The most dazzling film of the Spring Festival season in 2019 is The Wandering Earth. As a domestic "phenomenon" film, the film not only received good reviews, but also sold a lot at the box office. It took only seven days to break the 2 billion yuan mark, while the recent American sci-fi blockbuster Aquaman took more than a month.

The Wandering Earth is adapted from the novel of the same name by famous science fiction writer Liu Cixin. The film uses two hours to tell the story of the sun is about to be destroyed, human beings have to implement the "wandering Earth" plan under the guidance of the coalition government: to build a propeller on Earth, by its power to fly the Earth out of the solar system, to find a suitable home.

One of the attractions of "The Wandering Earth" is undoubtedly its scientific elements, with the scene that "the world's sea levels rise by 300 meters in 10 years, swallowing up large coastal areas" earning a lot of attention. As the movie says, if the global sea level rises by 300 meters, not only will the coastal alluvial plains be destroyed, but many hinterlands below 300 meters will also be submerged. Many netizens even started an online discussion on "where is the safest place to escape if the sea level rises 300 meters?"

However, from a scientific point of view, the claim of 300 meters of sea level rise simply does not hold, because the main factor causing sea level rise is the melting of continental ice shelves. The remaining continental ice sheets on Earth are the Antarctic Ice Sheet and the Greenland Ice Sheet. These two ice sheets account for about 97 percent of the world's total glacier area and 99 percent of the total ice volume. The average thickness of the Antarctic ice sheet is about 2,000 to 2,500 meters, and the largest known thickness is 4,267 meters. If the entire Antarctic ice sheet were to melt, it would raise world sea levels by about 60 metres. Greenland's ice sheet, if all melted, would contribute six metres to sea level rise.

There are many other factors contributing to sea level rise, including the thermal expansion of oceans and the melting of mountain glaciers, in addition to the most important melting of continental glaciers. According to a study from the National Center for Atmospheric Research, sea levels could still rise for hundreds of years, assuming global greenhouse gas emissions stabilize and global temperatures stop rising. This is because, even if the global temperature is stable, there will still be a difference between the temperature of the sea surface and the temperature of the deep sea. The temperature of the deep sea will slowly increase, which will lead to the thermal expansion of more sea water, and then the overall volume of sea water will expand and the sea level will rise. This reaction lasts for a long time and stops only when the water reaches a certain equilibrium with the atmospheric temperature. This is the thermal expansion of the ocean.

Even if all the Arctic and Antarctic ice caps melted, sea levels would rise only 66 meters, which is not nearly as dramatic as the 300 meters in the movie. Liu Cixin also admitted that the Wandering Earth, a science fiction, has many loopholes. Of course, the novels and movies are just artistic hyperbole, but it's true that global warming is slowly melting continental ice sheets and raising sea levels. In fact, the impact of global sea level rise on human society is far more profound than portrayed in movies or other science fiction works about sea level rise. The potential damage from melting ice is not just a rise in sea levels that will flood human cities, but a cascading change in climate and the environment around the world. Vast amounts of methane are trapped beneath Arctic and Antarctic glaciers, which, if released, would exacerbate the greenhouse effect. In addition, ancient bacteria and viruses trapped beneath Arctic and Antarctic glaciers could be carried into the global biosphere, with unpredictable consequences.

In the past, many scientists have made very pessimistic predictions based on changes in Antarctica. Although there is no consensus on the course of climate change due to the uncertainty of scientific predictions, it is certain that the Earth has warmed in the past half century, glaciers are melting at an accelerated rate, and sea level rise will be difficult to contain. Whether human civilization can continue to develop is closely related to the earth's environment. The endless exploitation of earth's resources will lead to the further deterioration of the living environment. In the past, people focused more on how to get food and energy from the ocean, but now we need to think about how to move away from just taking from the ocean and build a new value system about the ocean. In the face of the ocean, we should not only think about what we gain, but also what we do not harm. To protect the earth is to protect ourselves.

(Source: China Ocean News)