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Global Warming

Global Warming

on Tuesday, 20 September 2011. Posted in Global Warming

Global Warming – How well prepared is the United Kingdom

Global warming is not the fertile imagination of scientists, or communities wanting to destabilize the human race. In modern times, the threat of global warming needs to be taken far more seriously. Human civilization should address related issues urgently and effectively so that life on this planet does not turn into a fight that no one wins. The preparedness or rather willingness to accept global warming as a real issue and institute measures to prevent a major catastrophe is far from satisfactory levels in the United Kingdom.

How big is the threat?

The creator has provided a series of protective measures for mankind as well as other living beings including the plants to co-exist in harmony and peace. Global warming was unheard of some hundred years ago because the human race treated nature and all its bounties with greater concern and respect. But, with the jet set age and radical lifestyle changes we experience today, nature and environmental concerns have been relegated to the back seat. The consumption of fossil fuels alone has risen several times over the last century and the trend is continuing unabated. Even in 2011 the density of automobiles to population is negligible except for a dozen or so industrially advanced nations. This ratio is slated to change dramatically over the next decade and more. Millions of cars will be manufactured around the globe and send up even more carbon into the atmosphere posing grave threat to the green house effect. It is projected that China alone will be consuming as much as 85 million barrels of oil every day in the year 2035. There are other factors like increased industrialization, more air travel, more thermal power, and similar factors that can seriously impact global warming.

What are the priorities for UK in particular?

The United Kingdom has plenty to address the issue of global warming on a war footing. But, let us examine some of the priority areas.

  • Planning land use

  • Water management

  • Building regulations and management

  • Wild life corridors

  • Carbon emissions

Planning land use for instance will include ensuring proper drainage of surface water, flood prone plains being kept free from homes, and measures to prevent floods. Similarly water management should encompass educating home owners on more effective water management at home, and regulatory measures where necessary to force disciplined use of water. New or modified building regulations and management is important to ensure better insulated homes during hot summers and retrofitting of old homes to achieve better thermal efficiency.

Wild life corridors are important because the habitat from the coastal region can migrate to safer areas when floods occur along the coasts. Apart from ensuring safety of the habitat, this will also create the much needed ‘space’ for water.

Carbon emission is among the bigger threats and more stringent regulatory measures are needed to tame the gas guzzlers. Encouraging alternative means of transportation, increasing availability of mass transit facilities in metros, incentives for use of bi-cycles and electric vehicles are among measures that can bring about significant reduction in the carbon emission levels, particularly in the metros.


Some of the measures suggested above call for funding by the government. But, in most cases, more effective regulatory frame work, a firm determination and smart deployment of financial resources will override the need for financial resources itself.

In the last decade, the world has witnessed a series of calamities and the heart-rending visuals of the 2004 Tsunami should bring into focus the urgency with which the government and the people of UK should act to prevent similar calamities (not necessarily a Tsunami) from striking the British soil. We owe it to ourselves and our posterity to take global warming more seriously before Mother Nature unleashes her fury.


on Tuesday, 20 September 2011. Posted in Global Warming


Basic Facts:

Occupants of the earth depend on the Sun for energy to sustain life. About one third of the sunlight that is focused towards the earth gets deflected by the outer atmosphere and gets scattered back into space. The rest of the light reaches the earth’s surface and is again reflected upward as a form of slow moving energy called infrared radiation. Air currents carry the infrared radiation aloft and get absorbed by “greenhouse gases” i.e., water vapor, carbon dioxide, methane and ozone, slowing down the escape of the infrared rays from the atmosphere.

Though only about 1% of the Earth’s atmosphere is made up of greenhouse gases, our climate is regulated by them, by trapping heat and holding it like a warm air blanket around the planet. Scientists call this phenomenon as “greenhouse effect”. According to scientists, without the “greenhouse effect” the average temperature on Earth would be colder by about 30 degrees Celsius. At that temperature, life on this planet would become unsustainable.

The Human contribution to Green House Effect:

Life on this earth would become unsustainable without the greenhouse effect. It is the protective blanket or insulation provided to mankind, by the creator. But, human activities tend to either distort or accelerate the natural process by infusing more green house gases into the atmosphere than are necessary to keep the planet warm at an ideal temperature.

How does that happen?

Burning of Hydrocarbons – The gasoline for automobiles, natural gas, coal and oil when burnt for any purpose, raises the level of carbon dioxide in the atmosphere.

Increase in levels of methane and nitrous oxide due to certain farming practices and land use changes.

Long lasting Industrial gases making a significant contribution to greenhouse effect and “global warming” presently under way.

Trees use carbon dioxide and give off oxygen in replacement, which helps maintain the optimal balance of gases in the atmosphere. With more and more trees being cut down for human use in various forms, the critical function performed by the trees also diminishes quantitatively.

With the kind of population growth, we are witnessing, more and more people use fossil fuels for transportation, manufacturing, heating etc. and the level of greenhouse gases sent up into the atmosphere increases exponentially.

Finally, when more and more greenhouse gases are sent into the atmosphere, more infrared radiation is trapped and held, leading to higher temperature on the surface of the earth and in the lower atmosphere.

Rapid increase in average global temperature:

During the whole of the 20th century, the average global temperature increased by approximately 0.6 degree Celsius (little over 1 degree Fahrenheit). Using computer aided data; scientists estimate that by the end of the year 2100, the average global temperature will increase by 1.4 degrees to 5.8 degrees Celsius (about 2.5 degrees to 10.5 degrees Fahrenheit). The changes are occurring at this speed, and do not hold out a comfortable picture for mankind.

Not everybody agrees:

Though this is the wide spread concern, there are some who do not subscribe to the fears expressed by the global community. A well respected American professor and climatologist holds the view that there is no reason to be overtly concerned. He has come to this view after analyzing millions of measurements from weather satellites to find a global temperature trend. His research did not show any global warming in the satellite data, and therefore believes that the global warming predictions, particularly those high levels, are factually incorrect.

Effects of Global Warming and the Greenhouse effect.

Scientists opine that even a small increase in global temperature can cause distinct changes in climate and weather and affect cloud cover, wind patterns, precipitation, severity and frequency of storms and duration of seasons.

Sea levels would rise as a consequence of rising temperature and result in reduced supply of fresh water because of floods along the coastlines worldwide and salt water reaching inland.

Several endangered species could become extinct since the rising temperatures affect their habitat.

Millions of people, particularly the poor, living in precarious locations or dependent on land for subsistence would be affected.

Certain types of diseases like malaria would become more prevalent since the carrier insects or animals would have an expanded range due to warmer conditions.

Every 20 years, the level of carbon dioxide in the atmosphere is increasing by over 10 percent and carbon dioxide constitutes 60 percent of the enhanced greenhouse effect. If carbon dioxide emissions continue to grow at current levels, the level of gas in the atmosphere can grow manifold. Not a very welcome thought.

You have company, if you are an optimist:

The picture portrayed above, are the views held by a majority of the scientific world, but there are equally authentic sources which claim that all the noise being made on the “green house effect” are not necessary. Sometime back, the United Nations reported that humans are very likely to be blamed for the global warming for the way they use fossil fuels. But, there are other climate experts who differ and state that there is not enough scientific evidence to prove this theory. They hold the view that global warming can be caused by an increase in solar activity like a massive eruption. A professor from the University of Ottawa has claimed that rise in carbon dioxide levels happened some 800 years before warmer periods of the Earth’s history.

Yet another salvo from those who rubbish the theory is that after the Second World War, inspite of the huge surge in carbon dioxide emissions, the global temperatures in fact, dropped for four decades after 1940.


In conclusion, there is plenty that is being said and written about the concerns on global warming and the “greenhouse effect”. Yet, to strike a common thread between these differing groups and understand whether the threat perception is indeed as gargantuan as it is portrayed to be, only time can say. Until then, some of the findings can be taken seriously by mankind, irrespective of whether he is going to help the cause of greenhouse effect or not.

Greenhouse Effect

on Saturday, 08 October 2011. Posted in Global Warming

What is the Greenhouse Effect?

"In the industrial era, human activities have added greenhouse gases to the atmosphere, primarily through the burning of fossil fuels and clearing of forests..."

The Sun powers Earth’s climate, radiating energy at very short wavelengths, predominately in the visible or near-visible (e.g., ultraviolet) part of the spectrum. Roughly one-third of the solar energy that reaches the top of Earth’s atmosphere is reflected directly back to space. The remaining two-thirds is absorbed by the surface and, to a lesser extent, by the atmosphere. To balance the absorbed incoming energy, the Earth must, on average, radiate the same amount of energy back to space. Because the Earth is much colder than the Sun, it radiates at much longer wavelengths, primarily in the infrared part of the spectrum (see Figure 1). Much of this thermal radiation emitted by the land and ocean is absorbed by the atmosphere, including clouds, and reradiated back to Earth. This is called the greenhouse effect.  

The two most abundant gases in the atmosphere, nitrogen (comprising 78% of the dry atmosphere) and oxygen (comprising 21%), exert almost no greenhouse effect. Instead, the greenhouse effect comes from molecules that are more complex and much less common. Water vapour is the most important greenhouse gas, and carbon dioxide (CO2) is the second-most important one. Methane, nitrous oxide, ozone and several other gases present in the atmosphere in small amounts also contribute to the greenhouse effect. In the humid equatorial regions, where there is so much water vapour in the air that the greenhouse effect is very large, adding a small additional amount of CO2 or water vapour has only a small direct impact on downward infrared radiation. However, in the cold, dry polar regions, the effect of a small increase in CO2 or water vapour is much greater. The same is true for the cold, dry upper atmosphere where a small increase in water vapour has a greater influence on the greenhouse effect than the same change in water vapour would have near the surface.

FAQ 1.3, Figure 1. An idealised model of the natural greenhouse effect. See text for explanation.

Several components of the climate system, notably the oceans and living things, affect atmospheric concentrations of greenhouse gases. A prime example of this is plants taking CO2 out of the atmosphere and converting it (and water) into carbohydrates via photosynthesis. In the industrial era, human activities have added greenhouse gases to the atmosphere, primarily through the burning of fossil fuels and clearing of forests.

Adding more of a greenhouse gas, such as CO2, to the atmosphere intensifies the greenhouse effect, thus warming Earth’s climate. The amount of warming depends on various feedback mechanisms. For example, as the atmosphere warms due to rising levels of greenhouse gases, its concentration of water vapour increases, further intensifying the greenhouse effect. This in turn causes more warming, which causes an additional increase in water vapour, in a self-reinforcing cycle. This water vapour feedback may be strong enough to approximately double the increase in the greenhouse effect due to the added CO2 alone.

Additional important feedback mechanisms involve clouds. Clouds are effective at absorbing infrared radiation and therefore exert a large greenhouse effect, thus warming the Earth. Clouds are also effective at reflecting away incoming solar radiation, thus cooling the Earth. A change in almost any aspect of clouds, such as their type, location, water content, cloud altitude, particle size and shape, or lifetimes, affects the degree to which clouds warm or cool the Earth. Some changes amplify warming while others diminish it. Much research is in progress to better understand how clouds change in response to climate warming, and how these changes affect climate through various feedback mechanisms.

The glass walls in a greenhouse reduce airflow and increase the temperature of the air inside. Analogously, but through a different physical process, the Earth’s greenhouse effect warms the surface of the planet. Without the natural greenhouse effect, the average temperature at Earth’s surface would be below the freezing point of water. Thus, Earth’s natural greenhouse effect makes life as we know it possible. However, human activities, primarily the burning of fossil fuels and clearing of forests, have greatly intensified the natural greenhouse effect, causing global warming.


http://co2now dot org/Know-the-Changing-Climate/Climate-System/ipcc-faq-greenhouse-effect.html

reliability of climate change predictions

on Saturday, 08 October 2011. Posted in Climate change, Global Warming

How Reliable Are the Models Used to Make Projections of Future Climate Change? 

"...models are unanimous in their prediction of substantial climate warming under greenhouse gas increases, and this warming is of a magnitude consistent with independent estimates derived from other sources, such as from observed climate changes and past climate reconstructions."

There is considerable confidence that climate models provide credible quantitative estimates of future climate change, particularly at continental scales and above. This confidence comes from the foundation of the models in accepted physical principles and from their ability to reproduce observed features of current climate and past climate changes. Confidence in model estimates is higher for some climate variables (e.g., temperature) than for others (e.g., precipitation). Over several decades of development, models have consistently provided a robust and unambiguous picture of significant climate warming in response to increasing greenhouse gases.

Climate models are mathematical representations of the climate system, expressed as computer codes and run on powerful computers. One source of confidence in models comes from the fact that model fundamentals are based on established physical laws, such as conservation of mass, energy and momentum, along with a wealth of observations.

A second source of confidence comes from the ability of models to simulate important aspects of the current climate. Models are routinely and extensively assessed by comparing their simulations with observations of the atmosphere, ocean, cryosphere and land surface. Unprecedented levels of evaluation have taken place over the last decade in the form of organised multi-model ‘intercomparisons’. Models show significant and increasing skill in representing many important mean climate features, such as the large-scale distributions of atmospheric temperature, precipitation, radiation and wind, and of oceanic temperatures, currents and sea ice cover. Models can also simulate essential aspects of many of the patterns of climate variability observed across a range of time scales. Examples include the advance and retreat of the major monsoon systems, the seasonal shifts of temperatures, storm tracks and rain belts, and the hemispheric-scale seesawing of extratropical surface pressures (the Northern and Southern ‘annular modes’). Some climate models, or closely related variants, have also been tested by using them to predict weather and make seasonal forecasts. These models demonstrate skill in such forecasts, showing they can represent important features of the general circulation across shorter time scales, as well as aspects of seasonal and interannual variability. Models’ ability to represent these and other important climate features increases our confidence that they represent the essential physical processes important for the simulation of future climate change. (Note that the limitations in climate models’ ability to forecast weather beyond a few days do not limit their ability to predict long-term climate changes, as these are very different types of prediction – see FAQ 1.2.)

FAQ 8.1, Figure 1. Global mean near-surface temperatures over the 20th century from observations (black) and as obtained from 58 simulations produced by 14 different climate models driven by both natural and human-caused factors that influence climate (yellow). The mean of all these runs is also shown (thick red line). Temperature anomalies are shown relative to the 1901 to 1950 mean. Vertical grey lines indicate the timing of major volcanic eruptions. (Figure adapted from Chapter 9, Figure 9.5. Refer to corresponding caption for further details.)

A third source of confidence comes from the ability of models to reproduce features of past climates and climate changes. Models have been used to simulate ancient climates, such as the warm mid-Holocene of 6,000 years ago or the last glacial maximum of 21,000 years ago (see Chapter 6). They can reproduce many features (allowing for uncertainties in reconstructing past climates) such as the magnitude and broad-scale pattern of oceanic cooling during the last ice age. Models can also simulate many observed aspects of climate change over the instrumental record. One example is that the global temperature trend over the past century (shown in Figure 1) can be modelled with high skill when both human and natural factors that influence climate are included. Models also reproduce other observed changes, such as the faster increase in nighttime than in daytime temperatures, the larger degree of warming in the Arctic and the small, short-term global cooling (and subsequent recovery) which has followed major volcanic eruptions, such as that of Mt. Pinatubo in 1991 (see FAQ 8.1, Figure 1). Model global temperature projections made over the last two decades have also been in overall agreement with subsequent observations over that period (Chapter 1).

Nevertheless, models still show significant errors. Although these are generally greater at smaller scales, important large-scale problems also remain. For example, deficiencies remain in the simulation of tropical precipitation, the El Niño-Southern Oscillation and the Madden-Julian Oscillation (an observed variation in tropical winds and rainfall with a time scale of 30 to 90 days). The ultimate source of most such errors is that many important small-scale processes cannot be represented explicitly in models, and so must be included in approximate form as they interact with larger-scale features. This is partly due to limitations in computing power, but also results from limitations in scientific understanding or in the availability of detailed observations of some physical processes. Significant uncertainties, in particular, are associated with the representation of clouds, and in the resulting cloud responses to climate change. Consequently, models continue to display a substantial range of global temperature change in response to specified greenhouse gas forcing (see Chapter 10). Despite such uncertainties, however, models are unanimous in their prediction of substantial climate warming under greenhouse gas increases, and this warming is of a magnitude consistent with independent estimates derived from other sources, such as from observed climate changes and past climate reconstructions.

Since confidence in the changes projected by global models decreases at smaller scales, other techniques, such as the use of regional climate models, or downscaling methods, have been specifically developed for the study of regional- and local-scale climate change (see FAQ 11.1). However, as global models continue to develop, and their resolution continues to improve, they are becoming increasingly useful for investigating important smaller-scale features, such as changes in extreme weather events, and further improvements in regional-scale representation are expected with increased computing power. Models are also becoming more comprehensive in their treatment of the climate system, thus explicitly representing more physical and biophysical processes and interactions considered potentially important for climate change, particularly at longer time scales. Examples are the recent inclusion of plant responses, ocean biological and chemical interactions, and ice sheet dynamics in some global climate models.

In summary, confidence in models comes from their physical basis, and their skill in representing observed climate and past climate changes. Models have proven to be extremely important tools for simulating and understanding climate, and there is considerable confidence that they are able to provide credible quantitative estimates of future climate change, particularly at larger scales. Models continue to have significant limitations, such as in their representation of clouds, which lead to uncertainties in the magnitude and timing, as well as regional details, of predicted climate change. Nevertheless, over several decades of model development, they have consistently provided a robust and unambiguous picture of significant climate warming in response to increasing greenhouse gases.


http://co2now dot org/Know-the-Changing-Climate/Scientific-Predictions/ipcc-faq-climate-projection-model-reliability.html

Sea Level Rise

on Saturday, 08 October 2011. Posted in Climate change, Global Warming

The IPCC Explains... Sea Level Rise PDF Print E-mail



Is Sea Level Rising?

...there is strong evidence that global sea level gradually rose in the 20th century and is currently rising at an increased rate, after a period of little change between AD 0 and AD 1900. Sea level is projected to rise at an even greater rate in this century. The two major causes of global sea level rise are thermal expansion of the oceans (water expands as it warms) and the loss of land-based ice due to increased melting... 

Yes, there is strong evidence that global sea level gradually rose in the 20th century and is currently rising at an increased rate, after a period of little change between AD 0 and AD 1900. Sea level is projected to rise at an even greater rate in this century. The two major causes of global sea level rise are thermal expansion of the oceans (water expands as it warms) and the loss of land-based ice due to increased melting.

Global sea level rose by about 120 m during the several millennia that followed the end of the last ice age (approximately 21,000 years ago), and stabilised between 3,000 and 2,000 years ago. Sea level indicators suggest that global sea level did not change significantly from then until the late 19th century. The instrumental record of modern sea level change shows evidence for onset of sea level rise during the 19th century. Estimates for the 20th century show that global average sea level rose at a rate of about 1.7 mm yr–1.

Satellite observations available since the early 1990s provide more accurate sea level data with nearly global coverage. This decade-long satellite altimetry data set shows that since 1993, sea level has been rising at a rate of around 3 mm yr–1, significantly higher than the average during the previous half century. Coastal tide gauge measurements confirm this observation, and indicate that similar rates have occurred in some earlier decades.

In agreement with climate models, satellite data and hydrographic observations show that sea level is not rising uniformly around the world. In some regions, rates are up to several times the global mean rise, while in other regions sea level is falling. Substantial spatial variation in rates of sea level change is also inferred from hydrographic observations. Spatial variability of the rates of sea level rise is mostly due to non-uniform changes in temperature and salinity and related to changes in the ocean circulation.

Near-global ocean temperature data sets made available in recent years allow a direct calculation of thermal expansion. It is believed that on average, over the period from 1961 to 2003, thermal expansion contributed about one-quarter of the observed sea level rise, while melting of land ice accounted for less than half. Thus, the full magnitude of the observed sea level rise during that period was not satisfactorily explained by those data sets, as reported in the IPCC Third Assessment Report.

During recent years (1993–2003), for which the observing system is much better, thermal expansion and melting of land ice each account for about half of the observed sea level rise, although there is some uncertainty in the estimates.

The reasonable agreement in recent years between the observed rate of sea level rise and the sum of thermal expansion and loss of land ice suggests an upper limit for the magnitude of change in land-based water storage, which is relatively poorly known. Model results suggest no net trend in the storage of water over land due to climate-driven changes but there are large interannual and decadal fluctuations. However, for the recent period 1993 to 2003, the small discrepancy between observed sea level rise and the sum of known contributions might be due to unquantified human-induced processes (e.g., groundwater extraction, impoundment in reservoirs, wetland drainage and deforestation).

Global sea level is projected to rise during the 21st century at a greater rate than during 1961 to 2003. Under the IPCC Special Report on Emission Scenarios (SRES) A1B scenario by the mid 2090s, for instance, global sea level reaches 0.22 to 0.44 m above 1990 levels, and is rising at about 4 mm yr–1. As in the past, sea level change in the future will not be geographically uniform, with regional sea level change varying within about ±0.15 m of the mean in a typical model projection. Thermal expansion is projected to contribute more than half of the average rise, but land ice will lose mass increasingly rapidly as the century progresses. An important uncertainty relates to whether discharge of ice from the ice sheets will continue to increase as a consequence of accelerated ice flow, as has been observed in recent years. This would add to the amount of sea level rise, but quantitative projections of how much it would add cannot be made with confidence, owing to limited understanding of the relevant processes.

Figure 1 shows the evolution of global mean sea level in the past and as projected for the 21st century for the SRES A1B scenario.

FAQ 5.1, Figure 1. Time series of global mean sea level (deviation from the 1980-1999 mean) in the past and as projected for the future. For the period before 1870, global measurements of sea level are not available. The grey shading shows the uncertainty in the estimated long-term rate of sea level change (Section 6.4.3). The red line is a reconstruction of global mean sea level from tide gauges (Section, and the red shading denotes the range of variations from a smooth curve. The green line shows global mean sea level observed from satellite altimetry. The blue shading represents the range of model projections for the SRES A1B scenario for the 21st century, relative to the 1980 to 1999 mean, and has been calculated independently from the observations. Beyond 2100, the projections are increasingly dependent on the emissions scenario (see Chapter 10 for a discussion of sea level rise projections for other scenarios considered in this report). Over many centuries or millennia, sea level could rise by several metres (Section 10.7.4).

http://co2now dot org/Know-the-Changing-Climate/Effects/ipcc-faq-sea-level-rise.html

sea-level rise in the UK

on Saturday, 08 October 2011. Posted in Climate change, Global Warming

Future sea-level rise in the UK

Uk 7m rise       Uk 13m rise     Uk 84m rise
Click on each link above to see  large jpeg (700kb each file)

During the 20th century, global sea level rose by around 20 cm, a rate that may be higher than at any time during the past thousand years. Without a reduction in Greenhouse gases, the UK Met Office estimates that sea-levels may rise a further 41cm by 2080, a reflection primarily of the melting of small glaciers and ice sheets and the thermal expansion of sea-water as temperatures continue to rise. This estimate takes no account, however, of catastrophic melting of major ice sheets, such as the Greenland and West Antarctic (WAIS) ice sheets, which is capable – at some time in the future – of raising sea levels by several metres.
In a visualisation study commissioned by UKTV, the ABUHC and UCL's Department of Geomatic Engineering produced three 'what if?' scenarios, showing the effects of 7m, 13m and 84m sea-level rises on the shape of the UK. When combined with aforementioned causes of future rising sea levels, the melting of either the Greenland or West Antarctic ice sheets, could be expected to raise sea level by around 7m – sufficient to inundate many of the UK's coastal towns and cities. If both melted, then a rise of around 13m could occur. Additional melting of the gigantic East Antarctic ice sheet (EAIS) could result in a cataclysmic rise of 84m, which would drown much of eastern and southern England and separate Scotland from England and Wales.
So what are the probabilities of any of these scenarios happening and how soon? Collapse and melting of the EAIS is extremely unlikely, and is probably only possible many thousands of years into the future if we doing nothing to moderate greenhouse gas emissions and a runaway Greenhouse Effect develops as a result. Some models predict that with a relatively small temperature increase, half the Greenland ice sheet may melt within a thousand years, and may disappear entirely within 3,000 years. Most worrying of all is the West Antarctic ice sheet, which is showing signs of becoming increasingly unstable, and which may have a 1 in 20 chance of collapsing and melting within the next 200 years.

http://www.abuhrc dot org/research/climatechange/Pages/project_view.aspx?project=21


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