How the Ocean Affects the Climate - Essay Example

How the Ocean affects the climate and how the climate affects the ocean Introduction Oceans cover about 70% of the Earths surface and typically the principle component of hydrosphere and contain roughly 97% of the Earths water supply. It plays very important role in the Earths climate by transferring warm as well as cold air and precipitation to coastal regions, where they may be carried inland by winds. The winds give energy to the sea surface that result in ocean currents. The currents carry heat from one location to another, changing the Earths surface temperature patterns and bring in changes in the atmosphere. Hence, ocean has a tremendous affect on climates and visa-versa. The thermohaline circulation (Oceanic thermohaline because it involves both heat, hence "thermo," and salt, hence haline) of the ocean distributes heat energy between the equatorial and polar regions of the earth while other ocean currents do the same between land and water. The sea interacts with the atmosphere in two different methods, physically and chemically. The physical way is through the exchange of heat, water, and momentum. More than 70 percent of the Earth’s surface is covered by ocean and contains about 97 percent of its surface water and stores huge amounts of energy in the form of heat. Besides, the sea has comparatively large temperature resistance to change. Today, it is understood that the biological and physical performance of the ocean can change rapidly over minute and large areas. It usually decides the timing and models of climate change. When the heat increases over the ocean which escapes to warm the atmosphere creates temperature variation in the atmosphere which in turn causes winds. As a result, winds move horizontally over the sea surface to drive ocean motion patterns. The variations in temperature and salinity cause vertical ocean currents which makes the warmer, fresher waters flow upwards as colder, denser or saltier water tends to move down. Eventually, a complex flow pattern is created through which the warm surface waters move pole ward where heat escapes fast to outer space, as cold, deep currents are established in the sea depths. Because of this complex ocean circulation movement system, the oceans and atmosphere get together to distribute heat and control climate. As this movement conveys huge amounts of heat and as a result more moderate climates on land areas that are nearer the ocean. It is not surprising to note that man’s increasing needs have simultaneously increased the load of greenhouse gases in the atmosphere. The burning of fossil fuels releases many harmful pollutants particularly the greenhouse gases into the atmosphere and contributes global warming. Increases of greenhouse gases in the atmosphere increases the earth’s temperature and results in malting of glaciers and ice sheets (Meehl, et al. 2005). Scientists estimate that global average air temperature near Earths surface raised 0.74 ± 0.18 °C (1.3 ± 0.32 °F) in just last one century. According to the Intergovernmental Panel on Climate Change (IPCC), "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations," (IPCC, 2007). Recently scientist have anticipated that over the period of the 20th century, the ocean has reduced surface warming by about half than the expected due to growing greenhouse gas levels. Scientist observes that as a result of the exchanges of heat and momentum between ocean and atmosphere, the average temperature of the ocean raises less. Hence its effectiveness at redistributing heat pole ward, the ocean is slowing and controlling global warming. But scientists are in doubt that the ocean’s role as climate moderator can continue over a long time. The evidence shows that huge and sudden changes in the ocean’s movement had major concern on global climate formerly. Few researchers doubt that whether the existing ocean movement pattern is stable enough to endure the stresses of rising temperatures, heightened greenhouse gases and fresh water runoff because of melting glaciers. When the fresh water flow increases, it reduces the salinity and density of ocean surface water, thus increasing its sub-zero point. These formations of ices over the surface would slow down the escape of heat and this could effect in a major restructuring of the ocean’s motion method and affect the global climate. Since the ocean is a resource and sink of greenhouse gases, the second way the atmosphere and ocean work together is through chemical. The large amount of heat that escapes the ocean is in the form of evaporated water vapor and the most plentiful greenhouse gas on Earth. This in turn causes the formation of clouds, which shadow the surface and results a cooling effect. CO2 is the most important green house gas because of its relations with human actions. World’s maximum carbon exists in in the ocean, and the method that causes the exchanges between the surface of the ocean and the atmosphere, and between the upper ocean and the deep ocean, are vital. The chemistry controls much of the move between these systems. Biological processes, such as photosynthesis also play a significant role. The continuous chemical relation between the ocean and atmosphere influence the regional and global climate in different ways. The ocean water vapor form low clouds that eventually cool temperatures at the surface. On the other hand, desert dust and carbon dioxide settle into the ocean and helps the growth of phytoplankton, thus improving the oceans absorbability of carbon dioxide from the atmosphere. This process is called as the ‘biological pump.’ It is difficult to predict the long-term trends since the natural variability is so high. A complete plan of observations and modeling is required to improve the predictions on the future course (NASAFacts, 1999). The growth and abundance of the ocean’s phytoplankton decreases when the climate gets warmer which can affect the marine life since the phytoplankton is a source of food for krill, fish and whales. There was a rise in ocean’s temperature since last fifty years and data from NASA shows the growth and abundance of phytoplankton around the world is decreasing. These findings are critical since it indicate effect of the changing global climate. It is estimated that phytoplankton is accountable for about half of Earths photosynthesis action, a method which takes carbon dioxide from the atmosphere and converts it into organic carbon and oxygen that needed for every ocean ecosystem. It is observed that since 1999, the climate was getting warmer and has seen the health of ocean plants diminish. The NASA’s satellite data helps scientists to resolve the amount of phytoplankton and the growth rates. There is an agreement among the worlds scholars that carbon dioxide, methane and other greenhouse gases generated from the burning of fossil fuels have added to natural carbon dioxide levels (Kay, 2006). Radiation of energy is taking place constantly from earth and all other object on earth. If the energy given out is more than it absorbs, the object become colder and the energy given out is less than it absorbs it gets warmer. If an object radiates and absorbs energy equally the objects temperature remains constant. Under this condition one can say that absorption and emission are in balance. The areas near the equator receive more solar energy than it loses and the regions near the poles lose more energy than it receives. For maintaining the balance, the atmosphere and oceans exchange the excess energy from the equator to the poles. The change in energy transfer causes climate change. The solar energy causes large quantities of water from the oceans to evaporate and these water vapors is then moved by winds to other regions where it concentrate into clouds and the rain. The rain water from land surfaces finally reaches to the oceans. This is named as the hydrologic cycle. 85 percent of the evaporated water vapors are from the oceans. Usually water has a high capability for storing heat energy and needs a fairly large amount of heat energy to cause a small temperature variation in water because if it’s a high specific heat. The surface of water reflects only a small amount of sunlight and absorbs large amount of solar energy. Because of these uniqueness and oceans cover about 70 percent of the earth, ocean has a great effect on weather and climate. The El Nino which is the warmer surface water temperature and the La Nina which is the colder surface water temperature are indicators of wind shift called the Southern Oscillation (Department of Natural Resources, 2007). As mentioned earlier the oceans have a tremendous capacity for storing heat energy. When the oceans warm up the rate at which the atmosphere warms up slowly retards. The greenhouse gases, ocean circulation, ocean temperatures, and melting of glaciers and sea ice, will determine the global warming which in turn will determine the speed of global climate change. In conclusion, there exists a delicate balance of ocean-atmospheric system between incoming and outgoing energy, if for any reason due to manmade or any other natural reasons this balance is disturbed even to a minute level, global climate can undergo a series of complex changes. References Department of Natural Resources, (2007) Global Climate Change:Oceans Effect on Climate, Retrieved April 18, 2007, from http://www.dnr.mo.gov/energy/cc/cc4.htm IPCC, (2007) Climate Change 2007: The Physical Science Basis, Intergovernmental Panel on Climate Change, Retrieved April 18, 2007, from http://www.ipcc.ch/SPM2feb07.pdf Kay, J. (2006) Ocean warmings effect on phytoplankton, December 7, 2006, San Francisco Chronicle, pp A – 12. Retrieved April 18, 2007, from http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/12/07/MNG1JMQUL01.DTL Meehl, G.A. et al. (2005) How Much More Global Warming and Sea Level Rise? Science, 18 March 2005: Vol. 307. no. 5716, pp. 1769 – 1772. NASAFacts, (1999) The Roles of the Ocean in Climate Change, Goddard Space Flight Center, Retrieved April 18, 2007, from http://earthobservatory.nasa.gov/Newsroom/MediaResources/Roles_Ocean.pdf Read More