I am responding to Jennifer Kim's Nov. 10 letter, "Myth of an overpopulated world," which claims that world overpopulation, now or in the near future, is a myth. Part of her argument involves living space, and I agree that physical living space, per se, is not currently limiting. It is simply untrue, however, that there are more than enough natural resources "to sustain the world's population many times over." At what level and for how long would these mega-populations be sustainable? Not even the present population of 7 billion is sustainable indefinitely at the current average global living standard. Many critical resources such as arable land and irrigation water for crops are already in short supply.

Likewise, fully half the world's fisheries are being maximally fished and 25 percent are overfished or depleted. The availability of resources like these will not double if the population doubles.

Sustainability is not only about resource availability. We humans are badly soiling our nest: Each day, combustion engines and power plants convert 85 million barrels of oil to carbon dioxide, which is overwhelming natural buffering systems like forests and oceans. Freshwater runoff from farming becomes contaminated with fertilizers and pesticides. Climate change — from carbon dioxide emissions — and pollution will decrease sustainability. Finally, every hectare of tropical forest cleared for human living space or agricultural land drives other species on Earth to extinction, and with each extinction, we lose something precious.

Kim seems to be in favor of (or at least not aghast at) a doubling or tripling of the current global population. Quantity of life does not equate with quality of life, and by any criterion one chooses, quality of life on Earth would be better if the population were halved or quartered over the long term, rather than doubled or quadrupled.

The opinions expressed in this letter to the editor are the writer's own and do not necessarily reflect the policies of The Japan Times.

matthew dick