Explain the cause of sea level change and the formation of resultant coastal landforms.
Explain the cause of sea level change and the formation of resultant coastal landforms. (15)
There are a number of factors that contribute to long and short-term variations in sea level. Short term variations generally occur on a daily basis and include waves, tides, or specific flood events, such as those associated with a winter snow melt, or hurricanes or other coastal storms. Long term variations in sea level occur over various time scales, from monthly to several years, and may be repeatable cycles, gradual trends, or intermittent anomalies. These long term variations in sea level can be caused by major glacial episodes, changes in the hydrological cycle, vertical land motion or even changes in the ocean and coastal circulation. These reasons can be put into two categories which are known as eustatic and isostatic change. Over the years the global sea level has overall significantly increased from 16BC which was when it was the world’s lowest sea level, however, it has fluctuated throughout the past thousand years.
Eustatic change is when there is a rise or fall in sea level changes relative to the land, due to an alteration in the volume of water in the oceans or, alternatively, a change in the shape of a drainage basin and hence a change in the amount of water the sea can hold. Throughout and after an ice age, eustatic change takes place. At the start of an ice age, the temperature falls and water is frozen and stored in glaciers inland, suspending the hydrological cycle. This results in water being taken out of the sea but not being put back in leading to an overall fall in sea level. Conversely, as an ice age ends, the temperature begins to rise and so the water stored in the glaciers will renter the hydrological cycle and the sea will be replenished, increasing the sea levels. Increases in temperature outside of an ice age will also affect the sea level since an increasing temperature will cause the ice sheets to melt, and therefore putting more water
There are a number of factors that contribute to long and short-term variations in sea level. Short term variations generally occur on a daily basis and include waves, tides, or specific flood events, such as those associated with a winter snow melt, or hurricanes or other coastal storms. Long term variations in sea level occur over various time scales, from monthly to several years, and may be repeatable cycles, gradual trends, or intermittent anomalies. These long term variations in sea level can be caused by major glacial episodes, changes in the hydrological cycle, vertical land motion or even changes in the ocean and coastal circulation. These reasons can be put into two categories which are known as eustatic and isostatic change. Over the years the global sea level has overall significantly increased from 16BC which was when it was the world’s lowest sea level, however, it has fluctuated throughout the past thousand years.
Eustatic change is when there is a rise or fall in sea level changes relative to the land, due to an alteration in the volume of water in the oceans or, alternatively, a change in the shape of a drainage basin and hence a change in the amount of water the sea can hold. Throughout and after an ice age, eustatic change takes place. At the start of an ice age, the temperature falls and water is frozen and stored in glaciers inland, suspending the hydrological cycle. This results in water being taken out of the sea but not being put back in leading to an overall fall in sea level. Conversely, as an ice age ends, the temperature begins to rise and so the water stored in the glaciers will renter the hydrological cycle and the sea will be replenished, increasing the sea levels. Increases in temperature outside of an ice age will also affect the sea level since an increasing temperature will cause the ice sheets to melt, and therefore putting more water