The Golden Globe sailors have now completed their voyages. They have been travelling through the world’s oceans as they are in 2018-19. The original race took place in 1968 -69, 50 years ago and there have been some important changes, many detrimental, in the oceans since the original race.
Human activities have produced a variety of changes which are dramatically altering the oceans. Climate change produce by our carbon dioxide inputs is already leading to warmer waters causing some species to migrate, oceans to become more acidic, glaciers and ice sheets to melt. Waste from our industry and general lifestyle now pollutes the oceans with chemicals, plastics, radioactivity and more.
So what changes can we expect to see in our oceans in the next 50 years?
How fast is sea level rising?
Sea level has varied over long timescales and is affected by many factors related to the shape of the oceans, the temperature of the water and the amount of water ‘locked away’ in ice. As more ice melts the sea levels rise, as sea water gets warmer it expands and sea level rises – both currently happening due to the overall climate change known as ‘global warming’ brought about by higher levels of carbon dioxide (CO2).
Watch the clip below to understand what impacts sea level change, how the sea level change is not uniform everywhere and how Satellites help us to map the sea-level.
Sea level has fluctuated in the geological past due to natural climate variability largely from climate variability. Sea level has also risen in the last century. In the recent decades, rate of global mean sea level rise has increased; In 2017 the average global mean sea-level was 77 millimetres higher than the 1993’s mean sea level, when the satellite record started. The reason for this rise is due to melting glaciers and ice sheets and expansion of warm seawater due to rising sea surface temperature.
United Nations report (published in 2017) highlights that approximately 10% of the global population live in the coastal areas that are <10 m above sea level. Therefore, coastal areas and people living there are particularly at risk. Unless humans can agree to reduce the levels of CO2 entering the atmosphere from fossil fuel, the sea level rise will impact major cities, livelihood of coastal communities, mass migration and world economy.
The animation below depicts how the rise in sea level will impact major cities around the world if we loose all the ice on Earth.
How our Oceans are changing and impacting marine ecosystem?
Many species are trying to adapt to warmer ocean waters by moving towards the poles but this has knock-on effects for other species and could change the important coastal fisheries for many countries.
Other marine species such as corals are drastically affected by warmer waters. But warming water is just one example of the change we expect over the coming decades. The oceans are gradually becoming more acidic as it absorbs high levels of anthropogenic atmospheric carbon dioxide. This has resulted in changing seawater chemistry, directly affecting calcifying organisms living at the base of the marine food web.
Additionally, rapid changes are taking place in levels of human-derived pollutants, such as plastics, now found in every river, beach and ocean in the world and noise levels due to busy shipping industry impacting marine animals’ ability to communicate or hear the signs of danger and thereby impacting their ecosystem.
It is true that our oceans are vast. In fact, they cover 70% of the Earth’s surface. However, it is not right to think that we can consider it being a dumping ground. What we are doing to it has direct and profound impact on us. In particular, marine pollution is something that we can tackle by changing our behaviour in reducing unmanaged waste:
What will the oceans look like in another 50 years? That all depends on the actions we take right now.
UN (2017) Factsheet: People and Oceans [Online]. Available at https://www.un.org/sustainabledevelopment/wp-content/uploads/2017/05/Ocean-fact-sheet-package.pdf (Accessed 2019).