| Introduction Overpopulation means that there are too many organisms of a certain species in a certain habitat, meaning that the number of organisms living there is larger than it’s carrying capacity. Therefore, the habitat cannot support these numbers over time without hurting itself. Some numbers?  Based on projections: Today, there are 7.190.000.000 people on Earth. Causes Overpopulation can result from an increase in births, a decline in mortality rates, an increase in immigration, or an unsustainable biome and depletion of resources. It is possible for very sparsely populated areas to be overpopulated if the area has a meager or non-existent capability to sustain life (e.g. a desert). Birth and Death Rates Significant increases in human population occur whenever the birth rate exceeds the death rate for extended periods of time. For example, when death rates fell during the 19th and 20th century – as a result of improved sanitation, child immunizations, and other advances in medicine – allowing more new-borns to survive, the fertility rate did not adjust downward fast enough, resulting in significant population growth. Prior to these changes, seven out of ten children died before reaching reproductive age, while today about 95% of new-borns in industrialized nations reach adulthood. Technological Revolutions From a historical perspective, technological revolutions have coincided with population explosions. There have been several technological revolutions, all of which allowed humans more access to food and technology resulting in subsequent population explosions. Effects . Inadequate fresh water for drinking and sewage treatment. . Depletion of natural resources, especially fossil fuels. . Increased levels of air pollution, water pollution, soil contamination and noise pollution. . Loss of ecosystems that sustain global atmospheric oxygen and carbon dioxide balance. . Changes in atmospheric composition and consequent global warming. . Mass species extinctions from reduced habitat. . Intensive factory farming to support large populations. . High infant and child mortality in poor countries. Effects  The future According to projections, the world population will continue to grow until at least 2050, with the population reaching 9 billion in 2040, and some predictions putting the population in 2050 as high as 11 billion. These numbers would stop growing, after a readjustment of the Third World. Developed Countries Birth rates are now falling in a small percentage of developing countries, while the actual populations in many developed countries would fall without immigration. The Future  United Nation's population projections by location Global warming Introduction Nowadays, our planet has some serious problems and the one that we should be more worried about is the global warming, because it has many consequences. If man doesn’t take some measures our children will suffer the consequences of all of these problems. What does it mean? Global warming is the gradual increase in global temperatures caused by the emission of gases that trap the sun’s heat in the Earth’s atmosphere, which in turn causes changes in climate. What does cause it? . Scientists have determined that a number of human activities are contributing to global warming by adding excessive amounts of greenhouse gases to the atmosphere. . Human use of fossil fuels is the main source of excess greenhouse gases into the atmosphere. This is done by driving cars, using electricity from coal-fired power plants, or heating our homes with oil or natural gas. Deforestation is another significant source of greenhouse gases, because fewer trees mean less carbon dioxide conversion to oxygen Why is it dangerous?  what is being done? To stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous were signed some protocols. One of them is the Kyoto Protocol to the United Nations Framework Convention on Climate Change. Countries (more than 160) that ratify this protocol commit to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in emissions trading, if they maintain or increase emission of these gases. What should/could be done? . Run your dishwasher only with a full load. Use the energy-saving setting to dry the dishes. Don’t use heat when drying. . Wash your clothes in warm or cold water, not hot. . turn down your water heater thermostat 120 degrees is usually hot enough. . Buy energy-efficient compact fluorescent bulbs for your most-used lights. . Whenever possible, walk bike, carpool or use mass transit. Conclusion After this work we can say that our planet is “sick”, but if we take all of the measures that we pointed and educate children that they could learn not to do our mistakes, our planet will become a healthier planet. __________________________________ Outros Trabalhos Relacionados | | Ainda não existem outros trabalhos relacionados | |