zhengzhou flood
© Reuters
An aerial view shows a flooded road following heavy rainfall in Zhengzhou, Henan province, last month. A UN report warned that climate change will lead to more intense rainfall and flooding in many parts of the world.
Global temperatures are expected to increase by 1.5 degrees Celsius or more in the next two decades from pre-industrial levels unless "immediate, rapid and large-scale" reductions in greenhouse gases are achieved, climate experts have warned.

Failure to stem the rot could render the goal of limiting global warming to 1.5 degrees by the next decades "beyond reach," the Intergovernmental Panel on Climate Change (IPCC), a United Nations body, said in a report on Monday. Human activities have raised temperatures by 1.1 degrees since 1850. The Paris climate agreement of 2015 seeks to limit the threshold of 1.5 to 2 degrees by 2100.

"Climate change is already affecting every region on Earth, in multiple ways," Panmao Zhai, co-chair of the IPCC Working Group, said in a statement. "The changes we experience will increase with additional warming."

Even if strong and sustained carbon emission reduction is achieved, it will take two to three decades for global temperatures to stabilise, and some of the impacts - such as an increase in sea level - will not be reversed for hundreds or maybe thousands of years, the report said.

The warning comes close on the heels of extreme rainfall recorded in some cities in Henan province in central China last month, where the provincial capital Zhengzhou recorded more rain over three days than what it normally receives in a year. The disaster caused 302 deaths - including 292 in Zhengzhou - and over 114 billion yuan (US$17.6 billion) of direct economic losses.


An ongoing heatwave and wildfires in Greece and Turkey has forced thousands of residents to flee their homes.

It is not too late to try to reverse climate change, Valerie Masson-Delmotte, co-chair of the IPCC's working group, told a press conference on Monday.

If immediate efforts are brought in for carbon emission to fall rapidly and substantially so that net zero emission is achieved by 2050, global warming can be limited to close to 1.5 degrees by mid-century and remain slightly lower than that level by the end of the century, she said.

The IPCC report provides new estimates of the chances of crossing the global warming level of 1.5 degrees in the next decades. Unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to close to 1.5 or even 2 degrees "will be beyond reach," it added.

The report, titled Climate Change 2021: the Physical Science Basis, was approved on Friday by the 195-member governments of the IPCC. It comes three months ahead of the next major global climate negotiation that will take place in Glasgow in November.

It is the IPCC's sixth report on climate change, which for the first time provides a more detailed regional assessment of climate change to facilitate risk assessment, mitigation and adaptation decisions. The previous report was published in 2014.

The report projects that climate change will bring more intense rainfall and flooding, and more intense drought in many regions. Coastal regions will see continued rise in sea levels throughout this century, contributing to more frequent and severe flooding in low-lying areas.

"Extreme sea level events that previously occurred once in 100 years could happen every year by the end of this century," the report said.

In East Asia, which includes China, the Korea peninsula and Japan, the experts have "high confidence" that heavy precipitation will increase in frequency and intensity, resulting in more frequent landslides in some mountainous areas.

They have "medium confidence" that droughts have become more frequent in much of the region, while the rate of intensification and the number of strong tropical cyclones have increased.

The global economy could be 11 to 14 per cent smaller by 2050 if the Paris Agreement commitments are not met, with global temperatures rising 2 to 2.6 degrees from pre-industrial levels, according to a study by reinsurer Swiss Re in April.

Asia is among the least climate-resilient regions because of its poor capacity to adapt and the risk of heatwave-induced economic losses, it noted.

Chan Wai-shin, head of HSBC's Climate Change Centre of Excellence and global head of ESG research, said investors must use their influence to push decision makers to make the bold emission reductions required to limit the most severe consequences of climate change.

"Humans have been implicated in the changes we have seen in the climate; there is still a chance for redemption but the window of opportunity is rapidly closing," he said.