Thermal Expansion of Polar Ice Caps

Introduction

        For years, researchers around the world have continued to analyze the main causes of the sea level increases that have happened across the globe over the past century. While many researchers believed that the main causes of the sea level increase was attributed to thermal expansion, other analysts believe that the main reason for this significant issue is a direct result of melting ice sheets and glaciers that has happened consistently over the past century because of various reasons.

        Each of the two arguments made for the main cause of the recent increase of sea levels globally both have statistical data in place to reinforce the arguments. Nonetheless, evidence also exists to show that perhaps the combination of both of the causes may be more of the answer than simply choosing one cause over the other. This paper will investigate both of the causes introduced and also the variables chosen that will determine whether one has more statistical data in place to explain the phenomena of the sea level increases over the last ten years.

Literature Review

According to a study in the Nature Geoscience Journal, between 2005 and 2011, melting ice sheets and glaciers were responsible for about 75% of sea level rise, while the effect of water warming and expanding playing a much smaller role (Roberts, 2013). The much smaller role being described is the process called thermal expansion in which sea water heats up and becomes denser in form which allows sea levels to rise (Roberts, 2013). This study uses density analysis research primarily with the use of altimeter based estimates to conclude that most of the change in ocean mass is caused by the melting of polar ice sheets and mountain glaciers (Chen, Wilson, & Tapley, 2013).  In the data summary section, the findings to support this hypothesis will be presented for comparative analysis.

The second article analyzed discusses that the near global temperature data sets made available in recent years shows a direct calculation of thermal expansion. It is believed that on average, over the period from 1961 to 2003, thermal expansion contributed to one quarter of the observed sea level rise, while melting of land ice accounted for less than half. During the recent years (1993-2003), for which the observing system is much better and the analytics improved, thermal expansion and melting ice sheets and glaciers each account for about half of the observed sea level rise, although there is some uncertainty in the estimates (The IPCC Explains.....Sea Level Rise, 2014).

In both studies, the acknowledgement of both of the factors of the sea level rise increase over the last two decades are identified as melting ice and thermal expansion. The Nature Geosciences Journal article stresses that the melting ice sheets play a significantly larger role on the sea level rise (75% to 25%) while the second article stresses that the sea level rise development shares approximately an equal level of responsibility (50% to 50%). While each article provides ample review data to reinforce their findings, different analysis tools and estimates have also come to play in helping to solidify each of the findings.