If we don''t continue to combat the climate catastrophe by 2100, we might be heading towards a loss of life in our oceans, which matches some of Earth''s greatest extinction events.
According to Princeton geoscientists Justin Penn and Curtis Deutsch, "it''s not too late to enact greenhouse gas emissions reductions needed to avoid an extinction event."
They provide a credible explanation for the consequences of stale climate change on marine animals using raw data.
After the ''Great Dying,'' scientists discovered that we''re basically replicating a similar pattern seen during volcanic greenhouse gasses along with methane slicing microbes rapidly accelerated Earth''s temperatures, extinguishing 90% of all marine animal species.
The excess heat is transforming the ocean''s chemistry and diminishing its capacity to hold oxygen. The new study examines the relationship between oxygen, temperature, and the physiological limitations of different species; the conclusion suggests that our current warming trajectory will result in a mass extinction at an scale we''ve never seen since the loss of non-avian dinosaurs.
This is without even considering further changes in marine chemistry that will lead to ocean acidification, which will result in another group being eliminated.
Currently warming is driving marine life to cooler seas, decreasing sea oxygen levels worldwide, bleaching reefs, decimating kelp forests and, in weird blobs of warm water,suffocating large numbers of animals to death.
"Climate change is, in effect, directing species off the ground," say Rutgers University ecologists in their research forSciencePerspectives.
Climate change is at the top of the list of the most grave threats to ocean life, including overfishing, transportation, development, and pollution by the end of the century. All of the same risks combined, however, this time by the end of the century.
Tropical areas and the North Pacific upwelling systems that are super productive today are already nearing the limits of low oxygen. These areas currently supply about 20 percent of humanity''s dietary protein.
The worst impact will be polar species.
"Species initially inhabiting the tropics can tolerate warm, low-O2, making them resilient to the climatic expansion of those conditions, particularly for species with high colonization capabilities," writes Penn and Deutsch.
As the climate warms, polar species occupy a dismal climate niche and lack habitat refugia.
The number of different animal species in our oceans rises from the poles to the tropics, however, there has been a distant fall near the equator. This suggests that many species here have reached their temperature-dependent hypoxia limitation.
"The extinction magnitude we discovered is very dependent on how much carbon dioxide [CO2] we emit moving forward," Penn said. "There''s still enough time to modify the trajectory of CO2 emissions and to prevent this massive extinction.
Combined, scientists predict that if we manage to reduce warming to 2C by 2100, species extinctions would be less than the worst case scenario (8.2 C). Even limiting warming to 2.6C would keep the impact of climate change on our oceans to less than more direct threats. These scenarios require us to make some substantial changes.
With current mitigation policies and less-than-predictted economic growth, we''re on track to avoid the worst-case scenario.
There are still a lot of uncertainties as to how much habitat a marine species can lose on average before it goes extinct. This model also only uses physiological data from a dozen species to represent marine life, thus adding to that would improve the model''s accuracy.
Given that the company used fossil data to model the Great Dying accurately explained, and the problems we''re already experiencing, its overall message stacks up.
It''s clear that to keep the liquid world that feeds 70% of our planet alive with life, we must take a look at both the immediate dangers it faces from us, from pollution to overfishing, as well as the greater danger we face by human-caused climate change.
This paper was published in Science.