Uniting and activating powerful voices for ocean conservation

Healthy Ocean, Healthy Climate

shallowsOur addiction to fossil fuels is crippling the Ocean, with it absorbing 25% of our excess carbon and more than 90% of the extra heat. The result? A warming, oxygen-depleted, 30% more acidic Ocean where shellfish suffer ‘osteoporosis’, 70% of coral reefs are destroyed or endangered, and low-lying coastal and island areas face devastation.  

The future? A healthy Ocean, not technological quick-fixes, is our greatest ally against climate devastation. We need to act now to implement the Paris Agreement on climate change, by dramatically cutting carbon emissions and strengthening Ocean resilience by fully protecting at least 30% of it – or await a harsher and more hostile future. The choice is ours.

Talking Points: Two sides of the Same Coin

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  • The Ocean is an integral part of the Earth system and it has suffered greatly because of our escalating use of fossil fuels.
  • As a gigantic natural carbon sink, the Ocean has already absorbed about one- third of the additional carbon dioxide we have put into the air. It has also absorbed about 90 per cent of the excess heat put into the atmosphere by carbon emissions. All of this comes at a significant cost to Ocean health and planetary resilience.
  • It takes a very long time for the full impacts of greenhouse gas emissions to be realised in the Ocean so even if we stopped using fossil fuels tomorrow, changes will continue percolating down to the deep Ocean for centuries. By the time we see the full range of damage it will be far too late to do anything about it. This is why we must act now.
  • In December 2015 at the UN climate change conference in Paris, countries committed to reduce their carbon emissions and to keep global warming ‘significantly below’ 2 degrees Celsius.
  • Somewhat unexpectedly, mainly due to the determination of a number of small island states, the deal also says countries should aim for the even more ambitious target of 1.5 degrees.
  • This is particularly important to people living on low-lying islands or coasts as it should limit the sea-level rise that is a result of climate change. It is also of critical importance if we are to save coral reefs.
  • The Paris climate Agreement came into force on the 4th November 2016, and has been ratified by over 120 countries.
  • However, despite these political advances, 2016 was the hottest year on record, and we are nudging closer to the 1.5°C warming threshold.
  • The world has also entered what has been called a “new era of climate change reality”, that sees global CO2 concentration levels in the atmosphere above 400 parts per millions (ppm, for every million air particles, 400 are CO2 molecules), exceeding the 350ppm threshold that has been deemed safe by scientists.
  • new study looking at the impact on the Ocean of the Paris climate agreement commitments warns that under governments' current pledges the present day risks to the Ocean from climate change would more than double by 2100, resulting in a future that we don’t even want to contemplate.
  • Under these current commitments global average temperatures are predicted to rise between 2.7-3.5C, sea surface temperatures by 2-2.6C and pH levels to drop by 0.26-0.34 units by 2100. These changes will significantly increase the risk to Ocean habitats, in particular having dire consequences for warm water corals, as well as negatively impacting valuable ecosystem services such as fisheries, tourism and coastal protection.
  • Even if temperatures were to stay within the 2C commitment, there will still be an impact on Ocean habitats and the functioning of ecosystem services (an increase in risk by a factor of 1.4). It is estimated that even if we meet the Paris climate targets, we will still see a die-off of some 90% of the world’s coral reefs by 2050. That is the best case scenario, which means it is essential to build the Ocean’s resilience to change and help rebuild marine species abundance.
  • According to a new study in Nature Communications (March 2017), more than half the Ocean will experience multiple climate stressors by 2030. If we continue another 15 years of current emissions, this will rise to 86% of the Ocean by 2050.
  • If all countries cut their emissions, as part of the Paris Agreement, this would give the Ocean more time for habitats and creatures to adapt. However, it may be too late for Arctic species, to find refuge from climate change, regardless of how quickly we act to cut emissions.

Coral Reefs

  • The Great Barrier Reef- the world’s most famous and iconic coral reef- is under severe threat with, back to back bleaching events in 2016 and 2017, which is affecting around two thirds of the whole reef. This is causing widespread alarm among scientists, who worry the frequency of bleaching events and the impact of water pollution, may mean the Reef loses its resilience to recover.
  • It is estimated that coral reefs, as they existed half a century ago, will likely disappear from Earth even if the implementation of the Paris climate agreement meets its targets. It is estimated that even if we meet the Paris climate targets, we will still see a die-off of some 90% of the world’s coral reefs by 2050. That is the best case scenario.
  • A new study in Nature (March 2017) says that the fate of the Great Barrier Reef and other coral reefs around the world depends on how effectively we can limit Ocean warming. Their survival depends on “urgent and rapid emissions cuts”.
  • An estimated 70 per cent of the world's reefs already threatened or destroyed, according to the US coral reef task force.
  • The scientific community is year by year becoming more concerned about the viability of protecting these ecosystems – which support 33 per cent of marine fish species – in the face of threats brought about by global warming.
  • According to scientists we are currently experiencing the longest global coral bleaching event ever observed. Warmer Ocean temperatures as a result of El Niño are the main culprit for this current mass bleaching event.
  • Corals that take centuries to form are being wiped out in a matter of weeks, reducing them to ghosts of their former selves.
  • While individual corals can survive and recover from a bleaching, repeated or extended bleaching events can kill them off for good.


  • Undisputed science shows that increased greenhouse gas emissions have boosted Ocean acidity by 30% since the beginning of the Industrial Revolution so that the rate of acidification now is faster than anything experienced in the past 250 million years raising the question of how and whether species can adapt to this speed of change.
  • We know that the pH of seawater is changing, becoming less alkaline. This acidification is having a profound effect on marine life.
  • Ocean acidification is sometimes called “climate change’s equally evil twin” with good reason. In particular, organisms that need to form hard parts, such as corals and anything with a shell, are less able to do so.
  • According to the most recent IPCC report, the Oceans absorb about a quarter of our CO2 emissions. As the Oceans warm as a result of climate change, they become less able absorb CO2 in the atmosphere.
  • Although CO2 absorption is by far the greatest driver, coastal zone pollution and large-scale release of methane seabed deposits (which are projected to occur when water temperatures rise and which have already begun in the Arctic) also contribute to Ocean acidification.
  • In extreme conditions, shells literally corrode to nothing. It’s as if they have osteoporosis.
  • The loss of shelled organisms at the bottom of the food chain also has broad cascading effects in existing food webs.


  • Ocean warming leads to a whole range of impacts on Ocean life, most importantly the forced migration of marine species. The knock on effects of these changes cannot be underestimated. They threaten food security; the very existence of coastal communities and the informal economies that keep these communities intact, and will play a role in human migrations as these changes impact on some of the most vulnerable peoples around the world.
  • If the same amount of heat that' went into the top 2 kms of the Ocean between 1955–2010, had gone into the lower 10 kms of the atmosphere, then the Earth would have seen a warming of 36°C. We therefore owe it to the Ocean that life goes on.
  • In addition to changing chemistry, the Ocean is also warming. A new paper in the journal Science Advances (March 2017), outlines that the rate of Ocean warming has quadrupled since the late 20th century, with increasingly more heat finding its way down into the deep Ocean.
  • About 93% of all the excess energy trapped in the Earth system by man-made greenhouse gases goes towards heating the Ocean - compared to 1% for the atmosphere.

Hypoxia/Lack of Oxygen


  • Warming also leads to hypoxia – lack of oxygen – in parts of the Ocean as it impacts on the microscopic plants that live in the Ocean and are responsible for more than half the oxygen we breathe.
  • A study  released in early 2017 indicates that the oxygen carrying capacity of the Ocean has declined by 2% globally.
  • This is coupled with fertilizer run-off from industrial agriculture and the growth of “dead zones” where nothing viable can live and breed.
  • Every second breath that we take comes from the Ocean, so keeping Ocean ecosystems healthy is critical to our daily lives. Try to live for an hour missing every other breath and see how well you do.

What Needs to Happen?

  • The pragmatic response is to cut carbon emissions as far and as fast as possible, and at the same time, to fully protect very large marine areas to help Ocean systems build resilience to the changes happening around them.
  • There is more and more evidence that ‘blue carbon’ plays a critical role in maintaining the health of our biosphere. This is the ability of mangroves, sea grass beds, fish and marine mammals to play a huge role in sequestering CO2. The math is simple: the healthier the Ocean, the bigger and greater the diversity of species there are, the better their capability to sequester CO2 and the healthier the planet, which is better for us all.
  • We also need to make sure that any extractive activities, like fishing or mining, are sustainable, precautionary, and take account of their impacts on the entire ecosystem, particularly in a time of change.
  • Studies have also shown that coral reefs for example have a much greater chance to recover from the effects of bleaching if fishing has been banned in these areas.
  • So many tech fixes are being devised to sequester carbon. Really, the most effective tech fix, is letting nature do what it does best by leaving huge areas of Ocean alone to do their thing and allowing animals and habitat to grow and flourish.
  • Building the Ocean’s resilience to change and helping to rebuild marine species abundance and diversity are not often mentioned as key climate change fighting tools, but they are. Governments should take action from the Arctic to the Antarctic and everywhere in between to reach the target of protecting 30% of the global Ocean by 2030.
  • We need to activate impactful voices around this call, unite the Ocean community around it, and create the social media and communications tools to drive this message, so that it becomes the unifying call to regenerate Ocean health that decision makers are compelled to deliver on.

For more information please visit the Nereus Program and Oceans Inc