Some Interesting Facts and Information About Automobile Emissions Control

Automobile emissions control


Automobile emissions control covers all the technologies that are employed to reduce the air pollution-causing emissions produced by automobiles. Exhaust emissions control systems were first required on 1966 model year vehicles produced for sale in the state of California, followed by the United States as a whole in model year 1968, although the overall reduction in pollution has been much slower.


The emissions produced by a vehicle fall into these basic categories:

1. Tailpipe emissions: This is what most people think of when they think of vehicle air pollution; the products of burning fuel in the vehicle's engine, emitted from the vehicle's exhaust system. The major pollutants emitted include:
1. Hydrocarbons: this class is made up of unburned or partially burned fuel, and is a major contributor to urban smog, as well as being toxic. They can cause liver damage and even cancer.
2. Nitrogen oxides (NOx): These are generated when nitrogen in the air reacts with oxygen under the high temperature and pressure conditions inside the engine. NOx emissions contribute to both smog and acid rain.
3. Carbon monoxide (CO): a product of incomplete combustion, carbon monoxide reduces the blood's ability to carry oxygen and is dangerous to people with heart disease.
4. Carbon dioxide (CO2): Emissions of carbon dioxide are an increasing concern as its role in global warming as a greenhouse gas has become more apparent.
5. Particulates. Particle of micrometre size.
6. Sulphur oxide (SOx) General term for oxides of sulphur, mostly sulfur dioxide and some sulfur trioxide, from coal or unrefined oil.

Tailpipe emissions control
Dual exhaust pipes attached to a car's muffler
Dual exhaust pipes attached to a car's muffler





Tailpipe emissions control can be categorised into three parts:

1. Increasing engine efficiency
2. Increasing vehicle efficiency
3. Cleaning up the emissions

Increasing engine efficiency

Engine efficiency has been gradually improved with progress in following technologies:

* Electronic ignition
* Fuel injection systems
* Electronic control unit

Increasing vehicle efficiency

Contributions to the goal of reducing fuel consumption and related emissions come from

* lightweight vehicle design
* minimized air resistance
* reduced rolling resistance
* improved powertrain efficiency
* increasing spark to the spark plug (this topic should be under the ignition system)
* regenerative braking

Each of these items breaks down into a number of factors.

Increasing driving efficiency

Significant reduction of emissions come from

* driving technique (some 10-30% reduction)
* unobstructed traffic conditions
* cruising at an optimum speed for the vehicle
* reducing the number of cold starts

Cleaning up the emissions

Advances in engine and vehicle technology continually reduce the amount of pollutants generated, but this is generally considered insufficient to meet emissions goals. Therefore, technologies to react with and clean up the remaining emissions have long been an essential part of emissions control.

Air injection

A very early emissions control system, the Air injection reactor (AIR) reduces the products of incomplete combustion (hydrocarbons and carbon monoxide) by injecting fresh air into the exhaust manifolds of the engine. In the presence of this oxygen-laden air, further combustion occurs in the manifold and exhaust pipe. Generally the air is delivered through an engine-driven 'smog pump' and air tubing to the manifolds.


Exhaust Gas Recirculation

Many engines produced after the 1973 model year have an exhaust gas recirculation (EGR) valve between the exhaust and intake manifolds; its sole purpose is to reduce NOx emissions by introducing a metered, and quite small amount of inert gas into the air/fuel mixture, lowering peak combustion temperatures. In the case of EGR, the exhaust gasses are inert enough to serve this purpose.

Catalytic converters

The catalytic converter is a device, placed in the exhaust pipe, which converts various emissions into less harmful ones using, generally, a combination of platinum, palladium and rhodium as catalysts. They make for a significant, and easily applied, method for reducing tailpipe emissions. Catalytic converters are damaged when used on engines that burn leaded fuels. Unleaded fuels were marketed in 1973 and by 1996 leaded fules were banned completely for use in the USA.

Evaporative emissions control

Efforts at the reduction of evaporative emissions include the capturing of vented vapors from within the vehicle, and the reduction of refuelling emissions.

Capturing vented vapors

Within the vehicle, vapors from the fuel tank are channelled through canisters containing activated carbon instead of being vented to the atmosphere. These are known as carbon canisters. The vapors are adsorbed within the canister, which feeds into the inlet manifold of the engine.

Emission Testing

In 1966, the first emission test cycle was enacted in the State of California measuring tailpipe emissions in PPM (parts per million). The Environmental Working Group used California ASM emissions data to create an Auto Asthma Index that rates vehicle models based on emissions of hydrocarbons and nitrogen oxides, the chemicals that create smog.

Some cities are also using a technology developed by Dr. Stedman,of University of Denver which uses lasers to detect emissions while vehicles pass by on public roads, thus eliminating the need for owners to go to a test center. Stedman's laser detection of exhaust gases is commonly used in metropolitan areas.

Some interesting facts and information about Nitrogen oxide [NOx]

Nitrogen oxide

The term nitrogen oxide typically refers to any binary compound of oxygen and nitrogen, or
to a mixture of such compounds:
* Nitric oxide (NO), nitrogen(II) oxide
* Nitrogen dioxide (NO2), nitrogen(IV) oxide
* Nitrous oxide (N2O), nitrogen (I) oxide
* Dinitrogen trioxide (N2O3), nitrogen(II, IV) oxide
* Dinitrogen tetroxide (N2O4), nitrogen(IV) oxide
* Dinitrogen pentoxide (N2O5), nitrogen(V) oxide
Chemical reactions that produce nitrogen oxides often produce several different
compounds, the proportions of which depend on the specific reaction and conditions. For
this reason, secondary[clarify] production of N2O is undesirable, as NO and NO2 — which
are extremely toxic — are liable to be produced as well.




NOx

NOx is a generic term for mono-nitrogen oxides (NO and NO2). These oxides are
produced during combustion, especially combustion at high temperatures.
At ambient temperatures, the oxygen and nitrogen gases in air will not react with each
other. In an internal combustion engine, combustion of a mixture of air and fuel produces
combustion temperatures high enough to drive endothermic reactions between
atmospheric nitrogen and oxygen in the flame, yielding various oxides of nitrogen. In areas
of high motor vehicle traffic, such as in large cities, the amount of nitrogen oxides emitted
into the atmosphere can be quite significant.
In the presence of excess oxygen (O2), nitric oxide (NO) will be converted to nitrogen
dioxide (NO2), with the time required dependent on the concentration in air as shown
below:
NO concentration in air
(ppm)
Time required for half NO
to be oxidized to NO2 (min)
20,000 0.175
10,000 0.35
1,000 3.5
100 35
10 350
1 3500

When NOx and volatile organic compounds (VOCs) react in the presence of sunlight, they
form photochemical smog, a significant form of air pollution, especially in the summer.
Children, people with lung diseases such as asthma, and people who work or exercise
outside are susceptible to adverse effects of smog such as damage to lung tissue and
reduction in lung function.[2]
Mono-nitrogen oxides eventually form nitric acid when dissolved in atmospheric moisture,
forming a component of acid rain. The following chemical reaction occurs when nitrogen
dioxide reacts with water:
2NO2 + H2O → HNO2 + HNO3
(nitrogen dioxide + water → nitrous acid + nitric acid).
Nitrous acid then decomposes as follows:
3HNO2 → HNO3 + 2NO + H2O
(nitrous acid → nitric acid + nitric oxide + water),
where nitric oxide will oxidize to form nitrogen dioxide that again reacts with water,
ultimately forming nitric acid:
4NO + 3O2 + 2H2O → 4HNO3 (nitric oxide + oxygen + water → nitric acid).
Mono-nitrogen oxides are also involved in tropospheric production of ozone.[3]
NOx should not be confused with NOS, a term used to refer to nitrous oxide (N2O) in the
context of its use as a power booster for internal combustion engines.

Definition of NOx and NOy in atmospheric chemistry

In atmospheric chemistry the term NOx is used to mean the total concentration of NO plus
NO2. During daylight NO and NO2 are in equilibrium with the ratio NO/NO2 determined by
the intensity of sunshine (which converts NO2 to NO) and the concentration of ozone
(which reacts with NO to give back NO2). NO and NO2 are also central to the formation of
tropospheric ozone. This definition excludes other oxides of nitrogen such as nitrous oxide
(N2O). NOy (reactive odd nitrogen) is defined as the sum of NOx plus the compounds
produced from the oxidation of NOx which include nitric acid and peroxyacetyl nitrate. In
this context nitrous oxide and ammonia are not considered as reactive nitrogen
compounds.

Industrial sources of NOx

The three primary sources of NOx in combustion processes:
* thermal NOx
* fuel NOx
* prompt NOx
Thermal NOx formation, which is highly temperature dependent, is recognized as the most
relevant source when combusting natural gas. Fuel NOx tends to dominate during the
combustion of fuels, such as coal, which have a significant nitrogen content, particularly
when burned in combustors designed to minimise thermal NOx. The contribution of prompt
NOx is normally considered negligible. A fourth source, called feed NOx is associated with
the combustion of nitrogen present in the feed material of cement rotary kilns, at between
300° and 800°C, where it is also a minor contributor.

Thermal NOx

Thermal NOx refers to NOx formed through high temperature oxidation of the diatomic
nitrogen found in combustion air. The formation rate is primarily a function of temperature
and the residence time of nitrogen at that temperature. At high temperatures, usually
above 1600°C (2900°F), molecular nitrogen (N2) and oxygen (O2) in the combustion air
disassociate into their atomic states and participate in a series of reactions.
The three principal reactions producing thermal NOx are:
(Extended Zeldovich Mechanism)
* N2 + O → NO + N
* N + O2 → NO + O
* N + OH → NO + H
all 3 reactions are reversible. Zeldovich was the first to suggest the importance of the first
two reactions. The last reaction of atomic Nitrogen with Hydroxyl radical, OH, was added
by Lavoie, Heywood and Keck to the mechanism and makes a significiant contribution to
the formation of thermal NOx.

Fuel NOx

The major source of NOx production from nitrogen-bearing fuels such as certain coals and
oil, is the conversion of fuel bound nitrogen to NOx during combustion. During combustion,
the nitrogen bound in the fuel is released as a free radical and ultimately forms free N2, or
NO. Fuel NOx can contribute as much as 50% of total emissions when combusting oil and
as much as 80% when combusting coal.
Although the complete mechanism is not fully understood, there are two primary paths of
formation. The first involves the oxidation of volatile nitrogen species during the initial
stages of combustion. During the release and prior to the oxidation of the volatiles,
nitrogen reacts to form several intermediaries which are then oxidized into NO. If the
volatiles evolve into a reducing atmosphere, the nitrogen evolved can readily be made to
form nitrogen gas, rather than NOx. The second path involves the combustion of nitrogen
contained in the char matrix during the combustion of the char portion of the fuels. This
reaction occurs much more slowly than the volatile phase. Only around 20% of the char
nitrogen is ultimately emitted as NOx, since much of the NOx that forms during this
process is reduced to nitrogen by the char, which is nearly pure carbon.
It is possible to revert NOx emitted from a diesel engine back into Nitrogen and Water by
using an SCR Selective Catalytic Reduction Unit. This requires the addition of an urea
based liquid re-agent namely AdBlue to initialise the chemical reaction.

Prompt NOx

This third source is attributed to the reaction of atmospheric nitrogen, N2, with radicals
such as C, CH, and CH2 fragments derived from fuel, where this cannot be explained by
either the aforementioned thermal or fuel processes. Occurring in the earliest stage of
combustion, this results in the formation of fixed species of nitrogen such as NH (nitrogen
monohydride), HCN (hydrogen cyanide), H2CN (dihydrogen cyanide) and CN- (cyano
radical) which can oxidize to NO. In fuels that contain nitrogen, the incidence of prompt
NOx is especially minimal and it is generally only of interest for the most exacting emission
targets.

Regulation and emission control technologies

The Kyoto Protocol, ratified by 54 nations in 1997, classifies N2O as a greenhouse gas,
and calls for substantial worldwide reductions in its emission.
As discussed above, atmospheric NOx eventually forms nitric acid, which contributes to
acid rain.NOx emissions are regulated in the United States by the Environmental
Protection Agency, and in the UK by the Department for Environment, Food and Rural
Affairs.
Technologies such as flameless oxidation (FLOX) and staged combustion significantly
reduce thermal NOx in industrial processes. Bowin low NOx technology is a hybrid of
staged-premixed-radiant combustion technology with a major surface combustion
preceded by a minor radiant combustion. In the Bowin burner, air and fuel gas are
premixed at a ratio greater than or equal to the stoichiometric combustion requirement.
Water Injection technology, wherby water is introduced into the combustion chamber, is
also becoming an important means of NOx reduction through increased efficiency in the
overall combustion process. Alternatively, the water (e.g. 10 to 50%) is emulsified into the
fuel oil prior to the injection and combustion. This emulsification can either be made in-line
(unstabilized) just before the injection or as a drop-in fuel with chemical additives for long
term emulsion stability (stabilized). Other technologies, such as selective catalytic
reduction (SCR) and selective non-catalytic reduction (SNCR) reduce post combustion
NOx.
The use of Exhaust gas recirculation and catalytic converters in motor vehicle engines
have significantly reduced emissions.

Biogenic sources

Agricultural fertilization and the use of nitrogen fixing plants also contribute to atmospheric
NOx, by promoting nitrogen fixation by microorganisms.

SOME INTERESTING INFORMATION AND FACTS ABOUT RAIN FORESTS

TROPICAL RAIN FORESTS

Of all the many and varied natural environments to be found on the earth, perhaps the most awe-inspiring and popular are the tropical rain forests. Although it is the forests of the Amazon which spring most readily to mind, it is important to remember that they also occur in parts of North America, Asia, Australia, and Africa, for the most part within a narrow band 4 degrees either side of the equator. These forests, with their mighty trees and extraordinary flora and fauna constitute the planet's richest habitats, and one of our most precious natural resources.

In this section we look at some of the fascinating animals, plants and people which inhabit the tropical rain forests along the meridian line, and we consider some of the conservation issues affecting these biological treasure houses. But before we do this, let's first get an idea of what a tropical rain forest actually is.

Tropical rain forests are mainly the product of climatic interactions, particularly temperature and rainfall. In general, tropical rain forests occur where a mean monthly temperature of between 20 and 28 degrees C is combined with an annual rainfall of between 1.5 and 10 metres, evenly distributed throughout the year. This last proviso is very important because it is only to those tropical forests which experience little seasonal variation in terms of rainfall that the term rain forest can legitimately be applied.

AFRICAN FORESTS

Less than seven per cent of Africa’s surface is covered with tropical rain forest, and the majority of this is concentrated in the centre of the continent. The Democratic Republic of Congo, Gabon, Cameroon and the Central African Republic all have substantial forest coverage of various types. However, West Africa is not without its share of this type of vegetation. Ghana has over 15,000 sq. km of rain forest, most of which is found along the coast, Nigeria has nearly 40,000 sq. km, Cote D’Ivoire has some 30,000 sq. km and Togo has around 1300 sq. km.

Africa’s rain forests are not as rich in species as those found in South America and Asia, but they still surpass every other region in terms of both the diversity and the density of the wildlife to which they are home. Much of Africa’s forest cover has been lost due to human activity, and this is examined along with other conservation issues in greater detail in another section.

We will be concerned with those tropical rain forests which lie on the meridian line, and consequently our attention will be focussed upon Ghana and Togo. Nevertheless, much of what is said in relation to these countries will also apply to forests found elsewhere on the continent.

TREES

The diversity of trees found in the tropical rain forests is quite extraordinary, and far exceeds that of any other kind of forest, sometimes with as many as 100 tree species per hectare. Equally remarkable are the heights and diameters of the trees, which while not the tallest or most massive on earth, still dwarf those of most other forest systems.

For example, Khaya ivorensis, a member of the family of trees collectively known as African mahogany, can attain heights of up to 60 metres, and diameters of 1.8 metres.

Because of the constantly high temperatures and extreme humidity found in the tropical rain forests, bacteria and other micro-organisms thrive in the top layer of soil, feeding on the mass of decaying matter which falls from the canopy. The result is that there is little matter left to accumulate, so the top soil is very thin and poor in nutrients.

Under normal circumstances large trees send out masses of roots which can extend for several metres. These roots absorb nutrients from the soil and give the tree a firm foundation. rain forest trees have a large number of roots, but these can only extend a small distance into the thin soil, and cannot therefore provide stability. The solution is to employ buttress roots which work in much the same way as buttresses on citadels or Christian cathedrals, and these can grow up to 5 m up the trunk of a tree.

EPIPHYTES LIANES AND STRANGLERS

Lianes

Not all plants which thrust their way into the forest canopy are trees. Lianes, for example, have their roots in the forest floor, but rely for their support upon existing trees.

Often starting out as shrubs, the lianes put out long branches which attach themselves to tree trunks and climb up until they reach the sunlight, at which point they generate leaves and frequently create large crowns.

Epiphytes

Like the lianes, epiphytes do not provide their own support, but in contrast they are not rooted in the ground at all. Instead, they grow on the surface of the canopy trees, rooting in crevices where humus has accumulated. These roots, however provide only an anchorage, and the epiphytes do not draw their nutrients from the host tree. Exactly where these plants do obtain their nutrients varies from one species to another, some collecting falling plant matter, others receiving organic matter from the insects which pollinate them. Common epiphytes are orchids, bromeliads and ferns.

Stranglers

Found only in the tropical rain forests, stranglers start out as epiphytes, but at a certain point in their growth they produce roots which wrap around the trunk of the tree on which they live, and descend into the ground. This provides them with increased nutrients, allowing them to grow towards the canopy. Eventually the strangler surrounds its supporting tree with roots, which ultimately kills it. However, the trunk of the tree remains, and continues to support the strangler. Most stranglers are figs.

ANIMALS

The remarkable abundance and diversity of plant life in the tropical rain forest ensures that there is always plenty of food available for herbivorous animals. Because most vegetation is concentrated high up in the canopy, it is here that many of the forest's animals are to be found, some descending only rarely to the ground. Among the most numerous of these are primates, several species of which inhabit the rain forests of Ghana and Togo. These include monkeys such as the black and white colobus, the spot-nosed monkey, and the Diana monkey, as well as larger apes such as chimpanzees, and smaller primates such as bushbabies. Also living in the canopy are an enormous variety of birds such as hornbills, parrots, and turacos, some of which feed on plant matter. Others enjoy a diet of insects, which are exceptionally numerous in the rain forest.

The forest floor, although not home to as many species as the canopy, still has its share of interesting fauna. Hoofed mammals, including various types of duiker, reptiles such as the common hinged tortoise, and larger mammals such as the pygmy hippopotamus and forest elephant, are just a sample of the creatures to be found on the ground.

Where herbivores abound there will inevitably be carnivores to prey on them, and the west African rain forests are no exception. Leopards prowl on the ground and in the trees, Nile crocodiles lurk in the rivers and pools, and birds of prey soar overhead, carrying off rodents and small primates. The forests are complex ecosystems, delicately balanced with every animal and plant playing its own role in maintaining the equilibrium. From the smallest plants and the insects that pollinate them, to the carnivores right at the top of the food chain, nothing is dispensable.

SOME INTERESTING FACTS AND INFORMATION ABOUT OCEANS

OCEANS

Humpback whale sounding in the Chatham Straits off Alaska

Life began in the oceans. Covering two-thirds of the Earth's surface, in the twenty-first century oceans remain crucial for our survival; for regulating climate, providing us with resources like fish and minerals, and potentially offering us cures for disease.

The oceans are home to half the world's biodiversity, and new species are being found almost daily. In fact, we know more about the moon than we do about the deep ocean. Marine life has adapted to exploit every niche, from the poles to the tropics, from estuaries to the deep ocean.

We take a look at the oceans and seas along the meridian, their importance to man, the diversity of wildlife that inhabit these waters, and some important conservation issues.

WILDLIFE

A Black-browed Albatross. Albatrosses are the largest of the sea-birds.

The oceans along the meridian line are home to a diversity of habitats and wildlife. Inshore habits like estuaries, mudflats and mangroves offer feeding and roosting areas for birds, and provide sheltered nursery areas for fish and shellfish.Offshore, fish species like tuna, toothfish and sharks, and birds like albatross and petrels patrol the vast oceanic expanses.

Phytoplanton (the marine equivalent of terrestrial grasslands), seaweeds and seagrasses form the base of the food web. In the Southern Oceans the stark seasonality provides a bounty of plant and animal plankton. The estimated production of phytoplankton in the surface waters of the Southern Ocean is 610 million tonnes a year.

Humpback Whale breaching in the waters off Alaska

Zooplankton (the marine equivalent of insects) feed on the phytoplankton and support abundant schools of squid, fish, and consequently a variety of larger marine creatures like seals, seabirds and whales. Half the zooplankton in the Southern Ocean are krill, a shrimp-like animal. Several species of filter feeding whale, like humpbacks, feed directly on krill. In 1994 the Southern Ocean was declared a sanctuary for the great whales.

SOME INTERESTING FACTS AND FIGURES

The cliffs of Harwick Head in the Orkney Islands are home to many seabirds

Did you know that?

• In some places the ocean is deeper than Mount Everest is high; for example, the Mariana Trench and the Tonga Trench in the western part of the Pacific Ocean reach depths in excess of 10,000 metres (32,800 feet).
• If all the land in the world was flattened out, the Earth would be a smooth sphere completely covered by a continuous layer of seawater 2,686 metres deep.
• Ocean water and ice make up almost 98 percent of all the water on Earth.
• Icebergs are formed by the calving (detaching of parts) of glaciers or of inland ice that reaches the sea. The valley glaciers of Greenland produce some 12,000 to 15,000 sizable icebergs every year.
• The Pacific Ocean is the largest ocean, containing more than twice the volume of water as the Atlantic Ocean.
• Earth is the only planet in our solar system to have oceans.
• Marine fisheries throughout the world catch over 80 million tonnes of fish every year.
• Hundreds of millions of tonnes of toxic chemicals, sewage, industrial waste, agricultural run-off and oil are dumped in the oceans every year – and up to 80 per cent originate on land.
• Each year 20 million tonnes of fish, seabirds, marine mammals and other ocean life are killed unnecessarily by indiscriminate fishing practices.
• Hydrothermal vents, fractures in the sea floor that discharge hot seawater laden with hydrogen sulphide, support the only ecosystem known to run on chemical energy rather than energy from the sun, including mussels, large bivalve clams, and huge tube worms.
• The deepest known point in the ocean is the Mariana Trench which reaches depths of over 36,000 feet (11,000 meters).

SOME INTERESTING INFORMATION AND FACTS ABOUT DESERTS

On our planet of extremes, perhaps the most frightening and yet fascinating environments are the deserts. Covering around a third of the earth's land surface, they are the harshest and most barren environments in the world - inhospitable and seemingly incapable of sustaining anything but the most rudimentary plant and animal life. In this feature we focus our attention upon those deserts which lie along the meridian line.

We begin by taking a look at the factors such as climate and landscape that make the deserts distinctive. Following this we consider the geography of deserts - where in the world they are to be found. Other sections explore the plant and animal life that can be found in the deserts along the meridian line, as well as some of the important conservation issues which we are facing in connection with this type of environment.

Hot and dry. These are the terms that characterise the desert climate in most people's minds, but is this an accurate depiction? As a general rule, areas subject to an average rainfall of less than 100mm a year can be classed as deserts. Sometimes a broader classification is used whereby deserts are split into three categories - semi-arid, arid and hyper-arid. Areas of the first kind receive less than 600mm of rainfall a year, areas of the second kind receive less than 200mm, whilst rainfall in hyper-arid desert regions never exceeds 25mm.

But low average annual rainfall is only half the story. Not only do deserts experience very little rain, but to make matters worse, this small amount is highly irregular, both in terms of time and space. Sometimes an area of desert will be without rain for years and then, seemingly for no reason at all, a few large storms will provide enough rain in a short period to bring the average annual rainfall back to normal. Desert storms can be extremely localised, centring upon one area and leaving adjoining parts entirely dry. These are some of the factors that contribute to making deserts some of the most inhospitable environments on the planet.

Water shortage in the desert is not limited to low rainfall. Humidity and consequently cloud cover are also in short supply. This in turn means that the surface, and any living things on it, are continually exposed to direct sunlight, causing intense evaporation of any water faster than the rain can replenish it.

Where deserts are to be found close to the sea, fogs often occur in the early mornings as a result of cold sea water meeting warm air. When the warm air, laden with moisture, comes into contact with the surface of the land, which is still cold from the previous night, it cools and condenses, leaving a film of water. The Namib Desert of southern Africa and Chile's Atacama Desert are both cases in point.

Contrary to popular belief, high temperature is not the most important feature of deserts: lack of water, as we have seen, is of much greater significance. However, it is true that most of the world's deserts are subject to extreme heat for at least part of the year. Many people are surprised by how much temperatures can vary. With cloud cover so scarce, air temperatures in the desert frequently reach 40° C, and in some circumstances they can soar to 50° C. The temperatures of the rocks and sand are even higher, up to 75° C. But these maximum figures can vary by up to 30° C. Seasonal temperature variation can also be considerable in the desert, particularly those furthest from the equator - and in some places, winter nights can even bring frost.

Deserts often experience high winds which, coupled with the sand and dust particles which are typical of most deserts, leads to the formation of the distinctive desert landscape.

The climatic extremes of deserts have created a wide range of landscapes. Try to picture a desert in your mind and the chances are you are imagining a vast featureless sandy plain as far as the eye can see, with only the odd cactus to break the monotony. Although this picture is not actually wrong, it only gives about a quarter of the story. Sand covers just 20 per cent of the world's desert.

Sand is formed by the erosion of rocks into tiny particles. This erosion is the result of a number of processes, the most important of which are the heating and cooling of rocks and the action of the wind and rain. The enormous temperature ranges experienced by most desert regions cause the rocks to expand and contract, eventually cracking and disintegrating in a process known as weathering. The smaller fragments of rock that break off are carried by the wind, and sometimes water, and they in turn erode other rocks. Gradually they become so small that they are merely grains.

The same wind that helps to form sand particles also shapes the landscape in other ways. Given the right conditions, the easily transported grains of sand will accumulate to form sand dunes. These extraordinary features can vary from small heap-like structures of only about a metre in height to enormous sand mountains of 1,000 metres. Some dunes often reach several kilometres in length. They are often found in large groups known as sand seas or ergs. The largest of these, covering around 560,000 square kilometers, is in the Arabian Desert. An important and intriguing characteristic of sand dunes is their tendency to move around. Typical annual movement of sand dunes is between 10 and 20 metres, depending upon size, but in extreme cases small dunes may travel up to 50 metres in a year.

But sand is just one of a number of landscape types to be found in the desert. Rocks and stones feature quite prominently in most of the world's arid places, often with vast plains covered in gravel, or large towering cliffs, eroded into extraordinary shapes by the action of wind and water. Elsewhere, the evaporation of ancient lakes has left enormous areas known as salt flats, which represent one of the greatest obstacles to plant and animal life to be found on the planet. Other areas are covered with clay or mud which has been dried hard by the heat of the searing desert sun. One feature that is common to many desert areas is the scarcity of soil, and consequently vegetation.

Deserts provide us with some of the most spectacular and stunning scenery on the planet. From the dramatic rock formations of Death Valley in the US, to the sand dunes of the Sahara, the world's arid zones constitute a natural gift that should be neither overlooked nor taken for granted.

Deserts occur in five of the world's seven continents. North America's Sonora and Chihuaua deserts, situated in the south-west corner of the continent, extend into Mexico, while the Great Basin, covering most of the states of Utah and Nevada, is home to the infamous Death Valley, and the Great Salt Lake Desert. Further south, in the states of Arizona and California, lie the Mojave or High Desert and the Colorado or Low Desert. The North American deserts are renowned for their spectacular landscapes and searing heat.

Between the Andean Mountains and the Pacific Ocean lie the coastal deserts of Peru and Chile on the South American continent. These are the Sechura and the Atacama respectively. Also in Peru is the Altiplano desert, which extends into Bolivia. This desert is known for its dry salt basins, which were left when ancient lakes evaporated. Patagonia in Argentina boasts large areas of cold semi-desert.

Chief among the African deserts, and probably the most famous of them all, is the Sahara. Extending from the Atlantic Ocean in the West, to the Red Sea in the East, and with an area of over nine million square kilometres - around the same size as the United States - the Sahara is the largest desert on Earth. In east Africa the Danakil, Ogaden, Nubian, Chalbi and Didi Galgalu deserts extend throughout Kenya, Sudan, Ethiopia, Eritrea and Somalia. Southern Africa is home to the Kalahari and Namib deserts, which together occupy large portions of Namibia, Botswana and South Africa.

The Gobi Desert in Mongolia and China is the fifth largest in the world. Tibet has substantial desert cover despite its very low temperatures, and many central Asian countries are subject to desert conditions. India, Pakistan, Iran and the Arabian Peninsula all contain large desert areas, including the Thar or Great Indian desert and the Arabian Desert.

Australia is the most arid continent on Earth. Its principal desert areas include the Simpson Desert, the Tanami Desert, the Great Victoria Desert, the Great Sandy Desert, and the Gibson Desert, and these are situated mainly in the centre of the country - the Outback.

The status of the vast continent of Antarctica is a matter of controversy. In many respects it resembles the deserts of other continents - particularly in its low annual rainfall - but many scientists feel dubious about including it in the same class as these.

The only true desert to be found along the 0° meridian line also happens to be world's largest. The Sahara covers most of north Africa, more than a third of the continent, and an area around the same size as the United States. It is a desert of extraordinary variety. Temperatures in excess of 55° C have been recorded in parts of Libya, while in some places frost can be seen during the winter. All the standard desert landscape types are present in the Sahara, from great fields of shifting sand dunes or ergs, to vast plains filled with rocks, known as reg.

Rainfall in most parts of the Sahara is scant and erratic - some areas endure several years without even a hint of a shower. In common with other desert regions, storms in the Sahara can be extremely localised, often affecting an area as small as 20 square kilometres. Strong, unpredictable winds are typical of the Saharan weather systems, and these have come to be known by names such as khamsin, sirocco, shahali, and simoom. These winds can blow for days on end, bringing with them vast amounts of dust and sand, which cover everything in their path and reduce visibility close to zero. From time to time, particularly powerful sandstorms can be extremely unpleasant and dangerous for anyone caught in them. Dust devils, which are like whirlwinds, also occur, hurling sand, dust, small animals and plants into the air.

The Sahara is crossed by the Nile and Niger rivers, which together support most of the desert's human population. Even so, it still presents a great obstacle to animal and plant life. In later sections we consider some of the animals and plants which inhabit the Sahara, and we look at how they have adapted so that they can live there.

Water is essential for all plants, so survival in arid environments is a real challenge. However, some of the ways in which desert flora have adapted are ingenious. Generally, they either avoid or endure periods of low rainfall. Ephemeral or annual plants survive periods where water is in short supply because their seeds germinate only after heavy rain, grow rapidly, and live their whole life-cycle in just a few days. These plants often produce large, brightly coloured flowers to attract the insects that are essential to their pollination.

Perennial plants take the alternative route, enduring the dry periods and making the most of the scarce water supplies. These plants utilise a number of interesting methods to survive.

Grasses
Grasses are extremely hardy plants and are found in most of the world's environments. They have extremely large and complex root systems that enable them to collect water over a wide area. During extremely hot and dry periods the parts of the plants that are above the surface may wither and die, but the root systems remain alive. They reproduce by growing new stems. The extensive root systems of grasses play an important role in keeping the sparse desert soils together.

Geophytes
These plants survive the harsh desert conditions by remaining underground for most of the time, often as bulbs. When rain does come they quickly produce stems and flowers.

Succulents
These plants take in large amounts of water during times of plenty and store it for use during times of drought. They have a low surface area in comparison with their volume, which reduces water loss due to evaporation. Succulents typically have vast, shallow root systems in order to make the most of any water reaching the ground.

Like most other plants, succulents use photosynthesis to convert carbon dioxide into organic compounds by means of the energy of sunlight. The best-known succulents are cacti. These are found almost exclusively in North and South America, and are often spectacular in shape and size. The most celebrated are the saguaro, which can grow up to 15 metres over many years. The African equivalents of the cacti are the euphorbia, which resemble their American counterparts in many ways.

Shrubs and stunted trees
Unlike succulents, these plants do not differ greatly from those found in other regions, and use more conventional methods of surviving drought. They are small trees or shrubs, normally with very small leaves that are often shed during the hottest part of the year. Their root systems are extensive, and can often penetrate as far as 50 metres into the ground in search of water. Sometimes they have short thick trunks that act as reservoirs for excess water taken up during wet seasons. Examples of this kind of plant are the tamarisk, the creosote bush, the acacia, the mesquite, and some species of eucalyptus. Like succulents, they grow slowly.

Desert plants often protect themselves against being eaten by animals by growing spikes or other deterrents.

If the desert is an inhospitable environment for plants, then it is even more so for animals. Shortage of water, lack of food, and extremes of temperature are just some of the obstacles that animals must overcome if they are to survive. However, all types of animal life are found in the world's deserts, from the smallest protozoa right up to large carnivores. Even fish are found in some parts of the North American desert!

Where maximum daily temperatures are consistently high, animals are at risk from overheating and water loss. To avoid this problem, animals will either spend most daylight hours in the shade of rocks or vegetation, or they will burrow into the sand where the temperature remains almost constant. The other alternative is to adapt to the high temperatures.

Did you know that:

• deserts cover a third of the earth's surface

• 13 per cent of the world's population live in deserts

• evaporation rates in deserts are often 20 times the annual precipitation

• a temperature of 58° C (136.4° F) has been recorded in the shade at Azizia in Libya

• no rain fell for over 40 years in the Atacama desert in Chile

• night temperatures in some deserts can fall below freezing

• sand dunes can reach heights of up to 300m

• sand covers less than 20 per cent of the world's desert areas

• dust from the Sahara has occasionally been carried as far afield as the UK and Germany

• the Sahara Desert accounts for around 8 per cent of the world's land area

• there are an estimated 1,200 species of plant to be found in the Sahara

• in the last 50 years the Sahara has spread south to cover an extra 65 million hectares

Help stop China's brutal dog culls!

www.animalsasia.org


It’s devastating to have to bring you such tragic, horrible news. A rabies outbreak involving 10 human cases, has prompted authorities in China's northwest Shaanxi Province to order a cull that has already seen as many as 30,000 dogs brutally slaughtered on the streets of Hanzhong and surrounding areas. This is one in 10 of the city's dogs.

Despite our best efforts – and those of other NGOs and many desperate local people – because of two more human cases of rabies, the dogs are still being brutally hunted down by gangs of men and women wielding bloody sticks, metal hooks and ropes, then heartlessly clubbed to death. Some are cherished family pets, while others are strays that have already suffered enough in their cruel, short lives on the streets.

The gutters are running with blood, but it’s the hands of the Hanzhong authorities that are stained. The slaughtered dogs were on the streets only because these people still refuse to act on the evidence before their eyes – that the only way to manage stray-dog populations (and therefore rabies and other diseases) is to implement broad vaccination and trap, neuter, release (TNR) programmes.

Over the past two weeks, families have sobbed and fallen to their knees as their beloved dogs were snatched from their arms, roughly collared with rope and beaten to death before their eyes. Often the dogs wag their tails once or twice and look up pathetically between careless heavy blows to the face, head and spine. The dogs’ cries are spine-chilling.

Other dogs whimper and cower nearby – all of them terrified, knowing their turn will come soon. Some of the killers are local men, ordered by the authorities to help in the slaughter. Others are taking part willingly, even laughing as they brutalise the dogs.

We are so grateful to Jiang Hong, founder of the Small Animal Rescue Centre of Xian, who along with representatives of several local animal-welfare groups, made an urgent trip to Hanzhong to plead our case with the authorities.

Sponsored by Animals Asia, Ms Jiang’s group spent three traumatic days witnessing and recording the cull and offering officials help with dog control. In Yangxian town, they saw no dogs alive – just rotting carcasses scattered around the streets and in the waterways, causing a serious risk to public health.

The authorities stubbornly went ahead with the cull despite receiving advice from international and Chinese experts that culls do nothing to eradicate rabies. Our own letter – passed on to Hanzhong officials by Ms Jiang – was virtually ignored, the officials seemingly unmoved and uncaring.

I’m deeply saddened by these events. I’ve grown to love China and hate to see such wanton disregard for the country’s image in the world, let alone the sheer disregard for the suffering of people and animals. But this is just a small part of the story. Every day, we are seeing amazing developments, particularly through our relationships with more than 60 local animal-welfare groups throughout the country.

Even in Hanzhong, the scene of such bloodshed earlier this month, there is positive news. More than 200 residents attended the lakeside vigil, forming a poignant “SOS” with lighted candles to mourn the victims, many of them their pets; and because of the cull, some animal lovers have formed an organisation to lobby their local authorities to adopt stray-dog management measures.

Other municipalities are listening. Just last month, Animals Asia – along with other animal-welfare groups – was able to convince officials in Hehei, Heilongjiang Province to abandon a similar cull.

Please help us with this! We urgently need funds to equip local groups with the materials and information they need to convince their local governments to work with them. With grants from Animals Asia, these groups will be able to produce their own flyers, leaflets and banners to send to the authorities, the media and public along with our Dr Eddie Education Packs, and to continue our TNR programmes.

More and more cities are listening and implementing regulations to control stray dog and cat populations. It is so important that we keep the momentum going. It is the local people themselves who are bringing about these changes. They no longer want to live in fear of walking their dogs on the streets.

These people are willing to work hard, but most are poor and lacking resources. Please help us to help them.

Sincerely,

Jill

Jill Robinson MBE
Founder and CEO
Animals Asia Foundation

PS: Please write a polite letter to your local Chinese embassy asking for an immediate stop to the Hanzhong cull and an end to cruel dog culls throughout China. Please also ask that the Chinese authorities work with Animals Asia to introduce effective, lasting and humane anti-rabies measures. See here for embassy addresses, or here for ideas.

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Some basic facts about mutual funds

To invest in mutual funds, you need to first understand what they are, and how they work.

Even more basic is your grasp of stocks and bonds. Very quickly, stocks stand for shares of ownership in a public company, and bonds are money lent to the government or company, on which you receive interest. These are the two most common forms of investment, owned and loaned (real estate and precious metals being examples of others), but we are presently concerned with these instruments, since most mutual funds invest in stocks and/or bonds.

Simply, mutual funds act as intermediaries and facilitate investments in various securities (stocks and bonds). The logical question here would be: why do I need a mutual fund? Why can't I just invest directly?

The mutual fund advantage
Investing in a mutual fund allows you to minimise risk and maximise returns, because it acts as a middle man for a group of investors with a shared and predefined investment objective. If your main objective is security in investment but you don't know how to begin, a mutual fund is one way to go.

Typically, a fund manager will maintain the fund, and since you are one shareholder in the fund, you have the added advantage of easy investment, and lower trading costs.

Who are these fund managers?
Asset management companies (AMCs) approved by the Securities and Exchange Board of India (Sebi) manage the funds by making investments in various types of securities. This means that all recognised AMCs are monitored by higher authorities and stringent regulations, and funds are managed by professionals who have the necessary expertise.

How is your risk minimised?
Typically, investing in a mutual fund means investing in more than one stock. Some fund managers will diversify and spread your investment further by buying a mosaic of stocks and bonds. Investing in a large number of assets, or diversification, means that a loss incurred on one investment is minimised by gains in others.

How are trading costs reduced?
Since the AMC buys and sells large amounts of securities at a time, transaction costs are reduced, and the benefit is extended to the investor, because the average cost of the unit is lowered.

There are three ways in which you will see returns on your investment in a mutual fund:

• Through dividends on stocks and interest on bonds;
  
• Through capital gains, if the fund sells securities that have increased in price and the fund distributes these gains; and
  
• By selling your shares when the holdings increase in price.

Mutual funds can either be open-ended or close-ended in nature.
With open-ended funds, you can either enter or exit the fund any time during the scheme period, by buying/ selling fund units -- this means a high degree of liquidity. Close-ended funds, as the term implies, means that an exit is possible only when the scheme period is over.

Mutual fund schemes in India are varied and cater to a wide range of requirements and profiles, based on financial position, tolerance to risk, and expectations of returns. Each mutual fund has a specific stated objective.

The fund's objective is laid out in the fund's prospectus, which is the legal document that contains information about the fund, its history, its officers and its performance.

High on risk and high on return are Equity funds. Also known as Growth Schemes, the aim of these schemes is to provide capital appreciation over medium to long term. These schemes normally invest a major part of their fund in equities and are willing to bear short-term decline in value for possible future appreciation.

They may be further classified into Diversified Equity Funds, Mid-Cap Funds, Sector Specific Funds and Tax Savings Funds (ELSS).

Debt funds, or Income Schemes, invest in debt instruments, typically issued by the government, private companies, banks and other financial institutions, and promise low risk and a stable income.

These schemes generally invest in fixed income securities such as bonds and corporate debentures. Capital appreciation in such schemes may be limited. Further classification includes Gilt Funds, Income Funds, MIPs, Short Term Plans and Liquid Funds.

Balanced funds are a mix of both equity and debt funds. They invest in both equities and fixed income securities, providing both growth and stability.

Money Market Schemes promise high liquidity, preservation of capital and a moderate income. These schemes generally invest in safer, short-term instruments, such as treasury bills, certificates of deposit, commercial paper and inter-bank call money.

Tax-saving schemes offer tax rebates to the investors under tax laws. For example, under Sec.88 of the Income Tax Act, contributions made to any Equity Linked Savings Scheme (ELSS) are eligible for rebate.

Index schemes track and emulate the performance of a particular index such as the BSE Sensex. The stocks in these portfolios will mirror those in the Index, as will the percentage of each stock retained. Returns will therefore mirror the movement of the Index.

Finally, a further benefit from investing mutual funds is the 100 per cent income tax exemption on all mutual fund dividends. For Equity Funds, short-term capital gains are taxed at 15 per cent. Long-term capital gains are not applicable.

For Debt Funds, short-term capital gains are taxed as per the slab rates applicable to you. Open-ended funds with equity exposure of more than 65 per cent are exempt from the payment of dividend tax for a period of three years from 1999-2000.

Know About Global Warming

It is important to know the true facts about global warming. Because it is not a small or localized environmental problem, it is going to require international cooperation as well as personal change from all of us to stop global warming. In fact, it may be the largest challenge humanity faces in the twenty-first century. Unfortunately, it has also become a highly politicized issue.

You need to especially carefully about the information concerning global warming-- you can learn which facts are accepted by the scientific community and which are created by ill-informed or political sources.

Comparison of modeled and observed temperature trends since 1860

Global Warming: A Fact or Myth?

It is a fact, not a theory. Global warming is a measurable process that is already underway. Temperature changes, alterations in rainfall patterns, and an increased frequency of storms are occurring and being measured around the world as we speak. The evidence against global warming is not convincing in light of the effects we are witnessing already.

Warming is destroying ecosystems worldwide that you and other people depend on, according to a highly detailed new study conducted by scientists at the Goddard Space Institute. The study found a trend of change all over planet Earth, including the "timing of plant flowering, bird nesting, ice melting, salmon migration and pollen release; declines in populations of polar bears, krill and penguins; and increased growth of Siberian pines and cool-water ocean plankton." This extensive study adds to the already voluminous evidence that global warming is real!

The Real Impact on Humans:
150,000 Dead Every Year

Global warming has changed precipitation patterns around the world, disrupting traditional agricultural practices that you and the rest of the world depend on to live. The area of land on the Earth suffering from drought conditions has doubled since 1970.Insurance costs in the coastal areas of the United States have escalated dramatically. These are the effects you can see already, and climate change is only beginning to make itself felt.

Climate-related deaths will double in 25 years according to a 2005 report from the World Health Organization. Climate change is already tied to 150,000 deaths globally every single year. These deaths are caused by more frequent heat waves and droughts, as well as by floods and more powerful storms linked to climate change. Global warming has increased deaths in urban areas as heat waves have exacerbated the effects of smog and related respiratory problems.

We Cause The Problem

The basic facts are well understood. Human activities are pumping increasing amounts of carbon dioxide, methane, and other heat-trapping greenhouse gases into the atmosphere. The elevated concentration of these gases is raising the temperature of the Earth's atmosphere, thereby warming the surface of the Earth. This process has been repeatedly demonstrated in laboratory experiments and is now being measured on the Earth as a whole.

Interesting Effects on Weather

Global warming does not mean a universal and uniform warming of planet Earth, nor does it mean the end of highly unpredictable weather patterns. However, weather patterns are the result of an enormously complex process, and the effects of global warming on this process could be horrific.

There is a lot of uncertainty about how the different "feedbacks" operate, given the complexity of global weather systems. There is concern that global warming could cause changes in massive ocean currents like the Gulf Stream, which is part of a global system referred to as the oceanic "conveyor" because it propels enormous volumes of heat around the world. If this happened, it would cause huge changes in global weather patterns.

The consequences will be enormous no matter which systems are disrupted first. Scientists are unsure about which systems in the world’s climate -- tropical currents versus polar currents, or events on land versus in the ocean -- cause or trigger changes in other systems. Even though you may live in a relatively stable climate, at some point the ecosystem you live in is greatly affected by climates around the world.

Is Uncertainty a Cause for Doubt?

Briefly, the answer is no. While we will never comprehend all there is to be known about such a vast and interdependent system, the larger trends are clear. You should use these uncertainties as a springboard for action, not a rationalization for further, unnecessary debate.

We Must Act Soon

The most alarming danger is that once warming reaches a certain level, it could cause global climate and weather patterns to shift quickly and dangerously. We now have a fairly detailed understanding of the Earth's climate from the last 600,000 years and more. In the past, the climate has not changed slowly, nor has it changed in a linear, incremental fashion.

Abrupt changes dramatically alter life on Earth. Sudden shifts in temperature or ocean currents result when a certain amount of pressure to change is put in place. Ocean currents like the Gulf Stream that distribute heat and moisture around the world have historically changed course in a matter of a few years, or even a few months. The historical record has shown us the devastation this sort of change can wreak on entire ecosystems.

Runaway Global Warming:
A Scientific Possibility

There is a chance we may trigger a runaway warming effect that would amplify itself uncontrollably. The most likely source of such runaway warming is the arctic tundra. In the polar regions, there are great expanses of tundra that have remained frozen year round for tens of thousands of years. These ice-locked fields contain enormous stores of organic matter. If these areas thaw, the decay of that organic matter will accelerate, releasing stored carbon and methane. That could create a powerful positive feedback loop catalyzing further warming.

It could mean and end of life as we know it. Runaway warming could produce an Earth like the one that existed in the age of the dinosaurs: a steamy planet with sea levels hundreds of feet higher than they are now.

Spiking Carbon Dioxide Levels

The scary fact is that we are seeing changes faster than any of the climate models had predicted, and that the rate of accumulation of greenhouse gases in the atmosphere is accelerating. Before the industrial revolution started pouring carbon dioxide into our atmosphere, the level of carbon in the air was about 275 parts per million (ppm). The average rate of carbon increase in the atmosphere from 1960 to 2005 was 1.4 ppm per year. But over the decade from 1995 to 2005, the average increase was 1.9 ppm per year, and in 2007 the increase leapt to 2.14 ppm. Carbon is accumulating in our atmosphere ever more quickly.

Growth in Methane Levels

In 2007, levels rose much faster than in previous years. Although there is much less methane than CO2 in the atmosphere, methane is by far the more potent greenhouse gas per unit volume. Scientists are worried that this spike in methane levels may indicate that global warming is escalating the release of methane from the arctic tundra. This could be part of a positive feedback loop that will lead to further warming, as mentioned earlier.

In spite of all the attention global warming has been getting lately, we are headed rather decisively in the wrong direction. That is why you have to act, and act now!

Some Critical Facts About Global Warming

Greenhouse Effect The earth is a natural greenhouse and is kept warm by water vapors, carbon dioxide (CO2), and other gases in the atmosphere, which absorb the sun’s energy and radiate it back toward the earth. This type of warming is called “natural greenhouse effect.” “Enhanced greenhouse effect,” on the other hand, causes global climate change due to excessive levels of CO2 in the atmosphere. Without the atmosphere to create a greenhouse-type effect, the average temperature on Earth would be just 5° Fahrenheit (F). Natural levels of CO2 in the atmosphere have varied throughout history between 180 and 300 parts per million (ppm). Today’s CO2 levels hover around 380 ppm, representing a 25% increase over the highest recorded natural levels. In the year 1997 alone, the concentration of CO2 in the atmosphere increased by 2.87 ppm; this increase is more than any other year on record. The year 2005 was the warmest on record, and the years 1998 and 2007 are tied for the second warmest. The eight warmest years on record have all occurred since 1998. Scientists expect a 3.5° F increase in average global temperatures by the year 2100, resulting in the warmest temperatures in the past million years. During the Pliocene epoch 1.8 million years ago, when the earth’s temperatures were roughly equivalent to today, sea levels were 12-18 feet higher. Geologists believe sea levels could rise between seven and 23 inches by the end of the century if current warming trends continue. Worldwide, one hundred million people live within three feet of sea level, and much of the world’s population is clustered in coastal areas. Fewer than 25,000 polar bears currently survive in the wild The polar bear, while surviving in drastically reduced numbers, is already effectively extinct in its natural habitat—and no amount of change can save it. Scientists estimate that just 20,000 to 25,000 polar bears still survive in the wild. The first forced relocation due to the effects of climate change occurred in 2007 when 100 residents of Tegua Island in the Pacific Ocean were evacuated due to rising sea levels and subsequent flooding. For the past million years, cool climate conditions have primarily prevailed throughout the world. It was under these conditions that the human species evolved. The earth has always experienced cyclical bouts of climate change. Recorded temperatures throughout history display graphs of peaks and valleys with occasional extreme periods, such as the Little Ice Age of the seventeenth and eighteenth century and the Medieval Warm Period of the eleventh century. According to NASA studies, average temperatures around the world have increased 1.4° F since 1880, with most of the change occurring in recent decades. During the twentieth century, the earth experienced two warming trends. The first was a burst in temperature from 1900-1930, and the second is a continuing increase in temperature beginning in the 1970s. The last two decades of the twentieth century were the hottest decades in more than 400 years and may have been the hottest decades for several thousand years. Climate models predict the loss of Arctic sea ice earlier and more rapidly than the loss of Antarctic land ice if warming trends continue. Since the 1950s, Arctic sea ice has declined by 15% and the average annual duration of northern lake and river ice has decreased by two weeks. As Arctic ice rapidly disappears, scientists believe the Arctic will experience its first ice-free summer as early as the year 2040. Average temperatures in the Arctic climates of Alaska, Canada, and Russia have risen at twice the global average in the last century. The effects of global warming could destroy the habitats of and threaten extinction for over one million species of plants and animals. Glaciers worldwide have lost 890 cubic miles of ice since 1961 Between the years 1961 and 1997, the world’s glaciers lost 890 cubic miles of ice. In 1910, Glacier National Park in Montana boasted 150 glaciers—today there are just 27. Deserts worldwide are increasing as a result of warmer temperatures. At the end of the year 2007, Australia lost 25% of crop production due to desertification. Swedish scientist Svante Arrhenius realized as early as 1896 that human industrial activity was already surpassing the earth’s ability to reabsorb CO2. Fossil fuel burning currently adds nearly six billion tons of CO2 to the atmosphere every year. Only half of this CO2 is removed by forests and oceans. Rampant deforestation currently causes 20% of the world’s global warming pollution by prohibiting the reabsorption of CO2. Between the first Earth Day in 1970 and the new millennium, human-made emissions of greenhouse gases rose 70%. The earth’s atmosphere now contains 40% more CO2 than before the Industrial Revolution. The United States represents less than 5% of the world’s population, yet Americans account for 25% of the world’s commercial energy consumption and 22% of the world’s industrial emissions of CO2. By 2030, the world will be driven on by more than a billion cars Cars amount to three-quarters of all transportation emissions. At the current rate, the world will be driven on by more than a billion cars in 2030 and a billion more by 2050. Roughly 75% of the annual increase in atmospheric CO2 is due solely to the burning of fossil fuels. About 20% of CO2 emitted into the atmosphere comes from the gasoline burned in motor vehicle engines. The vast majority of emitted CO2 is a result of fossil fuel burning in power plants for electricity generation. While increased concentrations of CO2 in the atmosphere certainly can increase temperatures, many geologists believe that water vapor accounts for more than 90% of the greenhouse warming effect. According to the Internal Energy Agency, the world will invest some $20 trillion in new energy research over the next 25 years in an attempt to slow the effects of global warming. Global warming research is primarily conducted by the Intergovernmental Panel on Climate Change (IPCC), a partnership formed in 1998 with the World Meteorological Organization and environmental agencies of the United Nations.