The Fragile Earth – Life in the balance (Part 1)

“We do not inherit the earth from our ancestors, we borrow it from our children.” – Native American proverb.

Very profound, and deeply insightful. Many of us may realise the implications, but only a few of us actually live our lives by this adage. Consider these bare statistics over the last few generations:

• 18 animal species have become extinct in the last seven years, and hundreds over the last century
• Since 1993, sea levels have risen by an average 3.5 mm per year, compared to the 1 mm per year for the previous hundred years, and 0.1 mm per year for 3000 years before that
• Nature magazine featured a study that found hurricanes have grown significantly more powerful and destructive over the past three decades

Clearly, we are not borrowing from our children; we are quite literally, robbing them blind. A time may soon come when the current generation would be derided in the annals of human civilisation for having brought it to the brink of extinction.

As the world debates the future course of action at the 2007 United Nations Climate Change Conference at Nusa Dua, Bali, Indonesia from 3 December to 14 December, let us look at what global warming is all about, and its implications to our fragile planet.

The earth in its bountiful splendour may seem to be a limitless mass of natural resources, all laid out for the taking. However, the truth is that it is just the third rock from an ordinary star at one end of a spiral galaxy, in a universe teeming with billions of such galaxies. And it is fragile. The ideal conditions that nurtured the cradle of life on earth are weights in a delicate balance; a balance mankind is bent on destabilising in its march to so called ‘progress.’

It is said that pictures speak a thousand words, and nowhere is this axiom truer than in the following photograph:

This photograph was taken by the Voyager 1 spacecraft on February 14, 1990. On first look it may not seem impressive; but considering that it was taken at a distance of 6.4 billion kilometres (that’s 160,000 times a round-the-world trip), and provides a unique view never seen before, the photograph’s exalted position as one of the best ever taken in space is justifiable. Earth shows up as a ‘pale blue dot’ in the grainy picture, taking up less than 0.12 pixels.

In a commencement address delivered May 11, 1996, renowned astronomer Carl Sagan related his thoughts on the deeper meaning of the photograph:

“Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilisation, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam.”

The importance of this blue dot is underlined in the following words:

“The Earth is the only world known so far to harbour life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.”

In recent times, the phenomenon of global warming and its debilitating future effects have become subjects of talk shows and water-cooler conversations. Notwithstanding the usual scorn associating celebrity endorsements with frivolity, the spread of climate change as a topic of discussion from scientific panels to dinner tables can be attributed to two documentaries helmed by celebrities –

1. An Inconvenient Truth by Al Gore
2. The 11th Hour by Leonardo DiCaprio

We will look at each of these in turn, in the second, and the concluding parts of this series.

First, let us understand the issue of global warming. It can be defined as “the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation”.

The global average air temperature near the Earth's surface has risen by around 1°C over the last hundred years, with most of the rise being attributed to greenhouse gas emissions.
Climate model projections simulated on supercomputers estimate a further rise of 1.1 to 6.4 °C in the 21st century, unless remedial measures are taken.

While this may seem quite trivial and its resolution a simple cranking up of the air-conditioner, the reality is far from simple – in fact it is quite horrifying. With increased temperatures, sea levels will rise as the polar ice caps melt, leading to flooding of several populated areas. Extreme weather events like cyclones and hailstorms may become commonplace, even in places where they haven’t been experienced ever before. Agricultural yields may decline leading to global food shortages, and several flora and fauna may become extinct. The changed conditions may give rise to new, drug-resistant disease vectors leading to worldwide epidemics. In short, civilisation as we know may cease to exist. It won’t happen in a day, or a month, or even a decade. But it WILL happen, if we continue on our present “road to perdition”.

To understand the phenomenon of global warming due to greenhouse gases, we first need to consider how a greenhouse works. A greenhouse, as we all know, is a glass structure inside which plants are grown. Now, a greenhouse retains heat because the shorter wavelength solar radiation passes through the roof while the longer wavelength radiation emitted by the interiors is blocked. Also, the sealed premises also prevent other modes of heat loss like convection. The term ‘greenhouse effect’ can be slightly misleading because the major warming in a greenhouse is done by suppressing convection and not radiation, unlike in the atmosphere.

It’s not that the greenhouse effect in the earth’s atmosphere is a man-made invention. It has existed for almost as long as the earth has had an atmosphere. In fact, it is its existence that makes the earth habitable in the first place. Without it, the earth would be a frozen wasteland. However, too much of a good thing can also be bad. Similar is the case with the greenhouse effect. Due to increased human industrial activity, the amount of carbon dioxide in the atmosphere has increased considerably over the last few decades. As a result, the longer wavelength radiation emitted by the heated surface is being increasingly absorbed by the atmosphere leading to what we know as ‘global warming’.
That is why the contributing factor to global warming is ‘anthropogenic greenhouse effect’ or man-made greenhouse effect, and not ‘greenhouse effect’ per se.

Let us look at the aforementioned documentaries, and the guiding players behind them who are trying to educate the world to open their eyes to the impending catastrophe that is global warming.

>> Global warming: time is running out (Part 3)
>> Al Gore speaks an Inconvenient Truth (Part 2)