Context: Coastal flooding
More in news:
- The study estimates that by 2050, without dramatic reductions in greenhouse gas emissions, at least 300 million people across the world, that is more than three times the currently accepted number of 80 million, will be at risk of annual coastal flooding.
- The new study by Scott Kulp and Benjamin Strauss published in Nature Communications in October 2019.
- A flood is a general and temporary inundation of normally dry land areas. When a coastal process such as waves, tides, storm surge, or heavy rainfall from coastal storms produces that flood, it is called a coastal flood.
- Coastal areas, like all areas, can also flood from high rainfall or overflowing streams.
- Coastal areas can experience various kinds of flooding. One type is nuisance or tidal flooding, which typically occurs during extremely high tides causing seawater to spill onto land and inundate low-lying areas until the tide recedes.
- Other types include moderate and major floods that can be caused by heavy rains, storm surges, and high waves that occur during coastal storms.
Sea level rise:
- Sea level rise is caused primarily by two factors related to global warming: the added water from melting ice sheets and glaciers and the expansion of seawater as it warms.
- Global sea level has risen by about 8 inches since reliable record keeping began in 1880. It is projected to rise another 1 to 4 feet by 2100.
- In the next several decades, storm surges and high tides could combine with sea level rise and land subsidence to further increase flooding in many regions. Sea level rise will continue past 2100 because the oceans take a very long time to respond to warmer conditions at the Earth’s surface. Ocean waters will therefore continue to warm and sea level will continue to rise for many centuries at rates equal to or higher than those of the current century.
- There are various effects of sea level rise such as coastal flooding, salt water intrusion into land, destruction of coastal infrastructure, communities and ecosystems.
Findings of the new study (by Scott Kulp and Benjamin Strauss):
- While earlier measures suggest that five million people in India will be annually affected by coastal flooding, the new estimates point to 36 million.
- In Bangladesh instead of five million, 42 million will be threatened.
- By 2050, in a scenario that limits warming to 2°C above average pre-industrial temperatures, about 150 million people worldwide will be permanently below the high tide line along the coast and, by 2100, the numbers will rise to 360 million people.
- The new estimates indicate that about a billion people reside on land along the coast going up to an elevation of 10 metres (the low elevation coastal zone) and the bulk of them, more than two thirds, are below the five-metre elevation.
- Most of the people found to be at risk from coastal events live in Asia — residing in countries like China, Bangladesh, India, Vietnam, Indonesia, Thailand, the Philippines and Japan.
- Coastal cities, such as Alexandria, Ho Chi Minh City, Basra and Shanghai are among the most vulnerable and large portions of Mumbai and Kolkata will be fully submerged by 2050.
IPCC and its special report on oceans and the cryosphere:
- The Intergovernmental Panel on Climate Change (IPCC) is the international body for assessing the science related to climate change.
- The IPCC was set up in 1988 by the World Meteorological Organization (WMO) and United Nations Environment Programme (UNEP) to provide policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation.
- IPCC assessments provide a scientific basis for governments at all levels to develop climate related policies, and they underlie negotiations at the UN Climate Conference – the United Nations Framework Convention on Climate Change (UNFCCC).
- The assessments are policy-relevant but not policy-prescriptive: they may present projections of future climate change based on different scenarios and the risks that climate change poses and discuss the implications of response options, but they do not tell policymakers what actions to take.
Findings of the special report on oceans and cryosphere:
- Seas are now rising at one-seventh of an inch (3.66 millimeters) a year, which is 2.5 times faster than the rate from 1900 to 1990.
- The world’s oceans have already lost 1% to 3% of the oxygen in their upper levels since 1970 and will lose more as warming continues.
- From 2006 to 2015, the ice melting from Greenland, Antarctica and the world’s mountain glaciers has accelerated and is now losing 720 billion tons (653 billion metric tons) of ice a year.
- Arctic June snow cover has shrunk more than half since 1967, down nearly 1 million square miles (2.5 million square kilometers).
- Arctic sea ice in September, the annual minimum, is down almost 13% per decade since 1979. This year’s low, reported Monday, tied for the second-lowest on record. If carbon pollution continues unabated, by the end of the century there will be a 10% to 35% chance each year that sea ice will disappear in the Arctic in September.
- Marine animals are likely to decrease 15%, and catches by fisheries in general are expected to decline 21% to 24% by the end of century because of climate change.
What can be done?
- Comprehensive vulnerability assessment of the entire coast should be conducted: More detailed information for the entire coastal region of India needs to be conducted in order to estimate the total risk to land, infrastructure, ecosystems, human population and livelihoods. This must include analysis of the potential for erosion and shoreline retreat, expected flooding and storm surges at different levels of SLR, subsidence, and the impact of other human activities such as ports, commercial activity and groundwater withdrawal on the coastal zone.
- Climate Change considerations should be integrated into all coastal infrastructure development: Existing structures in the area of high risk will need to be modified to withstand SLR and its impacts. Development in areas of high risk needs to be limited and proposed structures need to consider SLR and its associated impacts in the evaluation.
- Wetlands need to be protected: The high protection value of wetlands along the Indian coast needs to be taken into consideration whenever any development threatening their survival is proposed.
- Coastal protection measures should be carefully assessed and carried out if necessary: These could include the following:
- Provide assistance to at risk communities, building resilience;
- Early warning systems;
- Better understanding of the role of coastal ecosystems acting as a guardrail;
- Anticipate migration and prepare inland facilities and prepare at risk communities;
- Plan for and implement shoreline protection measures, where feasible and necessary.
Initiatives taken by Tamil Nadu:
- In view of the fact that local vulnerabilities due to climate change can be addressed more adequately at local level itself, the State of Tamil Nadu has prepared its State Action Plan on Climate Change (TNSAPCC) keeping in mind the overall Vision Tamil Nadu 2023.
- Realizing the global importance of climate change impact on coastal systems and the functionality of coastal systems in our Country as physical, geographical and ecological interface of land and ocean, the Government of Tamil Nadu has prioritized Coastal Area Management as one of the seven sectors in the TNSAPCC.
- The TNSAPCC is endorsed by the Ministry of Environment, Forests and Climate Change (MoEF&CC), Government of India (GoI) and thus forms the basis for implementing all the strategies to tackle climate change impacts.
- According to the TNSAPCC the key issues related to climate change impacts on coastal areas are Coastal inundation and damages to infrastructure; impact on coastal ecosystem and biodiversity and climate impacts on accretion.
- The strategies are to:
- develop an Integrated Coastal Protection Plan for Tamil Nadu to adapt to projected sea level rise, enhanced intensities of cyclones, storm surges, and extreme rainfall;
- avert enhanced coastal erosion due to Climate Change and protect the coastal zone;
- strengthen resilience of coastal communities in view of projected climate change;
- avert enhanced salt water intrusion in the ground water and ensure water security in coastal Tamil Nadu;
- conserve biodiversity in the coastal zone;
- avert pollution of water and soil in the coastal zones caused by industrial (power plants and other industries) and domestic wastewater and solid waste management practices.