Context:

• Scientists have warned that the global sea level may be rising faster than previously thought.  The research questions the reliability of how sea-level rise is measured. It further stated that the current measurement method underestimates the severity of the problem. Relative sea-level rise, which is a combination of rising water level and subsiding land, is traditionally measured using tide gauges but tide gauges tell only a part of the story.
• The study found that while tide gauges can accurately measure subsidence that occurs below their foundations, they miss out on the shallow subsidence component. With at least 60 per cent of subsidence occurring in the top five meters of the sediment column, tide gauges are not capturing the primary contributor to relative sea-level rise.
• An alternative approach is to measure shallow subsidence using surface-elevation tables, inexpensive mechanical instruments that record surface elevation change in wetlands.
• The data can then be combined with measurements of deep subsidence from Global Positioning System (GPS) data and satellite measurements of sea-level rise. Rates of relative sea-level rise obtained from this approach are substantially higher than rates as inferred from tide-gauge data. How does sea level rise is measured and what are its deficiencies? List the steps needed to arrest the sea level rise.