What are the human impacts on the evolution of coastal landforms?

My marine ecology course asked this question in relation to the Moeraki Boulders, the pancake rocks at Punakaiki and Farewell Spit – three iconic coastal features of New Zealand’s South Island.

While researching the terrestrial, atmospheric and coastal influences on these features, the concept that humans could have influenced these features seemed laughable.  These three features have been formed because of a mix, over millions of years, of geologic and coastal processes, plus some fine tuning by weather. 

I was thinking of the erosion caused by visitors’ feet – surely not.  At Farewell Spit, visitors are limited to prevent damage to the fragile ecosystem of the dunes and the mudflats.  I imagined the power of the waves at Punakaiki – human effects must surely be negligible.  And the millions of years to grow a single boulder?  What could humans be doing that could affect these features?

Then I remembered climate change.

We are told that human induced climate change brings bigger and more frequent storm events – leading to more erosion, more deposition, more destruction of fragile intertidal ecosystems.  And rising sea levels – the power of waves will reach higher and further.  And finally acidification of the ocean due to increased absorption of carbon dioxide.  This is particularly relevant in the colder Southern Ocean and is expected to mean that many marine species will struggle to build their shells – this could have an impact on food, and even on the future formation of the ocean substrate.  It may even mean that the sea water is more corrosive.  And what happens when the ocean can no longer absorb our carelessly discharged carbon dioxide?

The effects are, as yet, unknown.   It is our generation’s responsibility to ensure that we reinstate the natural balance.



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