The Fate of Our Oceans

Chris Whitelaw — 11 June 2020
Human activity is steadily destroying our waterways. Unless we seriously rethink our approach they will soon be irreversibly damaged.

Australia claims the third largest marine jurisdiction of any nation on Earth — 13.86 million sq. km — more than double the size of its land mass. We have sovereign rights over much of this vast area of ocean, along with the fishery, mineral and petroleum resources within it. Our coastal waters contain internationally renowned marine reserves such as the Great Barrier Reef and Ningaloo Reef, all with high levels of biodiversity, much of which is endemic to the region. 

The marine estate is also an important and rapidly growing economic asset. The national value of production across marine-based industries (oil and gas exploration and extraction, tourism, fishing, boatbuilding, shipping, ports) is about $44 billion. It is estimated this will increase to around $100 billion by 2025 with expansion of current industries and development of new opportunities in renewable energy, aquaculture and wild-catch fisheries. 


Nevertheless, despite relative economic and social security, Australia is vulnerable to the same challenges that face other maritime nations — climate change, food and energy security, biodiversity conservation, management of marine resources and extreme weather phenomena. Eighty-five per cent of the country’s population (projected to reach 36 million by 2050) lives within 50km of the coastline, putting pressure on the marine environment through urban development, agriculture, maritime traffic, wastewater discharge and pollution.

The oceans surrounding our island continent play a critical role in Australia's climate. Global ocean currents transport heat and set the large-scale patterns of temperature, rainfall and evaporation that determine our regional climate. The cycle of droughts and floods that characterise our land environment is controlled by ocean circulation patterns and their interaction with the atmosphere in the Indian, Pacific and Southern Oceans. Australia, more than any other continent, is subject to atmospheric fluctuations such as the El Nin~o Southern Oscillation phenomenon, the Indian Ocean Dipole and the Southern Annular Mode, which have increased in frequency and intensity in the past two decades.

Changes in these climatic influences will impact our marine resources and biodiversity from the tropics to Antarctica, through global warming, rising sea levels, altered circulation patterns, increasing ocean acidity and extreme weather events.

The oceans are warming as a result of man-made emissions of greenhouse gases. Warming oceans drive rising sea level through thermal expansion, melting of glaciers and polar ice caps and effects on the Antarctic sea-ice. Warmer oceans will hold less carbon and thus exacerbate atmospheric carbon dioxide concentrations. A warming ocean may also catastrophically alter global ocean circulation patterns by disrupting thermohaline circulation in the great ocean basins. Rising sea temperatures will impact ecosystems through range shifts of species, alterations in food web dynamics, and changes in growth and reproductive rates of some species.

The impacts of climate change are expected to be greatest in the tropical north, where sea temperatures have risen by almost 0.5 degrees in the last 30 years, coinciding with mass bleaching, mortality and changes in community structure on coral reefs. Projections reveal that sea temperature may soon exceed the thresholds for coral bleaching on a yearly basis, with potentially severe consequences for reef health and biodiversity, food production and tourism, particularly on the Great Barrier Reef. 

The oceans currently absorb about one third of our carbon dioxide emissions. This hidden ocean service to our regional ecosystems represents an estimated $25 billion subsidy to the Australian economy each year. However, this vital service comes at the cost of ocean acidification, with grave consequences for the marine biosphere, especially for coral reefs in our tropics, planktonic plants and animals in the high latitudes of the Southern Ocean, and commercially important stocks of abalone, oysters, lobsters and large predatory fish.

In Australia, cyclones and other severe storms have the largest economic impact of any natural hazard due to their extreme wind and rain, and associated waves and tidal surge. In the last three decades the frequency of severe cyclones (category 3 to 5) has almost doubled. Projected increases in storm severity will intensify shoreline erosion and increase risks to maritime operations (shipping and defence) and infrastructure (ports, coastal cities, gas pipelines, processing facilities). These intense weather events will also impact marine ecosystems, especially coral reefs. Recent analysis of long-term monitoring data for the Great Barrier Reef showed that approximately 48 per cent of the decline in coral cover recorded between 1985 and 2012 was attributable to storms. An increase in the frequency of more severe cyclones has been predicted to increase coral mortality by 60 per cent, with far-reaching consequences for reef-dependent communities and industries.

The oceans are vitally important for Australia’s economy, our society and environment. The great bulk of our valuable commodity trade is done by maritime trade routes. An increasing proportion of our energy is derived from our marine estate. The ocean provides us with food and opportunities for recreation. Australia’s beaches and reefs are the cornerstone of its international tourism sector. Most importantly, the ocean provides critical ecosystem services such as climate regulation and nutrient cycling. It is clearly in our national interest to support our burgeoning ‘blue economy’ by looking after our ocean ecosystems. Carefully managed and wisely used, a healthy marine estate can generate wealth, food, energy and sustainable livelihoods for generations to come.


Australia’s declining marine ecosystems do not stand alone; they exist within a broader context of global reductions to the health of natural environments. On 6 May 2019, a UN-sponsored international science agency delivered its assessment of the state of nature on our planet, and the news is not good. 

Compiled by 145 experts from 50 countries, the landmark report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) analyses data collected over the past five decades and provides a comprehensive picture of the current global environment. In presenting a 39-page summary of the Global Assessment Report (the full six-chapter version exceeding 1500 pages will be published later this year), IPBES Chair, Sir Robert Watson, said “The overwhelming evidence presents an ominous picture. The health of ecosystems on which we and all other species depend is deteriorating more rapidly than ever. We are eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide.”

In a nutshell, nature is declining globally at rates unprecedented in human history and the rate of species extinction is accelerating, with grave consequences for people in all regions of the world. Whole ecosystems and entire species of plants and animals are shrinking, deteriorating, or vanishing. The report ranks (in descending order of relative impact) the five main causes of this environmental decline to be degradation of land and aquatic habitats, exploitation of wild populations, climate change, pollution and introduction of alien species — all a direct result of human activity.

Current negative trends in biodiversity and ecosystems will also prevent the achievement of many international social and environmental goals, such as those embodied in the Aichi Biodiversity Targets and the 2030 Agenda for Sustainable Development, relating to poverty, hunger, health, water, cities, climate, oceans and land.


To arrest the decline, the report emphasises the need for “transformative change” — a fundamental, systemic reorganisation of social attitudes, economic values and technological goals. We have already seen the first stirrings of impetus for change in many countries, such as innovative policies by governments and businesses, and community activism in the protection of local environments. From the young global shapers behind the #voicefortheplanet movement to school strikes for climate, there is a groundswell of understanding that urgent action is needed if we are to secure anything approaching a sustainable future.

The report tells us that it’s not too late to make a difference, and presents a wide range of actions for achieving sustainability in many sectors — agriculture, forestry, marine and freshwater systems, urban areas and energy. Underlying all proposals is the need to integrate biodiversity considerations in global decision-making on the many critical environmental, economic and social challenges to modern society.

Healthy biodiversity is the essential infrastructure that supports all forms of life on earth, including human life. Nature makes human development possible but our relentless demands on the planet’s resources are accelerating extinction rates and devastating the world’s ecosystems. The IPBES Report comes at an opportune time, on the eve of the 2020 UN Biodiversity Conference, which will set the course for future ecologically sustainable pathways for people, the planet and our global economy. 

As Audrey Azoulay (Director-General, UNESCO) said in her endorsement of the Global Assessment Report, “This essential report reminds each of us of the obvious truth: that present generations have the responsibility to bequeath to future generations a planet that is not irreversibly damaged by human activity.” 

For more information on the report, visit 


  • Oceans cover 75 per cent of the planet (363 million sq. km) and contain 97 per cent of the earth’s water.
  • There has been more than a 3mm annual average global sea level rise over the past two decades.
  • Oceans contain nearly 200,000 identified species, but actual numbers may be in the millions.
  • Over three billion people depend on the oceans as their primary source of food.
  • The global market value of marine and coastal resources and industries is estimated at $3 trillion per year or about 5 per cent of global GDP.
  • Oceans absorb about 30 per cent of carbon dioxide produced by humans, buffering the impacts of global warming.
  • More than 55 per cent of ocean area is covered by industrial fishing.
  • Marine fisheries directly or indirectly employ over 200 million people.
  • 33 per cent of marine fish stocks are being harvested at unsustainable levels.
  • 33 per cent of the world’s fish catch is illegal, unreported or unregulated.
  • There’s a 25 per cent projected decrease in fish biomass by the end of the century in high climate warming scenarios.
  • There’s 6500 offshore oil and gas ocean mining installations (in 53 countries).
  • 100-300 million people in coastal areas are at increased risk due to loss of coastal habitat protection.
  • Fertilisers entering coastal ecosystems have produced more than 400 ocean ‘dead zones’, totalling more than 245,000 sq. km. 
  • Coastal eutrophication (over-enrichment by nutrients inducing excessive algae growth) is expected to increase in 20 per cent of marine ecosystems by 2050.
  • Acidification of the open ocean has increased 26 per cent since the start of the Industrial Revolution.
  • Almost 33 per cent of reef-forming corals, sharks and shark relatives, and more than 33 per cent of all marine mammals are threatened with extinction.
  • 50 per cent of live coral reef cover has been lost since 1870.
  • There’s been a larger than 10 per cent decrease in seagrass meadows since 1970.
  • In the absence of mitigation measures, climate change will increase the cost of damage to the ocean by an additional US$322 billion per year by 2050.


  • Since 1970 the global human population has more than doubled (from 3.7 to 7.6 billion).
  • Urban areas have increased by more than 100 per cent since 1992.
  • There’s been a 15 per cent increase in global per capita consumption of materials since 1980.
  • 11 per cent of the world’s population is undernourished.
  • Food crop production has increased 300 per cent since 1970.
  • More than 33 per cent of the world’s land surface and nearly 75 per cent of freshwater resources are now devoted to crop or livestock production.
  • Since 1980, greenhouse gas emissions have doubled, raising average global temperatures by 1 degree.
  • The distribution of 47 per cent of land-based mammals and almost 25 per cent of birds have been negatively affected by climate change. 
  • 8 per cent of total greenhouse gas emissions are from transport and food consumption related to tourism.
  • There was a 40 per cent rise in the carbon footprint of tourism (to 4.5Gt of carbon dioxide) from 2009 to 2013.
  • 75 per cent of the land-based environment and 66 per cent of the marine environment have been “severely altered” by human actions. 
  • 60 billion tons (54 billion tonnes) of renewable and non-renewable resources are extracted globally every year, nearly doubling since 1980.
  • 290 million hectares (6 per cent) of native forest was lost from 1990–2015 due to clearing and wood harvesting (4 billion cubic metres in 2017).
  • 85 per cent of wetlands present in 1700 had been lost by 2000, at a rate three times faster than forest loss.
  • 100–300 million people are at increased risk from floods and hurricanes due to loss of coastal habitats and protection.
  • There’s estimated to be 8 million animal and plant species on earth (including 5.5 million insect species).
  • Around 1 million animal and plant species are now threatened with extinction.
  • More than 500,000 (9 per cent) of the world’s terrestrial species have insufficient habitat for long-term survival.
  • The average abundance of native species in most major land-based habitats has fallen by at least 20 per cent, mostly since 1900. 
  • Plastic pollution has increased tenfold since 1980.
  • 80 per cent of global wastewater is discharged untreated into the environment.
  • 300–400 million tons (270–360 million tonnes) of heavy metals, solvents, toxic sludge and other industrial wastes are dumped annually into the world’s waters.


Global waterways Pollution Climate change Marine life