Climate Change and civilizations…

In my previous post on the topic of global warming and its impact on planet’s climate, I had delved into the causes behind global warming and varying opinions of different authority figures. This time, I would like to trace the effects of climate change on the evolution of humanity.

I came across an interesting article by Dr Nachiketa Das – where he discusses the topic of climate change and its effect on river Ganges.

He is of the opinion – “Global warming, now in 2008, is real, and upon us. How will global warming affect the rivers in India; will they all dry up? Can the holy Ganges, the river that has shaped and sustained Indian civilization through the ages, who we Indians revere as the life-giving mother, run dry! Many climate experts and environmentalists, in the last ten years, have been making dire predictions of the Ganges becoming seasonal. Some doomsayers have even gone to the extent of boldly predicting the river to be ephemeral by the year 2035, which is barely a generation away! Is it really possible that the Ganges will run dry by 2035! Is this calamity an inevitability that should be accepted as fait accompli, or is there anything we, the people of India, collectively can do to save the holy Mother Ganges from extinction”.

The concerns are valid. The Ganges originates from Gangotri glacier, which is one of the largest valley glaciers located in western Himalayas. 30.2 km long and 0.5 to 2.5 km wide Gangotri lies recumbent at the altitudes between 4,120 and 7,000 m above sea level. The total area occupied by the glacier complex (in 2001) that feeds Ganges, is 260 square km, which contains 40 cubic km of ice (in 1999). During a 60 year period between 1936 and 1996, Gangotri has receded by as much as 1,147 m, 850 m of which happened during a 25 year period between 1971 and 1996. In a three year period between 1996 and 1999 Gangotri retreated by 76 m. When this result is contrasted with the 2,000 m retreat over the last 200 years, the significantly accelerated rate of retreat has become obvious.

Also, Global warming does not mean uniform amount of warming at each and every place on the globe. Although vast majority of the places on this earth will become hotter due to global warming, however strange it may seem, certain parts will in fact become cooler.

Why? Well, it has to with how the weather and heat transfer systems work on our planet. Unlike the frozen wastes of Mars or lead melting surface of Venus, our planet is blessed with a very complex, yet delicate ecosystem.

The Gulf Stream is a vast oceanic current that carries warm waters from the tropics to the temperate regions of northern Europe and North America. This ocean current originates in the Gulf of Mexico, flows past the east coast of the USA and Newfoundland in Canada, and then crosses the Atlantic Ocean. It then branches into two, with the northern stream moving to northern Europe. The Gulf Stream is about 80 to 150 km wide and a 1,000 m deep river of sea that transports 1.4 petawatts (1 petawatt is 1,000 million megawatts) of heat, which is equivalent to almost 100 times the current energy demand of the entire world. Around Cape Hatteras on the coast of North Carolina in the US, the Gulf Stream transports water at the rate of 80 million cubic meter per second, and is much bigger than any river system of the world; in fact the combined release of all the waters from all the rivers flowing into the Atlantic is only 0.6 million cubic meter per second.

The Gulf Stream has significant localized effects on the climate of the east coast of Florida and Massachusetts in the US; and the west coast of Britain, which is a good few degrees warmer than the east coast. The warming effect of the Gulf Stream is most dramatic in the western islands of Scotland, so much so that the small township of Plockton (latitude 57.33oN) that is located east of the Isle of Skye, has a mild climate that allows sub-tropical cabbage-palm-trees to grow. The local climate in Plockton in the absence of the Gulf Stream would be freezing cold as latitudinal it lies further north of Moscow (latitude 55.45oN) by almost two degrees.

Due to global warming, there is every possibility that the Gulf Stream may change course or it may lose its strength. In fact in November 2004, it completely stopped for full ten days, and there are reports saying that in the last 50 years (since 1957) its deep return flow has weakened by as much as 30%. Any change in the characteristics of the Gulf Stream, would cause significant localized cooling in Scandinavia and Britain. At a time of global warming, the western islands of Scotland will experience substantial cooling.

The effects on human population and civilization can be imagined.

This, however, is the not the first time that climate change has affected humanity on such a scale.

The river Sarasvati for example, is widely considered to have supported the Harappan culture. Movement and ultimate decline of the Harappan culture are often attributed to climate change and its ultimate effect on river Sarasvati. Some Rigvedic verses (6.61.2-13) indicate that the Sarasvati River originated in the hills or mountains (giri), where she "burst with her strong waves the ridges of the hills (giri)". It is a matter of interpretation whether this refers not merely to the Himalayan foothills like the present-day Sarasvati (Sarsuti) river. The Sarasvati is described as a river swollen (pinvamānā) by other rivers (sindhubhih). Another reference to the Sarasvati is in the geographical enumeration of the rivers in the late Rigvedic Nadistuti sukta (10.75.5, this verse enumerates all important rivers from the Ganges in the east up to the Indus in the west in a strict geographical order), as "Ganga, Yamuna, Sarasvati, Shutudri", the Sarasvati is placed between the Yamuna and the Sutlej, consistent with the Ghaggar identification. It is clear, therefore, that even if she has unmistakably lost much of her former prominence, Sarasvati remains characterized as a river goddess throughout the Rigveda, being the home river of the Puru and later on, the Kuru tribe.

While Sarasvati River might still be remembered, its influence on Indian history cannot be discounted. Nor can its decline be overlooked.

However, climate change need not always be so bad for human culture. After all, our present day humans ascended to our current position in evolutionary terms due to ending of an ICE AGE.

Sahara desert, the largest one on our planet, used to be a very lush and green place before the change in climate led to its present state and forced a lot of human tribes into the valley of the Nile, leading up to its fabulous civilization and myriad dynasties.

Sustenance played a crucial role in the founding of Egyptian civilization. The Nile is an unending source of sustenance. The Nile made the land surrounding it extremely fertile when it flooded or was inundated annually. The Egyptians were able to cultivate wheat and crops around the Nile, providing food for the general population. Also, the Nile’s water attracted game such as water buffalo; and after the Persians introduced them in the 7th century BC, camels. These animals could be killed for meat, or could be captured, tamed and used for ploughing — or in the camels' case, travelling. Water was vital to both people and livestock. The Nile was also a convenient and efficient way of transportation for people and goods. The Nile played a major role in politics and social life.

But at the end of the day, it was climate change which led to rise and fall of these civilizations….

So what are we worried about?

It’s just that we humans are much more numerous now and spread of more area of the planet than at any time in our history. So climate change this time, turns out to be very inconvenient indeed and because it might lead to decline of our current global civilization and ultimately bring misery to untold billions, that we are so concerned.

We humans seem to be standing too much in the way of nature to be left unscathed by the fury that will be unleashed by the current spell climate change, arguably induced by our actions only…

Global Warming and its effects on Planetary Climate

There is a lot of buzz on the planet about global warming and its adverse effects on planet’s ecology, our society and civilization at large. But what is all this debate about?

Thanks to the media attention, many people are concerned about global warming, but they do not know what to do about it. The first thing is to understand the problem and its apparent root cause: increase in the amount of Carbon Dioxide in planet’s atmosphere or is it?

According to Victor Miguel Ponce – “The concentration of carbon dioxide in the atmosphere determines to a large extent the present world climate, with temperature being an important component. Through geologic time, carbon dioxide entering the atmosphere from natural sources such as volcanic eruptions and weathering of rocks, has been gradually used by vegetation, through the process of photosynthesis. In the past two-and-a-half billion years, carbon has been temporarily stored above the Earth's surface as standing biomass and litter. During this time, excess quantities of carbon were permanently stored below the surface as fossil deposits of coal, petroleum, and natural gas”.

However, it is an opinion which although backed with some facts, is not unanimous.

There is a somewhat informational site from Environmental Defense Fund which provides arguments against the common misunderstandings that people (in general) have about global warming. It can be accessed here à Global Warming Myths and Facts. There even a climate atlas available on this site.

Even the National Geographic has covered this topic of literally global concern. So it is happening? The answer is emphatic yes. There is more and more energy being pumped into global weather/ climate system causing ever more violent weather – hurricanes, stronger monsoons, etc. An upsurge in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts. Tragedy on human life is increasing since humanity is more spread and numerous on the planet now than it ever was in the entire history of our species or the planet.

T J Nelson provides an insight into cold facts (contrary to mass hysteria) about global warming in this illuminating article. I strongly recommend a reading. In this article, Nelson attempts to provide a balanced and scientific view of facts related to global warming. His assertion is essentially this – current hysteria about global warming is largely a hype created by media and certain so called scientific papers.

According to him – “Although carbon dioxide is capable of raising the Earth's overall temperature, the IPCC's predictions of catastrophic temperature increases produced by carbon dioxide have been challenged by many scientists. In particular, the importance of water vapor is frequently overlooked by environmental activists and by the media. The above discussion shows that the large temperature increases predicted by many computer models are unphysical and inconsistent with results obtained by basic measurements. Skepticism is warranted when considering computer-generated projections of global warming that cannot even predict existing observations”.

http://www.junkscience.com/Greenhouse/ tries to debunk the entire mythology around global warming. This article (or set of it) actually tries to delink the “greenhouse effect” and global warming and the entire concept of climate change. It is very reassuring to the skeptic in me that there are people out there who are actually questioning blind following and mass hysteria being created by certain circles.

So is there no cause for worry? Have humans caused this global warming? The opinion though not unanimous, is overwhelmingly in favor of human causality. To know in a more coherent manner, one has to understand a few facts first:

• There is general agreement amongst scientists of this planet that our planet was “The Earth” was formed about 4,540,000,000 years ago – that’s 4.54 billion years.
• At the time of beginning and for quite sometime after that, the Earth's atmosphere contained very little oxygen (less than 1% oxygen pressure).
• Popular belief among the scientific community has it that early plants started to develop more than 2 billion years ago, probably about 2,700,000,000.
• It is an established fact that through photosynthesis, plants uptake carbon dioxide into the biosphere as organic matter, and release oxygen as a byproduct.
• Through geological ages, oxygen accumulated gradually in the atmosphere, reaching a value of about 21% of atmospheric gases at the present time. So our planet and its current atmosphere were terra-formed slowly over millions of years and concerted action of biological agents. It is not a “natural” occurrence, rather it would be safe to put it in these terms – life shaped earth’s climate and atmosphere to suit itself and brought about the present distribution of gases which we breathe.
• It is also believed that through geological ages, surplus organic matter has been sequestered in the lithosphere as fossil organic materials (coal, petroleum, and natural gas).
• Early animals (the first organisms with external shells) started to develop around 600,000,000 years ago
• Animals operate in the opposite way than plants: they take up oxygen, burn organic matter (food), and release carbon dioxide as a byproduct
• Early humans (Australopithecus anamensis) began to develop about 4,100,000 years ago
• Cool climatic conditions have prevailed during the past 1,000,000 years. The species Homo sapiens evolved under these climatic conditions
• Homo sapiens, that’s us, dates back to no more than 400,000 years.
• Estimates for the variety Homo sapiens sapiens, to which all humans belong, range from 130,000 to 195,000 years old
• The concentration of carbon dioxide in the atmosphere was as low as 190 ppm during the last Ice Age, about 21,000 years ago.
• The last Ice Age began to recede about 20,000 years ago
• The agricultural revolution, where humans converted forests and rangelands into farms, began to develop about 10,000 years ago.
• The agricultural revolution caused a reduction in standing biomass in the biosphere and reduced the uptake of carbon dioxide in midlatitudinal regions, indirectly contributing, however so slightly, to global warming.
• The concentration of carbon dioxide in the atmosphere increased gradually from a low of 190 ppm 21,000 year ago, to about 290 ppm in the year 1900, i.e., at an average rate of 0.00478 ppm per year
• The industrial revolution, where humans developed machines (artificial animals, since they consume fuels, which are mostly organic matter), began in England about 240 years ago (1767).
• In October 1999, the world's population reached 6,000,000,000, which is double that of the year 1959 (the doubling occurred in 40 years)
• The global fleet of motor vehicles is estimated at 830,000,000 (2006).
• The global fleet of motor vehicles has been recently growing at the rate of 16,000,000 per year.
• Motor vehicles (cars, trucks, buses, and scooters) account for 80% of all transport-related energy use
• The concentration of carbon dioxide in the atmosphere, which was at 290 ppm in the year 1900, rose to 316 ppm in 1959, or at an average 0.44 ppm per year
• Measurements of the concentration of carbon dioxide since 1959 (316 ppm) have revealed an increase to 378 ppm in 2004, or at an average 1.38 ppm per year
• The concentration of carbon dioxide has increased an average of about 1.8 ppm per year over the past two decades
• The year 1998 was the warmest of record. The year 2002 was the second warmest (to that date). The year 2003 was the third warmest (to that date). The year 2004 was the fourth warmest (to that date). The year 2005 equaled 1998 as the warmest of record. The year 2007 equaled 1998 as the second warmest of record.
• About 75% of the annual increase in atmospheric carbon dioxide is due to the burning of fossil fuels
• The remaining 25% is attributed to anthropogenic changes in land use, which have the effect of reducing the net uptake of carbon dioxide. Anthropogenic changes in land use occur when forests are converted to rangelands, rangelands to agriculture, and agriculture to urban areas.
• Other patterns of land degradation--deforestation, overgrazing, over-cultivation, desertification, and salinization--reduce the net uptake of carbon dioxide, indirectly contributing, however slightly, to global warming.
  

What's could Happen?

A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.

• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.
• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.
• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.
• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.
• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.
  

We need to remember, Dinosaurs died out 65 million years ago – primarily due to climate change. It wasn’t only the asteroid which struck the earth and wiped out 99% species on land and oceans. It wasn’t just the impact – but the climate change induced by that impact which killed the species.

Can we do anything to stem this rising tide?

Sure! Just follow the tips on this wonderful blog. The Grinning planet provides some clues – which I would have anyway recommended even if our planet wasn’t threatened with global warming and so called catastrophic climate change!

Other resources:

• global-warming myths and facts at Undo-It.org
• climate change science at RealClimate.org