The rise in temperatures, the reduction of oxygen and the consequent increase in the metabolic rate of species could cause a mass extinction in the Earth’s oceans in the next three centuries, to a magnitude not recorded in the last 250 million years .
Researchers from Princeton University, in the United States, have concluded in a new study recently published in the journal Science that our planet is facing a process of mass extinction in the oceans in the next 300 years, similar to what occurred during the so-called “Great Extinction” at the end of the Permian Period, 250 million years ago. In addition to the demise of the dinosaurs, about 90 percent of marine life went extinct in that extreme event.
According to a press release, the scientists reached these conclusions after analyzing different models of the future, which project a milder or more pronounced increase in global temperatures. At the same time, they compared these situations with what is known about the conditions that existed during the “Great Extinction”. Although some processes are already irreversible, specialists believe that if the increase in temperatures is kept below 2 degrees Celsius, up to 70 percent of the fatal consequences could be avoided.
Extinctions would be caused by a combination of factors. In principle, the increase in ocean temperatures would result in a decrease in dissolved oxygen. Under these new conditions, marine species would raise their metabolic rate to cope with changes in the environment. Each factor would put pressure on the other, causing the situation to become increasingly complex.
Faced with this, some marine animals would try migrate to the poles, in search of better conditions. Some might succeed and survive, but in warmer areas, such as the tropics, many species would die out without a chance.
In the case of species whose habitat is closer to the poles, in many cases they would suffer the total elimination of the direct environment in which they interact and live. These organisms would disappear completely from the face of the Earth.
Two possible scenarios
Almost all marine species can tolerate only a series of environmental conditions. For example, they require a certain amount of oxygen in the water and a specific range of temperatures to survive. When these ranges are distorted, they begin to die.
Consequently, if the favorable habitat of an organism disappears, the number of individuals begins to decline. If the population decreases beyond a certain threshold, in most cases there is no going back: the species becomes extinct and biodiversity is reduced.
Both hypothetical scenarios proposed by the researchers, both the slightest and the most complex, already contemplate irrecoverable losses for the biodiversity of the oceans. However, in an article published in Scientific American, scientists argued that if society takes this threat seriously and global temperatures can be contained, there is still time to avoid the most catastrophic scenario.
Avoiding ocean mass extinction from climate warming. Justin L. Penn and Curtis Deutsch. Science (2022). DOI:https://doi.org/10.1126/science.abe9039