Is it possible that humankind will be destroyed by global warming?

It is said that July 2021 was 'the hottest month in the last 142 years', and 'global warming ', in which the average temperature of the entire world gradually rises, is regarded as a problem. The cause is said to be human activity since modern times, and it is said that if nothing is done, it will have a great impact on the earth's ecosystem. Live Science, a science news site, discusses the possibility that such global warming will lead to the destruction of humankind.

Could climate change make humans go extinct? | Live Science

Regarding whether global warming directly threatens humankind in the first place, Luke Kemp, a researcher at the Center for Survival Risk Research at the University of Cambridge, said, 'The impact of climate change directly leads to the extinction of humankind is the case of the runaway greenhouse effect. It ’s just that. ” According to Kemp, when the greenhouse effect of carbon dioxide and methane gas goes out of control, the amount of heat absorbed by the earth exceeds the amount of heat released, positive feedback continues to loop, and finally the sea can evaporate and sustain life. It will disappear.

However, even if the runaway greenhouse effect is theoretically possible, it is considered unlikely that it will actually occur. In order to absorb more heat than it releases, the level of carbon dioxide in the atmosphere needs to be nearly 10 times higher than usual, or a huge amount of methane gas needs to be released.

Still, 'climate change has led to massive extinctions in many cases,' Kemp said. For example, from the end of the Ordovician period to the Silurian period , about 440 million years ago, 85% of the species were extinct due to the sudden drop in temperature. On the contrary, it is said that 80% of the species became extinct in the Triassic to Jurassic period about 200 million years ago due to the rapid rise in temperature.

Kemp also pointed out that archaic subspecies may have become extinct due to climate change. For example, there is a theory that the Neanderthals became extinct about 40,000 years ago because the eruption of a volcano caused severe climate change, resulting in the lack of food and the extinction.

On the other hand, Homo sapiens, to which modern humans belong, has high adaptability to various environments. Humans can also use the resources of animals and plants and use information to survive in a changing world.

A paper published in July 2021 argued that 'some island nations, such as New Zealand and Ireland, are relatively cool and resistant to climate change, allowing humans to remain habitable through agriculture.' Therefore, it is considered possible for human beings with strong adaptability to survive in places where the effects of climate change are small.

However, climatologist Michael Mann, known for the hockey stick controversy , said, 'When the world temperature rises above 3 degrees Celsius, social infrastructure collapses, large-scale anxieties and conflicts occur, and Hollywood dystopian movies There is a possibility that such a future will come. '

According to Mann, food shortages and social unrest caused by climate change such as global warming can contribute to the collapse of human civilization. It is quite possible that climate change will adversely affect food production and reduce yields. Food shortages not only increase the number of people who starve to death, but also cause social and political instability, increasing the risk of social collapse.

Kemp said, 'If resources are reduced due to climate change, a war that threatens humankind can be triggered. When water resources are depleted, resource shortages become serious, and the living environment deteriorates significantly, a sudden nuclear war will occur. Of course, there are concerns that the threat will increase. ' In other words, even if the effects of climate change do not directly extinct humankind, the lives of hundreds of millions or billions of people can be lost due to food shortages and conflicts triggered by climate change. ..

'If we can't significantly reduce carbon dioxide emissions over the next decade, we'll be competing for extreme weather conditions that are already in danger, inundation and sinking due to melting ice and rising sea levels, and scarce food and water. This can lead to various problems, such as further pressure on limited resources. Now, if humanity acts boldly, the worst effects can be avoided. '

in Note, Posted by log1i_yk