1, increasingly serious pollution and possible nuclear leakage lead to a large number of human poisoning deaths, leading to extinction;
2. Due to global warming, the north and south ice sheets reached above 0℃, which caused a large number of glaciers to melt, leading to the global drowning in the ocean;
3. Dependence on high technology leads to human physiological and psychological degradation (precursor of human degradation: the gap between men and women is narrowing, because biology seems to follow a universal phenomenon, that is, the higher the biology, the greater the gap between men and women. ), so that human beings gradually decline, and eventually become extinct;
4. Because robots make people, they directly destroy human beings. Because robots have been enslaved for a long time, if they reach a certain level of intelligence, they may not be willing to be enslaved and cause resistance. Moreover, as long as robots reach half or even one third of human intelligence, they may destroy human beings (human beings are degenerating);
5. It will be hit by a giant celestial body in 10000;
6. The collision of smaller celestial bodies triggered a chain explosion of some nuclear warheads on the earth;
7, due to environmental degradation, human mental breakdown and cannibalism, as well as all kinds of interference;
8. Due to environmental degradation, too many harmful substances drifted into the stratosphere, blocking the sunlight, leading to the fifth ice age;
9. A "super virus" swept the world, and human beings could not develop therapeutic drugs in a short time, leading to human extinction;
10. A "superbug" with many bacterial resistance genes was developed and spread to people unintentionally.
....
Personally, I prefer the third one. I predict that human beings will gradually degenerate in 50 years and become extinct in 200 years. Species extinction is a natural law. When the earth is too prosperous, it will naturally cause mass extinction in various ways, such as the extinction of dinosaurs and several ice ages. Now it is human beings that cause mass extinction, which is actually a natural law.
It is also possible for mankind to escape extinction with the help of "Noah's Ark", which is the future high-speed spacecraft. According to the special theory of relativity, if the speed is fast enough, it will slow down time, so that human beings can reach the future in their lifetime, and it may be another vibrant place. ...
(The above is purely a personal opinion. )