Climate Change and how a Hadley cell works

Climate Change and how a Hadley cell works

Climate Change

1.. Telluride and Silverton are two large ski resorts in southern Colorado. Under continued climate change, the northern hemisphere Hadley cell (an element of atmospheric circulation) will extend its reach northward above 30 degrees of latitude. Explain what it would mean to the ski areas mentioned above? [30 pts] start at least 5 paragraphs.

Firstly, it is important to understand how a Hadley cell works in order to identify the effects of the mentioned changes caused by climate change. In the Hadley cell, the circulation of air passes through the equator, flows towards the earth’s poles, returns to the earth’s surface before flowing back to the equator. In this circulation, the airflow is caused by heat from the sun on the earth’s surface near the equator (Hastenrath, 2012)

Further, the rising of the warm air leads to the development of a low-pressure band at the equator. Upon reaching the troposphere, the rising air moves towards the south and north poles. Eventually, the Hadley cell moves the air back to the earth’s surface at 30 degrees south or northern latitude.

As a result, the air near the surface flows into the low-pressure area near the equator, thus replacing the rising air. The area of converging winds and the low-pressure area is known as the inter-tropical convergence zone. As such, these winds are directed towards the west leading to the creation of tropical easterlies.

Therefore, in the above scenario, the Hadley cell extension would result in the melting of the snow around Colorado. The two ski resorts depend on snow to host skiing sports in the area. As such, the descending air from the north pole would be dense, evaporating large amounts of moisture from the earth’s surface (Johanson & Fu, 2009).

Given this, the loss of moisture from the dense descending air would lead to a very dry earth surface. As such, the two ski resorts would be forced to shut down due to the absence of snow used for skiing purposes. In summary, the extension of the Hadley cell’s reach above 30 degrees would mean the closure of the two resort areas in Southern Colorado.

2. Global temperatures have generally trended up since the 1950s (more on this next week), but there was a pause in that increase between 1998 and 2013. One explanation invoked for that pause is that a large amount of heat was transferred into deep ocean waters. How did that happen? Your answer should include an explanation of what makes water good at holding heat, and by what mechanism that heat could have ended up in very deep parts of the ocean. [30 pts] start at least 5 paragraphs.

 Firstly, water has a high heat capacity, thus making it possible to absorb an enormous amount of heat before it begins to become hot. Heat capacity can be defined as the ability of a substance without becoming warm. Upon heating water, the initial input energy is utilized in breaking hydrogen bonds.

Further, for water to increase its temperature, the water molecules are required to move at a faster rate and hence require the breaking of hydrogen bonds. As a result, the breaking of hydrogen bonds leads to the absorption of the initial heat introduced in the water. Generally, the ocean absorbs much of the heat without experiencing a significant increase in temperatures.

The reduced heat from the earth’s surface during the pause (1998-2013) was achieved through a redistribution of heat within the oceans. As such, understanding how the ocean redistributes heat within its waters is essential to understanding the pause. Notably, the heat content between the surface and floor of the sea is critical in understanding the level of warming on the earth’s surface (Xie & Kosaka, 2017).

The ocean surface absorbs heat from the atmosphere when the atmosphere is relatively warmer than the ocean. Consequently, the ocean loses heat when the atmosphere is cooler than the ocean surface. As the warm air from the earth’s surface enters the atmosphere, it is absorbed by the ocean surface.

The explanation to the scenario in question is that the layer of the ocean below 100m was absorbing more heat than it previously did. As such, it can be concluded that the ocean heat uptake was modified in 1998, thus leading to the intake of more heat than previously identified.

3. Compare the two main greenhouse gases, carbon dioxide, and methane. What makes them different in terms of sources, greenhouse effect potential, longevity, etc.? [20 pts] start at least 5 paragraphs.

 The most important aspect of greenhouse gases is their ability to absorb heat as well as their longevity in the atmosphere. Today, carbon dioxide is emitted into the atmosphere through the burning of fossil fuels like coal and oil. On the other hand, methane is generated from wetlands, animal digestion.

Therefore, the two greenhouse gases differ in terms of sources since carbon dioxide is generated from burning substances as opposed to methane that does not require burning. The EPA’s review of greenhouse gases estimates that 82% of all greenhouse gas emissions are caused by carbon dioxide.

Although methane is the second most emitted greenhouse gas after carbon dioxide, it only accounts for nine percent of the total greenhouse gas emissions. While carbon dioxide can be removed from the atmosphere through “natural sinks” like forests, the process involved in eliminating methane proves insufficient for considering the rate at which methane is produced.

Today, continued deforestation has led to the release of enormous amounts of carbon dioxide in the atmosphere, accounting for 25% causes of global warming. With the current conditions, the forests can only offset about 15% of carbon dioxide. On the other hand, methane is generated primarily from petroleum systems and natural gas (Chettiar & Schwartz, 2009).

According to EPA measurements, methane traps more than 100 times moiré heat as compared to carbon dioxide in a five-year period. Consequently, methane traps 72 times the amount of heat trapped by carbon dioxide within a period of 20 years. The EPA report also reveals the Global warming potential of methane to be 21. Put simply, every molecule of methane produced today has a potential of trapping atmospheric heat by about 100 times more than the molecules of carbon dioxide. As such, methane has more greenhouse effect potential and longevity than carbon dioxide (Chettiar & Schwartz, 2009).

4. Water vapor is also a very effective greenhouse gas, but it is quite different than carbon dioxide and methane. Why are we not as concerned about water vapor as a greenhouse gas? [15 pts] start at least 5 paragraphs.

Arguably, water vapor is the most abundant greenhouse gas in the atmosphere today. However, humans have focused on addressing other greenhouse gases, including methane and carbon dioxide. Additionally, water vapor absorbs longwave radiation and also radiates it to the earth’s surface, thus leading to global warming.

Further, despite being the most effective greenhouse gas, it has lower longevity. Unlike other greenhouse gases like carbon dioxide and methane, the water stays in the atmosphere for a short period before descending into the surface in the form of rain and precipitation. On the other hand, carbon dioxide and methane can stay in the atmosphere for longer periods of time, ranging from years to centuries (Dessler et al. 2013).

As a result, other greenhouse gases have longer longevity, thus leading to longer periods of global warming as compared to water vapor that is short-lived. Additionally, the presence of water vapor into the atmosphere cannot be attributed to human activities. As climatic conditions changes, it leads to the rise of air temperatures that cause more evaporation of water from land and other water sources like the ocean.

The increased amount of water vapor in the atmosphere is caused by warmer air. Notably, warmer air is able to hold huge amounts of water vapor than cold air. In other words, the presence of water vapor in the atmosphere is attributed to the warming effects caused by other greenhouse gases like methane and carbon dioxide (Wallington et al. 2009).

While water vapor is responsible for the doubling of the greenhouse effect, humans do not address this issue since it does not originate from human activities. Also, the fact that water vapor has lower longevity than other greenhouse gases makes it less harmful than other gases that can stay in the atmosphere for longer periods of time. Overall, the atmospheric water vapor is not an issue of concern since it precipitates out.

Reference

Chettiar, I. M., & Schwartz, J. A. (2009). The road ahead: EPA’s options and obligations for regulating greenhouse gases. Institute for Policy Integrity, New York University School of Law, Report, (3).

Dessler, A. E., Schoeberl, M. R., Wang, T., Davis, S. M., & Rosenlof, K. H. (2013). Stratospheric water vapor feedback. Proceedings of the National Academy of Sciences, 110(45), 18087-18091.

Hastenrath, S. (2012). Climate and Circulation of the Tropics (Vol. 8). Springer Science & Business Media.

Johanson, C. M., & Fu, Q. (2009). Hadley cell widening: Model simulations versus observations. Journal of Climate, 22(10), 2713-2725.

Wallington, T. J., Srinivasan, J., Nielsen, O. J., & Highwood, E. J. (2009). Greenhouse gases and global warming. Environ Ecol Chem, 1, 36.

Xie, S. P., & Kosaka, Y. (2017). What caused the global surface warming hiatus of 1998–2013?. Current Climate Change Reports, 3(2), 128-140.