The marine world on earth will face extinction by 2100, if human-caused emissions continue unabated, according to a new study report published in Journal Science.
The authors of the report, Justin Penn and Curtis Deutsch, from the University of Washington and Princeton University respectively, noted that limiting global warming to two degrees Celsius above pre-industrial levels will prevent such a catastrophe.
Dire warning from researchers
The authors used ecophysiological modelling to balance species' physical limits against expected maritime temperatures and oxygen depletion – a difficult challenge given the paucity of previous research in the field.
The findings were alarming: if global warming continues at its current rate, marine ecosystems around the world could face a catastrophic extinction similar to the end-Permian catastrophe known as the "Great Dying." This incident happened 250 million years ago, and it resulted in the extinction of more than two-thirds of marine species due to warming and oxygen depletion, similar to what is happening now.
Relocation to higher latitudes for survival
While tropical oceans would lose most species, many would relocate to higher latitudes to survive. Polar species, on the other hand, would become extinct in large numbers when their habitat types vanish from the earth.
According to the report, limiting global warming to 2 degrees Celsius, the highest limit specified by the Paris Agreement, "would reduce the severity of extinction by more than 70%, averting a marine mass extinction."
According to UN climate experts, the desired goal of reducing warming to 1.5 degrees Celsius is difficult to attain with current international agreements.
"Marine animals have physiological mechanisms that allow them to cope with environmental changes, but only up to a point," Penn said.
The researchers also discovered that polar species are more likely to become extinct globally if global warming occurs.
Penn expressed concern that climate change would render significant parts of the ocean unusable. He also added that "extreme warming would lead to climate-driven extinctions that, near the end of the century, will rival all current human stressors combined."
