In the near and distant future, life on Earth will face global catastrophes. "Ribbon."ru knows whether the climate change or other disasters lead to the extinction of human civilization within the next million years.
Soon, very soon
Researchers estimate, due to the melting of glaciers, the land sinks into the oceans at a speed of three to four millimeters per year. Scientists believe that this rate will remain unchanged in the coming decades the ice cap will start to disappear faster. Depending on different scenarios (which take into account the different volumes of anthropogenic emissions of greenhouse gases), the ocean level will rise by 2100 0.3-2 meters.
This will increase coastal erosion, exacerbate the effects of storms and hurricanes and will affect the groundwater levels. Humanity will lose not only tropical beaches. Deteriorate the quality of soil and fresh water, which will affect agriculture, which affects three-quarters of the poor human population. The rise in sea level of 40 cm in the Bay of Bengal flood 11 percent of the land area of Bangladesh, where now lives of 7-10 million people.
It is clear that the global sea level will rise not so sharply. But and smooth this process will not be called. The sea will reclaim the land through the flood, the stronger and more frequent. Of course, to determine which regions are most vulnerable, must take into account many factors, such as coastal storms, tidal currents and the topography of the shore. It is quite difficult, so various models differ in how exactly happens the flooding of the land around the globe.
Malé, capital of Maldives
Photo: Shahee Ilyas / Wikipedia
If before the land was flooded by a five-meter layer of the water every 100 years, but now, according to a study published in the journal Scientific Reports, this will happen every 25 years. Major flooding is more likely in the tropics. There frequency of natural disasters will double by 2030 (if ocean levels rise by 5-10 centimeters). Therefore, the most vulnerable part of the population — are island Nations.
This is consistent with the opinion of experts. So, the UN group on the environmental risk assessment concluded that if the rate of sea level rise does not change by the year 2100 people will have to leave the Maldives. The same fate threatens island States of Polynesia. For example, Bank of Tuvalu go under the water at a rate of 1.2 millimeters per year. Due to shoreline erosion, as reported in 2016, has gone to five of Solomon Islands.
As for the major coastal cities (NY, London, Venice), they need extra protection from storm surges. In addition, countries with developed economies can save cities from floods with dams or partial displacement.
Global warming accelerating geologic processes lasting thousands of years. For example, the thawing of the Wilkes basin in East Antarctica could increase the level of the ocean at three or four meters. Pool Wilkes plays the role of the tube, holding in place the entire East Antarctic ice sheet with an area of 10 million square kilometers. If the "tube" to melt, then the glacier will slide into the ocean. Similar situation with glacier pine island, has lost its "cap." Scientists have recognized that the process of disappearance of Pai island, whose area is 160 thousand square kilometers, is already irreversible.
Crack in the Antarctic shield
Photo credit: NASA / John Sonntag
Wilkes pool may collapse during the next several centuries. The very melting of the East Antarctic ice sheet is 5-10 thousand years.
What about by humanity? According to optimistic forecasts, the people will not disappear. It's hard to say what social and economic challenges facing Homo sapiens for such a long period of time. However, it is clear that the flooding of coastal areas will accelerate panmixia — the mixing of various populations of people.
Even without considering global warming, by 12 000 a year on Earth, researchers estimate (based on current pace of globalization), will disappear regional genetic variation. That is, no more races, as human populations characterized by similar external features (Negroid, Mongoloid, Caucasoid and Australoid race). But this does not mean that such phenotypic features as black leather, epicanthus or light hair color will cease to exist. They just evenly spread around the world.
However, there are pessimistic scenarios. Some experts, including astronomer Francis Drake and mathematician Brandon Carter, came to the conclusion that after 10 thousand years of human civilization for one reason or another disappear from the face of the planet. According to the Drake, the average lifetime of a technologically advanced civilization — just 10 thousand years, during which she tries to make contact with intelligent life forms from other planets.
Carter suggested that the so-called theorem of the doomsday (Doomsday argument). According to her, the modern man is in the middle of the entire history of Homo sapiens. This, in turn, means that in 10 thousand years with a probability of 95 percent of mankind will die.
If, however, people will survive, more than 50 thousand years, they will face a new ice age. This is not unexpected consequence of global warming. The so-called interglacial — time intervals between the glaciations were caused by the Milankovitch cycles, which have an astronomical nature. These cycles determine how much sunlight reaches the earth's surface. Yourself cycles, in turn, are formed due to various factors, including periodic changes in the inclination of the rotation axis of the Earth, precession of this axis of rotation in the planet's orbit and eccentricity.
The ice cover of Antarctica
Photo: Stephen Hudson / Wikipedia
Although global warming can delay glacial, it will happen anyway. However, it is striking the very ability of people to affect global geological cycles. So, German scientists from the Potsdam Institute to examine the impact of climate found that the periodicity of ice ages is affected by the content of carbon dioxide in the atmosphere. Even small industrial emissions of carbon dioxide will affect the fate of the ice shields. The conclusion of the researchers — interglacial era will end only after a hundred thousand years.
Imagine that humanity will not disappear, and after a hundred thousand years. Then people will have to endure the eruption of the volcano, which will lead to the release of 400 cubic kilometres of lava. After about 300 thousand years our planet has to face a large asteroid with a diameter of a kilometer. In a million years there will be another major eruption with emission of more than three thousand cubic kilometers of incandescent rocks. This is comparable to the super eruption of Toba volcano 75 thousand years ago that caused mass extinctions of some species and a sharp decrease in the human population (although the number of scientists with this assessment of lethality Toba disagree).
In any case, to the nearest million years, no astronomical or geological event does not guarantee human extinction. However, this does not mean that technological civilization do not disappear, as predicted by the Drake.
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