Sea level rise is an incredibly pressing issue affecting everyone and everything on the planet in some way or another. From direct flooding to changes in weather patterns and climate; the oceans of the world influence many things and subtle changes can have much larger and sometimes disastrous effects.
Causes of sea level rise
Climate change and global warming are the main causes of sea level rise. Greenhouse gasses, such as CO2, released into the atmosphere through human activity insulate the earth like a blanket and trap heat from the sun. This, in turn, causes the temperature of the earth to rise, resulting in the melting of polar icecaps, contributing to rising sea levels. This process is compounded by a phenomenon called thermal expansion, whereby warmer water is less dense and therefore expands, further raising the sea level.
Current estimates compiled by the IPCC 2018 report expects that by 2100, a 3oC temperature increase would have occurred. The picture below shows that the sea level has risen by over 20cm since 1880. This is expected to increase over the coming decades.
Sea level change (mm) from 1880 to 2013
Photo credit: Coastal tide gauge records
Impacts of sea levels rising
The most obvious and potentially the greatest impact of sea level rise is the increased threat of flooding to coastal areas. Many of the world’s largest cities and most inhabited areas lie along the coasts of the world’s continents, putting untold amounts of people and property in danger from flooding. Large amounts of low-lying land will become inundated by saltwater, increasing the demand for inland or high-ground housing and agriculture. Saltwater contamination (salinization) will also reduce the amount of freshwater available for drinking and agricultural irrigation, further putting pressure on global communities (especially in developing countries) to sustain themselves in an already over-populated world.
Global biodiversity will also be adversely affected. Corals will become bleached and die at a faster rate as many are adapted to grow at certain depths and temperatures. These important ecosystems will then collapse, taking with them many of the fish that people rely on for food and tourism. The same may also be true of terrestrial ecosystems inundated by seawater.
Global weather is dependent on the oceans. The Gulf Stream, flowing from the equator northwards through the North Atlantic, would be affected by sea level rise and an influx of colder meltwater, changing much of Europe’s weather and climate. Global storms will also become more erratic and regular, increasing the risk to people and property.
If more is not done to curb greenhouse gas emissions and global warming, effects such as sea level rise will cause a plethora of problems to both humans and the natural world.