Some more about green house

    Seen from space, our atmosphere is but a tiny layer of gas around a huge bulky planet. But it is this gaseous outer ring and its misleadingly called greenhouse effect that makes life on Earth possible  and that could destroy life as we know it.more.       A Climate History of Change: The Normality of Global Warming

The climate is warming  so what? The Earth has warmed up and cooled down for billions of years! Unfortunately, man-made global warming is different. Here is how we know about prehistoric climate and what this could teach us about the future.

Effects of Acidity on Plants and Animals

As a first example of the effects of acid rain, we can examine a case which is not obvious - effects on non-aquatic, tree nesting birds. This study was carried out in the Netherlands. It was observed that the proportion of birds laying defective eggs rose from roughly 10% in 1983-84 to 40% by 1987-88. The defective eggs had thin and highly porous egg shells, which resulted in eggs failing to hatch because of shell breakage and desiccation. As a result, there was also a high proportion of empty nests and clutch desertion. It was also observed that these effects were limited to areas of acid rain. Since the birds did not appear to be directly affected by the acidity, the food chain was examined (these birds are positioned at the upper part of the local food chain). The difference between areas of normal soil pH (buffered by high calcium content due to limestone and marble outcrops and bedrock) and those with acidic soil appeared to be the presence of snails. The snails depend on the soil as their calcium source as they secrete their shells. With much of the CaCO3 leached out of the soil by the acid precipitation, the snails could not survive in the area. The birds did not, at first, appear to be affected, because they continued to eat spiders and insects which, while supplying a sufficiently nutritious diet for the birds, where a poor source of calcium.
To test the hypothesis that the lack of calcium was the cause of the bird's laying defective eggs, ecologists "salted" the area with chicken egg shell fragments. The birds began to eat the chicken egg shells, and those that did laid normal eggs.
In this case, acid precipitation had affects that passed on up the food chain.

Acid Formation in the Atmosphere

    First, let us review some basic chemistry as it applies to acid precipitation. Carbonic acid forms naturally in the atmosphere due to the reaction of water (H2O) and carbon dioxide (CO2),
H2O + CO2 -> H2CO3
   while the burning of coal and other organics adds sulfur dioxide (SO2) and Nitrous oxides (NOx) to the atmosphere where they react to form sulfuric acid and nitric acid,
2SO2 + H2O + O2 -> 2H2SO4
4NO2 + 2H2O + O2 -> 4HNO3
    All of these acids will be buffered by reacting with rocks, minerals, etc. on the earth's surface. The most important (and fastest) buffering comes from the reaction with (weathering of) calcite in the form of limestone, dolomite or marble.
H2CO3 + CaCO3 -> 2HCO3- + Ca+2
   When this reaction occurs, the acid is neutralized and the calcite dissolved. While the reaction with calcite is very fast (the standard test for calcite in introductory geology labs is to put very dilute acid on a sample to see if it bubbles (reacts)), the reaction with other rocks is very slow, so most of the acid is not affected. This is why ponds in the Adirondacks became acidified (non-calcite rock in those areas), while Lake Champlain (abundant calcitic bedrock) did not.
   The degree of acidification is the pH of the water, which is defined as the negative logarithm of the concentration of hydrogen ion (H+), or
pH = -log [H+].
(This to a certain degree comes from the old definition of an acid as a proton donor. A hydrogen ion is little more than a proton, so think of it as the amount of free protons floating around).
A pH of 7 is considered neutral, while a pH less than 7 is considered acidic. For example, wine has a pH of about 3.5 and your stomach digestive fluids have a pH of about 1.9.
We should also be aware that increased acidity does not have to be constant, but instead can be episodic. High surface water discharge events (storms, snowmelts) can increase the pH of streams and ponds to dangerous levels for short times.

Effects of Acid Rain

     We generally consider acid rain to affect areas which are downwind of pollution generating sites. The northeastern United States, for instance, suffers from acid precipitation generated both locally and by coal fired plants in the mid-western states. As a result, ecosystem damage is localized. However, acid precipitation can be caused by some natural events (volcanic eruptions, erosion and oxidation of organic-rich sedimentary rocks) and some catastrophic events (bolide impact) which increase the amounts of CO2, NOx and SO2 in the atmosphere. As a result, it is important to understand the effects of acid rain on animals inorder to evaluate both possible causes for past extinction events, as well as the potential for modern ecosystem damage.

Sensitive areas

    There is solid evidence that lakes in certain "sensitive" areas of North America and Europe have become more acid in recent decades. Sensitive areas are downwind of major industrial areas and where the underlying rock is granite rather than limestone. In North America, the Adirondacks of New York, the mountains of northern New England as well as large areas of southern Quebec have been particularly hard-hit. Both the plant and animal life in a lake become altered as the pH drops. The productivity of the lakes, and their content of desirable fish, decline.

What is polution?

  Pollution is the introduction of a contaminant into the environment. It is created mostly by human actions, but can also be a result of natural disasters. Pollution has a detrimental effect on any living organism in an environment, making it virtually impossible to sustain life.

How to Prevent Water Pollution

The best way to prevent water pollution is to not throw trash and other harmful chemicals into our water supplies. Here are a few more ways you can prevent water pollution:
•Wash your car far away from any stormwater drains
•Don’t throw trash, chemicals or solvents into sewer drains•Inspect your septic system every 3-5 years•Avoid using pesticides and fertilizers that can run off into water systems
•Sweep your driveway instead of hosing it down
•Always pump your waste-holding tanks on your boat
•Use non-toxic cleaning materials
•Clean up oil and other liquid spills with kitty litter and sweet them up
•Don’t wash paint brushes in the sink

Facts about Water Pollution

Here are a few facts about water pollution: •Over two-thirds of U.S. estuaries and bays are severely degraded because of nitrogen and phosphorous pollution
•Every year almost 25% of U.S. beaches are closed at least once because of water pollution
•Over 73 different kinds of pesticides have been found in the groundwater that we eventually use to drink
•1.2 trillion gallons of sewage, stormwater and industrial waste are discharged into U.S. waters every year
•40% of U.S. rivers are too polluted for aquatic life to survive
•Americans use over 2.2 billion pounds of pesticides every year, which eventually washes into our rivers and lakes

Land Pollution

Here are a few facts about land pollution: •Every year one American produces over 3285 pounds of hazardous waste
•Land pollution causes us to lose 24 billion tons of top soil every year
•Americans generate 30 billion foam cups, 220 million tires and 1.8 billion disposable diapers every year
•We throw away enough trash every day to fill 63,000 garbage trucks
•Every day Americans throw away 1 million bushels of litter out their car window
•Over 80% of items in landfills can be recycled, but

How to Prevent Water Pollution ?

The best way to prevent water pollution is to not throw trash and other harmful chemicals into our water supplies. Here are a few more ways you can prevent water pollution: •Wash your car far away from any stormwater drains
•Don’t throw trash, chemicals or solvents into sewer drains
•Inspect your septic system every 3-5 years
•Avoid using pesticides and fertilizers that can run off into water systems
•Sweep your driveway instead of hosing it down
•Always pump your waste-holding tanks on your boat
•Use non-toxic cleaning materials
•Clean up oil and other liquid spills with kitty litter and sweet them up
•Don’t wash paint brushes in the sink

Polution on political boundries

     Acid rain does not respect political boundaries. The lakes of Norway and Sweden suffer from the air pollution generated by the industrial areas to their south and southwest. Canadians are distressed by the damage from the air pollution generated by the industrial heartland of the U.S. The U.S. is not entirely to blame for their problems, however. Sensitive areas in Quebec are also downwind of the smelters in Sudbury, Ontario, which have the dubious distinction of generating more sulfur dioxide pollution than any other place in the entire world.

How can air pollution hurt my health?

many ways with both short-term and long-term effects. Different groups of individuals are affected by air pollution in different ways. Some individuals are much more sensitive to pollutants than are others. Young children and elderly people often suffer more from the effects of air pollution. People with health problems such as asthma, heart and lung disease may also suffer more when the air is polluted. The extent to which an individual is harmed by air pollution usually depends on the total exposure to the damaging chemicals, i.e., the duration of exposure and the concentration of the chemicals must be taken into account.




Examples of short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Other symptoms can include headaches, nausea, and allergic reactions. Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. In the great "Smog Disaster" in London in 1952, four thousand people died in a few days due to the high concentrations of pollution.



    Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys. Continual exposure to air pollution affects the lungs of growing children and may aggravate or complicate medical conditions in the elderly. It is estimated that half a million people die prematurely every year in the United States as a result of smoking cigarettes.
Research into the health effects of air pollution is ongoing. Medical conditions arising from air pollution can be very expensive. Healthcare costs, lost productivity in the workplace, and human welfare impacts cost billions of dollars each year.
       Additional information on the health effects of air pollution is available from the Natural Resources Defense Council. A short article on the health effects of ozone (a major component of smog) is available from the B.A.A.Q.M.D.

Air pollution

    When people think about air pollution, they usually think about smog, acid rain, CFC's, and other forms of outdoor air pollution. But did you know that air pollution also can exist inside homes and other buildings? It can, and every year, the health of many people is affected by chemical substances present in the air within buildings.

    A great deal of research on pollution is being conducted at laboratories and universities. The goals of the research are to find solutions and to educate the public about the problem. Two places where this type of work is being done are LBNL and the University of California, Berkeley.
Let's take a closer look at the various types of air pollution, the effects that they have on people, and what is being (or not being) done to correct the problem.

Affects on aquitic life

Mollusks - snails and clams. - these invertebrates are highly sensitive to acidification because of their shells which are either calcite or aragonite (both forms a CaCO3) which they must take from the water.

- in Norway, no snails are found in lakes with a pH of less than 5.

- of 20 species of fingernail clams, only 6 were found in lakes with pH of less than 5.

Arthropods

- crustaceans are not found in water with a pH less than 5.

- crayfish are also uncommon in water where the pH is less than 5. This is an important consideration because crayfish are an important food source for many species of fish.

- many insects also become rare in waters with a pH less than 5.

Amphibians

- as you may know, many species of amphibians are declining. To what extent acid rain is contributing to this decline is not exactly known. However, one problem is that in places like northeastern North America amphibians breed in temporary pools which are fed by acidified spring meltwater. In general, eggs and juveniles are more sensitive to the affects of acidity.

Zooplankton in lakes

- changes in diversity among zooplankton have been noted in studies carried out in lakes in Ontario, Canada. These studies found that in lakes where the pH was greater than 5 the zooplankton communities exhibited diversities of 9 - 16 species with 3 - 4 being dominant. In lakes where the pH was less than 5, diversity had dropped to 1 - 7 species, with only 1 or 2 dominants.

Periphytic algae

- many acidified lakes exhibit a large increase in the abundance of periphytic algae (those that coat rocks, plants and other submerged objects). This increase has been attributed to the loss of heterotrophic activity in the lake (i.e., the loss of both microbial and invertebrate herbivores in the lake).

Fish

- as a result of acidification, fish communities have suffered significant changes in community composition attributed to high mortality, reproductive failure, reduced growth rate, skeletal deformities, and increased uptake of heavy metals.

Mortality

- effects on embryos and juveniles:

- Atlantic salmon fry have been observed to die when water with pH < 5 was introduced into breeding pools.

- in fish embryos, death appears to be due to corrosion of epidermal cells by the acid. Acidity also interferes with respiration and osmoregulation. In all fish at a pH of 4 to 5 the normal ion and acid/base balance is disturbed. Na+ uptake is inhibited in low pH waters with low salinity. Small fish are especially affected in this way because due to their greater ratio of body and gill surface area to overall body weight, the detrimental ion flux proceeds faster.

- in all fish low pH water causes extensive gill damage. Gill laminae erode, gill filaments swell, and edemas develop between the outer gill lamellar cells and the remaining tissue.

- at pH <3 coagulation of mucus on gill surfaces clogs the gills, which leads to anoxia and subsequent death.

Reproductive Failure

Reproductive failure has been suggested as the main reason for fish extinction due to acidity. In Ontario, Canada it was observed that in acidified lakes female fish did not release ova during mating season. When examined, the fish were found to have abnormally low serum calcium levels which appears to have disrupted their normal reproductive physiology.

Growth

Growth may increase or decrease depending on resistance of a species to acidity. For resistant species, growth can increase due to the loss of competing non-resistant species. On the other hand, growth can decrease due to increase in metabolic rate caused by sublethal acid stress. In this case the organism's rate of oxygen consumption goes up because the excess CO2 in the water increases the blood CO2 level which decreases the oxygen carrying capacity of the hemoglobin.

Skeletal Deformity

This occurs in some fish as a response to the lowered blood pH caused by increase in CO2 described above. Bones decalcify in response to a buildup of H2CO3 in the blood as the body attempts to maintain its normal serum osmotic concentration (i.e., the body attempts to return to a normal blood pH level).

IN WARNING

     Unfortunately, burning fossil fuels is not the only thing that we humans are doing to increase the amount of carbon dioxide in the atmosphere. In many parts of the world today, forests are being destroyed at an alarming rate. Enormous numbers of trees are being cut down, both to provide timber and to clear the land for farming or ranching. This destructive process is called deforestation. In order to clear forests for agriculture, people cut down and burn all the trees in area. When the flames die down, nothing is left but acres of blackened, lifeless countryside. The fire destroys all the plants and kills or drives off the animals. Because there has been little attempt to replant trees in deforested areas, the world's forests are disappearing very quickly.

      If we can reduce the greenhouse gases going into the atmosphere, we probably can slow the rate of global warming and climate. There are a number of things that we can do to prepare for the changes that are coming. If we act now, perhaps we can "soften the blow" of the greenhouse effect. In the future, the weather cold change much more dramatically from year to year than it does now. As global warming alters habitats, many kinds of animals will be on the move, but all sorts of barriers will stand between them and a new place to live. To help animals get around these barriers, it might be necessary to set up migration corridors that connect natural areas with one another. Without human intervention, many kinds of plants also may not survive as the earth's climate changes. Forests, in particular, may need our help. If climate changes come rapidly, few tree species will be able to spread into new areas fast enough to keep up with changing conditions.
     Glaciers are large, thick masses of slow-moving ice that persist from year to year. They cover about a tenth of the earth's land surface. The vast ice sheets of Antarctica and Greenland account for most of this area. Smaller ice caps are found in Scandinavia, Caffin Island, Iceland, and elsewhere. In addition, there are tons of thousands of valley glaciers that follow stream channels down mountain slopes. All together, glaciers contain about seventy-five percent of the available fresh water of the earth. Because global warming is expected to be greatest in polar and temperate regions, scientists expect the glaciers to melt more rapidly than they do today. An executive summary of a United Stations survey published in 1990 concluded that if worldwide "business as usual" continues, the resulting global temperature increased would produce mean sea-level rise of about twenty-five inches by the end of the next century. Other studies predict such increases will occur as soon as 2040. Much depends on how fast the polar ice melts. If global warming accelerates and the ice melts faster than expected, ocean levels may rise as much as ten feet by 2100.