This is an essay handling global warming and the earth and in particular how it can threaten the earth's physical structure. Global warming is mostly the rise in the earth's temperature due to fossil fuels, industries and factories, agricultural processes caused by man as a result of population increase, natural phenomenas and other gas emissions. This leads to an increase in emission of greenhouse gases. We also have the issue of waves in that short-wave solar radiation sinks into the Earth's atmosphere and warms its surface while long-wave infrared radiation emitted by earth's surface are absorbed and then re-emitted by trace gases (Kriegle, 2007).Carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, and water vapor are examples of greenhouse gases; these gases occur naturally and in other cases they are as a result of human activities. Problems arise when higher concentrations of greenhouse gases are in the atmosphere of the Earth because they enhance the earth's heat trapping capability thus affecting the o-zone layer (UNEP, n.d.).A majority of scientists agree that the globe is going through a major climatic change and that the level of carbon dioxide is rising drastically, a good example is the case where nations are experiencing more water shortages and hurricanes, typhoons and cyclones are seen to be increasing in speed and frequency. This is seen through satellite images and various researches that ice caps are melting faster leading an increase in the sea levels and there's a possibility of changing the flow of the North Atlantic Current. This has caused immeasurable effects to the earth; it has also changed weather patterns (UNEP)There are many misconceptions about global warming. Some people believe that pollution causes global warming but the fact is that global warming is as a result of the buildup of harmful gases in the atmosphere released from burning fossil fuels, coal and oil that release carbon dioxide. The gases that are released into the atmosphere are measured by emission inventories- where they count the amount of air pollutants released into the atmosphere (Kriegle, 2007)How Global Warming Affects the Physical StructureThe following changes were observed in the 20th century: The Arctic air temperatures arose by about five degrees Celsius, this increase was estimated to be ten times faster the average of the global surface temperature while the sea-surface temperature of the Arctic increased by one degree Celsius over the last 20 years. The Arctic sea-ice depth has also reduced by forty percent during the late summer and early autumn over a period of thirty years. Northern Hemisphere, the spring and sea-ice cover reduced by twelve percent within 50 years. Also the sea-ice coverage in the Nordic seas had reduced by thirty percent within a period of 130 years. The forests of Alaska's boreal had expanded buy some 100 kilometers northwards for each degree Celsius of temperature increase. Precipitation had increased significantly over the Antarctic especially the Peninsula; the rest of the continent also experienced a marked warming trend (Jim Hansen, 2006).The waters on the surface of the Southern Ocean had become less saline and warm. Also the water flowing to the Arctic Ocean from the Atlantic had warmed considerably; also the Beaufort Sea's water had become less saline. The common breeding grounds of different creatures had been affected to a greater extent e.g. at the Bering Sea, the numbers of fur-seal had reduced sharply between 1950 and 1980 (Jim Hansen, 2006).
The following has been noted in the 21 century: The arctic and Atlantic have continued to warm. Ice caps are continuously disappearing in the Arctic; this allows ships to move safely through wide expanses of the ocean previously blocked by the ice. Across the extremely large expanses of the Arctic, a forest will substitute the tundra. A lot of plant and animal species will migrate, decrease in numbers, become extinct or those able to adapt will flourish under new habitat conditions. The marine mammals like Wales, polar bears, seals and the rest that rely on ice floes for resting, feeding and breeding will be greatly threatened. The populations of the krill and other small organisms will turn down as the ice recedes, this will have large consequences on fish, whales and other marine mammals. Because of the significance of the krill in many food chains, the whole marine food web may be adversely affected (UNEP, n.d.).The native people who have lived in the ice-covered North for centuries will be the most directly affected. The understanding of how their seasons occur will be unpredictable hence their knowledge on where and when to hunt, fish and gather food plants is already becoming less dependable as sea-ice dwindles, land-ice melts; birds, fish, plants and animals change their regular distribution and site. Those who live in the modern towns and settlements in the furthest north will also be affected as the permafrost continues to liquefy. This will lead to the terrain subsiding and this will damage all types of infrastructure. The Polar Regions are the key drivers of the global weather patterns, thus any changes caused by global warming could cause these regions to intensify the greenhouse effect in a number of ways. Example, warming dries the tundra which then dries and decomposes giving off extra carbon dioxide and methane gases (UNEP, n.d.).The oceans circulation is also driven by the Polar Regions. Salt is shed when the ocean water freezes. This makes the water under the ice becomes saltier and heavier thus falling to the bottom of the ocean creating a momentum that drives the oceans' main currents. When sea ice and glacier melts, the upper layers of the concentration of salt in sea waters becomes less, this reduces the quantity of very salty water available to sink to the bottom and thus deteriorating the driving effect on the global ocean flow. This will have substantial effect on the regional climates; like shutting off the Gulf Stream that warms the northern Europe, this in turn will reduce the supply of nutrients available to the marine creatures (UNEP, n.d.).
Precipitation under a lot of mid-latitude to high-latitude land areas in the Northern Hemisphere has become more intense. Rainfall in general has declined in the tropics and sub-tropics of both the hemi-spheres. When the rain falls, it is normally so heavy that it leads to soil erosion and flooding. An example is the parts of Eastern Europe where peak stream flows have highly developed from spring to winter, since a lot of precipitation falls as rain rather than snow, hence getting to rivers more quickly than previously. Another example is the Africa's largest catchment basins where the water level has dropped sharply by forty to sixty percent (Philander, n.d.).Deserts are expanding due to lower average yearly rainfall, runoff and soil moisture, especially in southern, northern and western Africa. Summer drying and the related risk of drought have been observed in other areas of the continent like the Central Asia and the Sahel. In various nations the effects of less precipitation and a lot of evaporation will cause a major strain on freshwater sources. Furthermore, countries that depend on run-off from mountains may suffer as glaciers retreat and the snow buildup reduces. The shortages of water could affect critically vital food production processes. Conflicts over water, particularly in rivers and lake basins shared by nations will increase as well. Plants like algae that grow more effectively in warmerConditions, when they decay, higher levels of nutrients accumulate in water. In the meantime, the intense rains will flush more pollutants from the immediate land and from overflowing waste facilities. In areas where the amount rainfall has reduced, pollutants will be more highly concentrated in the remaining water. (Jim Hansen, 2006).The increase in frequency of occurrence of floods, landslides, melting permafrost and sea-level will pose widespread risks to human settlements as the climate changes. Because snow and rainfall will be heavier, it will lead to more harsh and recurrent floods and mud flows. The coastal communities will be greatly threatened by the Coastal storm surges caused by more destructive higher temperatures and the increase in the sea-level. As those who live along the riverbanks and seacoasts face clear risks, urban flooding due to extreme precipitation will be a problem in all the regions. This will be especially dangerous in places where outdated storm-water drains; water distribution and sewage systems are by now running near capacity or are badly maintained (Kriegle, 2007).The squatters and other informal urban settlements will be at a greater danger; this is due to many people living close together and under poor shelter, with little or no access to clean water, sanitation and health services among other resources. There is less they can do to avoid floods and landslides or run away from disaster when it strikes. The tropical cyclones or hurricanes or typhoons and tornadoes will become more destructive in a warmer world and create the next most serious threat after flooding. Windstorms, wildfires and droughts are other risks which are also expected to rise. Heat waves will encourage more energy use as people turn on their air conditioning systems because of the heat, in turn this will cause more illness and death. When winds and storms break power lines, energy supplies will be further affected. In other regions, dwindling water supplies will destabilize hydro electric power generation. Thus, those countries that their main source of income is from the primary industries such as agriculture, tourism, mining and fisheries will be adversely affected than those that do not rely so much on natural resources (Anatole and Falcon, n.d.)4. Wildlife and ecosystemsThe geographic distribution of plant and animal kinds around the globe is shaped by the climate. For example, various plants can fruitfully reproduce and grow only within a limited temperature range and in addition to the right amounts and seasonal supply of precipitation. As the century progresses and global warming affects the climate; plants, animals, insects, birds, reptiles, amphibians, fish and all types of micro-organisms will have to acclimatize to the new climatic conditions so that they can survive. Some species will get on while others will reduce in numbers or become extinct. Those animals and insects not able to adjust will simply move to more favorable environments. However, some plant species may respond positively increasing concentration of carbon dioxide gas in the atmosphere thus grow faster while using less water (National Association of Geoscience Teachers, 2009 ).Global warming is mostly the rise in the earth's temperature and sometimes a drop in temperature. This leads to an increase in emission of greenhouse gases. Greenhouse gases can occur naturally but they mostly emitted as a result of human activities. Problems arise when higher concentrations of greenhouse gases are of the Earth's atmosphere because they enhance the earth's heat trapping capability thus affecting the o-zone layer. Global warming threatens the life of different creatures and interferes with the physical structure of the earth. It also favors the productivity of many plants because they all require a plenty supply of carbon dioxide. In some cases, plants that grow only within a limited temperature range and in addition to the right amounts and seasonal supply of precipitation are also favored.