Faster ocean warming due to climate change – One of the reasons of catastrophic sea level rising:

Faster ocean warming due to climate change – One of the reasons of catastrophic sea level rising:

a. It has been reported recently by some of the climate research agencies in US, Australia, UK etc. that, oceans all over the world are getting warmed at a much faster rate than it used to be earlier or what was thought to be. It is estimated that, the rate of warming of world’s oceans is about 50% faster over the last half century than it was thought previously. Thus, world’s oceans have warmed more quickly due to climate change than expected.

b. It may be noted, higher the ocean temperatures, higher the expansion of ocean water – which contributes to rise in sea levels. Expansion ocean water means more floods, submerging smaller island nations, threatening to wreak havoc in low-lying places and densely-populated delta regions around the globe. A third of the world’s population living within 50 km of the coasts and a great proportion and a large proportion of them live much closer to the shoreline. Even a modest sea level rise could inundate low-lying regions, accelerate coastal erosion and force the relocation of communities and infrastructures.

c. Rising sea levels are driven by two things – (i) the thermal expansion of sea water, and (ii) additional water from melting sources of ice. Both these processes are caused by global warming.

d. For example, the glaciers or ice sheet that cover Arctic region contains enough water to raise world ocean levels by seven meters, which would bury sea-level cities from Dhaka to Shanghai in Asia and many more similar cities in other parts of the world. If the Greenland and the West and East Antarctica ice sheets were to melt, it would be enough to raise the sea level by approximately 65 meters. A one-foot rise in sea level might well translate to a 200-foot retreat of shoreline. Therefore, it could be imagined about the future coastal map how catastrophic it would be. Among the most vulnerable are countries with large populations in deltaic coastal regions such as Bangladesh, Vietnam, China and Egypt. Two populous island nations, the Philippines and Indonesia, have millions who face displacement from their homes from sea level rise. Several small island state nations including the Maldives in the Indian Ocean and the Marshall Islands and Tuvalu in the Pacific could face extinction.

e. Global heating effects are strong in melting of snow and ice, rising global mean sea level, widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones. The rate of rise in temperatures depends on if and how fast emissions are reduced and on possible adverse feedbacks in the climate system. Temperatures are sure to rise faster in the next decades as well. Experts opine that, hot extremes, heat waves, and heavy precipitation events will continue to become more frequent. It is certain that the ocean would become more acid from taking up more carbon dioxide.

f. Therefore, it is very important, now, to figure out and estimate how much each of these factors contributes to rising sea levels. Further, it is critically important to understand global warming, climate change and forecasting future ocean temperature rise, as well. The fact is, up to now there has been a perplexing gap between the projections of computer-based climate models, and the observations of scientific data gathered from the world’s oceans.

Expected impacts of global warming:

Expected impacts of global warming – would certainly be very harmful and dangerous:

A large body of scientific studies, exhaustively reviewed, has produced a long list of possibilities of impacts of global warming. Nobody can say that any of the items on the list are certain to happen. But most of the climate experts agree that the impacts listed below are more likely to happen. The exact timings, for them, are difficult to predict, but they are in the opinion that, if humanity manages to begin restraining its emissions within the next few decades, so that greenhouse gases do not rise beyond twice the pre-industrial level (we are already 35% above it and rising each year, at an accelerating rate) the consequences would certainly be very dangerous - probably including a radical reorganization and impoverishment of many of the ecosystems that sustain our civilization. Expected impacts are:

(1) Most places will continue to get warmer, especially at night and in winter. The temperature change will benefit some regions, at least for a time, while harming others like, patterns of tourism will shift. The warmer winters will benefit health in some areas, but globally, mortality will rise due to summer heat waves and other effects.

(2) Sea levels will continue to rise for many centuries. The last time the planet was 3°C warmer than now, the sea level was roughly 5 meters higher. That submerged coastlines where many millions of people now live. Also, storm surges will cause emergencies.

(3) Weather patterns will keep changing, probably toward an intensified water cycle with stronger floods and droughts. Most regions that are now subject to droughts are expected to get drier (because of warming as well as less precipitation), and most wet regions will get wetter. Changes in extreme weather events are hard to predict, but in some regions storms with more intense rainfall are liable to bring worse floods. Mountain glaciers and winter snowcap will shrink, jeopardizing many water supply systems. Each of these changes has already begun to happen in some regions.

(4) Ecosystems will be stressed, although some managed agricultural and forestry systems will benefit, at least in the early decades of warming. Uncounted valuable species, especially in the Arctic, mountain areas, and tropical seas, must shift their ranges. Many that cannot will face extinction. A variety of pests and tropical diseases are expected to spread to warmed regions. Each of these problems has already been observed in numerous places.

(5) Increased carbon dioxide levels will affect biological systems independent of climate change. Some crops will be fertilized, as will some invasive weeds (the balance of benefit vs. harm is uncertain). The oceans will continue to become markedly more acidic, gravely endangering coral reefs, and probably harming fisheries and other marine life.

(6) There will be significant unforeseen impacts. Most of these will probably be harmful, since human and natural systems are well adapted to the present climate.

Climate Change Science – Global warming – an overview:

Climate Change Science – Global warming – an overview:

A. Climate change is a global issue that affects us all. Changes in climate patterns mean that extreme weather events such as heat waves, floods, storms, droughts and bushfires will become more frequent, more widespread or more intense. Climate change science is providing a better understanding of the causes, nature, timing and consequences of climate change. Climate change science is a very complex subject. Various investigations, studies, reports suggest that world is warming up, but how this will affect us in the future is difficult to qualify. Climate change is the result of changes in our weather patterns because of an increase in the Earth's average temperature. The weather elements at a given location vary from time to time throughout the year, but generally are expected to remain within set limits over a long time period. This is known as our climate. This natural variation in temperature ensures we have cold and warm years. This is actually a natural and essential feature of our atmosphere without which our planet would be uninhabitable.

B. If go back to history of climate change and find people behind postulating the probable cause of it; we may more or less say that in the 1930s people started realizing that the United States and North Atlantic region had warmed significantly during the previous half-century. Scientists supposed this was just a phase of some mild natural cycle, with unknown causes. Only one lone voice, the amateur G.S. Callendar, insisted that greenhouse warming was on the way. In the 1950s, Callendar's claims provoked a few scientists to look into the question with improved techniques and calculations. The new studies showed that, contrary to earlier crude estimates, carbon dioxide could indeed build up in the atmosphere and should bring warming. Painstaking measurements drove home the point in 1961 by showing that the level of the gas was, in fact, rising, year by year. In the early 1970s, the rise of environmentalism raised public doubts about the benefits of human activity for the planet. Curiosity about climate turned into anxious concern. Alongside the greenhouse effect, some scientists pointed out that human activity was putting dust and smog particles into the atmosphere, where they could block sunlight and cool the world. Most scientists agreed on was that they scarcely understood the climate system, and much more research was needed. Research activity did accelerate, including huge data-gathering schemes that mobilized international fleets of oceanographic ships and orbiting satellites. People have come to know that, this is caused by increases in greenhouse gases in the Earth's atmosphere. By 2000, scientists knew the most important things about how the climate could change during the present century.

C. Therefore, when we talk about global warming, as described above, we generally talk about the 'greenhouse effect'. This process works by the principle that certain atmospheric gases (called greenhouse gases) allow short wave radiation from the sun to pass through them unabsorbed, while at the same time absorbing some of the long wave radiation reflected back to space. The net result; more heat is received from the sun than is lost back to space, keeping the earth's surface warmer than it would otherwise be. Man, in the process of industrialization and development, is adding to and changing the levels of the gases responsible for the greenhouse effect and is therefore enhancing this warming.

D. The effect of global warming is that, global ice sheets have decreased, so has global snow cover. There have been warmer periods in the history – some millions of years ago. However, the present rise is the most rapid rise in temperature since the end of the last ice age. Carbon dioxide (CO2) is the gas most significantly responsible for greenhouse effect. Plant respiration and decomposition of organic material release more than 10 times the CO2 than released by human activities, but these releases have generally been in balance during the centuries. Since the industrial revolution amounts have increased by 30%. Other greenhouse gases include Methane, Nitrous oxide, CFC's (manmade) and Ozone. The major problem is that these gases can remain in the atmosphere for decades. The combustion of fossil fuel (oil, natural gas and coal) by heavy industry and other human activities, such as transport and deforestation, are the primary reasons for increased emissions of these harmful gases. Aerosol, from human made sulfur emission, also increases in the atmosphere along with CO2. The small particles of aerosol have a property to reflect back some of the sunlight and hence act to slow down the cooling. However where carbon dioxide can remain in the atmosphere for 100 years, sulfate aerosols only last a few days and can be easily removed by rain (acid rain). Therefore they only temporarily mask the full effect of CO2.

E. In order to try and predict possible consequences of this warming for the future, researchers use climate modeling to simulate the climate and oceans over many decades. Climate models also predict changes in rainfall and rise in sea level. Sea level rises will be due to thermal expansion of the ocean along with the melting glaciers and mountain snow and ice. The recent estimate of sea level rise is by more than 50cm by 2100, but this will vary considerably with location.

Global warming and greenhouse gasses:

Global warming and greenhouse gasses:

The earth is surrounded by a cover of gasses as atmosphere. This atmosphere allows most of the light to pass through, which reaches the surface of earth. This light from sun is absorbed by the earth surface and converts into heat energy. This heat energy is re-emitted by the surface of the earth during night. Due excessive presence of some gasses in the atmosphere, this escape of heat from earth surface is prevented, resulting in heating of earth called ‘global warming’. The gasses which are responsible for causing global warming are called ‘greenhouse gasses’.

The harmful effects of presence of greenhouse gasses in atmosphere are global warming, climate change, ozone depletion, sea level rise, adverse effects on biodiversity etc. One way or another these adverse impacts are all directly or directly related to the presence of greenhouse gases in the atmosphere. A number of human activities, processes and consumptions produce waste gasses or greenhouse gasses that are harmful to the environment. They include:

(a) Fuel combustion
(b) Energy industries
(c) Manufacturing industries and construction
(d) Vehicle Transport and automobiles
(e) Fugitive emissions from fuels
(f) Burning of solid fuels
(g) Use of oil and natural gas
(h) Mineral products
(i) Chemical industry
(j) Metal production
(k) Production of halocarbons and sulfur hexafluoride
(l) Consumption of halocarbons and sulfur hexafluoride
(m) Solvent and other product use
(n) Enteric fermentation
(o) Manure management
(p) Rice cultivation
(q) Agricultural soils
( r) Prescribed burning of savannas
(s) Field burning of agricultural residues
(t) Solid waste disposal on land
(u) Wastewater handling
(v) Waste incineration

Much of these harmful gases are produced either naturally or by various human activities; which we should reduce. Brief description and effects of six important greenhouse gases are given below:

Carbon dioxide (CO2) - A naturally occurring gas produced by living organisms and fermentation. It is a normal component of the breath we exhale; it is hazardous in concentrated volumes. Large quantity of carbon dioxide is produced by the combustion of carbonaceous fuels. Carbon dioxide emissions from fuel burning, responsible for about 87 percent of global warming, have increased by about 27 percent since the industrial revolution.

Nitrogen oxides (NOx) – Nitrogen oxides are naturally occurring from microbial action in soil. NOx is also produced by fuel burning. Scientists say its production is increased by the use of nitrogen based fertilizers in agriculture, as well as by the use of catalytic converters in automobiles.

Methane (CH4) – Methane is a naturally occurring, in-flammable gas. Methane is produced by geological coal formations and by the decomposition of organic matters. Leading man-related sources of methane are landfills; livestock digestive processes and waste, especially ruminants (cud-chewing animals); and wetland rice cultivation.

Hydroflurocarbon gasses (HFCs) - Chlorofluorocarbons (CFC), the coolant, cleaning, and propellant gases were blacklisted internationally due to its ozone-eating characteristics. HFCs do contribute to global warming. Global warming potential of HFCs is 4,000 to 10,000 times that of CO2.

Perfluorocarbons (PFC), or perflurocompounds - Man-made replacement gases for CFCs but result also as a by-product of aluminium smelting. PFCs also used as a purging agent for semi-conductor manufacture and small amounts are produced during uranium enrichment processes. Global warming potential of Perfluorocarbons (PFC), or perflurocompounds is 6,000 to 10,000 that of CO2.

Sulfur hexafluoride (SF6) - Very low atmospheric concentration makes it an ideal test gas for gas concentration monitors. Principle uses: insulating material for high-voltage equipment like circuit breakers at utilities. Also used in water leak detection for cable cooling systems. SF6 is a man-made gas.