16/10/2020

Restoring Farmland Could Drastically Slow Extinctions, Fight Climate Change

New York Times - Catrin Einhorn

Returning strategic parts of the world’s farmlands to nature could help mitigate both climate change and biodiversity loss, a new study found.

A red-fronted brown lemur in the Kirindy forest reserve near Morondava, Madagascar. Scientists said that restoring a portion of agricultural land to a wild state would not only help reduce extinctions but aid in the fight against global warming. Credit...Baz Ratner/Reuters



The twin crises of climate change and biodiversity loss are intertwined: Storms and wildfires are worsening while as many as one million species are at risk of extinction.

The solutions are not small or easy, but they exist, scientists say.

A global road map, published Wednesday in Nature, identifies a path to soaking up almost half of the carbon dioxide that has built up since the Industrial Revolution and averting more than 70 percent of the predicted animal and plant extinctions on land.

The key? Returning a strategic 30 percent of the world’s farmlands to nature.

It could be done, the researchers found, while preserving an abundant food supply for people and while also staying within the time scale to keep global temperatures from rising past 2 degrees Celsius, the upper target of the Paris Agreement.

“It’s one of the most cost effective ways of combating climate change,” said Bernardo B.N. Strassburg, one of the study’s authors and an environmental scientist with Pontifical Catholic University of Rio de Janeiro and the International Institute for Sustainability. “And it’s one of the most important ways of avoiding global extinctions.”

The researchers used a map from the European Space Agency that breaks down the surface of the planet into a grid of parcels classified by ecosystem: forests, wetlands, shrub lands, grasslands and arid regions.

Using an algorithm they developed, the scientists evaluated which swaths, if returned to their natural states, would yield the highest returns for mitigating climate change and biodiversity loss at the lowest cost.

It was not enough simply to lay one result on top of the other. “If you really want to optimize for all three things at the same time,” Dr. Strassburg said, “that leads to a different map.”

A similar and complementary tool, The Global Safety Net, was released last month. It identifies the most strategic 50 percent of the planet to protect, filtering for rare species, high biodiversity, large mammal landscapes, intact wilderness and climate stabilization.

A growing number of campaigns seek to address the world’s environmental emergency by conserving or restoring vast swaths of the planet. The Bonn Challenge aims to restore 350 million hectares by 2030. The Campaign for Nature is pushing leaders to protect 30 percent of the planet by 2030.

Credit...Wahyudi/Agence France-Presse — Getty Images


In the latest study, the scientists found that benefits rise and fall depending on how much land is restored.

Relinquishing 15 percent of strategic farmlands, for example, could spare 60 percent of extinctions and sequester about 30 percent of the built up carbon in the atmosphere.

The authors estimate that at the global level, 55 percent of farmland could be returned to nature while maintaining current levels of food production by using existing agricultural land more effectively and sustainably.

“It’s really impressive,” said J. Leighton Reid, a specialist in ecological restoration at Virginia Tech who was not involved in the study. “The authors do a good job of acknowledging some of the limitations of the work at the same time as they’re proposing this big vision.”

The biggest challenges appear to be political will and finding the money to pay farmers to restore so much land to nature. But the authors point to the hundreds of billions or trillions of dollars per year that subsidize fossil fuels and unsustainable farming practices.

“There’s a lot of money available for investment,” said Robin Chazdon, a longtime biologist with the University of Connecticut and one of the study’s authors. “The world is invested in destruction.”

The study was requested by the United Nations Convention on Biological Diversity, a global treaty that aims to preserve biodiversity. One of the authors, David Cooper, is its deputy executive secretary.

A recent report by the convention showed that world leaders had failed to meet their last round of targets. The United States is the only state in the world, with the exception of the Vatican, that has not signed the treaty.

The study will be used to help inform global commitments at the United Nations biodiversity and climate conventions next year. But because the new study highlights nature’s disregard for national borders, it presents a diplomatic challenge.

“This lays out the much higher benefits overall if you ignore the country boundaries and just look at where these priorities are,” said Dr. Chazdon.

The most strategic places are distributed very unevenly; tropical forests and wetlands, for example, hold outsized potential for carbon storage and biodiversity protection.

“Do we say, ‘We’re just going to forego all those benefits and be provincial about this?’” she asked. “Or are there ways to cooperate internationally?”

The authors note that the conservation of existing wilderness remains the most important way to protect biodiversity, and see their proposed restoration as a critical addition.

Other essential steps Dr. Strassburg listed: Stopping the use of fossil fuels; reducing food, energy and plastic waste; and making sustainable choices when buying things like food, cars and clothes.

“Once consumers start changing their patterns,” he said, “companies react really quickly.”

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Rewild To Mitigate The Climate Crisis, Urge Leading Scientists

The Guardian - 

Restoring degraded natural lands highly effective for carbon storage and avoiding species extinctions

Scientists note the importance of appropriate nature restoration to enhance biodiversity and beat climate change. In the Flow Country, Scotland, above, restoration of the blanket bog, a vast natural carbon sink, involves removing forestry plantations. Photograph: Murdo MacLeod/The Guardian


Restoring natural landscapes damaged by human exploitation can be one of the most effective and cheapest ways to combat the climate crisis while also boosting dwindling wildlife populations, a scientific study finds.

If a third of the planet’s most degraded areas were restored, and protection was thrown around areas still in good condition, that would store carbon equating to half of all human caused greenhouse gas emissions since the industrial revolution.

The changes would prevent about 70% of predicted species extinctions, according to the research, which is published in the journal Nature.

Scientists from Brazil, Australia and Europe identified scores of places around the world where such interventions would be most effective, from tropical forests to coastal wetlands and upland peat. Many of them were in developing countries, but there were hotspots on every continent.

“We were surprised by the magnitude of what we found – the huge difference that restoration can make,” said Bernardo Strassburg, of the Pontifical Catholic University of Rio de Janeiro, and the lead author of the study. “Most of the priority areas are concentrated in developing countries, which can be a challenge but also means they are often more cost-effective to restore.”

Only about 1% of the finance devoted to the global climate crisis goes to nature restoration, but the study found that such “nature-based solutions” were among the cheapest ways of absorbing and storing carbon dioxide from the atmosphere, the additional benefits being the protection of wildlife.

Rhinoceros hornbill, an inhabitant of Malaysia’s biologically rich 130m-year-old Belum Temengor forest – which benefits from protection but is also subject to human interference, such as lake creation. Photograph: Fazry Ismail/EPA

Restoring nature did not have to be at the expense of agriculture and food production, Strassburg said. “If restoration is not properly planned it could lead to a risk to agriculture and the food sector, but if done properly it can increase agricultural productivity. We can produce enough food for the world and restore 55% of our current farmland, with sustainable intensification of farming.”

The study also says that planting trees, the “nature-based solution” that has received most support to date, is not always an appropriate way of preserving biodiversity and storing carbon. Peatlands, wetlands and savannahs also provide habitats for a wealth of unique species, and can store vast amounts of carbon when well looked after.

Strassburg said: “If you plant trees in areas where forests did not previously exist it will mitigate climate change but at the expense of biodiversity.”

Nathalie Pettorelli, a senior research fellow at the Zoological Society of London, who was not involved in the research, said: “This paper provides further scientific evidence that ecological restoration is a sensible and financially viable solution to address the global climate and biodiversity crises. How ecosystems will be restored is however as important as where and how much will be restored. Ensuring that the best science is used to make decisions about how to restore each local ecosystem will be key.”

Three-quarters of all vegetated land on the planet now bears a human imprint. But some scientists have a target of restoring 15% of ecosytems around the world.

Alexander Lees, senior lecturer in biodiversity at Manchester Metropolitan University, who was also not involved with the study, said: “[This] analysis indicates that we can take massive strides towards mitigating the loss of species and increasing atmospheric carbon dioxide by restoring just 15% of converted lands. The global community needs to commit to this pact to give back to nature post-haste – it’s the deal of the century, and like most good deals available for a limited time only.”

The study focused on land, but the oceans also offer vast benefits linked to biodiversity and opportunities for absorbing carbon dioxide and mitigating climate change, said Richard Unsworth, senior lecturer in marine biology at Swansea University, and director of Project Seagrass, which restores vital marine habitats.

Unsworth said: “Marine habitat restoration is also vital for our planet and arguably more urgent given the rapid degradation and loss of marine ecosystems. We need restored ocean habitats such as seagrass and oysters to help promote biodiversity but also to help secure future food supply through fisheries, and lock up carbon from our atmosphere.”

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(AU) 'There Is No Time To Lose': Great Barrier Reef Has Lost Half Its Corals

Sydney Morning Herald - Miki Perkins

The Great Barrier Reef has lost half its corals, with a decline in the number of shallow and deep water corals across almost all species in the past two decades.

The decrease was most marked in branching and table-shaped corals, which were the worst affected by record-breaking temperatures that triggered mass bleaching in 2016 and 2017. The study was completed before another mass coral bleaching event this year, which has probably exacerbated the decline.

The number of small, medium and large corals dropped more than 50 per cent between 1996 and 2017, researchers from the Townsville-based ARC Centre of Excellence for Coral Reef Studies, who assessed coral communities and their colony size, have said.

Half of the Great Barrier Reef's corals have been lost. Credit: Tony Chase


These surveys also showed fewer baby coral and large breeding corals, lead researcher Dr Andy Dietzel and co-author Professor Terry Hughes said in a study published in Proceedings of the Royal Society on Wednesday.
There is no time to lose - we must sharply decrease greenhouse gas emissions ASAP
Study authors
“The loss of big corals is important because they make all the babies - they’re responsible for a huge proportion of the breeding that’s done every year by adult corals,” Professor Hughes said.

The climate crisis has driven marine heatwaves, with the research recording steeper deterioration of coral colonies in the northern and central Great Barrier Reef after mass coral bleaching in 2016 and 2017.

Dead coral at the Great Barrier Reef. Credit: Tony Chase

The southern part of the reef was also exposed to record-breaking temperatures and extensive bleaching in early 2020 (this data was not included in the study).

Corals rely on algae known as zooxanthellae to provide the bulk of their energy and much of their vibrant colour. When exposed to sustained abnormal heat - measured in so-called degree-heating days - corals begin to expel the algae, leading to mass bleaching.

Branching and table-shaped corals provide shelter and habitat for reef inhabitants such as fish, and their loss reduces fish abundance and the productivity of coral reef fisheries.

Bleaching on the Great Barrier Reef corals near Cooktown in March 2020. Credit: Via Terry Hughes

“These types of corals are three-dimensional - they make the nooks and crannies that are essential for the biodiversity of the coral reef,” Professor Hughes said.

Better data on the demographic trends of corals is needed to understand how their populations are changing, the researchers found.

“We used to think the Great Barrier Reef is protected by its sheer size—but our results show that even the world’s largest and relatively well-protected reef system is increasingly compromised and in decline,” Professor Hughes said.

The authors are concerned about the shrinking gap between bleaching events because there is little opportunity for corals to rebound.

“There is no time to lose - we must sharply decrease greenhouse gas emissions ASAP,” the research paper states.

Global temperature increases would need to stabilise between 1.5 and two degrees for the reef to remain, even if it was quite different to what exists now, Professor Hughes said. “If it’s three or four degrees then forget about it.”

This year, February had the highest monthly sea surface temperatures ever recorded on the Great Barrier Reef since the Bureau of Meteorology’s records began in 1900.

The warming ocean is affecting reefs worldwide, including off the coast of Brazil, in parts of Melanesia and Indonesia.

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