Instructor Jesús Rivera
16 October, 2018
The Atmosphere’s Relationship to Oceans
The ocean is responsible for a lot of the stability associated with the Earth’s climate. Over 70% of the world is covered by oceans, and 70% of the Earth’s atmosphere is in direct contact with the oceans. Since the onset of the industrial revolution, humans have contributed more greenhouse gases to the environment such as carbon dioxide, nitrogen, and water vapor. These gases trap heat and energy and raise the global temperature levels. Although oceans have increased in temperature at a more gradual rate than the atmosphere, the heating of the oceans have a number of implications for both the environment and mankind. In this lab we examined some causes and effects of global warming on both land and oceans
In this lab, we tested the implications of melting ice caps and the difference in heat capacity for land and water. Our results demonstrated the effects of the melting cryosphere and its implications on the global sea levels worldwide. Also, in the second part of the experiment, our results demonstrate the ability of water to undergo gradual temperature changes relative to land.
Oceans play a huge part in the regulation of our climate and atmosphere. Water, because of its chemical structure, has a higher heat capacity than other liquids. The polarity of water allows it to absorb a great deal of heat and energy. Water molecules bond together and with other solutes because of hydrogen bonding. The high polarity and dipole structure allow water to be tightly held. For example, some animals can float on water because of surface tension. Also, it takes extra energy to change the form of water. Water has a higher heat of fusion and heat of vaporization because it has a large specific heat. Even after the large amount of heat required to raise the temperature of water, it requires more energy in order to change the state.
The implications of water’s high heat capacity are tremendous for the oceans and global warming. It is estimated that the oceans have absorbed over 90% of the heat trapped in the atmosphere by greenhouse gases. Although the oceans have seen a very gradual rise in temperature, it has enormous effects on the environment. For example, the cryosphere which contains the ocean’s icecaps are melting at an alarming rate. This will lead to an increase in sea level which has potential devastating effects for coastal regions (Milne). Each coastal region has seen an uptick in coastal flooding, and the Midatlantic region has seen these effects the greatest (Climate Change Indicators: Oceans).
Greenhouse gases do not just increase the temperature of the oceans. As seventy percent of the atmosphere is in contact with the oceans, the water will dissolve carbon dioxide out of its gaseous form in the atmosphere. This has implications with the acidification of oceans from the additional strain put on its buffer system. These effects are being studied by scientists on reefs such as the Great Barrier Reef and the reef off the coast of Florida. Acidity levels are expected to skyrocket in the coming centuries (Raisman).
In this lab, multiple aspects of the implications from greenhouse gasses are examined. In the first exercise, the melting of ice in water and its effect on water levels are examined. In the second exercise, the specific heat of water is compared to the specific heat of land. These are solid models of the natural phenomena caused by greenhouse gases. These are particular poignant in demonstrating potential effects of greenhouse gases in raising ocean temperatures and sea levels.
For the first exercise, a block of ice is placed in water. This is supposed to simulate the melting of the polar ice caps in the cryosphere. As the ice block melted, the levels of water in the tank were measured. This exercise demonstrated the rising sea levels caused by the melting cryosphere.
For the second exercise, the specific heat of land and water was compared. Side by side were two tanks of equal volume: one full of organic matter, the other full of sea water. A heat lamp of equal intensity was shone on each receptacle. The temperature within the concoctions as well as the ambient temperature of the atmosphere above it were taken on thermometers. The lamps were on for twelve minutes and each temperature on each one of the four thermometers were recorded each minute on the minute. After twelve minutes had passed, the lights were turned off to simulate night time. The four temperatures were again recorded on the minute every minute for twelve minutes. After, the data was analyzed.
For the first exercise, it was observed that the water level in the tank increased as time went on and the ice block melted.
For the second exercise, it was observed that both the temperature of the seawater and the ambient temperature above it were slower to increase and increased at a much smaller magnitude than that of the temperatures associated with the soil mixture, and cooled at a slower rate. This means that the seawater has higher specific heat than the soil.
Temperature (degrees C) Time (min) Above Soil Below Soil Below Water Above Water
1 24 25 23 25
2 25 26 23 26
3 25 27 23 27
4 25 27 23 27
5 26 28 23 27
6 26 28 23 27
7 26 29 24 27
8 26 30 24 27
9 27 30 24 27
10 27 30 24 27
11 27 30 24 27
12 27 30 24 27
13 27 30 24 27
14 26 30 24 27
15 26 30 24 26
16 26 29 24 25
17 25 29 24 25
18 25 28 24 25
19 25 28 24 25
20 25 28 24 25
21 25 28 24 25
22 25 28 24 25
23 25 28 24 25
24 24 28 24 25
All temperatures are in degrees Celsius and times in minutes.
Figure A: Displays the progression of temperature for the four locations in tablature format.
Figure B: Displays in time series graphical format the progression of temperature for the four locations by time.
The first exercise demonstrated the rising sea level caused by melting ice in the oceans. This has particularly poignant implications because it means that coastal areas will be encroached upon by the rising tide. Since 1850, the sea tide has risen an estimated 8 inches. However, more generous estimates have projected ocean levels rising by almost three feet (Ballard). This could lead to a lot of potential flooding especially in regions below current sea level.
The second exercise demonstrates that oceans have a higher specific heat than land. They heat up at a slower rate and at a slower magnitude than land, as displayed above in Figure A and B. They also have a more stable temperature when exposed to more heat than does land. This is reflected in that oceans have probably absorbed over 90% of the ambient heat trapped in the atmosphere by greenhouse gases (Milne). Oceans serve as a regulatory agent for the earth.
The ocean has a higher specific heat capacity than do the continents. They have absorbed the lion share of the heat trapped in the atmosphere by greenhouse gases. However, the temperature change has shown more gradual and less pronounced than on land. With additional strain placed on the ocean, more ice in the cryosphere will melt leading to flooding and destruction in coastal areas.
Ballard, Joanne R. U.S. Energy Infrastructure?: Climate Change Vulnerabilities and Adaptation Efforts. Nova Science Publishers, Inc, 2015. EBSCOhost. Pp. 8-10.
“Climate Change Indicators: Oceans.” EPA, Environmental Protection Agency, 2 Aug. 2016, www.epa.gov/climate-indicators/oceans.
Milne, Glenn. “How the climate drives sea-level changes”. Astronomy ; Geophysics, Volume 49, Issue 2, 1 April 2008. Pp. 2.24-2.26.
Raisman, Scott, and Daniel T. Murphy. Ocean Acidification?: Elements and Considerations. Nova Science Publishers, Inc, 2013. EBSCOhost.