The Earth's oceans may be sitting on a precipice of a major extinction.
A new study has discovered that if humanity does not take action and global warming continues unabated, life in Earth’s oceans could suffer a mass extinction, a loss in biodiversity that could surpass the planet’s previous great extinctions.
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Extinction risk for marine species
The study, published in the journal Science, states that the emission of massive volumes of human greenhouse gases into the atmosphere is fundamentally changing the Earth's climate system.
These unprecedented changes are putting many species at risk of extinction. In order to unearth the stark reality of the situation, a team of researchers, Justin Penn and Curtis Deutsch, utilized extensive ecophysiological modeling that weighed a species’ physiological limits against projected marine temperature and oxygen conditions to assess the likelihood of extinction for marine species under various climate warming scenarios.
The researchers have discovered that if global temperatures continue to rise at their current rates, marine ecosystems around the world are likely to experience mass extinctions comparable to the size and severity of the end-Permian extinction, the "Great Dying". Said extinction occurred roughly 250 million years ago and wiped out 57 percent of biological families, 83 percent of genera, 81 percent of marine species, and 70 percent of terrestrial vertebrate species. The scientific consensus is that the reasons for the end-Permian extinction were high temperatures and widespread oceanic anoxia, and acidification caused by the massive volumes of carbon dioxide generated by the Siberian Traps eruption.
An extinction event comparable to the "Great Dying"
The team also found patterns in future extinction risk: Tropical oceans, for example, are predicted to lose the most species due to climate change, with many likely relocating to higher latitudes and more suitable conditions to survive. On the other hand, Polar species are likely to become extinct if their habitats vanish from the earth entirely.
In addition to climate-driven ocean warming and oxygen depletion, there are also direct human impacts like habitat destruction, overfishing, and coastal pollution that endanger marine species. And with the rate of catastrophic climate change, the future of ocean life as we know it remains unknown. However, there is hope, as the study has also found that reducing or reversing greenhouse gas emissions might reduce extinction rates by up to 70 percent.
And according to an IPCC report released in April, the time is "now or never." Global emissions must peak by 2025 in order to meet the Paris Agreement's target of limiting temperature increases to 1.5 degrees Celsius, and then they must fall by 43 percent by 2030 from 2019 levels. Only then there can be hope.