Climate change and British marine life: threats and challenges

Our oceans perform a variety of valuable and irreplaceable ecosystem services, yet are becoming increasingly under threat from climate change and pollution.

Author

Natalie Clarke

British waters are home to a diverse array of marine biodiversity, providing a variety of habitats for species from sheltered sea locks to deep-water coral. Importantly, the marine life populations these habitats support are vital for local livelihoods and industries, from fishing and trade to tourism. Yet these valuable waters have become increasingly under threat from unsustainable economic and harvesting activity, and, critically, challenges presented by climate change. 

How are British waters valuable ecologically?

British waters, from inland estuaries to the deeper waters offshore, are home to over 330 different types of fish, from species occupying fundamental roles at the base of the food chain to wonders such as basking sharks, dolphins and Atlantic grey seals and a diverse array of birdlife.
 
Where does climate change come into this?

As greenhouse gas emissions continue to increase, climate change is accelerating, having serious effects on the world’s weather systems and conditions and putting the delicate balance of many of the world’s natural ecosystems and habitats, including those of British marine life, at risk.

Home to a diverse range of marine and dependent terrestrial species, it is vital that we keep our oceans healthy, both to support the species they are home to and the industries and livelihood that depend on them. The ocean performs a variety of invaluable- and, crucially, irreplaceable- ecosystem services: for instance, around half of the oxygen we breathe is produced by the sea, or specifically by phytoplankton, and absorbs around half of manmade CO2.

However, due to the complexity and scale of the problem of climate change, and the fact that we still know so little about our planet’s oceans, there is no quick solution. Despite covering 71% of the Earth's surface, our knowledge of the effects of climate change in oceans is limited compared to terrestrial ecosystems, making the problem harder to tackle and the scale of the impacts harder to predict. Attempts to address climate change need to work with related issues such as overfishing and pollution of the seas- the WWF, for instance, has already developed initiatives to bring together actors from governments, science, industry, and stakeholders to find sustainable ways of managing our shared marine environment. In this way, it is important to understand the threats the world’s oceans are facing as a problem that cannot solely be addressed by tackling climate change- if our world’s oceans are to remain sustainable for future generations and marine biodiversity, the issue needs to be tackled in all its complexity.
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Climate change continues to pose a significant threat to British marine life, whether directly as a result of changing marine conditions of indirectly through adverse effects on prey distribution. Atlantic Grey seals, for instance, often sighted in colonies around UK waters, are experiencing threats as a result of changing distributions of their prey, particularly sand eels, for which they will come into increasing competition with fishermen and other predators as prey availability dwindles. 

British species are being affected both directly and indirectly from the effects of climate change- the Atlantic grey seal in particular is at threat from scarcity of prey and loss of available breeding grounds.

Other terrestrial species reliant on marine environments and ecosystems are also expected to be affected: coastal erosion and flooding are already posing threats for species such as the Atlantic Grey seal, where rising sea levels are seeing the the isolated shingle beaches that grey seals favour to give birth to their pups in the autumn become narrower, increasingly the likelihood of pups being washed away. Internationally important breeding colonies of terns that nest close to the sea edge are also at risk from rising sea levels and increasing stormy weather. Wetland birds are also at risk: species such as the redshank will find their habitats inundated by the sea while moors and wet grasslands will dry up during hot summers, all of which carry wider implications for the food web and are expected to see changes in migration patterns in response to the stresses brought by habitat change in response to global warming. 

British marine and terrestrial species are already experiencing the adverse effects of rising sea levels on habitats and food chains.

The vast effects of climate change in these areas has been observed in particular in the Orkney islands. Warming of British waters offshore is thought to have completely altered the plankton regime, meaning dependent species such as sand-eels have nothing to feed on. As a result, sand-eel numbers have dropped dramatically and seabirds are struggling to find food.
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Our oceans remain a vital resource for both livelihoods, economic activity and, crucially, biodiversity, and exist in a complex relationship with our atmosphere and natural ecosystems. Attempts to address climate change therefore need to take into account how changes implemented at one site carry repercussions for the rest of the ocean system. While this is by no means an easy undertaking, it remains crucial that our world’s oceans are healthy and protected from overexploitation and pollution, the effects of which will only become more severe in light of climate change and continue affect wildlife in British waters.