Global warming on the planet is being caused by an overwhelming amount of heat trapping gases in the atmosphere, due mainly to human pollution. This is causing a significant rise in sea levels, which have been going up between 0.04 and 0.10 inches annually since 1990. This is approximately twice the average speed in which it went up in the previous 80 years. There are three main ways in which global warming is causing a rise in sea levels. These are:
Thermal Expansion – The hotter water is the more it expands, and as the earth’s temperature increases sea water expands to take up more space in the ocean basin. The land masses create a boundary for the water and since there is nowhere else for it to go, the levels of the seas constantly rise.
The Melting of Glaciers and Ice Polar Sheets – Every summer a significant part of the world’s glaciers melt. In winter this part is replaced by snow, caused by evaporated sea water, which freezes to reform ice sheets and glaciers. In this way the height of the ice sheets normally remains the same. Unfortunately, with the higher temperature caused by global warming more of the ice is melting each year and less snow is falling to replace it. Seasons are also affected by global warming, causing late winters and early springs that mean more ice will melt.
Ice Decreasing in Greenland and West Antarctica – The ice sheets that cover these areas are melting at a significantly increased rate. Ice streams become water and move into the sea faster every year. The Antarctica ice shelves are even melting from below sea levels, and large chunks of ice break off and float away to melt in warmer waters.
The Effects of Rising Sea Levels
40% of the world’s population lives in an area that is on or near the coast. The damage that can result from rising sea levels puts millions of lives at risk and creates the potential for an extensive amount of property damage. The higher water levels mean that storm surges will occur more frequently. This threatens the natural protection of the sea, and barrier islands, beaches, mangroves and sand dunes retreat inland or end up under water. The impact this has on the area is the destruction of the habitat of many birds, fish, other animals and plants that we rely on either directly or indirectly for sustenance. Man-made protective structures are also at risk and those that are not simply swept away, suffer from foundational erosion.
Our drinking water and agriculture is also being negatively affected. Salt water from rising seas can enter pipes and contaminate the fresh water supply. If the water levels get much higher unpredictable flooding can occur and agricultural and grazing fields will be covered, killing both plants and livestock.
Global warming is already forcing massive human migrations. In the central tropical Pacific, the 112,000 citizens of the island-chain nation of Kiribati (pronounced Kirri bas) are being forced to abandon their homes and their islands due to ocean flooding. Many of the Kiribati citizens are now living as landless, nationless, climate refugee in camps in Australia. The ocean inundated Kiribati island of Kiritimati (pronounced Christmas) is the location of the seasteaded city of Venus in the science based fiction, Endless Fire Future Furies.
Unless we take drastic action to decrease global warming, scientists have predicted that sea levels will continue to rise. In as quickly as a couple of generations, our descendants may not be able to even see the same places that we now know and love.