Broken water cycle

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Tiistai 29.8.2023 klo 15:42 - Mikko Nikinmaa

The civilization as we know it is dependent on appropriate availability of water. Water availability has been adequate and constant for the past 10000 years. It has enabled the development of agriculture followed by industrialization. Feeding the billions of people has been possible, as there has been enough water at right time.

However, it appears now that humans are breaking the water cycle. Intensive agriculture is using more fresh water than would be available. Climate change affects the timing, duration and place of precipitation. Also, glaciers, which are the source of many rivers, have melted to such an extent that the river flow is reduced. Deforestation affects the rains in the areas in the vicinity. All in all, although roughly ¾ of Earth’s surface is covered with water, the cycle of fresh water, needed for civilization as we know it, seems to be in peril.

It is easy to blame climate change for the fresh water problems, but it is only part of the problem. Because of climate change, droughts and heat spells become more common, heavy rains come irregularly and at unexpected places. Often they occur after severe drought, whereby the soil cannot bind the water, which flows to the sea. An important component of the water cycle in equilibrium is that the upper soil is moist. It is then able to bind additional water.

As for many other resources, mankind is overusing water. Intensive irrigation and domestic water use have emptied Jordan, Sacramento River, Colorado River etc., caused almost total disappearance of Dead Sea and Aral Sea, and lowered ground water level to such an extent that Earth’s poles have shifted slightly.

With regard to deforestation, rainforests are much more than important carbon dioxide sinks. They suck moisture from soil, liberate water in the air, and thus cause development of rains in the surrounding areas. With deforestation, this cycle is weakened with the result that rainforest may turn to savannah. It is estimated that when ¼ of the forest is cut, this happens. We are nearing this  percentage both for Amazonas and Congo rainforest.

In view of the disturbed water cycle, one should make every effort to diminish water use in any area to the amount which is certainly replaced by inflow. In terms of plants that are grown, this means that we should at least stop using cotton products, as there is already a sustainable alternative for cloth fibre, i.e., wood fibre. Deforestation of rainforests should be stopped. In this context it would be valuable to be able to stop population growth, as it inevitably causes the need for increased agricultural production, which is a primary reason for breaking water cycle.

Avainsanat: climate change, agriculture, deforestation, population growth

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