During one of the basic physics classes recently, one kid innocently asked “why do we need to conserve water if it cannot escape our planet’s atmosphere and comes back as a part of water cycle.” It was a question which all the amateur environmentalists should ask themselves.
Well water is not going to run away anytime soon unless methane percentage in our environment increases many folds leading to Methanogenesis which causes water to split into Hydrogen and Oxygen of which Hydrogen escapes into space. As the research of Emily Pope and her colleagues show that earth lost quarter of its water in the four billion years of its existen due to high methane percentage in the atmosphere in Earth’s infancy. A very interesting research and gives us hope that we can still save what’s left if we reduce methane percentage. Amateur environmentalists have to read between the lines to divert some attention to methane generating sources – home and community composting, dirty lakes and water bodies, natural gas and many more.
Which brings us back to the question once again – when we still have billion years why the necessity to conserve water.
Every year billions and billions of cubic meters of water comes back to the surface as rain. Major part of it evaporates quickly or is taken up by the plant kingdom. Another major portion flows down to the oceans by rivers and gives the right salinity for marine life. About 1/10th of this rain water is being used by us and that also goes right back to the atmosphere to come back again. No water is actually ‘lost’ in this freshwater cycle. Why conserve it then?
This urgency to save water is due to two facts – Uneven distribution of freshwater precipitation in space & time and conversion of local water into inaccessible and unusable form . For both the reasons humans are alone to be blamed.
For thousands of years humans settled into areas where water was present in huge amounts. Decreasing green cover led to lesser and lesser rains in these areas which made them more and more dry. All that was evaporated went to areas where there was green cover. Heavy rains in green covered areas caused flood down the rivers destroying remaining vegetation in those regions. Pictures of 2014 Uttarkhand floods and trees falling like matchsticks is still clear in our minds.
One can still increase the rains in a region by painstakingly increasing green cover. Lots of desert reclamation work is done around the world but sadly not in India. Egypt is one such nation which is trying to reclaim desert by using untreated sewage water. Back home most of the plantaion drives to increase green cover are unscientific. People plant easy and maintenance free trees which further dry up land like Eucalyptus. Our farmers are dying in southern states of India due to drought for long while people in some Middle Eastern desert countries are enjoying heavy rainfalls and Gondola rides on city streets.
Many amateur environmentalists dream about redistributing water between the areas of plenty to areas of scarcity. One state was ready to send tanker trains to another drought stricken state. Ambitious plans do exist like the joining of all the rivers in our country or the great Chinese water pipeline. These will have their own deep impact on the environment but till now have been kept on shelf due to other cost effective means available.
The most important impact of such a plan would be the need for tremendous amount of energy which along with its associated carbon emissions will not be insignificant in the efforts to arrest climate change. Until we have abundant clean energy sources to power such re-plumbing of the planet’s water sources, we should not be investing in them. One example of clean energy application for water pumping and desalination for aqua is in Australia but still most of the desalination plants are energy extensive methods which damage marine ecosystem.
Which leaves us with no choice than to manage the local water. Theoretically this can be done but due to contamination use of local water has become more and more energy extensive and costly. Its not that contaminated and sewage water cannot be cleaned due to lack of technology. Pure water for drinking and personal use is affordable to people who can invest in it. This has made local water practically unusable and water- business flourish
At the same time reduction in rainwater due to destruction of green cover has created this scarcity. Once the water evaporates it doesn’t come to a region devoid of green cover. Farmers are facing drought due to years of unscientific irrigation which has caused all the water to evaporate and go somewhere else. Traditional way of surface irrigation causes huge water loss. Subsurface irrigation, drip irrigation or covered soil should be used to stop evaporation.
Once the surface water goes off we start pumping out ground water which again goes back to another region having green cover . Finally as water is sucked out of aquifers, the overlying soil and rock compact or collapse into the dewatered void, causing tall buildings to teeter like Mexico City, automobiles to tumble into sinkholes like Florida, or swallowing tourists on the fringes of the shriveling Dead Sea in Israel and Jordan.
The real meaning of conservation of water then is to keep the amount of water available locally, constant. It should not go away to greener pastures or become too contaminated to be used again. To prevent its evaporation to greener pastures most of it should go back to ground by aquifer recharging till green cover is established for a normal rain cycle.
All the water conservationists should make it absolutely clear that if we don’t use water prudently and cut trees in the name of development or smart cities or digitisation our precious water will go away to our neighbouring less developed but green countries.
We do many things to please Gods and Goddesses but fail to invite rain God who comes when there is green cover. At this time we don’t have blessings of rain God anymore in India.