too much water

A study published in 2021 in the journal Geophysical Research Letters found that there is more water underground in soil or rock pores than in Earth’s ice sheets and glaciers. These are all so-called groundwater.

For comparison:

• The ice in Antarctica contains approximately 27 million cubic kilometers of water.
• Greenland has approximately 3 million cubic kilometers.
• In glaciers outside Antarctica and Greenland – 158,000 cubic kilometers.

The world’s oceans remain the largest water reservoir on the planet, containing approximately 1.3 billion cubic kilometers of water. However, the study stated that groundwater, along with the oceans, is the second largest water reservoir in the world.

Another 2015 study published in the journal Nature Geoscience found There are 22.6 million cubic kilometers of water in the upper 2 kilometers of the earth’s crust. On the other hand, in the research in 2021, it was preferred to look at groundwater in the 10 kilometer thick layer of the earth’s crust. This is because previous estimates of deep groundwater below the top two kilometers have focused only on low-porosity crystalline rocks such as granite. The 2021 study included sedimentary rocks that are more porous than crystalline.

Generally, The 2021 study more than doubled the amount of groundwater believed to exist 2 to 10 kilometers below the Earth’s surface, from approximately 8.5 million cubic kilometers to 20.3 million cubic kilometers. This new estimate is almost as large as the 23.6 million cubic kilometers they calculated for shallow groundwater.

Ferguson noted that the thickness of the Earth’s crust is typically between 30 and 50 kilometers; This is much greater than the 10-kilometer depth considered in the 2021 study. They focused on the upper part of the Earth’s crust because it is relatively fragile and contains cracks that can trap water. According to him, the bottom of the crust becomes much less porous but also probably contains some water.

Shallow groundwater aquifers, mostly fresh, are used for drinking and irrigation purposes. unlike them deep groundwater is salty and cannot easily circulate or flow to the surfaceThis largely cuts them off from the rest of the planet’s water, Ferguson noted.

But the relative isolation of deep groundwater means that in some places it remains trapped for very long periods of time. This means that valuable information about Earth’s past can be found here.

We know little about these waters deeper than a few kilometers, making them a frontier zone for science.
– said Ferguson.

Additionally, these ancient waters may have supported unknown microbial ecosystems that are still active today. Such deep biological communities could shed light on how life evolved on our planet and how it might develop on other worlds that are likely to have water deep beneath their surfaces.