Does Urban Heat Island effect add to the global warming trend?

It's well established that urban areas are warmer than surrounding rural areas. However, does Urban Heat Island (UHI) contribute to the global warming trend? Short answer, no. Two thirds of global temperature data comes from ocean records, free of UHI effect. For land records, urban trends are compared to nearby rural data - anomalous urban trends are homogenized to match rural records (Hansen 2001). However, in most cases, the urban temperature trend is observed to be little different to the rural trend. A new paper Urbanization effects in large-scale temperature records, with an emphasis on China (Jones et al 2008) looks at this in more detail.

Comparing rural and urban sites in London and Vienna

The paper begins by looking at 5 sites in and around London. Figure 1 shows absolute temperatures, clearly indicating a UHI influence on the urban sites at London Weather Centre (brown) and St. James Park (dark blue). The coolest record is the rural based Rothamsted (dark green). However, the excess urban warmth has no effect on the temperature trend - all sites show the same overall trend.


Figure 1: Annual temperature trends for five sites in and around London. Brown and dark blue are urban sites, green are rural.

A similar comparison was made between two sites in Vienna. Again, the absolute temperature is greater for the urban site but both sites show near identical trends.


Figure 2: Annual temperature trends for two sites in Vienna – Hohewarte in the center (brown) and the rural location of Grossenzersdorf (green).

Comparing rural and urban networks in China

So established urban areas show the same trends as surrounding rural areas. What about urban areas that are still developing? China, in contrast to Europe, has experienced rapid economic growth over the last 30 years with a dramatic increase in its city areas. If there were to be significant urban-related warming, it ought to be in this region and over recent decades. Figure 3 compares a range of temperature datasets:


Figure 3: Annual average temperature anomalies. Jones et all (dotted green and brown) is a dataset of 42 rural and 42 urban sites. Li et al (solid green and brown) is a homogenized dataset of 42 rural and 40 urban sites. Li (blue) is a non-homogenized set of 728 stations, urban and rural. CRUTEM3v (red) is a land-only data set (Brohan et al., 2006). This plot uses the 1954–83 base period.

That there are hardly any differences between the six series tells us several things. Small datasets of 40 stations show the same result as the 728 station dataset. In other words, for a region of this size, the average can be constructed from a limited number of sites, implying that for the 728 station network there is considerable redundancy.

As the scale increases, the overall impact of homogeneity adjustments diminishes. This might be a bit heartbreaking for those hard working boffins who spend hundreds of hours pouring meticulously over station data, ensuring the data is all homogenised (but of course, they don't do it just to calculate global trends).

And of course, the most significant finding: the trend is the same for both urban and rural groups over any of the periods. Even in the case of developing urban areas, when averaged out over large areas, urban heat island has little impact on the warming trend.

Globle warming

What is global warming?   Global warming is when the earth heats up (the temperature rises). It happens when greenhouse gases (carbon dioxide, water vapor, nitrous oxide, and methane) trap heat and light from the sun in the earth’s atmosphere, which increases the temperature. This hurts many people, animals, and plants. Many cannot take the change, so they die.     What is the greenhouse effect? The greenhouse effect is when the temperature rises because the sun’s heat and light is trapped in the earth’s atmosphere. This is like when heat is trapped in a car. On a very hot day, the car gets hotter when it is out in the parking lot. This is because the heat and light from the sun can get into the car, by going through the windows, but it can’t get back out. This is what the greenhouse effect does to the earth. The heat and light can get through the atmosphere, but it can’t get out. As a result, the temperature rises. The sun’s heat can get into the car through the windows but is then trapped. This makes what ever the place might be, a greenhouse, a car, a building, or the earth’s atmosphere, hotter. This diagram shows the heat coming into a car as visible light (light you can see) and infrared light (heat). Once the light is inside the car, it is trapped and the heat builds up, just like it does in the earth’s atmosphere. Sometimes the temperature can change in a way that helps us. The greenhouse effect makes the earth appropriate for people to live on. Without it, the earth would be freezing, or on the other hand it would be burning hot. It would be freezing at night because the sun would be down. We would not get the sun’s heat and light to make the night somewhat warm. During the day, especially during the summer, it would be burning because the sun would be up with no atmosphere to filter it, so people, plants, and animals would be exposed to all the light and heat. Although the greenhouse effect makes the earth able to have people living on it, if there gets to be too many gases, the earth can get unusually warmer, and many plants, animals, and people will die. They would die because there would be less food (plants like corn, wheat, and other vegetables and fruits). This would happen because the plants would not be able to take the heat. This would cause us to have less food to eat, but it would also limit the food that animals have. With less food, like grass, for the animals that we need to survive (like cows) we would even have less food. Gradually, people, plants, and animals would all die of hunger.    What causes global warming? Many things cause global warming. One thing that causes global warming is electrical pollution. Electricity causes pollution in many ways, some worse than others. In most cases, fossil fuels are burned to create electricity. Fossil fuels are made of dead plants and animals. Some examples of fossil fuels are oil and petroleum. Many pollutants (chemicals that pollute the air, water, and land) are sent into the air when fossil fuels are burned. Some of these chemicals are called greenhouse gasses. We use these sources of energy much more than the sources that give off less pollution. Petroleum, one of the sources of energy, is used a lot. It is used for transportation, making electricity, and making many other things. Although this source of energy gives off a lot of pollution, it is used for 38% of the United States’ energy. Some other examples of using energy and polluting the air are: Turning on a light Watching T.V. Listening to a stereo Washing or drying clothes Using a hair dryer Riding in a car Heating a meal in the microwave Using an air conditioner Playing a video game Using a dish washer

Overpopulation in the world

 

The world's population will soon reach a level where there will not be enough resources to sustain life as we know it. Growth must be checked to avoid this catastrophe. Many environmental, social, and economic problems either stem from or are increased in magnitude by the overpopulation problem. With an exponentially increasing population, the problems created by overpopulation grow correspondingly. To ensure population stability not only in the increasingly wealthy third-world areas, but also in the industrialized areas, countries and individuals must work together to achieve zero population growth.

The earth does not contain enough resources to indefinitely sustain the current enormous population growth. For instance, there is a limited area of arable land and living space. China, home to 1.2 billion people or 1/5 the world's population, is an excellent example of the kinds of problems that arise in an increasingly crowded society. Trying to increase the standard of living of its people, China has industrialized and the economy has grown (Hanson). This increase in wealth has increased the demand for food in China. The demand is so great that China went from exporting 8 million tons of grain in 1992 to becoming a net importer of 16 million tons of grain in 1994 (China News Digest). This causes a world-wide grain shortage which raises prices, which in turn puts food out of reach of even more people.

In many areas, there is simply not enough food to feed the growing populations. Each day 40,000 children die from malnutrition and its related diseases. 150 million children in the world suffer from poor health due to food shortages (Turbak, 20).

Another resource, which cannot keep up with an increasing population, is water. The supply of fresh water is limited. The recent California drought exemplifies this problem. Conflicts ensue between farmers, municipalities, environmentalists, and others over water rights. Recently, environmentalists battled with Los Angeles over the diversion of water from Mono lake to the LA basin. The Mono Lake incident and the aqueduct fights highlight some of the conflicts that arise over water. Creating fresh water can be expensive. A swelling population may have to turn to desalinization for their clean water. Oil-rich Saudi Arabia is the only country for which this process has had any success. However, Saudi Arabia does not require the vast amounts of agricultural water that California and other areas need. Another possible solution to the fresh water shortage is towing icebergs from the polar caps. This is just too costly for many areas.

In addition to depleting resources, overpopulation increases environmental problems. Pollution is an environmental problem whose magnitude is increased by overpopulation. As more people drive more cars, use more electricity, throw away more trash, and cut down more trees, the environmental problems we experience are greatly increased. The earth could easily sustain a small population of highly polluting people. But as more people such as ourselves pollute, massive problems occur. Pollution is magnified in developing nations. As those nations with larger growing populations become richer, their pollution increases with their wealth. Developing nations often promote industries that pollute to compete economically. These industries are less tightly regulated in order to stimulate growth.

Besides causing the environmental strains on the earth, overpopulation causes a large number of the social problems in today's society. One example of this is described in the recent study by Ohio State University showing that children whose family sizes were larger did worse in school. "The research, to be published in October's American Sociological Review, found that as family size increases, parents talk less to each child about school, have lower education expectations, save less for college and have fewer educational materials available" (CAPS).

Each individual's political power is reduced with increased population. As the population increases, each representative in the US and state congresses (as well as senators) represents a wider segment of the population. This problem was initially addressed by increasing the number of representatives. However, when the number of US representatives reached 435, the sheer numbers became unimaginable and led to a cap on the number of representatives. In Lincoln's time, there were 185,000 residents in a congressional district. Today, there are about 600,000 people in each district (Oberlink). The only alternative would be increasing the number of representatives, however this would only decrease congresses' efficiency.

Social funding per capita is also reduced when the population grows. Again, California provides an excellent example. In 1990 there were 5.7 million children enrolled in California's K-12 schools, while there will be 7.9 million in 2000 (Bouvier 41). "Our secondary school population is growing by 177,000 a year. The Dept. of Education projects that 35,333 new classrooms, or approx. 1,399 K-12 schools will be needed by the year 2000. That is almost a school a day. California already has some of the largest class sizes in the nation (Phillips)." With this growth in school needs, the state cannot meet the budget requirements. This has significantly contributed toward the state's deficit, as well as reduced the quality of education.

In the 1980's, there was a 10% population density increase in the US. This led to a 20% decrease in housing affordability. The supply has not kept up with the demand for housing, which caused the real estate boom. This causes continually growing urban communities such as Los Angeles, which has experienced problems due to its sheer massiveness (Johnson).

The traffic problems we face daily are another result of overpopulation. Just in California, 300,000 hours are wasted in traffic congestion each year at an estimated annual cost of over 892 million dollars. In addition, these idiling motors add to the pollution problem (Oberlink).

Many people feel that efforts to stop the rising population are unnecessary. They feel the population is under control and, in effect, the population bomb has fizzed. Ben Wattenberg, in The Birth Dearth, cites that a shrinking population will put developed nations at a severe disadvantage. It will cause military, economic, politic, and cultural weaknesses in relation to other countries.

People against population controls cite statistics in their favor. According to the 1994 US Census, the fertility rate of 59 countries is below 2.1 births per female which is the number of children per family needed to maintain the population. China is down to 1.8, and Spain is down to 1.4 (Verburg). These people also claim Africa is experiencing shortages of laborers, even though they reject technology because of the reduced labor it requires.

Anti-population control advocates feel that the resource problems may not be as bad as earlier expected. Since 1960, the world's food supply per capita has increased 27% and the food production in developing nation has increased 20%. The world's oil reserves have increased from 100 billion cubic meters in 1980 to 158 billion cubic meters in 1993. Only 50% of the world's arable land is used. Grain production increased 2.1% in the 80's, well above the 1.4% necessary to feed the increasing population (Verburg). According to the UN, the world's population may stabilize at 7.5 billion in 2015.

Although opponents to population stabilization cite statistics in their favor, the overwhelming majority of statistics point toward a severe problem. One in four births in the developing world outside China is unwanted (Verburg). It took 123 years, from 1804 to 1927 for the world to produce its second billion people, yet it took just thirteen years, from 1974 to 1987, to produce the fifth billion (UN Population Division). There are three more people in the United States every second with nine births and three deaths every two seconds (Universal Almanac, 173). In 1960 Europe was the most densely populated continent. By 1991 Asia surpassed Europe's denseness with 176 persons per square mile while Europe only had 168 persons per square mile. Americans can barely feel this squeeze with only 43 persons per square mile ("Population," World Book Encyclopedia). If the population continues to grow at current rates with no further decline (a highly unlikely scenario), there will be 694 billion people on the Earth by 2150 (Verburg).

The Catholic Church represents major religious opposition to controlled population. The Church's official stand is against any birth control whatsoever. They believe God should plan families. The problem includes Catholics obeying John Paul II's Human Vitae, the church using its political power in stopping abortion and birth control advances, and protesting the discussion of family planning at world forums such as the UN Women's conferences (Ehrlich, 22).

Zero Population Growth is the foremost American activist organization for population control. They cite several solutions for the population problem including family planning services, international awareness, population education, improving women's status, and economic incentives. Many of these solutions have been implemented in various countries with success. These are easy solutions with few adverse side-effects.

The Chinese government has been able to control population by creating economic incentives for families with less than two children. With 1/5 of the world's population and only 7% of the land, population checks were badly needed. Population control was achieved using education, government propaganda, and community pressures. For instance, a couple promising to have only one child receives a one-time reward of money and rice. If that child does not live to maturity, the couple is allowed another. The child will receive a private plot of 70 square meters of land, compared to 50 for a child in a larger family (Mings, 479).

Similar techniques could be implemented in the United States by slowly removing the tax write-off for more than 2 children. Families will not experience extreme economic hardship if the decline were gradual enough. Moreover, government revenue could increase. An example of such a solution would be amending the current US H.R. 6, a middle-class tax cutting bill, to limit the $500-per-child tax credit to two children.

Birth control and family planning is another excellent way of slowing the surging population growth. Japan is a crowded nation the size of California with a population equal to about half the US population. Population controls were badly needed. Condoms have proven to be an extremely successful way of slowing the growth. With dedicated stores, such as Condomania, and aggressive advertising, condom usage reached 547 million in 1991. This is almost as much as the 561 million the US used with twice the population.

Another factor attributing to the decrease in population growth in Japan is the stressful working conditions. Men concentrate heavily on work and less on recreational activities. Because of the resulting high stress levels, overall sexual activity has declined and the sperm count with it. These factors, coupled with the high condom usage, has slowed Japanese population growth. The slowed growth has resulted in a temporary aging of the population, which creates minor problems, but is unavoidable in any fix to population growth (Watanabe).

Population growth is slowed as women's rights are increased. This is evident in developed nations where fewer births occur as the woman's role in society changes. Elevating women out of their lower-class status in many nations will greatly aid progress. As women gain economic, political, and reproductive power in today's industrialized nations, birth rates drop dramatically and now most of western Europe is at or below replacement level.

Finally, all the people of the world must be made aware of the situation. The problem is not popularized in the media as much as other problems which stem from overpopulation such as the environment, AIDS, and lung cancer. Children and adults are well informed on how to help the environment, how to avoid AIDS, and that smoking is bad for their health. But they are not well informed about all of the problems of overpopulation. Overpopulation information needs to be more widespread than it currently is. This can be reasonably achieved with information in TV segments and in science and social studies classes.

While less developed countries face the biggest problems, solutions also need to be implemented here in the US. In California, the fertility rate grew from 1.947 in 1982 to 2.480 in 1989 (Bouvier 13). Educating the public will ease California's population growth.

Successful steps have been made in fighting the problem. The first step, recognizing the problem, was reached by Thomas Malthus with An Essay on the Principle of Population in 1798. Malthus pointed out that population tends to grow at an exponential rate while the food production grows at a geometric rate. Thus population growth must be checked. He mentioned "positive checks" such as war, famine, and disease, and "preventative checks" such as celibacy and contraception ("Population," Encarta).

In 1968 Paul Ehrlich and Anne Ehrlich wrote The Population Bomb. They were the first to popularize how serious the problem had become. While incorrectly predicting short term large-scale famine and plague, the book awakened the world to the upcoming problems.

Today, the United Nations Population Fund is collecting information on the problem. Events such as the UN Women's conference in support of family planning and birth control have raised the status of women, an important step in reducing population. Family planning was not even on the agenda in the 1972 conference, but it was stressed in the 1992 UN Conference on Environment and Development, as well as the 1994 Women's Conference (Marshall).

With an impending crisis looming over the horizon, the afore outlined steps must be followed to ease the population problem and the many other problems which are directly related to it. When people are educated to the benefits of limiting family size, they respond with lower birth rates. Education, coupled with economic pressure, will end the overpopulation problem and ease many of the other problems faced by today's society.

 

 

The evidence for plate tectonics

 
  The evidence for plate tectonics includes the past and present distribution of earthquakes, changes in the earth's magnetic field, meteorites, chains of islands and volcanoes. Increasingly, geologists study plate tectonics with the use of satellite laser ranging techniques and rock magnetism as well as echo-sounders and small explosions to detect shock waves in the earth's interior. The study of seismic waves also enables geologists to examine the theory of plate tectonics. By determining the speed and the path of these shock waves through the earth geologists are able to identify the density and thickness of rocks that lie thousands of kilometres within the earth's interior.
 

 In the seventeenth century Frances Bacon noted that the coastline of the eastern side of the Americas was very similar to the coastline of the western side of Africa and could fit together like pieces in a jigsaw. In addition settlers in the New World found that huge coal deposits in the American continent were similar in location to their European counterparts. In 1857 the Irish civil engineer Robert Mallet produced the first scientific investigation of earthquakes. He produced a map which included land earthquakes as  well as submarine earthquakes. Many of the seaquakes, as they were called, were found around the centre of the Atlantic Ocean. In the late nineteenth century and early twentienth century it was realised that many earthquakes were caused by rocks suddenly breaking along faults such as the 1906 San Francisco earthquake along the San Andreas fault.
 

  In the early twentieth century an Amercan, Harry Hess, suggested that convection currents would force molten rock (magma) to well up in the interior and to crack the crust above and force it apart.
In the 1960s research on rock magnetism supported Hess. The rocks of the Mid-Atlantic Ridge were magnetised in alternate directions in a series of identical bands on both sides of the ridge. This suggested that fresh magma had come up through the centre and forced the rocks apart. In addition with increasing distance from the ridge the rocks were older. This supported the idea that new rocks were being created at the centre of the ridge and the older rocks were being pushed apart.
  In 1965 a Canadian geologist J Wilson linked together the ideas of continental drift and sea floor spreading into a concept of mobile belts and rigid plates, which formed the basis of plate tectonics. He argued that the earth consists of an outer layer of six or more major plates which move over a hot partially molten asthenosphere. New material is formed at the mid-ocean ridges. Due to the sea floor spreading continents move relative to each other. In some areas there is subduction whereby one crustal block of dives underneath another and is melted and taken back into the asthenosphere.


  In some areas geologists believe they have discovered rocks from part of the mantle. In North Italy, South East Turkey, the Persian Gulf and New Guinea dark heavy rocks known as peridotites are composed of olivine and pyroxene silicate minerals that are formed only at high pressure and these are very hich in iron and magnesium.


 

geography

                             What is geography?&Why we need to study geography?

 
Geography is the study of Earth’s landscapes, peoples, places and environments. It is, quite simply, about the world in which we live.

Geography is unique in bridging the social sciences (human geography) with the natural sciences (physical geography). Human geography concerns the understanding of the dynamics of cultures, societies and economies, and physical geography concerns the understanding of the dynamics of physical landscapes and the environment.

Geography puts this understanding of social and physical processes within the context of places and regions - recognising the great differences in cultures, political systems, economies, landscapes and environments across the world, and the links between them. Understanding the causes of differences and inequalities between places and social groups underlie much of the newer developments in human geography.

Geography provides an ideal framework for relating other fields of knowledge. It is not surprising that those trained as geographers often contribute substantially to the applied management of resources and environments.

Geography is, in the broadest sense, an education for life and for living. Learning through geography – whether gained through formal learning or experientially through travel, fieldwork and expeditions – helps us all to be more socially and environmentally sensitive, informed and responsible citizens and employees.