Sea Level Rise and the Impacts on Human Population

Sea Level Rise and the Impacts on Human Population

Earth Science 274

Randon MacKinnon

201504160

Presented to: Dr. Kellman

Date: March 30 2017

StFX University

Introduction

In the world today there are many factors that contribute to the rise of sea level all over the globe, climate change plays a significant role. Many people are vulnerable to sea level rise, and the impacts can be devastating to these populations. Due to the possible impacts posed by sea level rise, it is a highly discussed issue in todays scientific world. This paper will aim to investigate and express the current scientific knowledge we know today about sea level rise, and how it is impacting human populations around the world. This includes; climate change and the factors that cause sea levels to rise, an in depth look at the consequences it has to human populations living in coastal areas, and what human populations are doing to deal with this issue.

Climate Change and its Impacts on Rising of Sea Levels

Climate change brings forth many harmful impacts to the earth, some of these directly relate to the rise of sea levels all over the world. Climate change causes there to be an increased concentration of greenhouse gases (GHG) in the atmosphere resulting in an increase of the earths air temperature. As the earths atmosphere and oceans interacts the oceans becomes warmer along with other large bodies of water. This is due to the concept of thermal expansion which causes water to expand at warmer temperatures   , causing it to take up more volume1. Along with the expansion of oceans, another impact that climate has on the increasing of ocean sea levels is the melting of glaciers. The melting of glaciers causes more fresh water to enter into the oceans, causing the volume of the oceans to increase. Sheppard et al (2007) discussed the contribution of two major ice sheets, the Greenland ice sheet and the Antarctic ice sheet, stating that the data of the extremely large ice sheets recorded from 1996 to 2006, the combined imbalance is 125 gigatons per year, which is enough to cause a 0.35 millimeter rise in sea level. This is a small fraction of the current overall sea level rise of 3.0 millimeters per year2. The melting of glaciers brings more fresh water into the oceans, causing overall salinity to decrease. The scientific world still is trying to improve its understanding of sea level rise, and a large part of this is understanding the past. Different areas in the world are impacted in different ways by climate change, affecting sea level differently as well.

Since 1992 high quality satellite altimeters have been very useful in viewing how sea levels have changed in different areas, allowing scientists to relate this with climate change3. Tidal gauges measure changes in sea levels relative to a fixed point or datum. These measurements have been useful in the past, but can do a poor job if affected by water motions unrelated to sea level rise, such as gravitational shifts. However, when combined with new technology of satellites, data recorded from both types of measurements can give scientists a greater understanding of sea level rise, allowing for more accurate future predictions. Recently this has allowed to scientists in a 2006 study to conclude that from 1995 to 2005, fifty percent of sea level rise has been due to thermal expansion4. As discussed earlier thermal expansion is mainly due to the impacts of climate change increase the ocean temperature. This shows that there is a strong correlation between climate change and sea level rise. The rise of sea level brings impacts to human populations, especially ones in lower coastal areas who can be dramatically affected in a number of ways.

Impacts on Human Population

Nearly one billion people in low lying coastal areas throughout the world are threatened by increasing sea levels (see figure 1). Coastal regions are home to many civilizations throughout the world, as they are areas that are capable of providing the essential resources for living. These areas however are at danger to the increasing sea levels that could quiet possible take over the land. Erosion, storm surges, and contamination of drinking water are some of the impacts that are posed by the increasing levels. Many homes, and human infrastructure are built very close to beaches and coast lines. Keqi Zehang (2004), states that about one hundred million people live within 1 meter of mean sea level, with an increased risk in the coming future. As sea levels rise it allows for waves to reach farther up shorelines, causing more sediment to retreat seaward, promoting erosion5. This impacts humans because many homes in coastal areas around the world are at risk to eroding away as levels continue to rise. Along with destruction of habitats, erosion causes close living humans to be more exposed to increased storm surges. Dasgupta et al (2009) related the increase in storm surges and cities that will be most impacted by the increase. The study concluded that the cities; Hai Phong (Vietnam), Barisal (Bangladesh), and Bugama (Nigeria) were the three cities at highest risk to intensification of storm surges due to increasing sea level. Dasgupta et al (2009) stated that these countries at high risk are low income areas. This poses potentially severe threats as these low income areas are outdated and not properly equipped (drainage) to deal with flooding caused by surges, which may result in deathly impacts on humans living in the low lying areas6.

Along with erosion and storm surges, a rise in sea level can have serious impacts on drinking water for many people around the world. An increase in sea level and storm surges can intrude fresh groundwater sources. Many coastal communities rely on these aquifers as the main resource for drinking water. When saltwater intrudes these aquifers it increases the salinization and can introduce water-borne diseases into the fresh water making it harmful and dangerous to consume7. This is more of an issue in previously discussed low income areas at high risk to sea level rise and surges. Vietnam, Bangladesh, and Nigeria are some of the countries that rely on groundwater as a main resource of drinking water. When intruded by seawater it can become unsafe. One solution to this issue is a water purification system, but for these low income developing areas that can very costly. Depletion of drinking water is a major issue, and as sea levels continue to increase it will worsen, especially for developing countries.