Ecology And Sustainable Development

Nowadays one of the most important things humans have to resolve is the Ecology challenge, because most of the activities we do, are damaging the environment, our home and the legacy for future generations. In 2005 the UN alerted the world: more than the half of the world population was already living in cities and if that continues with the same rhythm, for 2025 the percentage will increase until 68% and that means that cities will grow but forests will decrease or finally disappear. The purpose of this work is to demonstrate how are the things now, some risks and the solutions for a warning planet.

It all started since the Second Industrial Revolution when people started to migrate from the country to cities, in those cities factories where beginning to build and the main source of energy was coal and then petroleum. Factories polluted a lot but most of the people did not care about the contaminants. Global Warming started since that time, global warming happens when the solar light enters to the atmosphere but they do not go out due to the layer of greenhouse gases, in its most Carbon Dioxide (CO2), there are other gases such as Methane (CH4), Chlorofluorocarbon compounds, Ozone (O3) and Nitrogen Oxides (NOX). If the concentration of these gases is higher, higher will be the heat on Earth. The consumption of coal and petroleum has raised the concentration of carbon dioxide in his maximum levels. In fact during the 19th and 20th centuries the percentage of carbon dioxide in the atmosphere has increased 28% and that is because of cities, transport and energy.

The population growth calculated for the next decades has altered the studies of the urban problems. The estimated projections reach the number of 12 thousand millions people for the second half of the 20th century, which restates where they are going to live and with what resources they are going to be satisfied. For some it represents a critical depletion of natural resources and the disappearance of many ecosystems. Population explosion, insufficient urban structure, environmental pollution and a low quality of life, are the problems that the world has to resolve.

Cities have turned into the first sources of contamination, due to the person's great quantity, big masses of people live there and most of them have to move and for that they must have an automobile or take the public transport. Automobiles, buses, motorbikes and other transport devices emit toxic gases, the ones that are mentioned in this work, and if that continues the pollutants will increase 2°C in the global temperature. This also cause a problem because with so many people and transport traffic increases, people stay many time in their devices and get frustrated, that also damages the health. Other thing cities have to deal with is water, with so many people sometimes water is not enough or other times water is wasted. Social classes influence in this because poor people many times don’t have water, but people that have it, waste it. Most of the water that comes from the cities goes directly to rivers and then to oceans, or other times to agricultural fields, and pollute them in huge scale. And finally energy. The forms of generation of energy still do not manage to do it in a sustainable way, most of it is generated from fossil fuels (55%), then from Biomass, wood and its derivatives (27%), then its Nuclear and Hydroelectric (17%) and finally the best ones, the ones that don’t pollute and are friendly with the environment, Geothermal, Wind, Solar and Tidal Energy (1%).

Until the 90's associations, governments, people and industries noticed that something was wrong with the environment and have to do something because changes started: weather increased in some countries, the resources diminished and they found a hole in the ozone layer. All these created laws and protocols to help the environment as the Kyoto and Montreal Protocol, and that gave birth

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