This new year 2020 was welcomed by pre-existing wildfire in the forests of Australia and the Amazon, increasing ocean warming, global warming, anthropogenic impacts of climate change, and depleting biodiversity.
Such events are happening due to global warming, which, in turn, is the result of our past discoveries of ‘steam power’ and ‘fossil fuels’ at the advent of the ‘Industrial Revolution’.
Greenhouse gases, especially Carbon Di-oxide (CO2), are the main culprits behind global warming and climate change. On 9th May 2013, Earth achieved a ‘sad milestone of 400 ppm atmospheric CO2 concentration’. This happened for the first time in human history.
Due to climate change and global warming, the lives of coastal people are getting worse. Following factors are making the lives of coastal people challenging:
‘Earth Poles’ are getting warmer, which will result in the melting of polar ice, rise of seawater level and ocean warming. Most of the excess energy stored in the oceans leads to thermal expansion and rise in the sea level, which will destroy housing and infrastructure and will force people to relocate.
As glaciers melt, freshwater floats over saltwater, and this prevents nutrients from reaching phytoplankton as the top layers of the ocean get constantly replenished superficially with freshwater, preventing mixing with the bottom layers. Such a phenomenon does not sustain phytoplankton. This, in turn, affects the food-web of the marine ecosystem in a cascading manner. It further results in loss of fish production because the phytoplankton is the primary food for several pelagic fish in the ocean, including Indian oil sardines.
As the sea level rises, storm surge events increase. Therefore, floods will also intensify and increase in frequency with each passing year. Additionally, ‘water currents’ will change as well, displacing existing fish population further and further away from the coast, and away from temperate or tropical regions.
The effects of ocean warming are adverse and are seen in the form of extreme weather, stronger oceanic waves, hurricanes, typhoons, tropical storms, sea ice melting, rising sea levels, coral bleaching, oxygen reduction, habitat loss, coastal erosion, ocean acidification, high sea surface temperatures, dangerous tides, shifting of habitats, migration of marine species and damage to marine life and ecosystem and changes in ocean biogeochemistry.
Localised ocean heatwave blobs have become more common over the last century and are a big threat to marine life. The frequency of blobs is expected to increase further as the planet will warm. According to a study, released by IPCC on 24th September 2019, titled ‘Special Report on the Ocean and Cryosphere in a Changing Climate’, heatwaves in the oceans have doubled globally since 1982.
The frequency of the heat waves is expected to increase 20 to 50 times depending on how much emissions are curbed. Staghorn corals are one species walloped by marine heatwaves in recent years.
Warming oceans are threatening food security, increasing the dispersion of diseases in marine animals, transmission of diseases from marine to humans through food, causing more extreme weather events and the loss of coastal protection.
Marine life is dying because they can’t adapt quickly to rising ocean warming. Marine fishes, seabirds and marine mammals are facing very high risks from increasing temperatures. El Nino also comes in conjunction with marine heatwaves, which affect delicate ecosystems like coral reefs that sustain a quarter of all aquatic species.
The IPCC, in its special report of 2019, warned that tens of millions of people could be displaced from coastal areas by the end of the century. Marine life forms are migrating in search of favourable environment, habitat, food and breeding grounds. Economic losses due to ocean warming are likely to run from tens to hundreds of billions of dollars.
Since the Industrial Revolution, our seas have become about 30% more acidic, a rate not observed in 300 million years. This has a wide range of consequences for marine ecosystems, as well as for the billions of people who depend on the ocean for food and survival. Since the industrial revolution, ocean pH has dropped from 8.2 to 8.1. At current emission rates, ocean pH may drop to 7.8 by the end of the century, creating an ocean more acidic than in the past 100 million years.
Healthy coral reefs are a sign of good health of an ocean, which are critical habitats for young fish and other sea life.
Rising ocean temperature and ocean acidification will affect the oceanic vegetation like corals and mangroves, which protect coastlines from erosion and sea-level rise, especially in low-lying island countries in the Pacific Ocean.
Ocean Acidification is making it more difficult for marine calcifying organisms, such as corals and plankton to form biogenic calcium carbonate, and such marine organisms become vulnerable to dissolution. The ongoing acidification of the oceans is a threat to the future oceanic food chains, and if uncontrolled, it will result in ecological collapse of the oceans.
According to IPCC, monsoon in India is expected to decline by 45%. Summers would get hotter and longer while monsoons will become shorter but more intense, both in India and elsewhere in the tropical belt.
Central Marine Fisheries Research Institute of India (CMFRI) has confirmed that there has been a decline in coastal marine fish production in India over the last few years. CMFRI data reveals a 9% decline in overall fish catch in 2018 as compared to 2017. The 2018 annual fish landing data showed a 54% decline of the Indian oil sardine (Sardinella Longiceps), a pelagic fish found abundantly in the Arabian Sea, particularly the coastal waters that cover Karnataka, since 2017.
Due to global warming, Kerala, known for its high consumption of fishes, is now depending on other states for sardines and mackerel that are not available along the Kerala coast.
The fishes have migrated to cooler waters. So, fisherfolk have to go further into the sea; this is raising issues of safety at sea due to natural disasters, hijacking by pirates and in the case of Gujarat and Tamil Nadu, the accidental crossing of international boundaries means getting arrested by the coast guards of neighbouring countries.
Fisherfolks say that the wind patterns have changed, winds being a crucial factor in deciding their trips to sea. The fisherfolk note that seasonal wind patterns have changed; winds don’t appear on time and are changing abruptly. Wind may blow in the normal direction for a while and then switch directions rapidly. This is unusual. They point out that cyclone frequency, direction and intensity have changed and now cyclones strike at unusual locations and show much greater intensity.
Fisherfolk contend that the wave height, frequency and intensity has reduced in coastal waters due to siltation of river mouths and weakening of nearshore winds. High levels of beach erosion, a decline of mangroves and the construction of harbours, etc. have caused wave action to be stronger in other areas.
Marine life is facing the dangers of plastic pollution and is under severe stress. The plastic bags float throughout the ocean; fishes, in small and big sizes, eat the plastics and feel full while they slowly starve to death. According to the United Nations, more than eight million tonnes of plastic waste is flooding our oceans every year, accounting for up to 80% of all the litter in the oceans. According to Trucost, the overall social and environmental cost of plastic pollution is $139 bn a year.
Climate change, a global process aggravated by local processes, is affecting coastal life and fisheries.
Globally, fishes are facing the impacts of anthropogenic climate change. According to John and Brenda Gaedke, who live in Washington and travel every year for fishing, they noticed a lot of changes in patterns of timing and migration of salmon.
Oceans are warming and ocean heatwaves are directly affecting the fishing industry. In India, there is evidence that fisheries have been affected by climate change over the past several years especially in states like Tamil Nadu, Kerala, Karnataka and Maharashtra. Fish yields started declining by the 1970s in India and are now expected to decline even more as the ocean acidifies and warms.
The IPCC special report, 24 September 2019, warns that without steep cuts to greenhouse-gas emissions, fisheries will falter, the average strength of hurricanes will increase and rising seas will increase the risk of flooding in low-lying areas around the globe. The vulnerability of the Indian coast can be characterized by a low-lying coastal area, high population density, frequent occurrence of cyclones and storms and a high rate of coastal ecology degradation.
This would effectively sink coastal cities of India like Chennai and Mumbai. Studies have already shown that the sea is creeping into the coastal land in Chennai.
The coastal people will be the first to have to face these climate change impacts. These people are not aware of ocean warming and most are ill-equipped to deal with it. Awareness, education, reducing carbon footprint, climate action, controlling plastic pollution, livelihood schemes, financial help and market support will help coastal people and ocean life to cope with climate change. Such steps will help to prepare a better future for the coastal people and the world.