maybe it's because fighting climate change in earnest would produce no short-term benefits in the way the previous environmental wins did in the 1970s and 1980s. Back then, the United States was able to introduce the Clean Air Act, the Clean Water Act, the Endangered Species Act and the Environmental Protection Agency. Leaded gasoline disappeared and the Montreal Protocol phased out the chlorofluorocarbons that were damaging the ozone layer. These measures improved the environment almost immediately.
The Paris Agreement still faces enormous political obstacles. Friday's signing ceremony was merely an intermediate step toward full implementation. Many countries now have to go back to their parliaments and national assemblies for ratification, which could take two years or longer. The big risk is the United States, the second biggest polluter after China. In a clever move, President Barack Obama will implement the agreement through an executive agreement, because it is not a legally binding treaty, meaning it would not have to be sent to the Senate, where it would be killed. Which raises the question: If it's not a legal treaty, how will it be enforced?
The biggest question is whether a Republican president – Donald Trump or Ted Cruz – would shred the Paris Agreement. They have said they would, in so many words, although doing so could take years. "If the United States does not implement the Paris deal, or pulls out, the deal is dead," says Peter Hoeppe, head of the geo risks unit at Munich Re.
Friday's signing ceremony in New York was a declaration of intent. The Paris Agreement, like all the agreements before it, could still fail. Meanwhile the planet gets ever warmer. A Pearl Harbor environmental event appears inevitable.