China was once the bad boy of climate change. But with US President Donald Trump on the verge of pulling out of the Paris climate agreement, it’s now poised to be the global leader. The United States and China are the top two polluters in the world, although Chinese carbon dioxide emissions are double that of the US – China released over 10 million kilotons of carbon dioxide in 2013. With the United States’ exit from the historic climate deal seeming increasingly likely, we take a look at the two countries’ changing climate policies. What is China’s climate change policy? In recent years, China has been pouring cash into low-carbon industries at home, and taking a leadership role on climate change agreements abroad. China plans to spend over US$361 billion on renewable energy by 2020, and has made low-carbon growth one of its top priorities. Last year it invested US$88 billion in renewable energy, the highest amount in the world, and spent a record US$32 billion on renewable projects abroad. During the 2015 Paris Climate Change Conference, China helped negotiate the world’s first comprehensive climate agreement, prompting former US president Barack Obama to thank Chinese President Xi Jinping for his help. How China would help soften impact if Trump abandons Paris climate accord Earlier this year, Xi defended the Paris climate agreement at the World Economic Forum and called for stronger international cooperation. China has promised to cut its carbon emissions by 40 to 45 per cent from 2005 levels by 2020 and reach peak emissions by 2030 or earlier. Experts believe the goal is within China’s reach. How has that changed? Over the past 30 years, China has shifted its climate change stance from completely unaware, to climate change denier, to a major leader on global warming action. Before 1988, China had no specialised climate change researchers or government department for monitoring and controlling greenhouse gases. After China was classified as a major emitter of greenhouse gases by the General Assembly of the Intergovernmental Panel on Climate Change that year, China started to make changes. In 1990, China set up a governmental group for climate change issues and a research programme to look into its impact. China signed the United Nations Framework Convention on Climate Change in 1992, which had a “common but differentiated responsibilities” principle that gave leniency to countries that were still developing. It was seen as a win for China. China signed the Kyoto Protocol in 1998 and ratified it in 2002. Despite pressure from other countries to take meaningful steps to reduce emissions, China was cagey about making real changes and stuck to the concept of different responsibilities for developing countries. Unsurprisingly, China’s stance was backed by other developing countries. Xi should persuade Trump to stick with Paris climate accord, says former US negotiator But China started to show an interest in engaging when the Clean Development Mechanism was introduced in 2007. The mechanism allowed countries to earn emission reduction credits when they established projects to cut emissions in developing countries. . After 2011, when climate change deniers were gaining traction in the United States, China’s era of climate denial stopped and a new strategy of taking steps to address the problem began. What is the United States’ stance on climate change? While environmental conservation emerged in the United States’ national consciousness in the mid-20th century, the country’s climate change policies have varied greatly under different administrations. Under Obama, the US was relatively assertive about tackling climate change on an international scale, leading the Copenhagen Accord agreement in 2009 and ratifying the landmark Paris climate change agreement last September. But Trump’s administration has shown a sharp reversal on climate policy, reflective of the president’s own scepticism on climate change. Trump has said climate change is an “expensive hoax” orchestrated by China. So far, he has rolled back several of Obama’s executive orders to combat global warming, declined to appoint a special envoy for international climate change negotiations, and proposed a budget that would slash money from climate change funds. What happens if the United States withdraws from the Paris climate deal? If the US decides to withdraw from the deal, it will immediately undermine the country’s position as a global leader, paving the way for China to step up and fill the vacuum. While it is not the first time the US has reneged on a deal it helped lead – George W Bush abandoned the 1997 Kyoto accord negotiated by Bill Clinton – a turnaround on the Paris deal will inevitably draw the ire of US allies and push China closer to European nations. The Paris deal was the result of more than two decades of diplomatic efforts, and included nearly 200 countries in the United Nations – leaving out only Syria, Nicaragua and possibly the United States. Its goal is to prevent global temperatures from increasing above pre-industrial levels by over 2 degrees Celsius. Analysts and think tanks have found that if the US declines to participate in the agreement, it could also add up to 3 billion tonnes more carbon dioxide to the atmosphere annually.