Tackle climate change and biodiversity loss together, say UN scientists in new report

More sustainable agricultural practices such as planting a diversity of crops instead of just one should be encouraged.
More sustainable agricultural practices such as planting a diversity of crops instead of just one should be encouraged.PHOTO: AFP

SINGAPORE - The climate crisis and the extinction plague sweeping the natural world have been dealt with as separate issues for decades.

But in a new report published on Thursday night (June 10) Singapore time, scientists are calling on governments to tackle the climate and biodiversity crises together.

This can be done, where possible, through the implementation of strategies that are win-win for both the global climate and local biodiversity - instead of solutions that may benefit one at the expense of the other, the report said.

Reforestation projects done in large areas with only a single tree species grown for fuel (such as oil palm), for instance, could affect the abundance of wildlife species at a site, since different animals require different plants for food.

Exotic monoculture species could also become invasive, outcompeting native flora that animals there rely upon.

Instead, more sustainable agricultural practices should be encouraged, say the authors of the new report. They include measures such as planting a diversity of crops instead of just one, for instance.

The report was delivered by 50 scientists from the United Nations' climate science and biodiversity panels following a four-day virtual workshop on ways of slowing down climate change and biodiversity loss.

The workshop and resulting report also mark the first collaboration between the Intergovernmental Panel on Climate Change (IPCC) and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).

Intertwined problems

At the launch of the report, the scientists said both the climate and biodiversity problems are driven by mankind, and are mutually reinforcing.

"Human-caused climate change is increasingly threatening nature and its contributions to people... The warmer the world gets, the less food, drinking water and other key contributions nature can make to our lives in many regions" said Professor Hans-Otto Portner, co-chair of the scientific steering committee that led the workshop.

The Amazon rainforest, valued for its rich biodiversity, has a profound impact on rainfall.

A 2018 paper in the journal Science Advances noted that the Amazon generates about half of its own rainfall by recycling moisture five to six times through evaporation and transpiration, as air moves from the Atlantic Ocean across the forest basin to the west. But deforestation could cause the cycle to degrade to the point of being unable to support rainforest ecosystems.

"Changes in biodiversity, in turn, affect climate, especially through impacts on nitrogen, carbon and water cycles," Prof Portner said.

A research team from Stanford University had in 2017 found that places where animals are most diverse correlate with places that have the most carbon locked up in the soil.

Animals contribute to the carbon cycle when they eat, breathe and decompose.

This is also the case underwater. When whales die and their carcasses sink out of the water column, they take carbon to depths where it cannot de-gas out into the atmosphere.

The report also highlighted the importance of halting the loss and degradation of carbon- and species-rich ecosystems on land and in the ocean - especially forests, wetlands, peatlands, mangroves, and seagrass meadows, among other habitats.

But the researchers also warned that banking on these nature-based solutions is just one part of the equation - conservation must also be accompanied by rapid cuts to fossil fuel use.

"Land and ocean are already doing a lot -absorbing almost 50 per cent of carbon dioxide from human emissions - but nature cannot do everything," said IPBES chair Ana Maria Hernandez Salgar.

She added: "Transformative change in all parts of society and our economy is needed to stabilise our climate, stop biodiversity loss and chart a path to the sustainable future we want."

Nature-based solutions have been increasingly discussed in Singapore, with the country announcing in May that it will be setting up Climate Impact X, a global exchange and marketplace where carbon credits can be bought and sold.

A source of such credits are projects in the region that restore natural habitats or prevent them from being cut down, so they can be left to stand to do what they do best: suck in planet-warming CO2.

Trade-offs

But the new IPCC-IPBES report cautioned that nature-based solutions used as carbon offsets are most effective when applied "subject to strict conditions and exclusions", and not used to delay mitigation actions in other sectors.

Such standards could include biodiversity requirements or safeguards, rather than climate mitigation targets alone, the authors recommended.

National University of Singapore (NUS) conservation scientist Koh Lian Pin said a biologically diverse forest ensures that the ecosystem continues to provide mankind with service such as carbon storage and sequestration - critical for climate change mitigation.

"In this way, policies to address biodiversity loss and climate change are inherently aligned and synergistic," said Prof Koh, who helms the new Centre for Nature-based Climate Solutions at NUS. "These policies should be developed with both considerations in mind."

Other solutions where biodiversity conservation and climate solutions could seem at odds with each other include the placement of solar panels.

These panels can harness sunshine to power electronic systems, reducing the need to burn fossil fuels.

But floating solar panels could impact a water body's physical, chemical and biological properties, "which should be considered when assessing their sustainability", said the authors of the latest report.

Singapore is pioneering such floating solar systems on its reservoirs and sea spaces, and environmental studies are being done to determine the impact.

Prof Portner said that solving some of the "strong and apparently unavoidable trade-offs" between climate and biodiversity will entail a profound collective shift of individual and shared values concerning nature.

"These include moving away from the conception of economic progress based solely on gross domestic product growth, to one that balances human development with multiple values of nature for a good quality of life, while not overshooting biophysical and social limits," he said.