Climate change hits the oceans

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Climate change hits the oceans

Thursday, 01 August 2019 | Kota Sriraj

Failure to mitigate and adapt to climate change will lead to dramatic falls in fishery productivity, with negative consequences for both people and the environment. Societies must be able to better cope with the impacts of a warming ocean

Oceans of the world have so far withstood the onslaught of climate change but the increasing vulnerability of fisheries to climate change has put food security at risk. Millions of people in India and abroad depend on the high seas for their livelihood but over-fishing, habitat destruction in addition to pollution is now eating into the ecosystem of the once healthy oceans. These are now getting amplified, thanks to climate change, which is contributing to the rise in surface temperatures of the seas.

Given the dwindling size of the average catch, the fishing community is increasingly finding itself in an unenviable position as mounting debts and reducing income is not only driving away traditional fishing families away from the occupation but also increasing the migration of such families into urban spaces. Existing fisheries management needs to be reformed to take into account shifts in fish population distributions, changing habitats and decreasing sizes of fish. Sustainable fisheries management must be prioritised alongside a reduction in fish discards. Encouraging consumption of non-traditional fish species and a transition to sustainable aquaculture methods are vital to alleviate the impacts of climate change.

 However, concerted and adaptive response to climate change can lead to more abundant marine resources and increased profits. The Government must commission studies that can eventually suggest how long-term sustainability of fish populations can be ensured in order to maintain healthy ecosystems and safeguard marine biodiversity. This will ultimately not only deliver a viable and sustainable seafood industry besides ensuring prosperity for the dependent population, but also ensure the conservation of the delicate oceanic ecology.

Climate change is unequivocal and the impacts will have severe repercussions for the ocean in many ways. Higher temperatures cause physical modifications to the marine environment: Warmer surface temperatures affect how water circulates at depth and disrupts complex food webs. Changing weather patterns bring more frequent and severe storms with implications for both coastal habitats and fisheries. In addition, warmer seas hold less oxygen, affecting ecosystems and species populations. By absorbing more CO2 from the atmosphere, the ocean’s chemical composition is changing at an unprecedented rate, resulting in a more acidic ocean with negative consequences for many species. In an ocean warming scenario of over 1.5°C, global catch potential is expected to decrease by over three million tonnes for every additional degree of warming. However, if the same temperatures are controlled and limited to 1.5°C above pre-industrial levels and full adaptive were to be put in place across the world, one can expect spectacular gains in seafood productivity.

The conditions pertaining to seafood productivity are not exactly good in other parts of the world as well. In the North Sea, for example, scientists have found that overfishing is making fisheries increasingly vulnerable to warming waters. Food security is a crucial challenge, especially in countries such as India and Philippines, as these places are warming faster than the global average and face potential reductions in annual catches of up to 50 per cent by 2050. As the global population looks set to reach nearly $10 billion by 2050 and requires more resources than ever before, it is unlikely that we will be able to rely on our marine resources as we did in the past — not nutritionally, economically, culturally, socially or recreationally.

Given the scientific advancements, India must pioneer documentation of exploitation of marine resources, which is based on scientific evidence. It must also invent systems and technology that can enable management of the fish population, harvesting within safe biological limits and allows stocks to remain at healthy and sustainable levels, otherwise understood as maximum sustainable yield (MSY). Conservation reference points, such as MSY, should be established for all stocks, including unintended catch and bycatch species. The absence of scientific data can no longer be a justification for failing to apply conservation and precautionary management measures. When fishing mortality exceeds reference points, harvest control rules should be implemented to bring the affected stock back to sustainable levels.

Maintaining abundant marine resources and healthy marine ecosystems are the most effective mechanisms to increase ocean resilience and help augment the ocean’s capacity to adapt to climate change. Establishing ecosystem conservation measures includes spatial and temporal protection of habitats, important for different species’ life cycle phases. Ecosystem-based management plans are critical to support the recovery of depleted marine stocks and the rehabilitation of marine ecosystems, in particular with sensitive and vulnerable species. With nearly 7,000 km plus coastline, India stands to gain immeasurably if these steps are implemented. In the face of the rapidly altering scenario in the wake of climate change, India needs to compose a calibrated response, starting with the significant and immediate reduction of greenhouse gas emissions. Climate change adaptation must, in turn, be further developed to protect and restore our ocean’s health and to support ocean resilience to the impacts of climate change that are already being observed.

India must also focus on building and mobilising the capacity of our societies to better cope with the impacts of a warming ocean — from individuals to communities to villages and metropolises. Done effectively, it will position us to eventually take advantage of the challenges and opportunities presented by climate change.

(The writer is an environmental journalist)

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