From Madagascar to the Amazon, warming could threaten up to 50% of species

From Madagascar to the Amazon and even to the Great Plains, climate change could threaten between a quarter and a half of species by 2080 in 33 of the world's most biodiverse regions, according to a report Wednesday.

A + 4.5 ° C warming compared to the Industrial Revolution – horizon that would emerge if nothing was done to reduce emissions of greenhouse gases – 48% of species would be likely to disappear at the local level.

But this risk would be halved if the increase in average temperature was contained at + 2 ° C, the limit set in the Paris agreement adopted in 2015 under the auspices of the UN, notes this analysis published by the review Climatic Change.

"Global biodiversity will suffer terribly during this century, unless we do everything in our power" against this, warns the Global Fund for nature (WWF) , which co-produced the study, presented as the most complete on these thirty zones.

Everywhere, the climate is added to the threats already weighing on the fauna and the flora: urbanization, loss of habitats, poaching, unsustainable agriculture …

 From Madagascar to the Amazon and even to the Great Plains, climate change could threaten between a quarter and a half of species by 2080 in 33 of the world's most rich in biodiversity, according to a report (AFP / Archives - Noah SEELAM)

From Madagascar to the Amazon and even in the American Great Plains, climate change could threaten between a quarter and half of species by 2080 in 33 regions of the world's richest in biodiversity, according to a report (AFP / Archives – Noah SEELAM)

Researchers from the universities of East Anglia (United Kingdom) and James-Cook (Australia) studied the climatic situation of 80,000 th Species in 33 regions considered "priority", as unique and diverse as the Amazon, the Namibian desert, the Himalayas, Borneo, Lake Baikal or southern Chile.

The now exceptionally warm seasons should become the norm, sometimes as early as 2030, and even with limited warming at + 2 ° C. More significant heat spikes, lower precipitation, long-lasting droughts are expected in many places.

Over these areas, more than half of the area (56%) would remain liveable at + 2 ° C. At + 4.5 ° C, this share could fall to 18%: what the WWF calls "refuge" zones.

– More mobile birds and mammals –

 The Great Barrier Reef, Australia , near the Whitsunday Islands coast, photographed on November 20, 2014 (AFP / Archives - SARAH LAI, SARAH LAI)

The Great Barrier Reef, Australia, near the Whitsunday Islands coast, photographed on November 20, 2014 (AFP / Archives – SARAH LAI, SARAH LAI)

Plants should be particularly affected, slower to adapt, moving less easily. Which in turn will harm the dependent animals.

At + 4.5 ° C, 69% of the plant species may disappear in the Amazon.

On the animal side, reptiles and amphibians are more likely to be " obsolete "than birds or mammals, more mobile."

Much will depend on the ability of species to move to follow their preferred climate: can they follow? Will they be blocked, for example by cities, mountains? Will they, on arrival, have a place to live?

Southwestern Australia, in the worst case scenario, sees close to 80% of locally endangered mammal species, a loss reduced to third in a world at + 2 ° C and in case of adaptability of species

Conclusion: "it will take much more important efforts to keep the temperature rise to their absolute minimum", insists the WWF.

At this stage, the emission reduction commitments made in Paris lead the globe towards a warming of more than 3 ° C. However, at + 3.2 ° C, 37% of the species are still at risk of disappearing locally, in the regions studied.

In addition, since the gases already emitted will continue to warm the planet, it will also be necessary to provide protective measures. local: biological corridors to promote the movement of species, identification of areas of "refuge" as a last resort, restoration of habitats …

The Mediterranean, which counts for example three species emblematic of marine tortures, would see close to one third of the plants, mammals and amphibians threatened with + 2 ° C, if no possibility of adaptation is left to them.

This publication comes as Saturday opens in Medellin (Colombia) an important conference on the state Biodiversity in the World.

Extinction does not mean just disappearance of species, says WWF, "but profound changes for ecosystems rendering vital services to hundreds of millions people, "whether it's food, but also supporting tourism or researching future drugs.

Antarctica, both victim and laboratory of global warming

" I have had the opportunity to come here for 15 years, and at the scale of a human life we ​​can already see the changes produced by global warming ", explains AFP Marcelo Leppe, director of the Chilean Institute of Antarctica (INACH). "The Collins Glacier shows rocks that we did not see five or ten years ago, and this is a direct proof of the retreat of these glaciers and the loss of mass" he continues . But if these glaciers melt visibly worried scientists around the world, the presence in Antarctic plants resistant to extreme conditions are also a source of hope for them as the planet warms up. [19659002] Significant evolutions in barely 14 years

Among the twenty or so countries with scientific bases on this icy continent, Chile has installed its own, "Professor Julio Escudero", on King George Island, where dozens of researchers are working to measure the effects of these upheavals on local flora and fauna. " We need to quantify this change to predict what can happen in the near future ," says Leppe. Precisely, the measurements made in 2017 by Chilean scientists, on the island of Doumer, showed that the temperature of the water had reached 2.5 degrees, whereas it should have been between 0 and 1.5. And at a depth of 40 meters, it still reached 2 degrees.

Melting ice in Antarctic © AFP – Nicolas RAMALLO

Algae Proliferation

This sea warming attracts new species, until then unknown in Antarctica, like the spider crab, a crab rather used to the waters of southern Chile. And it also causes a proliferation of green algae, essential for the local ecosystem, especially for crustaceans. " Algae and micro-algae are very small, albeit very small, for the balance of the food chain ," says Nelson Valdivia, professor at the Faculty of Science at the Southern University. . " They provide nutrients to the rest of the ecosystem, and we know that the amount of species in the same ecosystem is very important to maintain it in good health ," he adds.

] But in the long term, this excess of algae could unbalance the ecosystem and the great fear is to " lose species of which we do not even know the existence ". Scientists also fear the effect of these milder temperatures on the rest of the world: according to NASA observations, between 2002 and 2016, Antarctica lost 125 gigatonnes of ice a year, causing an increase in the global level of sea ​​of ​​0.35 millimeters a year. Antarctica which accounts for 62% of the world's freshwater reserves is not a trivial thaw and should help desalinize the world's seas, a fatal mechanism for many marine species. 19659002] Adapting Plants

But the white continent may also hold the key to better adapting flora and fauna to the new temperatures of the planet. Antarctic plants, which are resistant to ultraviolet radiation and extreme weather conditions, are now biotechnology tools for developing sun creams, antioxidants and natural sugars. To survive, these plants accumulate indeed sugars to feed during the harsh winter months, under the snow. Under miniature greenhouses, Marisol Pizarro, a doctor of biotechnology at the University of Santiago de Chile, studies how Antarctic plants react to an artificial increase of 1 or 2 degrees Celsius.

Marisol Pizarro, a doctor of biotechnology from the University of Santiago de Chile, studies plant responses to temperature changes on February 2, 2018 on King George Island, Antarctica (AFP – Mathilde BELLENGER).

His observation: the mosses are resistant to these new conditions, an asset that could be used for other plants in the future. " We could transfer a gene linked to drought tolerance to a common plant such as lettuce or rice, in order to give this plant the capacity to tolerate drought ," says the researcher. " Therefore, it will be less affected by adverse adverse conditions due to the decrease of water in its environment ". While Antarctica is one of the fastest-warming regions of the world, scientists are racing against the clock: Chilean scientists are currently carrying out about 100 projects, from penguin genetics to solar activity on the polar environment, including a comparison of mollusc species between this region and South America

Pesticides, warming: agriculture has found "its limits"

Whether to reduce pesticides or to combat the effects of global warming on plants, agronomic research "progresses" and "gives rise to a lot of hope", explains to AFP the President of INRA , Philippe Mauguin.

"The general approach of the National Institute of Agricultural Research", presented this week at the Agriculture Fair, "focuses on the diversity of resources within a single species" to explain how "crosses of wild varieties naturally resistant to certain diseases can genetically reinforce varieties currently used in agriculture or arboriculture," said Mauguin in an interview on Wednesday.

Because according to him, l French agriculture as it has existed since the Second World War "has found its limits".

After the war, "we had organized the choices of varietal selections with the aim of feeding the country, and we have multiplied yields by three in a few decades thanks to genetic selections, inputs and agrochemistry. "

" But we saw the limits of this system in the late 1990s, with case of water pollution, especially via the effects induced by a weed-killer, atrazine, which was finally banned in 2003 but which leaves long-lasting effects ", underlines Mr. Mauguin.

For several years, Agriculture has tried to correct the side effects of chemistry on the earth and the environment, with "reasoned" practices that limit the use of pesticides.

"But the answers were not fast enough, and we saw the limits of the plan + Ecophyto +", launched by President Sarkozy in the wake of the Grenelle Environment Forum, admits the one who was director of cabinet from the previous Minister of Agriculture Stéphane Le Foll: "a simple optimization of the use of phytosanitary products is not enough".

– Radical Change –

After stating that "farmers do not use pesticides for pleasure, but to protect their crops, "Mr. Mauguin stresses that the goal is to" change the entire agricultural production system in a radical way. "

" But it is not obvious ", recognizes -he.

He presented Tuesday the new agronomic approaches under study to Ministers Frédérique Roussel (research) and Nicolas Hulot (Ecological Transition).

The first is the increase of biocontrol, that is to say Neutralization of aggressors with their predators, usually insects. Trichogramma, for example, destroys corn borer, which attacks maize in particular

The second approach is to improve varietal selection in order to make seed varieties more resistant to diseases and thus limit the use of chemical pesticides.

INRA presents on its stand the first four vine stocks from its research, carrying genes resistant to powdery mildew and mildew, which will reduce by more than 70% the use of pesticides on the market. vine: Vidoc, Voltis, Floreal and Artaban

"In January, we included in the catalog of varieties these first four resistant grape varieties, two for red wines and two for white wines," says Mauguin. INRA is expected to release about twenty more in 2019.

This approach is developed for all species. "We accompany the seed companies for the first stage of propagation" and then they continue, explains Mr. Mauguin.

On some species the work is very long and frustrating. For lettuce, for example, "in 20 years, we have found about 30 resistant genes, but the aggressors still bypass, defend themselves and we must constantly seek new resistant genes."

On the disputed herbicide glyphosate, INRA estimates that it is able to offer alternatives "that can be complicated to set up" for 80% to 90% of use cases.

"We evaluated technical dead ends between 10% and 20%", essentially in the field of soil conservation agriculture, says Mauguin.

This type of agriculture is of great interest in the fight against global warming, since by removing plowing, it can store carbon in the soil. But it requires the use of a weed killer once a year to clean the soil before sowing, to allow the seeds to grow.