After a champagne moment in Paris, where ministers from around the world crafted a pact to fight perilous climate change, now comes the hard part.
Experts are under no illusion that celebrations and high-flown rhetoric are enough when it comes to rolling back greenhouse-gas emissions.
If anything, they say, the divisions that beleaguered the nearly two-week haggle have underscored the political and economic obstacles that now lie ahead.
The deal finally struck on Saturday, a day into extra time, enshrines the goal to cap global warming at two degrees Celsius over pre-industrial levels — and at an even more ambitious 1.5°C if possible.
But the bad news is that humanity may already have used up almost 1°C of that allocation, the UN’s World Meteorological Organisation warned in November.
And the emissions-curbing pledges submitted by 185 countries to give the agreement substance, even if fully honoured, set the stage for a 3°C warmer world.
The only hope lies in hard-fought provisions in the pact to encourage nations to ramp up their actions over time, and thus keep a 2°C goal in focus.
“This is the key thing to ensure that the actions get stronger and stronger so that we get to two degrees and below,” WWF climate expert Tasneem Essop said.
Two degrees Celsius is the threshold at which politicians hope humankind can avoid the worst climate change impacts: dangerous storms, drought, sea-level rise, water wars, mass migration and the spread of diseases.
The agreement itself admits “with concern” that current national plans are not enough. As a result, it has built in a number of checks to try and keep the fast-closing 2°C window ajar.
Scattered over different sections of the 31-page document, the measures collectively make up what has become known as a “ratcheting up” mechanism.
It could play a vital part in a pact where emissions commitments are voluntary and there is no single timetable for achieving carbon reductions, which scientists point to as a gaping flaw.
The first step will be a stock-taking in 2018, two years before the agreement enters into force, of the overall impact of countries’ progress in abandoning fossil fuels like oil, coal and gas in favour of renewable sources like solar and wind.
The findings must inform the next round of country pledges to replace those that will enter into force with the agreement, in 2020.
“This will be a significant political moment where governments will be urged to ramp up their efforts,” said Mohamed Adow of Christian Aid, which lobbies on poverty issues.
