Sea level rise is the inevitable result of global warming and coastal areas of intensified human activities, and it affects the sustainable development of society and economy of the coastal areas in the 21st century. Global average sea levels have risen roughly 19 centimetres (7.5 inches) since the 19th century, after 2,000 years of relatively little change. The rate of sea-level rise has continued to increase in recent decades.

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Thermal influence and Sea level rise:

• The two major causes of global sea level rise are thermal expansion caused by warming of the ocean and increased melting of land-based ice, such as glaciers and ice sheets.
• The oceans are absorbing more than 90 percent of the increased atmospheric heat associated with emissions from human activity.
• When water heats up, it takes up more space. That means as oceans warm, sea levels rise. The study says this effect alone could make sea levels rise 30cm (12 inches) by the end of the century.
• Many large cities around the world, much built on reclaimed land, that are not more than 30cm above sea level. Example: Mumbai, Sydney
• But on top of that, warming oceans are causing polar ice sheets to melt faster, which will make sea levels rise even more.
• The combination of melting ice and expanding water could cause sea levels to rise by up to a meter by 2100. Hundreds of millions of people could be forced to be climate refugees.
• Warmer oceans make tropical storms more intense and longer lasting.
• Cyclones become worst by unusually warm ocean temperatures.
• For coastal areas already struggling with rising seas, those storms will bring even more flooding.
• Warming temperatures also mean changing rainfall patterns. Redistribution of water vapour in the atmosphere takes place. Higher temperatures lead to more evaporation, so parts of the earth will get wetter and parts will get drier.

Tectonics and Sea level rise:

The tectonic processes at work on the Earth influence the size of ocean basins and therefore, sea level in many, complex ways. The following list gives an idea of some of these processes and their interactions and feedback mechanisms:

• Rifting of tectonic plates at divergent plate boundaries.
• Assembly of micro-continents, volcanic terrains, continents – especially supercontinents like Rodinia, Pangea, etc.
• Subduction of tectonic plates at ocean trenches at convergent plate boundaries.
• Eruption and formation of large igneous provinces that originate from massive extrusions of lava, oceanic plateaus, hotspot volcanic island chains, etc.
• High rates of volcanism on the seafloor volumetrically displace water out of the ocean basin producing higher sea levels, called transgression of sea level.
• When rates of volcanism are high, it takes longer for the rocks to cool, and sea level remains higher for longer periods of time after the rate of volcanism subsides.

Conclusion:

The sea level rise caused due to Tectonic movements is out of human control. However, those due to Thermal expansions caused by global warming can be controlled by limiting the greenhouse gas emissions, increasing the green cover on earth, strengthening the scientific research for cleaner fuels and global efforts like Paris deal.