I recently saw a video of people living in Vietnam dealing with flood. The images reminded me years ago. When my family had to use electric pump to get the water out of grandpa’s house.

So why is that?

World Economic Forum (WEF) made a list of sinking cities in 2019. The first city in the list was Jakarta, Indonesia. The article mentioned two main reasons of sinking cities: increasing sea level and ground water pumping.

The first reason links to Greenhouse gases. They are gases that trap heat including CH4, N2O, CO2 and others (HFC, PFCs,SF6, NF3). The ocean will absorb that heat and expand. Additionally, due to heat, ice from Greenland and Antarctic are melt. The water then flows to the ocean, raising the sea level. In the last 30 years, sea level is double compared to 90 years ago from 1902 to 1992.

Excessively extracting water from the ground is the second reason. As we pump too much water out, there is nothing to hold the ground above. Subsequently, ground will sink. This effect impacts many coastal cities.

Rapid urbanization is another reason that is not mentioned in the article above. The process has removed lakes, and rivers. More asphalt roads block water going back to the groundwater reservoir.

So why some cities are flooded, and the others are drought?

We can look back at the first condition, global warming. Most of the cities in WEF’s list are near the ocean. They may get more moisture and the rain will be heavier. The other inland cities may get less moisture; however, according to an article from theguardian weather seems to be strange recently. Some wet cities turn to dry and vice versa.

So what are we missing here?

The above information does not explain why cities switch from wet to dry. There are more aspects to research such as how cities deal with flood. How the drainage system works. Additionally, looking back to see how and why cities such as Pavlopetri is emerged in water. The world is large and our time is short.