There are two main reasons why sea levels are rising, firstly as air temperatures rise (due to climate change) the water in the oceans is warmed and expands. This process is called thermal expansion. The second reason being that as ice sheets and glaciers melt, they increase the amount of water in the oceans. Both of which are rather straightforward.
Scientists have shown that in the past there have been periods of significant sea level change due to natural factors. However, current measurements and predictions indicate that human activity is now the main driving force.
Sea level rise is not a uniform process, it totally depends on the region there are rapid variations from region to region, there are many factors that affect the level to which the sea rises, with prevailing winds, ocean currents, and land rebound or subsidence being important considerations. For example Scotland might not see any significant sea level rise in the near future, whilst somewhere like the Chesapeake Bay, USA may see a rise above the average level.
Following a recent report ‘climate change scientists predict that for each one degree Celsius of increase in global temperature, sea levels will rise 2.3 meters. They say their estimate may be accurate for as long as the next 2,000 years.’
This is not very encouraging information, especially when, in the same report, according to the World Bank, global temperatures may rise as much as 2 degrees Celsius (above the ‘pre-industrial era levels’), over the next 30 years or so, due to increasing concentrations of greenhouse gases in the atmosphere.
This will mean that generally, the sea levels will rise unavoidably by 50cm by the year 2050. It will have pronounced effects at the equator, especially around densely populated areas such as Bangkok, Thailand and Ho Chi Minh City, Vietnam. Scientists predict more intense tropical storms, food shortages, dangerous heat waves, and eventually flooding that could