Sea Level Rise

Context: Recently, a new study published in the journal Scientific Reports noted that the sea-level rise (SLR) is a “well accepted” consequence of climate change.

Key Highlights of the Report

  • It predicted that by 2100, the global population potentially exposed to episodic coastal flooding will increase from 128-171 million to 176-287 million.
  • The value of global assets exposed to coastal flooding is projected to be between $6,000-$9,000 billion, or 12-20 per cent of the global GDP.
  • The study has found that globally, of the 68 per cent area that is prone to coastal flooding, over 32 per cent can be attributed to regional sea-level rise (SLR).
  • By the year 2100, for most of the world, flooding incidents that are typically associated with a 1 in a 100-year event could occur as frequently as 1 in 10 years.
  • As per this assessment, 0.5-0.7 per cent of the world’s land area is at a risk of episodic coastal flooding by 2100.

Factors linked with Sea Level Rise

  • Thermal expansion: When water heats up, it expands. About half of the sea-level rise over the past 25 years is attributable to warmer oceans simply occupying more space.
  • Melting glaciers: Large ice formations such as mountain glaciers naturally melt a bit each summer.In the winter, snows, primarily from evaporated seawater, are generally sufficient to balance out the melting. But persistently higher temperatures caused by global warming have led to greater-than-average summer melting as well as diminished snowfall due to later winters and earlie g the massive ice sheets that cover Greenland and Antarctica to melt more quickly.

Reasons for Sea Level Rise

  • The world’s seas have absorbed more than 90 percent of the heat from greenhouse gases as humans continue to pour these gases into the atmosphere.
  • With continued ocean and atmospheric warming, sea levels will likely rise for many centuries at rates higher than that of the current century.
  • Sea level rise at specific locations may be more or less than the global average due to local factors such as land subsidence from natural processes and withdrawal of groundwater and fossil fuels and changes in regional ocean currents.

Impact of Sea Level Rise

Economic Impact

  • The rising seas that swamp cities and coastal infrastructure could cost the world more than 4 percent of the global economy each year by 2100.
  • The regular flooding means a large potential impact on municipal tax bases which help fund schools, emergency services, roads, and other vital local services and infrastructure.

Social Impact

  • When sea levels rise as rapidly as they have been, even a small increase can have devastating effects on coastal habitats farther inland.
  • The flooding in low-lying coastal areas is forcing people to migrate to higher ground, and millions more are vulnerable from flood risk and other climate change effects.
  • The prospect of higher coastal water levels threatens basic services such as Internet access, since much of the underlying communications infrastructure lies in the path of rising seas.

Ecological Impact

  • It can cause destructive erosion, wetland flooding, aquifer and agricultural soil contamination with salt, and lost habitat for fish, birds, and plants.
  • The higher sea levels are coinciding with more dangerous hurricanes and typhoons that move more slowly and drop more rain, contributing to more powerful storm surges.

Source: The Indian Express

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