Nature-based solutions key in tackling climate change: Expert

She almost did not make it to this year's Singapore International Water Week (SIWW 2022).

Last week, the house of Dr Debra Roberts, co-chair of a working group under the United Nations' top climate science body, was flooded when violent storms battered Durban, South Africa.

Ankle-deep floodwaters reached her house, and the water supply plunged as the aqueduct was broken. The floods and mudslides killed more than 440 people, leaving thousands homeless and houses and infrastructure in ruins.

"This is part of the new normal that a city like mine is going to have to deal with," said Dr Roberts in her keynote speech on Monday at SIWW on how climate change is affecting water systems.

Scientists believe the south-eastern coast of Africa is becoming more vulnerable to violent storms and floods as greenhouse gases are warming the Indian Ocean.

Dr Roberts, 61, co-chairs the Intergovernmental Panel on Climate Change's (IPCC) Working Group 2, which released its major report in February. She highlighted the sobering implications that rising temperatures, sea-level rise and other indicators will have.

"Our report shows very clearly that two-thirds of all adaptation is in response to water-related hazards," she said. Adaptation refers to implementing ways to reduce climate risks, such as building seawalls to keep out rising sea levels.

In an interview with The Straits Times yesterday on the sidelines of SIWW 2022, Dr Roberts noted that nature-based solutions play a key role in managing water-related impacts. For example, restoring floodplains and wetlands can help to reduce flood risks, as wetlands enable more natural water retention. Restoring mangroves will help mitigate climate change impacts with their ability to soak up planet-warming carbon dioxide.

But nature-based solutions will start to fall off the table as the temperature increases beyond the 1.5 deg C threshold, she warned.

Limiting warming to 1.5 deg C above pre-industrial levels is a key goal of the 2015 Paris climate agreement.

"By the time we reach global warming levels of 1.5 deg C, we will probably experience irreversible losses of warm water coral reefs and coastal wetlands, so they won't be able to play that (adaptation) role," she noted.

Moreover, poor planning can cause adaptation measures to backfire and spark other environmental issues, she warned. For example, sea walls at some coastal sites can cause coastal erosion further down the coastline.

She also emphasised that science and technology, and the knowledge of indigenous people should be brought together to tackle the climate crisis since those local communities know their land well.

Dr Roberts recounted how an Inuit hunter from Canada had noticed that an ice sheet was about to break off. However, satellite images did not spot anything wrong with the glacial ice.

"But that ice sheet broke away. It's that combination of (having) people who understand their environment from the soles of their feet, (and using) sophisticated technology. That brings us to our best state of knowledge of the world."

She said putting together the just over 3,000-page Working Group 2 report was no small feat, with 270 scientists labouring over it for five years. It is the second of three that collectively make up the IPCC's sixth assessment report.

Dr Roberts hopes the three reports will communicate the urgency of finding different ways to make deep cuts in emissions, and raise climate justice and equity.

SIWW 2022 is being held at the Sands Expo and Convention Centre until tomorrow.