Last reviewed 14 February 2017

Paul Clarke asks why scientists know far more about the dark side of the moon than they do about areas making up more than 70% of their home planet.

Recently, a European Space Agency exploration vehicle, Rosetta, completed its mission with a controlled impact onto the comet it had been tracking for more than 12 years. It was more than 440 million miles from Earth when it made its rendezvous with a ball of ice and dust that was just two and a half miles across and travelling at 24,600 miles per hour. A remarkable example of man’s ability to uncover the secrets of the solar system, then, but by no means unique.

As well as the manned visits to the moon, unmanned spacecraft have landed on Venus, Mars and several asteroids and passed close to all the major planets. NASA recently announced that its New Horizons probe would move onto photograph a small object called 2014 MU69, which lies about one billion miles beyond its original target, Pluto.

The question therefore arises: why, given this level of commitment to exploration, do scientists know far more about the dark side of the moon than they do about areas making up more than 70% of their home planet? Since 1969, 12 people have walked on the moon: only three have descended the 10km necessary to take them to the deepest part of the ocean in the Mariana Trench.

Blue planet

As Scientific American said recently, less than 0.05% of the ocean floor has been mapped to a level of detail useful for detecting items such as aeroplane wreckage. Certainly, the entire ocean floor has been mapped but only to a maximum resolution of around 5km (that is, most features larger than 5km across can be seen). This means that the best maps available of the world’s ocean floors are less detailed than maps of Mars, the moon or Venus, leaving plenty of room for surprises when more detailed exploration takes place. For example, the first phase of searching for missing Malaysian Airlines flight MH370 in the Indian Ocean, which involved mapping from ships to plan future surveys by underwater vehicles, found underwater mountains and other features that simply did not show up on satellite-derived maps for the area. It is the lack of detailed exploration at this level that gave Scientific American its 0.05% figure.

The Earth moves

Fifty years ago, the great science fiction writer Arthur C Clarke, said: “How inappropriate to call this planet Earth when it is quite clearly planet Ocean.” And he had a point: the Pacific alone occupies almost an entire hemisphere. It is possible to travel across it for more than 10,000 miles and not touch land: covering 64 million square miles, it occupies almost one-third of the planet’s surface.

The Pacific has another significant claim to fame, as a mover of continents. It hides the longest mountain chain in the world (65,000km in length) which circles the globe, occasionally rising above sea level as it does in Iceland, and dropping more than 4km into the Cayman Trough. The reason why it impacts on continents is that the mountain range marks the point where tectonic plates are moving apart and where new volcanic material is emerging. As the ocean floor spreads outward from these ridges, the continents at either side move away on their plates; some slowly, with the North American Plate heading west at about 20mm a year; some at speed, with the Pacific Plate moving north-westerly at a rate of knots (2cm per year).

Breaking away from Europe

Coming a little closer to home, what about the waters that currently divide Great Britain from the mainland of Europe? First of all, of course, they are a relatively recent phenomenon. At the end of the last Ice Age ― a blink of an eye in geological terms at merely 10,000 years ago ― the North Sea and the Channel were all dry land. It took a huge tsunami (possibly the biggest ever) to flood the low-lying land and create the seas after enormous landslides in Norway (in 6000BC) produced waves up to 33 feet high. What was destroyed is now known as Doggerland, a rich habitat connecting Great Britain to mainland Europe.

In recent years, vessels have dragged up remains of mammoth, lion and other land animals, and small numbers of prehistoric tools and weapons from the area. Professor Vince Gaffney, Anniversary Chair in Landscape Archaeology at the University of Bradford, explained the problem scientists still face. “Although archaeologists have known for a long time that ancient climatic change and sea level rise must mean that Doggerland holds unique and important information about early human life in Europe,” he said, “until now we have lacked the tools to investigate this area properly”.

Britain’s Atlantis

Professor Gaffney and his team hope to use remote sensing data to reconstruct the ancient landscape which they believe was roughly the size of Ireland. “The human-occupied land under the sea is one of the last places to be explored,” he said. “It is a huge, unexplored landscape just off the coast and has been called one of the last frontiers.” The North Sea thus covers one of the largest and best preserved prehistoric landscapes in Europe. Another member of the research team, Dr Richard Bates, Senior Lecturer in Earth and Environmental Sciences at the University of St Andrews, said: “Using new technologies ― DNA and agent-based modelling ― from core samples, together with wide-area seismic data, we will be able to unlock the environmental sequence background to key periods of pre-history. This heralds a completely new approach to both offshore and land archaeological investigations that has the potential to revolutionise the way in which archaeological prospecting is conducted.”

Backed by funding from the European Research Council, the team will be using the vast remote sensing data sets generated by energy companies to reconstruct the past landscape now covered by the sea. Specialist survey ships will meanwhile recover core sediment samples from selected areas of the landscape. Uniquely, the project team will use the sediments to extract millions of fragments of ancient DNA from plants and animals that occupied Europe’s ancient coastal plains. The data will be combined within computer simulations, using a technique called “agent-based modelling”, to build a comprehensive picture showing the dynamic interaction between the environment and the animals and plants that once inhabited the area.

A vision for the oceans

Generally in the UK, research in the area of marine science comes under the remit of the National Oceanography Centre (NOC), a research centre wholly owned by the Natural Environment Research Council (NERC). In Setting Course: A Community Vision and Priorities for Marine Research, Professor Ed Hill, the Centre’s Executive Director, outlined the goals and priorities identified by the marine research community for this decade. This “aims to ensure that the oceans are fully recognised for their ability to provide solutions to the big challenges facing society, which concern sustainable use of natural resources and the management of environmental risks and hazards”. The vision statement uses the same term as Arthur C Clarke ― Planet Ocean ― and stresses how human society depends upon the marine environment for a life-sustaining climate, as well as for much of our energy and food; even the air we breathe.

EU dives in

In November 2016, the EU celebrated Ocean Week, with the European Commission setting out its plans for the future, as well as highlighting the problems to be overcome. Activities during Ocean Week included Ocean Action Day at the November 2016 COP 22 meeting in Marrakesh. The Conference of Parties (COP) regularly reviews the implementation of the UN Framework Convention on Climate Change (UNFCCC). The Action Day was intended to provide political support and suitable policy options in implementing actions on issues affecting oceans, seas, coasts and Small Island Developing States (SIDS) in the context of the Paris Agreement on climate change.

Back in Brussels, EU Environment Commissioner Karmenu Vella warned: “The oceans are becoming more acidic. Plastic fragments are choking our seawater. Fish, sea mammals and plants are dying in vast numbers. Piracy threatens the livelihoods and sometimes even the lives of honest fishermen. Our basic data of the ocean floor is lacking.” In response, the Commission has issued International Ocean Governance: An Agenda for the Future of Our Oceans, a paper that proposes actions for safe, secure, clean and sustainably managed oceans. Existing ocean rules need to be further developed and better enforced, the Commission argues, to address areas beyond national jurisdiction or implement internationally-agreed Sustainable Development Goals, such as creating the 10% target for Marine Protected Areas by 2020. “The EU will co-operate with international partners to ensure implementation and will host in October 2017 the ‘Our Oceans’ conference to build on these commitments,” Mr Vella confirmed.

The Commission report sets out detailed actions to shape international governance in three priority areas which include the following.

  1. Improving the international ocean governance framework.

  2. Reducing human pressures on the oceans and creating the conditions for a sustainable blue economy.

  3. Strengthening international ocean research and data.

Returning to the issue with which this article began, the report also notes that an estimated 90% of the oceans’ seabed remains uncharted. A map available on the European Commission website shows the Exclusive Economic Zones (EEZs) where countries have special rights regarding the exploration and use of marine resources. This reveals that 60% of the oceans lie outside the borders of national jurisdiction but, as the Commission points out, with the oceans producing half of the oxygen in the earth’s atmosphere and absorbing 25% of carbon dioxide emissions, it is no one’s responsibility to care for their future, it is everyone’s.