Paris UN climate conference 2015: Xi Jinping heads for Paris as China labours under smog

Air quality index readings surged beyond 500, more than 20 times levels considered safe by the World Health Organisation, on Monday morning, prompting local authorities to issue an "orange alert" requiring factories to shut down or cut production and construction sites to down tools. The elderly and children have been urged to stay indoors.

The problem is far from restricted to the nation's capital. Thick smog has blanketed a 530,000 square kilometre area in northern China - the equivalent of 32 Beijings and more than twice the size of Victoria. And it comes just weeks after AQI readings hit a record 1200 in Shenyang, after central heating was turned on for winter in the north-eastern city.

China's toxic air pollution is the most visible catalyst of the country's evolution from a relative climate change laggard to a major force agitating for global action in Paris; for decades, cheap coal-fired power had propelled its staggering economic growth, but at devastating environmental cost.

Mr Xi is the first Chinese president to personally attend a United Nations annual international climate change conference, and has made historic joint pledges with US President Barack Obama and French President Francois Hollande in the lead-up.

A new report released by the Ministry of Science and Technology, involving 550 environmental experts, warns of the devastating consequences from global warming for China, from rising seas in its east to melting Himalayan snowcaps on its western frontier and shifting snow and rainfall patterns in the north.

The 900-page study, "The Third National Climate Change Assessment Report", says rising temperatures will cause erratic rainfall patterns, straining the Three Gorges Dam and causing both longer droughts in dry seasons and more intense floods in wet seasons.

Despite the political will behind reaching a global accord, Chinese negotiators will not agree to shouldering a disproportionate burden. While China's longstanding position that it is a developing nation with low per capita income remains, the report recognises that as the world's leading polluter by far, China faces immense international pressure to further commit to curb greenhouse gas emissions.

"There is an unavoidable trend for all countries to participate in emissions cuts, and for the major developing countries to shoulder larger emissions-reduction responsibilities," the report said. "China must fully prepare for this."

China's chief negotiator Su Wei said on Sunday that "international cooperation" was needed to reach an agreement by the conference's conclusion on December 11.

"Time is quite pressing, we will make every minute and second count," he told the official news agency Xinhua.

In Beijing, the only factor preventing the first-ever "red alert" – which will force half the city's cars off the roads – are weather forecasts predicting a cold front that will generate winds to blow away the fine polluting particles, known as PM2.5, on Wednesday.

Greenpeace China's climate and energy director, Dong Liansai, said while some 80 per cent of Chinese cities failed to meet their own air quality standards (which are laxer than the WHO's), the introduction of tougher environmental measures and greater transparency in air quality monitoring had seen some early signs of improvement.

"In the first three quarters of 2015, PM2.5 intensity dropped 12 per cent compared to the same period last year," he said. "But people in 80 per cent of cities still live under air pollution and everyday they breathe in air which is harmful to their health."

with Sanghee Liu