Sea level rise: Don’t worry too much, long-term changes are still difficult to predict

Sea level rise has always been one of the "ultimate disasters" under some theories.

The IPCC report pointed out that in the past ten years, the extent of Arctic sea ice has been at its lowest level since 1850. The frequency of marine heat waves has doubled since the 1980s. Conservative estimates suggest that human activities have influenced the generation of most marine heat waves since 2006. Mountain and polar glaciers will continue to melt for decades or centuries, and carbon losses from melting permafrost are irreversible over millennia. Due to uncertainty about the ice sheet melting process, global sea level rise averages are likely to exceed expectations under the highest emissions scenario - rising by 2 meters by 2100 and 5 meters by 2150. Even under the strongest emissions reduction scenarios, sea levels will continue to rise for hundreds or thousands of years to come.

So, as global warming has intensified in recent years, how fast is sea level rising?

According to the 2018 "China Climate Change Blue Book" released by the Climate Change Center of the China Meteorological Administration, China's annual average surface temperature has shown a significant upward trend since the 20th century. The past 20 years have been the highest since the early 20th century. warm period. From 1980 to 2017, China's coastal sea level showed a fluctuating rising trend, with an average rising rate of 3.3 mm/year.

If this rate remains unchanged, it will take 606 years for the sea level to rise by 2 meters. A rise of 2 meters by 2100 means that global warming will increase explosively and accelerate exponentially. This should be a relatively extreme expectation.

The earth’s atmospheric environment is still a relatively complex subject. For example, volcanic eruptions will erupt large amounts of greenhouse gases and carbon dioxide, but the dust that rises to high altitudes will block sunlight and cause the earth's average temperature to drop.

For another example, melting glaciers in the Antarctic and Arctic will bring a large amount of fresh water to the ocean, thereby weakening the effect of ocean currents and disrupting the existing ocean temperature cycle, resulting in cooling and extreme cold. climate, thus increasing the area of ​​glaciers. The American movie "The Day After Tomorrow" borrowed this speculation about oceans and climate change and gave it a Hollywood-style extreme presentation.

Weather forecasting is very difficult to accurately predict the weather one month from now. It is still very difficult to predict the marine environment in 80 years using existing data models.

However, planning to reduce environmental pollution, lower emissions, and try our best to reduce human impact on the environment is still a positive attitude for mankind to face the unknown. However, don't worry too much about rising ocean levels. If it does happen, it will definitely be the Antarctic and Arctic being bombed by nuclear bombs, or the earth being hit by solar wind... Human beings can't escape, so there is no need to worry about anything.

It’s not easy for people in the city. The psychological pressure is quite high. There is no need to be more stressed.

PS: Glaciers currently have area data, but the actual glacier volume is still quite lacking in data. In fact, it is not clear how much water glaciers can bring, and whether this water will evaporate and turn into rain and fall on the land, or form water vapor, which will reduce the energy of sunlight falling to the ground, thereby cooling the earth.