Let us resolve to follow the three Rs of environmental awareness — reduce, reuse, recycle.

The fact that Mother Earth faces an environmental crisis is indisputable. It is also clear that much of it is due to our unsustainable use of natural resources. Earth just cannot support seven billion (and growing) human beings. No wonder all our resources, from water to petrochemicals, are being depleted at an alarming rate.

Water tables, laid down over thousands (if not millions) of years, are fast disappearing. Mountain glaciers, the source of many rivers and storehouses of fresh water, are receding within the lifetime of a sherpa. Traditional fisheries are disappearing so fast that fishermen have to venture farther and farther out for ever-smaller catches. Many staple fish species have become extinct in their catchment areas. Our existing method of agriculture is able to feed an ever-growing population because of its unsustainable use of petrochemical-based fertilizers. Once petrol supplies disappear, we are certain to face mass starvation.

Coral reefs, built slowly over millions of years and which act as natural barriers against coastal erosion, are dying because the greenhouse-gas-induced global warming has caused sea temperatures to rise. The vast ecosystem of plant and animal life supported by the reefs is dying with them. Global warming is also causing the polar ice caps to melt and raise the sea level. This spells doom for many island and coastal communities, because their lands lie at or below sea-level. A recent study has shown that the next big mass extinction is already upon us, and it is almost certainly caused by human action. Mass extinctions have occurred at least five times in the history of life on Earth, with the most significant ones occurring 251 million years ago (Permian-Triassic boundary) when about 96 per cent of all marine species and about 70 per cent of land species including insects became extinct, and more recently 65.5 million years ago (end Cretaceous) when the dinosaurs became extinct and made way for the evolution of big land mammals including humans.

Coincidentally, these two events occurred simultaneously with large basaltic lava eruptions (formation of Siberian traps and Deccan traps, respectively), which spewed enormous amounts of greenhouse gases into the atmosphere. The resulting climate change was one of the most likely reasons for the extinction. Humans are causing similar climate change, but over a time scale of a few hundred years, and not the millions of years in the case of volcanic eruptions. And this mass extinction will be the first time that a species which is part of the same ecosystem has caused it, and not natural events. Most mammalian species have a lifespan of a million years before they go extinct, but several have gone extinct in human history, lasting only a few thousand years, due to a combination of climate change, habitat destruction, and poaching.

The amazing thing is that Mother Earth has recovered quite spectacularly from these past extinctions, so there is no reason to fear that she will not recover from the present human-caused one. Unfortunately, it is quite likely that we will not be around to see this recovery. Unfortunate because humans are the first species to have received from evolution the gift of consciousness, the mental awareness of our own existence and the ability to foresee the dire consequences of our actions.

Earth is being constantly churned by volcanic eruptions that bring molten rock from the mantle to the crust. In some sense, this is new Earth because it wipes out completely what was there before. Such new Earth teems with life within a couple of years. It is thus likely that we cannot do anything to harm Earth on its timescale of millions of years, but we can certainly do damage on human timescales, and kill ourselves in the process.

I do not want to end this piece as a doomsday predictor, but would like to suggest that we can prevent much of this from happening if we act now and act fast. Let us resolve to follow the three Rs of environmental awareness — reduce, reuse, recycle — and not just repeat this as some mantra but consciously work to implement this in our daily lives. Conserving water, the most important requirement for life, should become an immediate national priority. Our biggest problem is our population.

We can ensure a sustainably high quality of life for future generations if we have about half of our current population. Therefore, we should voluntarily limit ourselves to having one child per family for the next few generations.

(The writer belongs to the Department of Physics, Indian Institute of Science, Bangalore. Email: vasant@physics.iisc.ernet.in)

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