The Current Rising of Sea Levels

1. INTRODUCTION

Inundation is defined as “water covering normally dry land”. 1 It is a natural process, however it can be intensified by human activity.2 Thirteen out of twenty of the world’s megacities are found along the coast 3 (Fig. 1) and more than 600 million people around the globe live less than ten meters above sea level.4 Due to the fact that coastal regions tend to be so heavily populated, inundation events can be catastrophic.3

1.1 General Causes of Inundation

There are three main causes of inundation.2 Storm surges are waves that are larger than usual, which occur during storm events such as tropical cyclones due to strong onshore winds, low barometric pressures and increased wave height. Tsunami are “large waves generated by an abrupt disturbance of the sea surface” 1, which can cause substantial flooding to coastal regions.1 Sea level rise is an increase in mean ocean levels largely due to climate change.1 Estimates suggest that sea level will continue to rise over time, however predicting the amount of change is not accurate and is thus very controversial.4, 6

1.2 Predicted Sea Level Rise

According to the International Panel on Climate Change (IPCC), sea levels have risen at an average rate of 1.7 ± 0.5 mm per year from the start of the 20th century.7 However, these changes have not been constant.7 From 1961 to 2003, the average rate was 1.8 ± 0.5 mm per year and from 1993 to 2003, these rates increased to 3.1 ± 0.7 mm per year.7 In the 2007 IPCC report, it was predicted that sea level rise would range from 0.18 to 0.59 meters by 2100 8, but new research indicates that ocean levels could rise by more than one meter in that time.9 These projections are approximately three times higher than those made by th...

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...what is to come.36 Glaciers and ice sheets are going to continue to melt, and immediate barriers can only help for so long.36

5. CONCLUSIONS

In conclusion, inundation events are dangerous hazards to coastal communities.1 These events are further exacerbated by sea level rise.1 Sea level rise is largely due to the warming climate, which causes thermal expansion of oceans, melting of ice caps and glaciers, and ice loss from major ice sheets.6, 11, 15 Current research suggests that sea levels may rise by more than one meter by 2100.9 The consequences of increased future sea levels could be catastrophic for populations and infrastructures14 situated on North American coasts, such Florida, New York20 and Vancouver.21 In order to cope, we can attempt to mitigate climate change through long-term strategies, or we can attempt to adapt through immediate measures. 30, 31