A_Ch5_OceanClimateChange

**[|Chapter 5: Observations: Oceanic Climate Change and Sea Level]**

 * This graph shows how much the ocean's temperature has increased over the last 50 years.**

The ocean has and essential role in the way that climate varies and changes. The amount of heat that the ocean can hold is about 1000 times greater than that of the atmosphere and since 1960 the total heat uptake is 20 times greater than the atmosphere’s. Most of this large amount of heat is stored in the top layers of the ocean and has a central role in climate change. Ocean currents transport heat and freshwater which, regionally, are important on the climates and globally, the thermohaline circulation system influences climate on a large scale. Sea life is subjected to the changes in the physical state and circulation of the ocean and also reliant on the biogeochemical status of the ocean. The changes that occur in ocean biogeochemistry directly feed back into the climate system in ways like additional release of carbon dioxide. For our human society, changes in sea level are linked to changes in ocean circulation. The main thermodine along with large-scale ocean circulation and formations of large bodies of water altogether make way for the transfer of freshwater, dissolved gasses, and heat from the ocean’s surface down into deeper depths. These pathways also transport those things that have been changed due to the conditions on the surface. Also, the way that heat is stored in the ocean and the way that it distributes how salty it is make the ocean expand and contract so sea levels are changed around the world and locally as well. The ocean has had a significant rise in overall temperature since the late 1950’s. Contributing to the rise in sea levels are melting ice caps, glaciers, and ice sheets as well as thermal expansion.

The climate system is challenging, but to start understanding we have to know about Earth’s heat balance and the freshwater balance and how they both contribute greatly to the World Ocean. In this chapter, evidence that directly or indirectly notes the changes that theses balances have gone through. Both the ocean heat content and salinity are changed due to changes in average temperature.



In the section 5.5 the main concern and problem is the global and regional sea level variations. Sea level can have a huge and drastic change in sea life but also the life of humans. Over the years the sea level has been studied with tide gauges and recorded. Sea level can be affected by the melting of the ice caps as well. The more global warming there is the more ice will melt and the consequences can really devastate some regions or small islands. In fact the two most common ways sea level rise is thermal expansion of the oceans and the loss of land-based ice due to increased melting. Global sea level rose by around 120 meters during the several millennia that followed right after the last ice age that took place approximately 21,000 years ago and stabilized 3000-2,000 years ago. However recent and more updated satellite observation shows that sea level is rising at approximately 3 millimeters a year which is significantly higher than the last century. Sea level however does not raise the same in all areas. In some areas around the world some sea level change is up almost 7 times the global mean. Over a period from 1961 to 2003 thermal expansion played a huge roll in contributing about a quarter of the sea level rise while melting ice contributed less than half. Not the entire raise in ocean level is naturally caused. Humans play an important fact in this by doing things such as groundwater extraction, impoundment in reservoirs, wetland drainage and deforestation. All of these can have a huge impact in the level in which the ocean rises.

The graph above shows the annual averages of the global mean sea level in mm. the red line shows the reconstructed sea level in 1870 and the blue line shows coastal tide gauge measurements from 1950. the black line represents satellite based altimetry. Scientists are predicting that I the 21st century there will be a much higher sea level rise.

Because of the fact that warm water expands more than cold water, the sea level will show that. If ocean temperature continues to rise the higher the level will raise. However if the water temperature is cooler than the less expansion you will have.

Sea level will vary based on if there is water being pushed in or out. Water can be pumped or dumped into the ocean by pumping water out of reservoirs and the amount of ice that is melting. All of this will affect the rise and fall of the ocean. Salinity changes can also alter the level of the oceans, and can be cause by global ice volume.

All together if you add up all of the factors of global sea level rise you can put them together in this chart. As you can see all of the factors of sea level rise can be seen and added up.

Vocabulary:
 is the tendency of matter to change in volume in response to a change in temperature.
 * Thermal expansion **

__**Gabrielle Martinez **__
__Summary - Ocean Biochemical Changes__  The changes, specifically an increase, in atmospheric carbon dioxide and changes in the physical properties of the ocean effect the biochemical cycles of the marine life. When carbon dioxide increases in the ocean the water becomes more acidic. When there are changes in the nutrient concentrations then that information can be used to look at the changes in physical and biological processes that will eventually affect the carbon cycle; as well as to look at the larger changes in marine biology. Changes in nutrient concentration have rarely been found. It is important to look at the changes in biological activity because it has an effect on the carbon cycle, but the changes cannot be applied to a worldwide scale. O2 and CO2 are affected by the same physical processes. **GM**

__Reflection__ This connects to my everyday life because changes in the ocean could affect the water quality and make the water acidic and be dangerous for humans to be around. The acidic water could also negatively affect the way the marine life survives thus affecting the way people live as well. If the carbon cycle is changed then there is a chance that we burn more fossil fuels and the Earth will heat up at a faster rate which will eventually lead to global warming. I don’t think this information is very common in the population. I think there are a lot of people who get the basic idea of global warming but they don’t really have a complete understanding of what it is exactly. **GM**

__Vocabulary__


 * Salinity – salt: the taste experience when common salt is taken into the mouth.
 * Biogeochemical – Relating to or denoting the cycle in which chemical elements and simple substances are transferred between living systems and the environment.
 * Chemical Equilibrium – a chemical reaction and its reverse proceed at equal rates.
 * Hydrological Cycle – The water cycle, also known as the hydrologic cycle or the H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth.
 * Anthropogenic Carbon – Anthropogenic carbon dioxide is that portion of carbon dioxide in the atmosphere that is produced directly by human activities, such as the burning of fossil fuels, rather than by such processes as respiration and decay.
 * Thermal Expansion – Thermal expansion is the tendency of matter to change in volume in response to a change in temperature. All materials have this tendency. **GM**

__Citation__ Bindoff, N.L., J. Willebrand, V. Artale, A, Cazenave, J. Gregory, S. Gulev, K. Hanawa, C. Le Quéré, S. Levitus, Y. Nojiri, C.K. Shum, L.D. Talley and A. Unnikrishnan, 2007: Observations: Oceanic Climate Change and Sea Level. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. **GM**

__Pictures and Graphs__

This graph shows the mean concentration of anthropogenic carbon in 1994 and it is averaged over the Pacific Ocean, Indian Oceans, and the Atlantic Ocean. **GM**