Greenhouse gas emissions could trigger a mass extinction of marine life to levels not seen since before the dinosaurs, a latest study says.
Researchers in Recent Jersey have modeled future extinction risks for marine life in all of the world’s oceans, under different projected climate scenarios.
If emissions should not curbed, the lack of marine species from global warming and oxygen depletion could mirror the ‘Great Dying’, Earth’s deadliest extinction event, by around 2100, they are saying.
Referred to as Earth’s deadliest extinction, the Great Dying saw the lack of 95 per cent of all marine species when it occurred around 250 million years ago.
It could also match other big extinction events in Earth’s history, including the End-Cretaceous mass extinction which killed the dinosaurs 66 million years ago.
Unless greenhouse gas emissions are curbed, marine biodiversity could possibly be heading in the right direction to plummet to levels not seen for the reason that extinction of the dinosaurs, a latest study says. The study authors modeled future marine biodiversity under projected climate scenarios and located that species resembling dolphinfish (pictured) could be imperiled as warming oceans decrease the ocean’s oxygen supply while increasing marine life’s metabolic demand for it
The researchers found that as emissions increase (grey), the lack of biodiversity (red) could be best in tropical waters, while polar species are at the very best risk of extinction. The researchers found that reversing greenhouse gas emissions could reduce the chance of extinction for marine life by greater than 70 per cent
In accordance with the researchers, tropical waters would experience the best lack of biodiversity, while polar species are at the very best risk of extinction.
THE GREAT DYING
Around 250 million years ago, a catastrophic event called the Great Dying saw just about all life on Earth worn out.
Scientists imagine around 95 per cent of all marine life perished through the mass extinction, and lower than a 3rd of life on land survived the event.
In total, it’s believed that 90 per cent of all life was worn out.
All life on Earth today is descended from the roughly 10 per cent of animals, plants and microbes that survived the extinction.
Through the Great Dying, a supercontinent called Pangaea covered the Earth.
On a more positive note, reversing greenhouse gas emissions could reduce the chance of extinction by greater than 70 per cent, the experts say.
‘The silver lining is that the longer term is not written in stone,’ said first writer Justin Penn at Princeton University’s Department of Geosciences.
‘The extinction magnitude that we found depends strongly on how much carbon dioxide [CO2] we emit moving forward.
‘There’s still enough time to alter the trajectory of CO2 emissions and forestall the magnitude of warming that might cause this mass extinction.’
The Great Dying marks a period where life on Earth has never been so near becoming completely extinct without recovering, either before or since.
Also often known as the Permian-Triassic event, it worn out 95 per cent of marine species and 70 per cent of terrestrial species on the time roughly 250 million years ago.
When the CO2 dissolved within the oceans, they became highly acidic and the extent of oxygen within the water was reduced, killing sea life.
Scientists have long debated the theories of the reason for the extinction starting from a meteor impact to volcanoes, which could have caused climatic and environmental changes making Earth inhospitable.
But should the following mass extinction event occur, history will place the blame squarely at greenhouse gas emissions resulting from human activity.
This illustration shows the share of marine animals that went extinct on the Permian-Triassic event (the Great Dying) by latitude
SIXTH MASS EXTINCTION EVENT HAS ALREADY BEGUN
Earth has experienced five mass extinctions brought on by natural phenomena, but a latest study suggests a sixth event is underway and human activities are accountable.
The research, led by the University of Hawaii at Manoa, reveals our planet has lost 150,000 to 260,000 (7.5 to 13 percent) of all its two million known species since 1500.
The study, led by Robert Cowie with the University of Hawaii, notes that the Red List of Threatened Species includes mostly birds and mammals, but leaves out most invertebrates – a bunch that has seen a dramatic loss.
Read more: Study warns Earth’s sixth mass extinction is HERE
For the study, Penn and co-author Curtis Deutsch, also at Princeton, combined existing data on marine species with models of climate change to predict how changes in habitat conditions will affect their survival.
The experts compared their model to the magnitude of the ‘Big Five’, five historical mass extinctions captured within the fossil record, of which the Great Dying is one.
Under ‘business as usual’ global temperature increases, marine life will likely experience mass extinctions potentially rivaling the dimensions and severity of the Great Dying, the researchers say.
Seeing because the Great Dying is Earth’s deadliest extinction event, the upcoming marine extinction would subsequently likely surpass the opposite 4.
Among the many events, they found a standard pattern – as ocean temperature increases and oxygen availability drops, there may be a pronounced decrease within the abundance of marine life.
Water temperature and oxygen availability are two key aspects that can change because the climate warms because of human activity.
Warmer water isn’t only a risk factor for species which are adapted for cooler climates; it also holds less oxygen than cooler water, which results in more sluggish ocean circulation that reduces the oxygen supply at depth.
Paradoxically, species’ metabolic rates increase with water temperature, so the demand for oxygen rises as the availability decreases.
‘Once oxygen supply falls wanting what species need, we expect to see substantial species losses,’ Penn said.
The researchers compared their model to the magnitude of Earth’s ‘Big Five’ mass extinctions. The illustration above indicates the share of biodiversity lost during each event (left). At lower right, the lack of marine life from the current to 2300 is projected for high- and low-greenhouse gas emissions scenarios with the accompanying global temperature change
Marine animals have physiological mechanisms that allow them to deal with environmental changes, but only up to a degree, the experts say.
Through the Great Dying, a supercontinent called Pangaea covered the Earth
The researchers found that polar species usually tend to go globally extinct if climate warming occurs because they may haven’t any suitable habitats to maneuver to.
Tropical marine species will likely fare higher because they’ve traits that allow them to deal with the nice and cozy, low-oxygen waters of the tropics.
To quantify the relative importance of climate in driving extinctions, the team also compared future extinction risks from climate warming to data from the International Union for Conservation of Nature (IUCN) on current threats to numerous marine animals.
They found that climate change currently affects 45 per cent of the marine species liable to extinction, but is just the fifth-most vital stressor after overfishing, transportation, urban development and pollution.
Nonetheless, Penn said, climate change could soon eclipse all of those stressors in importance.
‘Extreme warming would result in climate-driven extinctions that, near the tip of the century, will rival all current human stressors combined,’ he said.
The study, ‘Avoiding ocean mass extinction from climate warming,’ has been published today within the journal Science.
EARTH HAS HAD FIVE GREAT EXTINCTION EVENTS WITH THE MOST FAMOUS A DINOSAUR KILLING ASTEROID
Five times, a overwhelming majority of the world’s life has been snuffed out in what have been called mass extinctions.
End-Ordovician mass extinction
The primary of the standard big five extinction events, around 540 million years ago, was probably the second most severe. Virtually all life was in the ocean on the time and around 85% of those species vanished.
Late Devonian mass extinction
About 375-359 million years ago, major environmental changes caused a drawn-out extinction event that worn out major fish groups and stopped latest coral reefs forming for 100 million years.
Five times, a overwhelming majority of the world’s life has been snuffed out in what have been called mass extinctions. Essentially the most famous often is the End-Cretaceous, which worn out the dinosaurs. Artist’s impression
End-Permian mass extinction (the Great Dying)
The most important extinction event and the one which affected the Earth’s ecology most profoundly took place 252 million years ago. As much as 97% of species that leave a fossil record disappeared without end.
End-Triassic mass extinction
Dinosaurs first appeared within the Early Triassic, but large amphibians and mammal-like reptiles were the dominant land animals. The rapid mass extinction that occurred 201 million years ago modified that.
End-Cretaceous mass extinction
An asteroid slammed down on Earth 66 million years ago, and is commonly blamed for ending the reign of the dinosaurs.