European Commission Joint Research Centre
The complex network of interdependencies between plants and animals multiplies the species at risk of extinction due to environmental change, according to a JRC study.
In the case of global warming, predictions that fail to take into account this cascading effect might underestimate extinctions by up to 10 times.
As an obvious, direct consequence of climate change, plants and animals living in a given area are driven to extinction when the local environmental conditions become incompatible with their tolerance limits, just like fish in an aquarium with a broken thermostat.
However, there are many elusive drivers of species loss that go beyond the direct effects of environmental change (and human activity) which we still struggle to understand.
In particular, it is becoming clearer that co-extinctions (the disappearance of consumers following the depletion of their resources) could be a major culprit in the ongoing biodiversity crisis.
While the concept of co-extinction is supported by a sound and robust theoretical background, it is often overlooked in empirical research because it’s extremely difficult to assess.
New JRC Study on Co-Extinctions
A new study led by the JRC took on this challenge in order to determine the importance of co-extinctions in conditions of environmental change.
JRC scientist Giovanni Strona, in collaboration with Professor Corey Bradshaw from Flinders University in Adelaide, Australia, constructed 2000 “Virtual Earths”, which they populated with thousands of plants and animals organized into a global system of inter-connected food-webs.
They then subjected the virtual Earths to extreme trajectories of environmental change, consisting in either a “global warming”, i.e. a linear, monotonic increase in temperature, or a “nuclear winter”, i.e. a progressive cooling, such as that which could follow multiple nuclear detonations or an asteroid impact.
They then tracked the loss of species diversity within two separate scenarios up to complete life annihilation.
In the first scenario, they only accounted for the extinction of a species when the temperature became too high or too low for that species to tolerate.
In the second scenario, starting from the extinctions triggered by the mismatch between local temperature and species tolerance limits, they also simulated co-extinction cascades.
By comparing the two scenarios, the scientists were able to provide a quantitative estimate of the relative importance of co-extinctions in planetary biodiversity loss.
They found that failing to account for interdependencies between species led to underestimation of the magnitude of mass extinctions triggered by climate change by up to 10 times.
Giovanni reflects that “conservationists and decision makers need to move fast beyond a species-specific approach, and look with increasing attention at species interaction networks as a fundamental conservation target. Whenever a species leaves our planet, we lose much more than a name on a list”.
Global Warming: IPCC Special Report on Global Warming of 1.5°C confirms the utmost urgency to act
The study also explored the worst possible scenario of temperature change due to global warming.
According to the simulations, 5-6°C of warming would be enough to wipe out most life on the virtual Earths the scientists created.
Giovanni recognises that “there are obvious limitations in our ambitious model, due to the multiple challenges of building realistic global ecological systems.
On the one hand, our results are consistent with real-world patterns for which we have empirical evidence.
This make us confident that the many assumptions we had to take in order to build a functional model are sound. On the other hand, however, it would be misleading to just focus on raw numbers.”
What is clear is that a warming Earth will put increasing pressure on the planet’s biodiversity, and co-extinctions will add to that impact.
While it is unlikely that the Earth will become 5-6°C warmer in the near future, it is quite likely that global temperatures will continue to increase.
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Read the full Scientific Report in Nature: Co-extinctions annihilate planetary life during extreme environmental change https://doi.org/10.1038/s41598-018-35068-1
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We have never seen a bird or a mammal go extinct in the modern era (last 500 years) from temperature changes or “environmental change”. Not one.
Given that, these predictions are a joke.
See my post entitled “Where Are The Corpses” for a full discussion of this issue.
w.
Two out of three species of inicilus toads agree!
https://wattsupwiththat.com/2017/06/whats-the-recovery-rate-from-extinction/
😉
The Rocky Mountain Locust is a strong candidate for extinction through “environmental change” in the form of agriculture. I agree that there have been no known extinctions through non-human environmental changes during this interglacial.
Willis,
In the case of the passenger pigeon, it was a combination of environmental change, ie the loss of eastern US hardwood forest habitat, and overhunting.
A similar combination led to the extinction of the Carolina parakeet.
The ivory-billed woodpecker, which might or might not be extinct, has also been driven to the brink by habitat loss.
In Europe, the wild ox, aurochs, went extinct in 1627 from previously unrestricted hunting, habitat reduction due to the spread of farming and diseases transmitted by domesticated cattle.
A couple of thoughts:
Since we live in a glacial period with extremely unstable climate every extant species (except a very few plants of recent hybrid origin) has already survived multiple climatic changes of their supposed ”extinction size”, or worse.
The only reasonably well investigated case of a rapid extreme warming (PETM) was also an interval of extreme (unprecedented?) diversity increase (and very limited extinction). For example most major mammal groups first occur during PETM.
During most of the time multicellular life has existed on Earth climate has been much warmer than now.
The last (fairly) major extinction (the “Grande Coupure” at the Eocene/Oligocene border) was coincident with the shift from a hothouse to an icehouse climate and the inception of major glaciation.
Yup, mammalian diversity spiked with heat at the PETM, during which the planet warmed rapidly from an already much warmer climate than now. Some 55.5 Ma, global temperatures rose by about six (5-8) degrees C in less than a thousand years.
Mammals extending their ranges into higher latitudes helps explain some of the increased diversity. Among the orders which benefitted from the PETM were the primates, the earliest true members of which date from the Late Paleocene.
“constructed 2000 “Virtual Earths”, which they populated with thousands of plants and animals organized into a global system of inter-connected food-webs.”
Wow, I am completely impressed. These people not only fully understand the intricacies and complete biology and pathophysiology of all life on earth but they fully understand the complete workings of the earth as it is now and how it is affected by the 8 other major and minor planets in our solar system along with the moon, the asteroid belt and the sun. I have to say that I have been spending my time in the wrong church on the weekends. The hubris of these people knows no bounds.
So more “modelled” buffoonery chasing P1 scenarios. Would the more real Medieval warm period be a better REAL starting place?
Given that so much plant and animal life already copes with temperature changes exceeding 5C on a seasonal or daily basis, the claim that 5-6C warming over many decades would wipe out “most life” on their virtual planets is difficult to take seriously as a newly discovered truth.
Where have I heard this before?
Oh, I remember. CO2 greenhouse effect will be about 0.5 degrees. But that bump will cause FORCINGS that raise temperatures another 3.0 degrees.
So they have discovered biological “forcings.” A very tenuous theory.
I know it won’t make those chair-dwelling computer geek labrats happy, but I’m going to make a forecast, so here it is.
1 – Since there is ice on the Moon (south pole) there will be primitive unicellular organisms found there, once we get started building stuff up there. There will be a zoo for them, completely set up for their needs.
2 – Iapetus, Callisto and several other large-ish satellites orbiting Jupiter and Saturn will also be found to harbor primitive unicellular life forms, which will have to have their own habitats fenced off so that ski lodges and ice climber chateaus will not disturb them. Titan will become a mecca for Bespin gas miners.
3 – Since water ice has been confirmed on Mars (as R. Heinlein predicted in Red Planet), more primitive unicellular life forms and some tardigrade relatives will be found in deep underground caves, having parties and wondering if they should challenge human occupation of their planet. Also, the Martina Olympics will include speed skating on the canals, once they’re built, and the 10-spin Axel will be a requirement to even be considered as part of the skating team. The quad toe loop will be SO dated, and replaced by the 50-spin toe loop, with height records set at every competition. Willis will announce the results.
4 – Not neglecting Pluto, either: Chthulhu Station will be built on a floating platform that takes into account the constant resurfacing of that ice field, and more advanced, but still primitive, lifeforms will be voted in as members of the United Planets Union Reserved Status (UPURS). Mother Thing will announce the honors at the next meeting of Concerned Galactic Citizens. Kip and Peewee will be presented as UPURS representatives until they have to go back to school in the fall.
5 – Sedna will be found and turned into an orbiting library, with a 3-D projected librarian who looks suspiciously like John de Lancie.
Three Galaxies – One Law!!
Ringworld has not been found yet.
Sara,
Much as I admire Heinlein, his 1947 and ’49 Mars books describe hypothetical canals, not ice as it’s now known to exist on the Red Planet.
The “hypothetical” canals froze in the cold season and were used for transportation in ‘Red Planet’. Jim and Frank skated on them when they left the school where the Headmaster had illegally tried to put all students under a form of house arrest, and tried to steal Willis.
Terraforming is something that will happen on Mars, once a bases is established there, so why not created canals and use them for transport?
In the past, ten degrees warmer than now has been optimum, but 5-6 degrees C would be better for life on Earth than our present 14 to 15 degrees.
http://www.geocraft.com/WVFossils/PageMill_Images/image277.gif
Too bad that even one degree more of warming is highly unlikely to happen before the next glacial advance.
These idiots are on the verge of thinking a “nuclear winter” will solve everything.
You heard it here first.