Hopes of a breakthrough in international climate change ambitions are being downplayed for a landmark meeting in New York Monday.
The United Nations climate action summit looks set to disappoint the thousands of campaigners who have been taking to the city's streets.
The summit is arguably the most important moment for climate change since the Paris climate deal was agreed in 2015. A key part of the historic agreement was that by 2020, countries would "ratchet up" the carbon-curbing plans they put forward for Paris, which are insufficient to meet the accord's goals.
UN Secretary-General António Guterres has called on leaders to come to New York with concrete, realistic plans, rather than "beautiful speeches." He has set the bar high for heads of state, who are expected to include Narendra Modi of India, Emmanuel Macron of France, Angela Merkel of Germany and the UK's Boris Johnson.
Guterres has made four specific requests: carbon neutrality plans for 2050, ways to tackle fossil fuel subsidies, taxing carbon and no new coal power beyond 2020.
Two days after the UN summit, scientists will issue a special report on how global warming will affect the planet's oceans and frozen corners.
But despite the spotlight these events will shine on the summit, hopes are relatively low.
"I don't think we should expect some huge breakthrough," says Nicholas Stern of the London School of Economics.
This is partly due to the EU and the US. The leadership role that the latter played ahead of the Paris summit was crucial to unlocking commitments from China, but such leadership has been absent under Donald Trump, who has kick-started the process of withdrawing the US from the Paris accord in 2020. The EU's failure this summer to adopt a goal of net zero emissions for 2050 also hurt momentum this year.
Despite the gloom, anywhere between 60 and 100 countries are expected to come with a plan. No major economies are expected to announce a stronger nationally determined contribution, UN jargon for countries' carbon-curbing plans, but some smaller ones may. Many will come with a commitment to commit later.
"For me it's a really important staging post, an inflection point where at leader level we get a sense of how transformational this can be for economies," says Nick Bridge, the UK's top climate envoy.
He believes Guterres has been right to make bold demands.
"A lot of this is getting back to the evidence and the science. Are we meeting what we need to do? No," Bridge said.
The ambition in existing NDCs needs to increase five times for the world to limit temperature rises to 1.5 degrees Celsius and three times for 2 degrees Celsius, the tougher and minimum targets of the Paris deal, says Niklas Hagelberg of the UN Environment Programme.
The expectation is that most countries will submit a new NDC in the first half of next year, ahead of a key UN climate conference in November likely to be co-hosted by the UK and Italy in Glasgow.
If current pledges are delivered, the world will warm by around 3 degrees Celsius by the end of the century, says Niklas Höhne of Climate Action Tracker. Those pledges, which include China peaking emissions by around 2030, will see emissions continue to rise for the next 10 years.
By contrast, for a 2 degrees Celsius world over that period, they must fall 30 percent, and 50 percent for a 1.5 degree Celsius world.
"We are not a little bit off, we are really far off," says Höhne. At best, the new NDCs in aggregate might shave something in the order of 0.1 degree Celsius off future warming, rather than a dramatic change like 0.5 degrees Celsius, he says.
However, he sees reasons for optimism beyond national governments. An analysis by CAT found that if cities, regions and businesses deliver all the emissions cuts they have promised by 2030, by that point the world could still stay under 2 degrees Celsius, albeit not 1.5 degrees Celsius.
"That is encouraging," he says.
Stern doesn't think this month's UN summit will be the point when we see promises materialize that close the gap between 3 degrees Celsius and "well below" 2 degrees Celsius as Paris demands. "I think the most important thing is the shared recognition of the magnitude of the task ahead," says Stern.
• This story originally ran on newscientist.com website. It is republished here as part of the Daily Herald's partnership with Covering Climate Now, a global collaboration of more than 300 news outlets to strengthen coverage of the climate story.