Want To Learn Global Warming? Start From The Ocean

Global warming refers to the continous rising in the average temperature of the Earth’s climate system. It is the current change in Earth’s climate. It also refers to the increase in the average temperature of air and sea at the Earth’s surface. Since 1971, 90% of the warming has occured in the ocean. That is why ocean is the right place to start understanding global warming phenomenon which occured in our blue planet. Global warming affects the global conveyor belt and other physical properties of ocean water.

The Global Conveyor Belt
Source: http://science.howstuffworks.com/

What is the global conveyor belt? It is the deep ocean current which is driven by density differences in the sea water. It is also called thermohaline circulation because water density affects by its temperature (thermo) and salinity (haline). Density is an object’s mass per unit volume. Colder and saltier water equals denser water.  When water freezes, salt does not necessarily freeze with it. So, at the earth’s pole, large volume of dense cold and salt water is left behind. This large volume of water sinks to the bottom and other large volume of water replace it, creating a current. This other large volume of water will get cold and sinks continuing the cycle. That is why the global conveyor belt starts near the North Pole and goes to south between America and Africa toward Antartica, partly directed by the land they face. In Antartica, it enchanced by more cold water and divided into two direction; one of it goes to the Indian Ocean and the other goes to the Pacific Ocean. Because both of them is close to equator, it warms up and goes to the surface; this phenomenon is called upwelling. When they encounter land and cannot go any farther, it turns back to the South Atlantic Ocean and finally gets back to the North Atlantic Ocean. Then the cycle starts again. It takes 1,000 years to complete one full cycle around the globe.

Climate change like global warming affects the ocean. First, it makes the ocean warmer because the ocean absorb 80% of the heat added to the Earth’s system. Second, rising in greenhouse gases as one of the cause of global warming, causing increased atmospheric temperature which cause the iceberg at the poles and glaciers to melt  Third, the first and second effect I have mention cause sea water level to rise. Fourth, changes in ocean temperature and wind patterns as the result of overall climate change, will affect and change the ocean’s major current system which is the global conveyor belt I have explained in the second paragraph. Increased precipitation and the widespread of ice melting caused by global warming could create a larger layer of fresh water that would slow or prevent normal thermohaline mixing that occurs and would affect the current offshore from Greenland and Newfoundland.  The normal thermohaline circulation has suddenly stopped and recovered in the past, causing the climate to keep changing from warm to cold to become warm again. Fifth, the burning of fossil fuels that increases greenhouse gas level in the atmosphere, is also changing the chemical composition of sea water, making it more acidic.

           

In conclusion, if you want to learn global warming phenomenon, it is better to learn it from the ocean, from the physical phenomenon that happens in the ocean. Global warming affects a lot of aspect in the ocean. It affects the temperature of the ocean and the polar ice to melt. These events lead to the rising of sea water level. Change in ocean temperature, wind patterns, increased precipitation, and the melting of ice would affect and change the global conveyor belt. Besides that, the burning of fossil fuels that causes global warming, also makes sea water more acidic.

Data Sources:

http://en.wikipedia.org/wiki/Global_warming

http://science.howstuffworks.com/environmental/earth/oceanography/ocean-current3.htm

http://www.conservation.org/Documents/Climate%20Change%20on%20the%20Ocean.pdf

http://www.neaq.org/conservation_and_research/climate_change/climate_change_and_the_oceans.php

Learning Physical Oceanography Is Essential For Me

I am a sophomore in ocean engineering program. When I entered physical oceanography class for the first time, the lecturer asked the class, “Why do ocean engineering students have to learn about physical oceanography?” Well that is what I am going to answer in this writing. To answer that question, we must know what do ocean engineers do and what would you get if you took a physical oceanography class. Why is that? Because the reason of why ocean engineering students have to learn about oceanography is there is a correlation between ocean engineers’ activities and the study of physical oceanography.

If you went to the beach, you probably would see a breakwater that protects the beach from powerful waves. That is one of ocean engineers’ work. They design, construct, and maintain breakwaters, oil rigs, ports, boats, ships, and other marine structures and vessels. In my university, the ocean engineering program covers offshore structure, coastal structure, ocean energy, marine geotechnic, and underwater acoustics. What am I going to construct when I become one of the ocean engineers? Well, I am interested in ocean energy. I am interested in how we can convert ocean energy into electrical energy and use it in our everyday life. Base on my knowledge, there are at least three energy that can be converted: tidal current energy, wave energy, and ocean thermal energy. To convert ocean energy to electrical energy, we also need infrastructures. Structures and vessels which ocean engineers design, construct, and maintain is located near the ocean (coastal structure) or is located in the middle of the ocean (offshore structure).

If ocean engineers’ works are located near the ocean or in the middle of the ocean, they need to know well about the ocean itself. They need to know about the physical conditions and physical processes which happen in the ocean. They need to learn about dimension of the ocean and physical properties of seawater, such as salinity, temperature, and density. Besides that, they also need to study about the basic theory and applications of ocean circulation. Moreover, they need to understand about the hypothesis of ocean conveyor belt and its effect to global warming. In addition, they have to learn about wave, tide, current, coast, and estuary. All of those knowledge can be learned in a physical oceanography class.

Why ocean engineers need to know about the physical properties of seawater? The need to know about the salinity of seawater because it can corrode metals and most marine structures use steel. Besides that, the salinity and temperature of seawater affect its density. The density of the seawater is important in the design of marine vessels and other floating structure. Moreover, knowing the temperature difference between the deep and shallow or surface ocean waters in certain location help them in calculation of ocean thermal energy conversion. In addition, the knowledge of wave, tide, and current also helpful in the design of tidal current energy conversion and wave energy conversion.

It is essential for ocean engineering students to sit in a physical oceanography class. Well not just sit in the class, I mean paying attention and learn the lecture given. They need that class because their job when they are graduated as ocean engineers will be designing, constructing, and maintaining structures and vessels that are located on coast or offshore. Almost all of those activities are happening near the ocean, on or in the ocean, and related to the ocean. So, its important for them to know the physical condition and physical processes of the ocean. The study of physical oceanography will be helpful in designing marine structures and vessels, including ocean energy infrastructure.