Chapter 2: Our ocean under pressure page 37Mining
Mining impacts on marine environments are not a new
phenomenon. Marine and coastal zones have been damaged by
mining activity since the dawn of the industrial revolution. Some
coastal areas have been used as repositories for coal discards and
metal mine tailings for centuries, both directly dumped offshore or
via river courses that were used, in effect, as industrial drains. Such
was the extent of this impact over the years that the accumulated
wastes are now periodically dredged to reclaim the minerals lost by
the inefficient technologies of earlier centuries. Thankfully many of
these practices have now long been outlawed, though some near-
shore coastal zones continue to struggle to recover.
There is also growing interest in the deep ocean, the
largest biome on Earth, as an untapped source of both precious
and semi-precious metals, and mineral deposits. With advances
in technology and in anticipation of rising demand and prices,
extracting this mineral wealth is drawing commercial interest and
raising conservation concerns. While no commercial deep-sea
mining operations have occurred to date, the International Seabed
Authority has issued licences covering 1.2 million square kilometres
of ocean floor in areas beyond national jurisdiction in the Pacific,
Atlantic and the Southern Indian Ocean (Shukman, 2014).
The impacts from this type of mining are unclear, limited by
the lack of knowledge about deep-sea biodiversity and ecosystem
complexity, but as huge areas of seabed have been licensed the
scale could be unprecedented. Understanding and knowing
how to manage these impacts, if indeed the impacts can be
acceptably managed at all, and avoiding development in areas with
unacceptable risk will be key in avoiding the damage of the past.
Land-based pollution
Pollution on land has a huge impact at sea, threatening ecosystems,
impacting human health, damaging livelihoods and spoiling our
enjoyment of beaches. Land-based sources are responsible for
around 80 per cent of all marine pollution (UN, 2004).
Poor water quality and sediment are the most serious
pollution threats to many coastal and marine environments in
populated areas (UN WWAP, 2014), with sewage being the greatest
contributor. In many parts of the world, sewage flows untreated, or
under-treated, into the ocean. According to the fourth UN World
Water Development Report, only 20 per cent of globally produced
wastewater receives proper treatment (UNESCO, 2012).