In my work as the British consul-general in Guangzhou, I am involved with a broad range of issues. But none is more important, in terms of the potential impact on our way of life and prosperity, than climate change. This is certainly the greatest existential challenge that the United Kingdom shares with China, especially the southern region of China.

The impacts can seem distant. But the need to act is real, urgent and relevant - particularly for us in the Pearl River Delta region.

China has set itself an ambitious target to tackle greenhouse gas emissions, with a peak date of 2030. The governments of Guangdong, Jiangxi, Hunan, Fujian, and Hainan provinces and the Guangxi Zhuang autonomous region are all working on their agenda for the 13th Five-Year Plan (2016-20) to accelerate China's low-carbon development.

A deal must be reached if we are to achieve our target of limiting global warming to an increase of no more than 2 degrees Celsius on historic levels.

At the same time, the risks of climate change are not always well articulated. But they are stark: even if the temperature increases by just 2°C, whole swathes of the PRD could be under water by 2100.

The generally accepted measure of sea level rise is 2.3 meters per 1°C increase in temperature. But a 5-meter rise in sea levels will submerge large parts of Guangzhou.

Rising sea levels not only bring flooding, but also increased coastal erosion and saltwater intrusion. The latter could be catastrophic for China, a country which is home to 21 percent of the world's population but only 6 percent of its freshwater supplies. Salt water will move into freshwater aquifers and contaminate drinking water sources. This will compound the existing problem of groundwater pollution from manufacturing, agricultural and industrial processes, and poorly treated sewage.