Unchecked global emissions are on track to start a mass extinction of marine life – Are you up to it?
UNIVERSITY PRINCETON
CREDIT: PICTURE OF EVAN DAVIS
As greenhouse gas emissions continue to warm the world’s oceans, marine biodiversity is likely to decline dramatically over the next few centuries, to levels before, according to a recent study in this journal. seen since the extinction of the dinosaurs, according to a recent study in this journal. Science by researchers from Princeton University.
The paper’s authors modeled future marine biodiversity under different projected climate scenarios. They found that if emissions were not curbed, the loss of species from warming and oxygen depletion alone could reflect the significant impact humans have had on marine biodiversity. around 2100. Tropical seas will experience the greatest loss of biodiversity, while polar species The authors reported the highest risk of extinction.
“Active and rapid reductions in greenhouse gas emissions are critical to avoiding the mass extinction of ocean species,” said the senior author. Curtis Deutschprofessor of geosciences and Environmental Institute High Meadows at Princeton.
However, research shows that reversing greenhouse gas emissions could reduce the risk of extinction by more than 70%. The first author said: “The silver lining is the future not written in stone. Justin Penn, a postdoctoral research associate in the Department of Geosciences. “The level of extinction we found is highly dependent on the amount of carbon dioxide [CO2] we emit to move forward. There is still enough time to change the trajectory of CO2 emissions and prevent the level of warming that could have caused this mass extinction. “
Deutsch and Penn, who initiated the study while both at the University of Washington, combined existing physiological data on marine species with climate change models to predict changes in how habitat conditions will affect the survival of marine species globally over the next few years. century. The researchers compared their model with the magnitude of past mass extinctions recorded in the fossil record, building on their earlier work linking the geographic model of the Great Extinction the late Permian race more than 250 million years ago – Earth’s deadliest extinction event – with underlying causes, namely climate warming and the loss of oxygen from the oceans.
The researchers found that their model predicts future marine biodiversity, the fossil record of the Late Permian Extinction, and indeed the distribution of species we see today. now follow a similar pattern – as ocean temperatures increase and oxygen levels decrease, the distribution of these species has decreased markedly. in the abundance of marine life.
Water temperature and oxygen availability are two key factors that will change as the climate warms due to human activity. Warmer water itself is a risk factor for species adapted to cooler climates. Warm water also holds less oxygen than cold water, resulting in slower ocean circulation, reducing the oxygen supply at depth. Paradoxically, the metabolic rates of species increase with water temperature, so the demand for oxygen increases as the supply decreases. “Once the oxygen supply falls short of the species’ needs, we see species suffer significant losses,” says Penn.
Marine animals have physiological mechanisms that enable them to cope with environmental changes, but only to an extent. The researchers found that polar species are more likely to become extinct globally if climate warming occurs because they will not have suitable habitats to migrate to. Tropical marine species will likely fare better because they have traits that allow them to cope with the warm, low-oxygen waters of the tropics. As the seas north and south of the tropics warm, these species may migrate to new suitable habitats. However, the equatorial ocean is already too warm and low in oxygen, so the extra temperatures – and the accompanying reduction in oxygen levels – could render many species locally uninhabitable.
The researchers report that the extinction pattern their model predicts – with more global extinctions of species in the poles than in the tropics – mirrors the pattern of mass extinctions in the past. A study by Deutsch and Penn published in Science in 2018 showed that a temperature-dependent increase in metabolic oxygen demand – combined with a decrease in oxygen availability due to volcanic eruptions – could explain geographic patterns of species loss during the Great Depression. species of the late Permian period, which killed 81% of marine species.
The new paper uses a similar model to show that anthropogenic warming could promote extinction of the same physiological mechanism on a comparable scale if warming is large enough, Penn said. . “The latitudinal patterns in the fossil record show traces of extinction predicted to be due to changes in temperature and oxygen,” he said.
The model also helps to solve an ongoing puzzle in the geographic modeling of marine biodiversity. Marine biodiversity increases steadily from the poles towards the tropics, but decreases gradually at the equator. This equatorial drop has long been a mystery – researchers aren’t sure what causes it, and some even wonder if it’s real. Deutsch and Penn’s model offers a plausible explanation for the decline in equatorial marine biodiversity – oxygen supplies in these warm waters are too low for some species to tolerate.
The big concern, says Penn, is that climate change will make similarly large seas uninhabitable. To quantify the relative importance of climate in driving extinctions, he and Deutsch compared future risks of extinction from climate warming with data from the National Union for Conservation of Nature. (IUCN) on current threats to various marine species. They found that climate change currently affects 45 percent of endangered marine species, but is only the fifth most important stressor after overfishing, transportation, urban development and pollution.
However, says Penn, climate change could soon overshadow all of these stressors: “Excessive warming will lead to a climate-driven extinction that, near the end of this century, will rival equal to all current human stressors combined.”
The article, “Avoiding Climate-Holled Ocean Extinction,” was published April 29 in the journal Science. The work was supported by grants from the National Science Foundation (OCE-1737282), the National Oceanic and Atmospheric Administration (NA18NOS4780167), the California Council of Oceans and SeaGrants, and the National Oceanic and Atmospheric Administration (NA18NOS4780167). UW Program on Climate Change.
JOURNEYS
Science
DOI
RESEARCH METHODS
Simulation / computational modeling
RESEARCH SUBJECTS
Animals
ARTICLE TITLE
Avoid ocean extinction due to climate warming
ARTICLE PUBLICATION DATE
April 29, 2022
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And this is Rud’s.
Ridiculous New Alarm — Climate Caused Mass Extinctions in the Oceans!!
Rud Istvan
I was reading the e-news today and discovered a summary on Google News of a WaPo piece lamenting a new article today (April 28, 2022) in the journal Science, “Avoidance climate-warming ocean mass extinction” by two Princeton researchers. This post consists of three parts: what WaPo reported, a summary of what the report said (the rest is a wall of fees), and what SI shows is happening.
WaPo
“A third of all marine animals will be extinct in 300 years, new research suggests.” (Horror…)
“New biological and climate models have been tested by simulating the Permian extinction.” (So they must be right.)
“Climate models predict species behavior (such as extinction) based on simulated organism types.” (Definitely climate models of simulated organisms.)
Abstract paper
“Global warming threatens marine life with losses of unknown magnitude. Here, we identify global and local extinctions in the ocean across a range of climate futures on the basis of the ecological limits of diverse animal species and correcting for chemical profiling. jelly. With the acceleration of greenhouse gas emissions, the loss of species from warming and oxygen depletion alone (poster’s comment – the argument is that warmer water holds less dissolved oxygen (correct) so the lack of oxygen is a mode of extinction) comparable to current direct human impacts (IUCN red list, 89% of marine species are NOT threatened) within a century AND up to culminating in a mass extinction comparable to those of Earth’s past species. ”
The editor of the Associated Science commented: “A clear future for ocean life.”
Okay, WaPo actually reasonably reported Science’s hypoventilation. They might even have ‘1/3 in 300 years’ from the body of the paper that I chose not to read after reviewing SI. Show only the alarm reverb chamber.
SI
This is always a cheap trick that raises skepticism, as it never pays off and often reveals the ‘dirty secret’ not within itself. Like here, extracted after downloading.
The climate models used are 16 from CMIP5 and CMIP6. Of course, the global warming scenario in both is physically RCP8.5.
‘Ecological models’ are based on tolerance to warm water and hypoxia across several different sets of marine life including bony fish, cephalopods, bivalves, etc. They are estimated in Fig. S3, with R^2: 0.08, 0.08, 0.21, 0.03, 0.08 0.05. In other words, just ‘ecological ecology’ garbage statistics.
SI has RCP8.5 models that warm the ocean over 500 meters at 2300 averaging a stunning 5C (!!, SI figure S8), resulting in O2 loss of about 30%. The point is, 30% hypoxia is not close to ocean hypoxia.
The most amazing thing (ironic) is how they validate all of this by showing that they can simulate the Permian extinction (when almost 90% of marine life went extinct). I have done considerable research on Permian extinctions. It was almost certainly caused by basaltic eruptions that flooded the Siberian Traps lasting nearly 1 million years. This released a large amount of SO2, which cools the atmosphere but acidifies the oceans by leaching. The eruptions also passed through vast coal deposits in Siberia, causing them to burn and release large amounts of CO.2 to warm the atmosphere. We know this from coal ash deposits from the Chinese lake bottom period. Now, SO2 and copper2 will offset some in the atmosphere, but NOT in the ocean. That is why the Permian extinction was most severe for marine organisms, not terrestrial plants and animals.
So these Princetoners claim to be able to simulate that and match the Permian fossil record using the CMIP5 and CMIP6 climate models, using statistically dodgy ‘ecologicals’. their millet. But their SI graphic evidence supporting this claim simply does not do so. It was also never possible. As SI figure 1a and amp 1B demonstrate.
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