An article by Mohan Pai
(This article was written by me for a publisher in Goa more then two years ago. It’s still very relevant and I thought I will reproduce it here for my blog readers.)
The Earth is heating up – and fast.
Cause for alarm ?
Global Warming issue is now really hotting up. The ‘Catastrophe’ that the world and humanity now faced with is of such mammoth proportions and unprecedented that humanity’s very survival is in question. Sceptics thought that it was a case of “crying wolf”. But the wolf now seems to be at our very doorstep.
11 of the last 12 years have been warmest on record.Intergovernmental Panel on Climate Change issued the summary of its fourth report in Paris on May 2 of this year. It is quite categorical about the fact that global warming is mainly due to anthropological (human-made) causes. Mainly the emission of greenhouse gases into the atmosphere due to human influence. For decades, this has been a topic of conjecture but no more. All the signs are now clearly there – the melting ice of the glaciers, increase in the number of heat waves, increased intensity of tropical storms, changing weather patterns and rising sea levels.
Worldwide, very little is being done to control or reduce the emissions of greenhouse gases. U.S.A. which is the largest emitter (25%) of greenhouse gases is not even a signatory to Kyoto protocol that is formed to control the greenhouse gases emissions. Deforestation, a major contributor to greenhouse gases emission, continues unabated in Brazil and Indonesia releasing billions of tons of Co2 into the earth’s atmosphere.
For India, the reality lies in some stark occurrences like farmer suicides or disappearance of two islands in the Sunderbans due to rising water displacing 6,000 people. Also the fact that the Himalayan glaciers are melting fast and some very clear signs of rise in sea levels.
For Goa, implications of global warming will be truly horrendous. Some predictions give the year 2020 when India’s shorelines will be inundated with one-metre rise in sea level. The entire West Coast will be devastated and Goa will go. One estimate puts the loss of property and assets in Goa at Rs. 5,000 billion. The three metros – Mumbai, Chennai and Kolkota are also expected to be submerged along with most of the coastal settlements of India.
It could happen by 2030 0r 2070 but, the probability is very high. The issue is of a global-scale and requires global-scale action. About time everybody woke up.
Are we going to shut the barn door after the horse has bolted ?
December 10. 2006
WHAT IS GLOBAL WARMING ?
The earth’s average temperature is on the rise. For decades this has been a subject of conjecture, but no more. The climate change is with us. According to Climatologists, 2005 was the warmest year in a century, with 1998, 2002, 2003 and 2004 next in line. The visible effects can now be felt in the form of melting glaciers in Greenland, Alaska, the Alps, the Himalayas and the polar regions of the Arctic and the Antarctic. Permafrost (permanently frozen soil) in Canada, Alaska and Siberia is melting at an alarming rate. Sea levels are rising. Hurricanes are becoming more numerous and more intense. According to some, humanity is sitting on a volatile time bomb – one that could send the entire planet into a tailspin of epic destruction, with detonation not far in the future. But is this a realistic scenario ?
This diagram predicts the global temperatures for the period 2070-2100 vs 1960-1990 average temperatures.
One of the most hotly debated topics on the earth today is the subject of climate change. The term ‘global warming’ which in common usage refers to recent warming and implies a human influence. According to the National Academy of Sciences, the average surface temperature of the earth went up by one degree Fahrenheit during the past hundred years, with accelerated warming occurring within the past 20 years and the decade of 1995-2005 being the warmest during the last hundred years
It is such an intricate and complex subject that even today’s super computers have been inadequate for correct predictions. Since 1950 there have been indications of rise in global average temperatures and in the seventies and the eighties of the last century the phenomena started becoming more prominent. Considering the seriousness of the threat, the United Nations set up the Intergovernmental Panel on the Climate Change (IPCC) in the year 1988. With hundreds of scientists and specialists working on the project, the Panel has built a massive data base and so far issued four reports. The fourth report was issued in the month of February, 2007 in which the IPCC has sounded the bleakest warning on Climate Change that human activity is the main driver, “very likely” causing most of the rise in global temperatures since 1950. The following graph indicates the probability of the phenomenon and the warning signs that are becoming apparent.
*Eleven of the last 12 years are among the warmest on record
*Oceans have warmed down to 3,000 metres
*Mountain glaciers and snow cover have declined
*Satellites have seen an acceleration in sea level rise
*More intense and longer droughts have been observed
*Arctic ice cover is shrinking in depth and in extent
It is very likely that human activities are causing global warming.
Possible temperature rise by the end of the century ranges between 1.1C and 6.4C (2-11.5F)
Sea levels are likely to rise by 28-43cm
Arctic summer sea ice is likely to disappear in second half of century
It is very likely that parts of the world will see an increase in the number of heat waves
Climate change is likely to lead to increased intensity of tropical storms
75-250 million people across Africa could face water shortages by 2020
Crop yields could increase by 20% in East and Southeast Asia, but decrease by up to 30% in Central and South Asia Agriculture fed by rainfall could drop by 50% in some African countries by 2020
20-30% of all plant and animal species at increased risk of extinction if temperatures rise between 1.5-2.5C
Glaciers and snow cover expected to decline, reducing water availability in countries supplied by melt water
Big questions remain about the speed and extent of some impending changes, both because of uncertainty about future population and pollution trends and the complex relationships of the emission of the greenhouse gases, clouds, dusty kinds of pollution, the oceans and the earth’s veneer of life, which both emits and soaks up carbon dioxide and other such gases.
The world’s primary international agreement on combating global warming is the Kyoto Protocol, an amendment to the United Nations Framework Convention on Climate Change (UNFCCC), negotiated in 1997. The Protocol now covers more than 160 countries globally and over 55% of global greenhouse gas emissions. The United States, the world’s largest greenhouse gas emitter (25% of the total world emission); Australia; and Kazakhstan have refused to ratify the treaty. China and India, two other large emitters, have ratified the treaty but, as developing countries, are exempt from its provisions. This treaty expires in 2012, and international talks began in May 2007 on a future treaty to succeed the current one.
These graphs show actual data and 2001 Ipcc predictions for carbon dioxide concentrations in the atmoshere in parts per million (top graph): changes in temperature relative to 1990 temperatures (middle graph) and changes in sea-levels relative to 1990 levels (bottom graph).
The earth’s climate and weather is driven by energy from the sun. The greenhouse effect is the rise in temperatures that the earth experiences because certain gases in the atmosphere (water vapour, carbon dioxide, nitrous oxide, methane and ozone, for example) trap energy from the sun. The energy heats the earth, which in turn radiates that heat back into space. But, much of this heat is retained by the greenhouse gases in the earth’s atmosphere. Without these gases, heat would escape back into space and the earth’s average temperature would be about 60 degrees Fahrenheit colder and obviously, this would not be an environment conducive for life and the earth would be inhabitable.
But the problem arises when the quantum of greenhouse gases increases to a higher level and the greenhouse effect becomes stronger increasing the heat in the atmosphere and making the earth warmer than usual. Even a little extra warming may give rise to serious problems for life on earth – humans, plants and animals.
The greenhouse effect was discovered by Joseph Fourier in 1824 and was first investigated by Svante Arrhenius in 1896. On earth, the major greenhouse gases are water vapour, which causes about 36-70% of the greenhouse effect (not including the clouds), carbon dioxide (Co2), which causes 9-26%, methane (Ch4) which causes 4-9% and ozone, which causes 3-7%. The atmospheric concentrations of Co2 and Ch4 have increased by 31% and 149% respectively above pre-industrial level since 1750. These levels are considerably higher than at any time during the last 6,50,000 years, the period for which reliable data has been extracted from ice cores.
About three-quarters of the anthropogenic (man-made) emissions of Co2 to the atmosphere during the past twenty years are due to fossil fuel (petrol, diesel, coal, etc.) burning. The rest of the anthropogenic emissions are predominantly due to land-use change, especially deforestation.
If current trends continue, we will raise atmospheric Co2 concentrations to double pre-industrial levels during this century. That will probably be enough to raise global temperatures by around 2 to 5 degrees Centigrade. Some warming is certain, but the degree will be determined by feedbacks involving melting ice, the oceans, water vapour, clouds and changes in vegetation.
The main causes for the increased greenhouse effect are the burning of the Fossil Fuels and Deforestation
Fossil Fuels and the Global Carbon Cycle
Huge amounts of carbon have been captured by plants and buried in the ground in the form of coal, oil, natural gas called fossil fuels. These fuels have accumulated over the course of millions of years. With the advent of Industrial Revolution, mankind began extracting and burning earth’s vast reserves of these fuels. This released millions of tons of carbon, in the form of Co2 in the atmosphere, thus increasing the levels of greenhouse gases that are now affecting the earth’s temperature. Since then, atmospheric concentrations of Co2 have increased nearly 30%, methane concentrations have more than doubled, and nitrous oxide have risen about 15%. These increases have enhanced the heat trapping capability of the earth’s atmosphere, and will continue to do so for years to come.
As per the IPCC report : “Annual fossil fuel carbon dioxide emissions increased from an average of 6.4 GtC (billion tonnes of carbon) in the 1990s to 7.2 GtC in 2000-2005.”
Deforestation and the Global Carbon Cycle
Carbon dioxide ( CO2) is the major gas involved in the greenhouse effect, which causes global warming. All the things that produce CO2 (like car burning gas) and the things that consume Co2 (growing plants) are involved in the “global carbon cycle”.
Tropical forests hold an immense amount of carbon, which joins with oxygen to form CO2. The plants and soil of tropical forests hold 460-575 billion metric tons of carbon worldwide. Each acre of tropical forest stores about 180 metric tons of carbon.
Deforestation increases the amount of CO2 and other trace gases in the atmosphere. When a forest is cut and replaced by cropland and pastures, the carbon that was stored in the tree trunks (wood is about 50% carbon) joins with oxygen and is released into the atmosphere as CO2.
The loss of forests has a great effect on the global carbon cycle. From 1850 to 1990, deforestation worldwide (including that in the United States) released 122 billion metric tons of carbon into the atmosphere, with the current rate being 1.6 billion metric tons per year. In comparison all the fossil fuels (coal, oil and gas) burned during a year release about 6 billion tons per year.
Releasing CO2 into the atmosphere increases the greenhouse effect, and may raise global temperature. The role of fossil fuels burned by cars and industry is well known, but tropical deforestation releases about 25% of the amount released by fossil fuel burning. Tropical deforestation, therefore, contributes a significant part of the increasing CO2 in the atmosphere.
GLOBAL TEMPERATURE PROJECTIONS
The Intergovernmental Panel on Climate Change predicts that temperatures are most likely to rise by 1.8 C – 4C by 2001. But the possible range is much greater; 1.1C – 6.4C. The maps above show how a range of three different scenarios will affect different parts of the world.
The emissions scenarios,B1, A1B, A2 used to create the maps above, are based on a range of detailed economic and technological data. These versions of the future consider different population increases, fossil and alternative fuel use, and consequent Co2 increases.
Carbon dioxide is the main greenhouse gas, its rise since the industrial revolution is clear. Burning coal, using oil and deforestation all place Co2 into atmosphere.
The other two main greenhouse gases are methane and nitrous oxide. Both gases have a much smaller presence in the atmosphere than Co2 but are much stronger greenhouse gases; methane has over 20 times the effect of Co2, whileNitrous oxide is nearly 300 times stronger.
What is the evidence of warming?
Temperature records go back to the late 19th Century and show that the global average temperature increased by about 0.6C in the 20th Century. Sea levels have risen 10-20cm – thought to be caused mainly by the expansion of warming oceans. Most glaciers in temperate regions of the world and along the Antarctic Peninsula are in retreat; and records show Arctic sea-ice has thinned by 40% in recent decades in summer and autumn. There are anomalies however – parts of the Antarctic appear to be getting colder, and there are discrepancies between trends in surface temperatures and those in the troposphere (the lower portion of the atmosphere).
How much will temperatures rise?
If nothing is done to reduce emissions, current climate models predict a global temperature increase of 1.1-6.4C by 2100. Even if we cut greenhouse gas emissions dramatically now, scientists say the effects would continue because parts of the climate system, particularly large bodies of water and ice, can take hundreds of years to respond to changes in temperature. It also takes greenhouse gases in the atmosphere decades to break down. It is possible that we have already irrevocably committed the Greenland ice sheet to melting, which would cause an estimated 7m rise in sea level. There are also indications that the west Antarctic ice sheet may have begun to melt, though scientists caution further research is necessary.
How Will the Weather Change ?
Globally, we can expect more extreme weather events, with heat waves becoming hotter and more frequent. Scientists predict more rainfall overall, but say the risk of drought in inland areas during hot summers will increase. More flooding is expected from storms and rising sea levels. There are, however, likely to be very strong regional variations in these patterns, and these are difficult to predict.
What will the effects be?
The potential impact is huge, with predicted freshwater shortages, sweeping changes in food production conditions, and increases in deaths from floods, storms, heat waves and droughts. Poorer countries, which are least equipped to deal with rapid change, will suffer most.
Plant and animal extinctions are predicted as habitats change faster than species can adapt, and the World Health Organization has warned that the health of millions could be threatened by increases in malaria, water-borne disease and malnutrition. The precise relationship between concentrations of carbon dioxide (and other greenhouse gases) and temperature rise is not known, which is one reason why there is such uncertainty in projections of temperature increase. Global warming will cause some changes which will speed up further warming, such as the release of large quantities of the greenhouse gas methane as permafrost melts. Other factors may mitigate warming; it is possible that plants may take more CO2 from the atmosphere as their growth speeds up in warmer conditions, though this remains in doubt. Scientists are not sure how the complex balance between these positive and negative feedback effects will play out.
What don’t we know?
We don’t know exactly what proportion of the observed warming is caused by human activities or what the knock-on effects of the warming will be.
What about the sceptics?
Global warming “sceptics” fall into three broad camps: those who maintain temperatures are not rising those who accept the climate is changing but suspect it is largely down to natural variation those who accept the theory of human-induced warming but say it is not worth tackling as other global problems are more pressing.Nevertheless, there is a growing scientific consensus that, even on top of the natural variability of the climate, something out of the ordinary is happening and humans are to blame.
THE GREAT MELTDOWN
The Arctic, one of the most forbidding environments in the world, is home to the polar bear. During the summer, these animals roam this region on large chunks of floating ice, drifting for hundreds of miles. This is how they find mates and hunt for seals, fattening themselves to prepare for the severe winter. If these palettes of ice did not exist, the polar bear would not survive.
Within the past three decades, more than one million square miles of sea ice—an area the size of Norway, Denmark and Sweden combined – has vanished. Presently, ice at the southern Arctic region of the polar bear’s range is melting about three weeks sooner than has previously been the case. This affords the bears less time to hunt, eat and store fat. Due to this early melting, the Hudson Bay polar bear population has declined by 14% during the past ten years.Some climate models predict that 50 to 60% of this vital summer sea ice will disappear by the end of this century; others predict that by just 2070, the Arctic will be completely ice-free in the summer. If this does indeed occur, the world’s largest bear could become extinct.
Meanwhile, glaciers in Greenland are receding at alarming rates. Within the last five years, those along the eastern and western coasts have receded about 300 miles each. Although a total meltdown is highly unlikely, with more than one-fifth of the population living less than two feet above sea level, not much melting is required to cause significant damage.Permafrost in the Arctic region is diminishing as well. According to a report in the Geophysical Research Letters, it could shrink by 60 to 90% by 2100. A National Oceanic and Atmospheric Administration climate scientist states that this will increase freshwater runoff into the Arctic Ocean by 28%, lead to the release of large quantities of greenhouse gases from the soil, and upset ecosystems within a wide area.
Huge, pristine, dramatic, unforgiving; the Antarctic is where the biggest of all global changes could begin. There is so much ice here that if it all melted, sea levels globally would rise hugely – perhaps as much as 80m. Say goodbye to London, New York, Sydney, Bangkok, Rio… in fact, the majority of the world’s major cities. But will it happen? Scientists divide the Antarctic into three zones: the east and west Antarctic ice sheets; and the Peninsula, the tongue of land which points up towards the southern tip of South America.
. “Everybody thinks that the Antarctic is shrinking due to climate change, but the reality is much more complex,” says David Vaughan, a principal investigator at the British Antarctic Survey in Cambridge, UK. “Parts of it appear to be thickening as a result of snowfall increases. But the peninsula is thinning at an alarming rate due to warming. “The West Antarctic sheet is also thinning, and we’re not sure of the reason why.” Temperatures in the Peninsula appear to be increasing at around twice the global average – about 2C over the last 50 years. Those figures are based on measurements made by instruments at scientific stations. Earlier this year, David Vaughan’s group published research showing that the vast majority of glaciers along the Peninsula – 87% of the 244 studied – are in retreat.
A little under 70% of the world’s Fresh water is locked up in ice
The ice dumped into the ocean as the glaciers retreat should not make much difference to global sea levels – perhaps a few cm. More worrying, potentially, are the vast ice sheets covering the rest of Antarctica. Making temperature measurements for the continent as a whole is difficult; it is a vast place – more than 2,000km across – there are few research stations, and temperatures vary naturally by 2-3C from year to year. But measurements indicate that in the west, melting is underway. “About one-third of the West Antarctic ice sheet is thinning,” says Dr Vaughan, “on average by about 10cm per year, but in the worst places by 3-4m per year.” The rock on which the West Antarctic ice rests is below sea level – and British Antarctic Survey researchers believe the thinning could be due to the ice sheet melting on its underside. “It may be that the ocean is warming and that’s causing the ice to melt, but there may be other reasons as well; for example, there’s lots of volcanism in that area and so that could change how much heat is delivered to the underside of the ice sheet.”
THE TEMPERATE ZONES
Glaciers snake over many of the world’s high regions – the Himalayas, the Andes, the Alps, Alaska. The recent signs are that these, like the Arctic, are feeling the impact of rising temperatures. Over the last five years, various teams have reported glaciers shrinking in Peru, Kazakhstan, Nepal and Alaska. “There is a global pattern of melting in most of the world’s mountain glaciers,” says Michael Hambrey, director of the Centre for Glaciology at Britain’s University of Aberystwyth. “There are exceptions – some glaciers are advancing – but overall the state of mountain glaciers is a dramatic shrinking since the 1970s. “Some have disappeared completely, and most could be gone by the end of this century.”
The year 2005 was a record-breaking one for Atlantic hurricanes, with the most named storms, the most hurricanes and the most Category-five hurricanes occurring—with New Orleans and the Mississippi Gulf Coast being nearly destroyed by Hurricane Katrina. In terms of barometric pressure, the Atlantic Basin also experienced its most intense hurricane ever that year, Hurricane Wilma. Some studies reveal that tropical storms around the world are intensifying, with computer models suggesting a shift toward extreme intensity. A big question on many minds is, “Does the warming of the earth have a direct effect on the strength of hurricanes?” Opinions are varied.Scientists caution that one must consider questions of climate change over decades, even centuries. A particularly rough hurricane season or two cannot be blamed on global warming.Preliminary evidence suggests that, once hurricanes form, they will be stronger if the oceans are warmer. However, much uncertainty exists about whether hurricanes and other storms will become more frequent.According to the Geophysical Fluid Dynamics Laboratory, which assesses natural climate variability, “The strongest hurricanes in the present climate may be upstaged by even more intense hurricanes over the next century as the earth’s climate is warmed by increasing levels of greenhouse gases in the atmosphere. Although we cannot say at present whether more or fewer hurricanes will occur in the future with global warming, the hurricanes that do occur near the end of the 21st century are expected to be stronger and have significantly more intense rainfall than under present day climate conditions.” This is based upon an anticipated increase of energy from higher sea surface temperatures.
An increase in global temperature can cause changes in the amount os precipitation. Overall, land prcipitation has increased by 2% since 1900, however, precipitation changes have been spatially variable over the last century. While there is a general increase of about 0.5-1.0%/decade over land in northern mid-high latitudes, there is a decrease pf about 0.3%/decade in precipitation in sub-tropical latitudes during the 20th century. But, the tropics appear to be getting drier.
SEA LEVEL RISE
Rises in sea levels are going to be one of the most devastating consequences of Global Warming.Rises in sea levels are predicted by the new report, threatening low-lying areas of land around the world. As the oceans warm, their waters expand, while rising temperatures also increase the melting of the ice sheets that cover Greenland and Antarctica .Both these factors contribute to rises in sea levels. In 2001, the IPCC predicted that sea levels would rise by between 9 and 88 centimetres by 2100, relative to 1990 levels. The new report says rises could range from 18 cm to 59 cm. But predictions of sea level rise are one of the most contentious areas of the report – very recent research has suggested that rises of up to 140 cm are possible. The problem is that the understanding of how warming affects Greenland and Antarctic ice sheets remains limited, and they are predicted to be the most important contributors to change. Estimates of the straightforward melting of ice are incorporated in the IPCC report. But warming may also accelerate the movement of ice in glaciers into the ocean, perhaps by meltwater lubricating the undersides of ice streams.Susan Solomon, one of the report’s lead authors, said there was no published research that quantified this effect, and so it was not included. But she added: “If temperatures exceed 1.9°C to 4.6°C above pre-industrial temperatures, and were to be sustained for thousands of years, eventually we would expect the Greenland ice sheet to melt. That would raise sea level by 7 metres.”
IMPACT OF GLOBAL WARMING ON INDIA
Warming is an environmental catastrophe that is staring in the world’s face. India needs to take a serious view of this impending danger which will bring about disastrous consequences for India.
The amount of greenhouse gases in the atmosphere will be doubled by 2040 and more than treble by the end of the century. Most of this century is going to witness soaring temperature, erratic weather patterns with more intense monsoons, increased cyclonic activities, severe droughts and floods, melting glaciers and rise in sea levels.
The oceanic region adjoining the Indian subcontinent is likely to warm at its surface by about 1.5-2.0 Celsius by the middle of this century and by about 2.3-3.5 Celsius by the end of the century.
Red areas indicate the shoreline andareas likely to be innudated as a resultof sea level rise.
This indication is derived from modern simulation studies. In a discussion on this issue in the Indian parliament, Minister of State in the Ministry of Environment and Forests, Shri Namo Narain Meena said that the past observations on the mean sea level along the Indian coast show a long-term rising trend of about 1.0 mm/year. The recent data suggests a rising trend of 2.5 mm/year in the sea-level along Indian coastline.
The corresponding thermal expansion, related sea-level rise is expected to be between 15 cm and 38 cm by the middle of this century and between 46 cm and 59 cm by the end of the century.
According to a study conducted by the Ministry of Environment & Forests on the impacts of climate change on various sectors including coastal zones, in the event of one meter sea-level rise, 5764 Km2 of land in coastal areas of India is projected to lose, displacing approximately 7.1 million people along with 4200 Kms of roads by the end of the 21st century. Further the coastal areas are also vulnerable to projected increase in frequency and intensity of extreme weather events like storm surges and cyclones. In the eastern coast, the vulnerable districts include Jagatsinghpur and Kendrapara in Orissa and Nellore in Andhra Pradesh and Nagapattinam in Tamil Nadu.
Himalayan glaciers ‘melting fast’
Melting glaciers in the Himalayas could lead to water shortages for hundreds of millions of people in India, Nepal and China according to the conservation group of WWF
In a report, the WWF says India, China and Nepal could experience floods followed by droughts in coming decades. The Himalayas contain the largest store of water outside the polar ice caps, and feed seven great Asian rivers. The group says immediate action against climate change could slow the rate of melting, which is increasing annually. “Yangtze and Yellow rivers are believed to be retreating at a rate of about 10-15m (33-49ft) each year.
Himalayan glaciers ‘melting fast’
“The rapid melting of Himalayan glaciers will first increase the volume of water in rivers, causing widespread flooding,” said Jennifer Morgan, director of the WWF’s Global Climate Change Programme. “But in a few decades this situation will change and the water level in rivers will decline, meaning massive eco and environmental problems for people in western China, Nepal and northern India.”
The glaciers, which regulate the water supply to the Ganges, Indus, Brahmaputra, Mekong, Thanlwin, Yangtze and Yellow rivers are believed to be retreating at a rate of about 10-15m (33-49ft) each year.
Hundreds of millions of people throughout China and the Indian subcontinent – most of whom live far from the Himalayas – rely on water supplied from these rivers. Many live on flood plains highly vulnerable to raised water levels. And vast numbers of farmers rely on regular irrigation to grow their crops successfully.
A study commissioned for the WWF indicated that the temperature of the Earth could rise by two degrees Celsius above pre-industrial levels in a little over 20 years.
Allowing global temperatures to rise that far would be “truly dangerous”.Nepal, China and India are already showing signs of climate change, the WWF report claims.
Nepal’s annual average temperature has risen by 0.06 degrees Celsius, and three snow-fed rivers have shown signs of reduced flows. Water level in China’s Qinghai Plateau wetlands has affected lakes, rivers and swamps, while India’s Gangotri glacier is receding by 23m (75ft) each year.
The Gangotri glaciers, which form the major chunk of Ganga water, has been retreating at the rate of 34 metre every year. It is now quite apparent that the melting glaciers are threatening the volumetric flow rate of Ganga, Brahmaputra and Yamuna which will ultimately affect the crop yield and drinking water supply.
While the sea level rise is going to affect the entire shoreline of India, a very large area of the Ganges delta will be totally submerged affecting millions. There are indication of sea level rise. Two islands in the Sunderbans area have already vanished from the map. 6,000 people had to be relocated here because there land is under water.
As the waters rise, it is expected that the entire delta region, home to the legendary Bengal tiger, will be submerged.
Scientists have already warned that global warming will reduce crop yields, spread diseases and cause loss of biodiversity and will also pose economic risks to water supplies, food production, electricity, road and rail infrastructure and coastal livelihood.
India’s agriculture depends largely on the monsoons and with rainfall pattern changing, western and central areas of India could have up to 15 more dry days annually while the Northeast is predicted to have 5 to 10 more days of rain each year. Which means that the areas which are dry will become drier and wet will become wetter. There will be longer droughts in some areas which will reduce wheat and rice yield.
Farmers Suicides – Is the changing climate responsible ?
A World Bank study has claimed that climate change and farmer suicides in India are corelated. The report says that poor farmers were unable to adapt to changing climates, which forced them fall into debts. Richer farmers were not affected because they had the resources to shift to other crops that suit the changed climate pattern. According to the study, in Pennar basin of Andhra Pradesh, decrease in yield is directly related to increase in temperature.
Hydropower projects & greenhouse gas emission
Latest scientific estimates show that large dams in India ar responsible for about a fifth of India’s total global warming impact. The study titled, “Methane emission from Indian Large Dams” estimates the total generation of methane from India’s reservoirs could be around 45.8 million ton, more than the share of any other country in the world. These gases are produced by the rotting of the vegetation and soils flooded by reservoirs, and of the organic matter (plants, plankton, algae, etc. Large dams have been known to be emitters of greenhouse gases like methane, carbon dioxide and nitrous oxide for over a decade now.
Indian hydropower projects are already known for their serious social and environmental impact on the communities and the environment. The fact that these projects also emit global warming gases in such significant proportion should further destroy the myth.
Mumbai, Chennai risk floods: UN
Many of the world’s largest cities like Mumbai and Chennai on the sea coasts and at the mouths of the great rivers face a considerable danger of being flooded due to extreme climatic events as a result of global warming, says a report.
Coastal cities are increasingly at risk from seaward hazards such as sea level rise and stronger storms induced by climate change, says a recent report released by United Nations Population Fund (UNFPA).Sea level rise, especially if combined with extreme climatic events, would flood large parts of coastal cities, says ‘State of World Population, 2007’.The report adds that sea level rise would also introduce salt water into surface fresh water and aquifers, affecting cities’ water supply, and modify critical ecosystems supplying ecological services and natural resources to urban areas.
The population especially when concentrated in large urban areas within rich ecological zones can be a burden on coastal ecosystems, many of which are already under stress, it added.Pointing out that the best way to prevent such a scenario would be to avoid policies that favour coastal development, it asked for a better coastal zone management.
Talking about other dangers that big cities will face due to global warming, the report says, dry cities like Delhi will face acute water crisis.In a vicious circle, climate change will increase energy demand for air-conditioning in urban areas and contribute to the urban heat island effect through heat pollution. Heat pollution, smog and ground level ozone are not just urban phenomena; they also affect surrounding rural areas, reducing agricultural yields, increasing health risks and spawning tornadoes and thunderstorms, it said.
The report further pointed out that changes in average and extreme temperatures or in intensity and length of seasons can have significant influence on things such as economic activities (for instance, tourism), productivity of workers, use of urban space for social interactions and water distribution etc.It mentioned that drought, flooding and other consequences of climate change can also modify migration patterns between rural and urban areas or within urban areas increasing the number of ‘environmental refugees’.
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