Saturday, January 23, 2010

Global Warming – Understanding the Four Ws


What?

Simply put it is the phenomenon that proves through observations (satellites, weather balloons, meteorological stations, etc) that earth as a whole is warming up. Over the last 100 or so years, the average temperature of Earth’s surface has gone up by around 1 deg C. Though this doesn’t seem much and most certainly will not cause the Himalayan glaciers to disappear over the next 25 – 30 years as it had been erroneously mentioned by certain authorities, neither will this rise in temperature cause such massive ice cap melts so as to inundate the oceans and low lying lands, yet it is an indication of our future, our near future and the catastrophes that it has in store for us.

Though humanity as a species will continue to flourish; large chunks of us would perish due to calamities that arise out of direct action of GW. Very briefly (and I will cover the effects of GW in a separate post), this slight increase in earth’s surface temperature has caused increased storms and flash floods and forest fires as well, all of which have accelerated in terms of frequency and magnitude of occurrence over the past decade or so. These are natural phenomenon for sure but they are being affected by GW, which in turn is being affected by us. Out of the 20 warmest years on record over the last millennium, it is worrying to note that 19 have occurred since 1980 and the three hottest years (average) have all occurred in the last decade. So let no one fool you into believing that GW is all hogwash and Al Gore’s money and PR generating campaigns. It is interesting to note that following the climate prediction models based on historical data Earth should presently be in its cooling stage (due to solar cycles and volcanic activities) and not in a warming up stage at all. We should ideally be heading for a mini ice age. Earth is not only warming up but is also warming up at an accelerated rate. A study says that the climate change (from cool to warm) might actually happen abruptly and far too suddenly, rather than being a slow and steady transition process, due to certain specific hotspots around the world.

Why?

Warming of earth’s surface and associated climate change and life habitat is a natural process that has been happening ever since our terra firma cooled down enough to generate oxygen rich atmosphere and gave birth to life. Warm periods have followed ice-ages and vice-versa through epochs ideally spaced out between 50,000 to 100,000 of earth years. More than anything else, what is important to our generation is the fact that why on earth is Earth warming up at such an accelerated rate that is beyond what nature would cause, more so over the last three decades than ever before. What are the reasons? Before we go any further, we must understand ‘Greenhouse Effect’ briefly.

Earth is surrounded by a thin layer of gases that makes up our atmosphere. This layer of gases actually causes the greenhouse effect, without which there would be no life on earth. Sun is our primary source of energy, and about one third of this solar energy is reflected back into the outer space by such reflective surfaces as glaciers, ice caps, water bodies, etc. The balance two third is absorbed by the Earth that warms up our oceans, lands and atmosphere. The process by which the heat is trapped and distributed in Earth’s atmosphere is called the ‘greenhouse effect’. They are caused by the presence of such greenhouse gases as carbon dioxide, methane, water vapor, etc in our atmosphere. They trap the heat that Earth reflects back to the outer space. This heat is further distributed and circulated like a giant fan evenly around the world therefore giving us a comfortable average temperature of 14 deg C. But for these gases Earth’s average temperature would plunge to 18 deg C below zero that would not breed life. Greenhouse gases and greenhouse effect is not bad, in fact we exist because of them. What is bad is its excess presence in our atmosphere and the rapidly increasing effects of greenhouse. To give the analogy of a glass greenhouse which has glass roofs through which sunrays and heat can penetrate. This in turn heats up the trapped air inside the greenhouse. Since this heated air cannot escape, the internal temperature of the greenhouse keeps rising. That’s exactly what Earth is facing right now. Earth, in place of glass walls, has atmosphere that acts nearly like the glass walls but in a manner far more complex. Nearly half of Sun’s energy reaches us in the form of infrared radiation while the balance when hits the surface and is reflected back changes into infrared radiation therefore the reflected energy that goes back into the atmosphere carry more infrared radiation than what originally came in. Though the atmosphere allows the shorter wavelength radiations to pass through it traps most of the longer wavelength infrared and further disburses across the globe.

The primary causes that have increased the rate of greenhouse effect to a scale where our atmosphere is trapping more heat than that is necessary are all created by us human beings. It is interesting to note that in the beginning; nearly 2.7 billion years ago there was so much carbon dioxide and methane in the atmosphere that Earth’s average surface temperature was 70 deg C. Then over millions of years through bacterial and other organisms and plant’s photosynthesis actions the carbon dioxide was broken down into oxygen to finally reach a concentration level below 300 parts per million (ppm). Since the advent of the 18th century the CO2 concentration has been rising steadily. Climate scientists across the globe universally believe that the human upper safety limit of CO2 in atmosphere is 350 ppm. We crossed this limit somewhere in the decade preceding 1980. This is directly attributable to increase in certain human activities both in volume and frequency that gives rise to increase CO2 ppm along with other greenhouse gases like methane and water vapor. The activities are: Agriculture, which is a major source of methane and nitrous oxide and accounts for 15% of the world’s greenhouse gas emissions. Industrialization, which accounts for more than 50% of CO2 emissions especially in energy producing and energy intensive industries. Transportation: Nearly 25% of all man induced CO2 emissions are directly related to our modes of transportation, be it car, planes, ships. Deforestation: to make room for urbanization, infra structure developments, population, agriculture, etc we cut trees at a pace that is impossible to regenerate and this causes around 25% of all CO2 emissions.

Where?

GW is an universally observed phenomenon and it is happening everywhere. It would be a fallacy to claim that GW is happening only at the already hot places on Earth like around the Equator, through the deserts or in the tropics. GW is happening at the poles and in the high Himalayan glaciers, as much as in cold Nordic countries as in tropical nations. Though it has been observed and naturally so that the rise in temperature is more obvious and higher in the vicinity of human habitation more so where it is heavily industrialized. This only proves that it is due to us that GW is growing at a rapid rate. So even if you find that this year’s winter is unsettlingly cold, remember that the earth as a body in whole is heating up notwithstanding your cold corner of the world. I might cover such local anomalies and the world’s hot regions (climatically) in depth in a post later.

When?

GW is happening right now. It has been happening all the while for more than a billion year for certain though it has gained alarming proportions only in the last century. Most developed countries are contributing more to it than the poor cousins. The western and cold nations generate more greenhouse gases than the others. But all these controversial facts and hypothesis at a later post.

1 comment:

  1. Most of the GW articles get so tedious and boring while yours is absolutely to the point and the language is nice and simple!

    Must download it for Ana's school GW project too, whenever needed. Do i need permission :-)

    ReplyDelete