(ORDO NEWS) — Be prepared for a lack of oxygen.
Throughout the history of the Earth, the climate on our planet has fluctuated between warming and cooling. Our planet is most likely in a global cooling phase right now, but human emissions of greenhouse gases are reversing this natural trend at a rapid and unprecedented pace.
About 304 million years ago, the Earth experienced a dramatic warming. For our planet, this was a serious shock: in about 300 thousand years, the amount of carbon in the atmosphere doubled.
Now, new research shows that about 23 percent of the seafloor was deprived of oxygen during this time. The study was published in PNAS.
The findings are based on a new analysis of trace elements in an ancient black shale slab in South China. Isotopes of carbon and uranium in this rock have shown that in addition to global warming, rising sea levels and melting glaciers, we also need to worry about ocean anoxia, that is, lack of oxygen.
This could happen as a result of climate change. The fact is that when the ice caps melt and increase the amount of fresh water in the oceans, which prevents the dissolution and circulation of atmospheric oxygen.
The new findings are supported by previous studies of ancient bedrock in South China, which have found severe biodiversity loss in the sea. In extreme anoxic conditions, also called “dead zones”, life in the ocean struggles to survive.
The scientists concluded that if human emissions had increased rapidly during a natural period of global warming, instead of global cooling, then ocean anoxia (lowering oxygen levels) would not have been such a big threat.
Perhaps the reason lies in the fact that greenhouse gases in the world are already so high, so emissions do not have such a strong melting effect on ice sheets and permafrost.
But during a period of global cooling, more glaciers appear, trapping fresh water, ready to penetrate the surface of the ocean and prevent oxygen from dissolving.
Researchers have not yet been able to figure out the exact cause of carbon emissions, but their results show a clear spike in greenhouse gas emissions followed by a significant rise in sea levels and a decrease in oxygen levels.
In other words, not everyone on Earth will have enough oxygen, and many creatures will have to adapt to new conditions. By the way, this situation is very similar to the model described by planetary scientists for Mars, which was left without oxygen in the atmosphere. Isn’t that the future for us?
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