COP21: what is the Paris climate change summit likely to achieve?
World leaders faced with mammoth task of securing a legally binding climate agreement for the first time
Hundreds of thousands of people have taken part in demonstrations around the globe as world leaders gather in France for a crucial summit on climate change.
The two-week conference, known as COP21, gets underway in Paris today with the goal of securing an ambitious and legally-binding treaty for the first time.
In London yesterday, more than 50,000 people took to the streets to demand stronger action, including Jeremy Corbyn, actor Emma Thompson and designer Vivienne Westwood.
"Those who are sitting around the tables in Paris have an enormous opportunity in front of them," the Labour leader told audiences, according to The Guardian. "Do not let them flake it or fool us."
After police in the French capital blocked a demonstration because of security worries prompted by last month's terrorist attacks, hundreds of shoes – include a pair donated by Pope Francis – were left in the city centre in symbolic protest.
So what exactly are leaders hoping to achieve this week in Paris – and are their goals realistic?
Who will be there?
Representatives from more than 190 countries will be attending one of the largest climate conferences ever organised, according to The Guardian. US President Barack Obama, China's Xi Jinping and India's Narendra Modi have all confirmed their attendance, as have leaders from Germany, Canada, South Africa and Brazil.
Heads of state will be invited to attend the first day of the summit – instead of the last, as is customary – in a bid to boost the chances of securing a deal. "The idea is to provide a political impetus at the beginning", French foreign minister Laurent Fabius told The Guardian.
What is the aim?
Leaders will be pushed to agree on a legally binding global climate treaty to curb carbon emissions and keep global warming below two degrees Celsius by the end of the century. If ratified, the treaty will come into effect in 2020 when current commitments on greenhouse gas emission expire.
Many of the biggest greenhouse gas emitters have already revealed their pledges. The EU has vowed to cut emissions by 40 per cent by 2030 and the US by at least 26 per cent. China has not set a specific target, but agreed last year that its emissions would peak by 2030 at the latest.
"The world is at a critical juncture in its efforts to combat climate change," warns the International Energy Agency (IEA). Last year, a leaked UN report revealed that climate change had already left its mark "on all continents and across the oceans", altering weather patterns, damaging food crops, spreading disease and melting glaciers.
Will the summit achieve its goal?
Difficult political hurdles will have to be overcome if the treaty has any chance of being ratified.
Developing countries argue that rich nations should be at the forefront of cutting greenhouse gases, as they have been contributing to the problem for longer. "But industrialised nations baulk at being saddled with a higher burden of responsibility," says The Guardian.
The UN's climate chief, Christiana Figueres, says she is confident that a deal will be reached but expects that it will fall short of the 2C goal. "As we speak, I see more and more political will because every country is realising they're all impacted," she told Sky News last month.
She insisted that the 2C point was still "the aim in the long run" but was "not the aim of Paris itself".
But failing to agree on the two-degree point would be catastrophic, warn delegates from the world’s least developed countries (LDCs), who argue that the limit should be set even lower at 1.5C.
"For the LDCs, economic development, regional food security, ecosystems, and the very survival of their populations and livelihoods are at risk if talks aim only for a 2C world," Giza Gaspar Martins from Angola told the BBC.
He added: "The heads of state will be in Paris to set the tone for the negotiations. We renew our call for an ambitious, robust and binding climate deal that does not leave behind the most vulnerable among us."