Solve sea level rise with collective grassroots action! Just store the water somewhere BESIDES the sea. So simple!


Increased global average temperatures may lead to increased sea levels. This could be a problem for coastal regions, but perhaps we can all do our part to mitigate sea level rise by storing the water elsewhere.

The Issue:

We have the following numbers (Fig 1):

  • The ocean covers ~360,000,000 km2 (surface area).
  • One estimate for sea level rise is ≤ 0.5 meters in the next 50 years.

If we want to be prepared for the 0.5-meter scenario, we’ll need to plan to handle up to this many cubic meters of additional water:

  • (360 trillion m2 * 0.5 m sea level rise) = 180 trillion m3
Fig. 1: With 360 million square kilometers of surface area times 0.5 meters of potential sea level rise, we end up with “a lot” of water to deal with.

If we don’t want the sea levels to rise, we’ll need to store that water somewhere. But where!

Proposal #1:

Everyone drinks a lot more water. Unfortunately, it turns out that every person would need to store more than 8 million gallons of water (each), which is substantially more than can be temporarily sequestered in an individual human body.

Even if we add camels to this mix, this plan clearly is not going to work.

Proposal #2:

Everyone stores some water in their basement, guest room, garage, or shed. If everyone does their part, we can help take this water “out of circulation” and prevent sea level rise.

Let’s estimate (roughly) that there will be an average of 5.4 billion adults with the resources to contribute. That means every person just needs to store the following:

  • (180,000,000,000,000 m3) / (5,400,000,000 people)
  • = 33,333 m3 of water per person, or ~8,800,000 gallons

This might sound like a lot of water, but it’s actually only a cube 32.2 meters (105 feet) on each side: about as tall as an 8-story building (Figure 2).

Fig. 2: Shown with a person and a car for comparison. The full height is shown, but only the partial width appears here. This 32-meter-on-a-side “water tank cube” would resemble a traditional 8-story rectangular office building.


A water tank of this size turns out to be technically feasible, as demonstrated by the 45,000 cubic meter Tala tank in India, built in the early 1900s.

PROS: Clearly within the realm of technical possibility.

CONS: It might be hard to secure a buildable 105 ft2 (~0.25 acre) plot of land for over 5 billion people.