World leaders gather in Paris next week for the start of crucial climate talks which aim to secure a new global deal on tackling climate change.
It is the latest step on a long - and often tortuous - road to securing international agreement on cutting greenhouse gas emissions in a bid to prevent global temperatures going more than 2C above pre-industrial levels and causing "dangerous" climate change.
The meeting kicks off as the world faces its hottest year on record in 2015, and the warmest five-year period recorded - with scientists warning that global warming is "unequivocal" and the human influence on the climate is clear.
Already human-induced climate change is making extreme weather such as heatwaves more likely, the latest assessment from the UN's World Meteorological Organisation has shown.
Polling for ActionAid suggests more than half (52%) of people in the UK are worried about climate change, more than a third (38%) are more concerned than they were five years ago, and 53% feel world leaders are not doing enough to tackle the problem.
Prime Minister David Cameron, US president Barack Obama and Prince Charles are among those leaders attending the beginning of the talks, taking place amid heavy security after 130 people were killed in Paris in terror attacks two weeks ago.
High-profile interventions from the likes of Pope Francis, moves by investors away from the most polluting fossil fuels, falling prices of clean technology such as solar panels and countries taking action domestically are all setting a more positive tone than in previous climate talks.
But negotiators will have to grapple with increasing ambition, as promises on the table from countries do not get the world on track for 2C rises, while funding to help poor nations develop cleanly and cope with the impacts of climate change will also be key.
Campaign group Avaaz's campaign director Iain Keith said: "While we know what gets agreed won't be the final destination in this journey, it could be a big step in the right direction.
"The Paris summit could agree a long-term goal to get the world off destructive dirty energy and onto clean power, which would mark a turning point in the fight against climate change.
"But that goal will only be seen as a clear signal if it is backed by solid plans from every country to cut emissions, a commitment to increase the ambition of those plans regularly, and money on the table to help developing countries make the switch to clean energy."
The UK is pushing for a strong deal, with a spokesman for Department of Energy and Climate Change saying: "We are committed to getting a global deal in Paris, which will create a level playing field for businesses, driving innovation and growing the low carbon economy.
"But securing an ambitious deal will require a global effort and there is much work still to do."
The UK has faced fierce criticism at home, however, for cuts to renewable and energy efficiency support and most recently for axing a £1 billion competition to develop technology to capture and store carbon emissions from power stations and industry.