climatic changes
...dispersions off Africa may have started as early as 700000 B.C. and it is believed that they headed towards Europe due to the presence of herds for food and many caves to protect from the cold. Life on the northern parts of Europe was unthinkable of during the periods of ice age. It was only around 10000 B.C., at about the same time England became an island, when a liveable climate established in northern Europe allowing life to flourish again. Less severe climatic phases have also occurred during the existence of human civilization, some 14000 years. Evidence of a migration through the Sahara in 900000 and 90000, the same period in which a climatic change provoked the Sahara to be green; the Trans-Sahara migration was caused by men following the herd through the green pastures of the “desert” and not by the simple desire of exploring a new world. The last ice age ends in 12000 B.C. and 8000 years after, the conditions seemed propitious for the northeast Asians to cross through the Bering land bridge and settle in America, becoming America’s Indians and Eskimos. The recent changes observed were (1) a global warming trend between 900 and 1300 AD when average global temperatures could have been 1°C higher than the present average and (2) at the first quarter of the 14th century it was the beginning of what became known as the little ice age, which lasted until the end of the 19th century and resulted in five centuries of climate variation. The impact on society was great. CLIMATE AND MIGRATION – MODERN DAYS There are enough scientific consensuses indicating that human activities are altering the composition and behaviour of the atmosphere. The release of greenhouse gases may be caused by several factors. The distribution and extraction of fossil fuels as well as, the carbon dioxide resulting from the fossil fuels, are sources of greenhouse gas emission into the atmosphere. The concentrations of greenhouse gases have been accumulating in the atmosphere since the industrial revolution and will continue to increase, provoking physical impacts such as global warming. Sea level rise is an important consequence of climate change. Global sea level has risen by about 10-25cm over the last 100 years. Increased temperatures will have caused some expansion of the sea water, and the retreat of glaciers and ice caps will have also contributed to the increase. Numerous scientists and authors have suggested that climate change on some vulnerable regions can possibly cause conditions of scarcity, human migration and lead to mass movement of environmental refugees. Poor people will be the most affected by climate change. Indeed, government of poor countries will be unable to meet the needs of the population due to the scarcity of resources and the competing priorities between development and environmental needs. As far as climate change is concerned, the USA and the EU each produce over 20% of the world's climate change gases. Scientists almost unanimously agree that climate change is a reality and though they disagree over the details of what we can expect over the next century, there is no doubt that most of it is bad. Climate-related migration can function in different ways. There could be short-term shocks of migration caused by a particular climatic stimulus. For example, in October 1998, Central America was hit by a huge hurricane, which caused the destruction of thousands of homes and a bad economy. Th...