COP26 is the 2021 United Nations climate change conference which is taking place in Glasgow, Scotland. This year will be the 26th annual summit. For nearly three decades the UN has been bringing together almost every country on earth for global climate summits – called COPs – which stands for ‘Conference of the Parties’. In that time climate change has gone from being a fringe issue to a global priority. In the run up to COP26 the UK is working with every nation to reach agreement on how to tackle climate change. World leaders will arrive in Scotland, alongside tens of thousands of negotiators, government representatives, businesses and citizens for twelve days of talks. Not only is it a huge task but it is also not just yet another international summit. Most experts believe COP26 has a unique urgency. To understand why, it’s necessary to look back to another COP. COP21 took place in Paris in 2015. For the first time ever, something momentous happened: every country agreed to work together to limit global warming to well below 2 degrees and aim for 1.5 degrees, to adapt to the impacts of a changing climate and to make money available to deliver on these aims. The Paris Agreement was born. The commitment to aim for 1.5 degrees is important because every fraction of a degree of warming will result in the loss of many more lives lost and livelihoods damaged. Under the Paris Agreement, countries committed to bring forward national plans setting out how much they would reduce their emissions – known as Nationally Determined Contributions, or ‘NDCs’. They agreed that every five years they would come back with an updated plan that would reflect their highest possible ambition at that time. Glasgow is the moment for countries to update their plans. The run up to this year’s summit in Glasgow is the moment when countries update their plans for reducing emissions. But that’s not all. The commitments laid out in Paris did not come close to limiting global warming to 1.5 degrees, and the window for achieving this is closing. The decade out to 2030 will be crucial. So as momentous as Paris was, countries must go much further than they did even at that historic summit in order to keep the hope of holding temperature rises to 1.5 alive. COP26 needs to be decisive. About 20,000 heads of state, diplomats and activists are expected to meet in person starting Oct. 31 to set new targets for cutting emissions from burning coal, oil and gas that are heating the planet. But China, Australia, Russia and India have yet to make new pledges to cut their pollution, and it’s not clear that they will before the summit. Meanwhile, only a few wealthy countries have allocated money to help poor and vulnerable nations cope with the impacts of climate disasters that they have done little to cause. Among those who so far have not RSVP’d in the affirmative: President Xi Jinping of China , the world’s largest emitter. Thousands of diplomats from nearly 200 countries will conduct the nuts and bolts of the negotiations, while business leaders, academic experts and activists, including Greta Thunberg, plan to monitor the proceedings and in many cases will advocate the most ambitious outcome.