A new report from UNESCO’s Oceanographic Commission has found that ocean ‘dead zones’ have quadrupled in size since the 1950s. These ocean dead zones are areas that have oxygen deficiencies are unable to support the vast majority of oceanic life, also having the potential to lead to mass extinction events in the future.

Dead zones are areas of the ocean that are unable to support most marine life. There are open ocean dead zones which are caused by the warming of the global oceans. As the oceans warm, they become increasingly deoxygenated and its believed that the burning of fossil fuels and other anthropogenic climate change drivers are the cause. Along coastlines around the world, dead zones are caused by the runoff of fertilisers and sewage into rivers and the sea.

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The graphic above (The Guardian, 2018) shows where the coastal and ocean dead zones can be found. A lot of the coastal dead zones tend to be found off the coast of many developed countries in North America and Europe (plus Japan and Australia), whilst open ocean dead zones are in areas where the climate has been recorded as getting warmer.

Countries around the world and their populations rely on the oceans for food and jobs; many of them are less developed or developing countries. 500 million people depend on the ocean for food and over 350 million people rely on it for work. Despite that dependence, these dead zones are not a priority for nations to deal with until there are severe problems that directly affect them. Even though the number of dead zones has increased more than tenfold since 1950, it’s a dangerous problem that countries must acknowledge and address before things get worse than they already are for our oceans.

It’s not impossible to clean up these dead zones and transform into a clean and important habitat for wildlife. After World War Two, London needed to be rebuilt. Many of the sewer systems that kept the River Thames clean were damaged and the river suffered because of it. By 1957, the National History Museum declared the Thames biologically dead. It had become one of the coastal dead zones identified above.

Despite some who argued that the River Thames was a natural way of getting rid of sewage and it shouldn’t be cleaned up, it was. As sewers were rebuilt through the 60s and 70s and people were becoming more environmentally-conscious, the river recovered and the wildlife returned. Now, the Thames River thrives with birds, porpoises, and seals returning to its shores.

The quality of London’s sewage system and awareness of the effects of fertilisers on the river is, fingers crossed, a problem that London had and overcome, but for anyone who’s reading this and has visited London over the past few years, you may have noticed that there’s a brand new challenge for the river; plastic.

Whilst a lot of the Thames’ initial problems were due to broken infrastructure and agriculture, this new problem is something that we can all tackle together (not just people living near or visiting the Thames). Plastics are being discarded into our natural water systems, eventually reaching the ocean and having dangerous impacts on the ocean environment.

Whilst you are more limited in what you can do to reduce your impact on ocean dead zones, other than take steps to reduce your carbon footprint, when it comes to plastic, there is a lot you can do. The graphic below describes just 9 simple steps that we can all reduce our plastic use. From using your own coffee cup (which the majority of coffee shops are more than happy to accept) to using your own cutlery/recyclable cutlery, there is plenty we can all do to reduce our environmental impact. Right now, there is plenty we can do to reverse the damage we are doing to this planet, but we must act soon!


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