The Threat Of Rising Sea Levels
- In a new assessment, the World Meteorological Organisation discovered that the world’s sea level is rising at an unprecedented rate, with potentially severe effects for weather, agriculture, the ongoing groundwater issue, and socioeconomic inequities.
- During the three decades for which satellite altimeter data is available (1993-2022), sea level has risen. However, while the rate of sea-level rise was 2.27 mm/year from 1993 to 2002, it increased to 4.62 mm/year from 2013 to 2022.
- Because the livelihoods of coastal people, especially their economic activities, are inextricably linked with the coastal ecosystem, changes in the coastal ecosystem as a result of GSML increase will further jeopardise these communities’ socio economic stability.
Points to ponder:
- The World Meteorological Organisation (WMO) has issued a report titled “State of the Global Climate 2022” warning that the world’s sea level is rising at an unprecedented rate, which could have disastrous consequences for weather, agriculture, groundwater, social disparities, and coastal communities.
- The report identifies several interconnected disasters, such as accelerating sea-level rise, consistent rise in global temperatures, record-breaking increases in greenhouse gas concentrations, glacier loss, sustained drought-like conditions in East Africa, record rainfall in Pakistan, and unprecedented heatwaves that hit Europe and China in 2022.
- According to the analysis, the pace of global mean sea-level (GSML) rise has more than doubled between the first and final decade of satellite data. For the last three decades for which satellite altimeter data is available (1993-2022), sea level has been rising. The rate of sea-level rise was 2.27 mm/year from 1993 to 2002, but it increased to 4.62 mm/year from 2013 to 2022.
- Ocean warming, ice loss from glaciers and ice sheets, and changes in land water storage are the causes of rising GSML. The loss of glaciers and ice sheets contributed 36% of the GSML rise between 2005 and 2019, whereas ocean warming contributed 55% and changes in land water storage contributed less than 10%.
- As carbon dioxide and other greenhouse gases increase in concentration, 90% of the ‘extra’ heat is stored in the oceans. This causes ocean warming, and as the ocean warms, it expands thermally, resulting in an increase in the GSML. In 2022, the ocean heat content (OHC) measurements set a new high.
- According to the paper, the cryosphere, which encompasses the Arctic and Antarctic areas (referred to as “sea ice”), glaciers, Greenland and Antarctica’s ice sheets, seasonal snow cover, and permafrost, has thinned.
- Experts are particularly concerned about the rapid rate of sea-level rise. It could lead to changes in land cover and an “acute shortage of land for human use” in coastal areas, disproportionately harming marginalised people and increasing socioeconomic inequality.
- Rising sea levels may also increase the likelihood of cyclones, which normally form in the open seas, hurting coastal areas and posing significant economic liabilities for tropical countries with dense populations, such as India and South Africa.
- According to experts, the report’s findings corroborate previously known patterns and are consistent with observations made by others and forecasts from climate models.