The UN’s climate change assessment panel found that the ocean is absorbing more than 90 per cent of the heat trapped in the climate system by humanity’s emissions of greenhouse gases. The ocean is also absorbing a quarter of our carbon dioxide emissions, which is causing seawater to acidify at a rate possibly unprecedented in 300 million years.
The Global Ocean Commission, an independent organisation working to restore the ocean to ecological health and sustainable productivity, called for governments urgently to invest in measures that improve resilience.
"Without the immense capacity of the ocean to absorb heat and carbon dioxide, we would be experiencing much more severe climate change impacts than we see today," said Trevor Manuel, Minister in the Presidency of South Africa and a Commission Co-chair.
"The clear implication is that we need to redouble our efforts to make the ocean resilient in the face of climate change and acidification.
"That means simple measures such as establishing marine reserves, but more fundamentally, tackling the gaps in governance of the international ocean that lies at the heart of many of its current issues."
Mr Manuel, South African Finance Minister for 13 years in the post-Apartheid era, jointly chairs the Global Ocean Commission with former Costa Rican President José María Figueres and David Miliband, President and CEO of the International Rescue Committee.
The Commission’s analyses show that the ecological health and productivity of the high seas, the internationally governed portion of the ocean, is in decline owing to a number of factors, including increasing demand for resources, advances in extractive technology and pollution.
"As if this list wasn’t long enough, the IPCC has now made it clear that climate change and acidification of seawater are bringing profound changes that will last for centuries," said President Figueres.
"The atmosphere holds only one per cent of the extra heat that our greenhouse gas emissions are trapping on Earth, the ocean more than 90 per cent – so by focusing on atmospheric temperatures we have been missing a huge part of the story.
"Fortunately the IPCC report shows that climate change can still be kept within manageable bounds – but only if governments act quickly to restrain carbon emissions."
The report from the IPCC’s Working Group One, on the physical science basis of climate change, shows that:
- the upper part of the ocean is warming by about 0.1C per decade
- the deep ocean is warming too, and will continue to do so for centuries even if emissions are curbed immediately
- sea levels are rising, currents are changing, the rapid shrinking of Arctic sea ice is freshening water around the region, and concentrations of dissolved oxygen are declining
- acidification will make up to half of the Arctic ocean uninhabitable for shelled animals by 2050.
All of these trends are projected to have major impacts on ocean life. And Mr Miliband, the former UK Foreign Secretary, highlighted the consequences for human wellbeing and security.
"Disruption to ocean life results in less food for people – that’s the stark reality," he said.
"With nearly a billion hungry people in the world already, we need to take every option we can for increasing our food supply sustainably, rather than allowing climate change to compromise it.
"As we look at development priorities for the future, including the Sustainable Development Goals that governments are now sketching out, we need to make sure that ocean concerns are adequately reflected, because in the end a healthy ocean will contribute massively to a healthy human society."
