Climate change sending ocean health 'spiralling downward' faster than previously thought

 

A A A

Scientists have warned that climate change has sent the health of oceans "spiralling downward" faster than previously thought.

A key international assessment of climate change last week revealed the oceans are absorbing much of the warming and unprecedented levels of carbon dioxide caused by human activity such as burning fossil fuels.

Now experts are warning the impact of rising greenhouse gases combined with a range of other problems is far graver than previously thought.

Oceans are being hit by decreasing oxygen levels caused by climate change and increased nutrient run-off from agriculture and sewage, and are becoming more acidic as more carbon dioxide dissolves into the sea, both of which harm wildlife.

Warming, as the oceans absorb much of the extra energy being trapped by greenhouse gases, is set reduce seasonal sea ice and lead to changes to sea layers, which will also cause lowering of oxygen levels.

Warming will also lead to increased venting of methane, a potent greenhouse gas, from the Arctic seabed, experts from the International Programme on the State of the Ocean (IPSO) and the International Union for Conservation of Nature (IUCN) said.

The "deadly trio" of warming, de-oxygenation and acidification is seriously affecting how productive and efficient the ocean is, with impacts throughout the chain of marine life, the scientists said.

In addition, continued overfishing is damaging the resilience of the oceans, and despite improvements in some areas, fisheries management is failing to halt the decline in key species and prevent harm to important marine ecosystems.

Last year the UN's Food and Agriculture Organisation (FAO) found that 70% of world fish populations were unsustainably exploited, and almost a third of those (30%) had collapsed to less than 10% of unfished levels.

The scientists called for urgent action to limit temperature rises to less than 2C above pre-industrial levels.

They warned that current targets for carbon emission reductions are not enough to ensure coral reefs on which humans and wildlife depend survive increasingly acidic oceans.

Potential knock-on effects of climate change in the oceans such as methane releases from the melting permafrost and coral dieback could lead to worse consequences for humans and nature than presently expected.

The scientists also called for effective management of fishing, which favoured small-scale fisheries, taking steps such as eliminating subsidies that back more fishing vessels than fisheries can support, and banning the most destructive gear.

And there needs to be "fit for purpose" global systems for governing the high seas, the experts said.

Oxford University professor Alex Rogers, scientific director of IPSO, said: "The health of the ocean is spiralling downwards far more rapidly than we had thought.

"We are seeing greater change, happening faster, and the effects are more imminent than previously anticipated.

"The situation should be of the gravest concern to everyone, since everyone will be affected by changes in the ability of the ocean to support life on Earth."

The IUCN's professor Dan Laffoley said: "What these latest reports make absolutely clear is that deferring action will increase costs in the future and lead to even greater, perhaps irreversible, losses.

"The UN climate report confirmed that the ocean is bearing a brunt of human-induced changes to our planet. These findings give us more cause for alarm - but also a road map for action. We must use it."

Additional reporting PA

Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Ashdown Group: Senior VMware Platform Engineer - VMware / SAN / Tier3 DC

£45000 - £55000 per annum + benefits: Ashdown Group: Senior VMware Platform En...

Recruitment Genius: Purchasing Assistant

£10000 - £16000 per annum: Recruitment Genius: A distributor of specialist ele...

Recruitment Genius: Sales Ledger Assistant

£17000 - £19000 per annum: Recruitment Genius: A distributor of specialist ele...

Ashdown Group: Automated Tester / Test Analyst - .Net / SQL - Cheshire

£32000 per annum + pension, healthcare & 23 days holiday: Ashdown Group: A gro...

Day In a Page

War with Isis: Iraq's government fights to win back Tikrit from militants - but then what?

Baghdad fights to win back Tikrit from Isis – but then what?

Patrick Cockburn reports from Kirkuk on a conflict which sectarianism has made intractable
Living with Alzheimer's: What is it really like to be diagnosed with early-onset dementia?

What is it like to live with Alzheimer's?

Depicting early-onset Alzheimer's, the film 'Still Alice' had a profound effect on Joy Watson, who lives with the illness. She tells Kate Hilpern how she's coped with the diagnosis
The Internet of Things: Meet the British salesman who gave real-world items a virtual life

Setting in motion the Internet of Things

British salesman Kevin Ashton gave real-world items a virtual life
Election 2015: Latest polling reveals Tories and Labour on course to win the same number of seats - with the SNP holding the balance of power

Election 2015: A dead heat between Mr Bean and Dick Dastardly!

Lord Ashcroft reveals latest polling – and which character voters associate with each leader
Audiences queue up for 'true stories told live' as cult competition The Moth goes global

Cult competition The Moth goes global

The non-profit 'slam storytelling' competition was founded in 1997 by the novelist George Dawes Green and has seen Malcolm Gladwell, Salman Rushdie and Molly Ringwald all take their turn at the mic
Pakistani women come out fighting: A hard-hitting play focuses on female Muslim boxers

Pakistani women come out fighting

Hard-hitting new play 'No Guts, No Heart, No Glory' focuses on female Muslim boxers
Leonora Carrington transcended her stolid background to become an avant garde star

Surreal deal: Leonora Carrington

The artist transcended her stolid background to become an avant garde star
LGBT History Month: Pupils discuss topics from Sappho to same-sex marriage

Education: LGBT History Month

Pupils have been discussing topics from Sappho to same-sex marriage
11 best gel eyeliners

Go bold this season: 11 best gel eyeliners

Use an ink pot eyeliner to go bold on the eyes with this season's feline flicked winged liner
Cricket World Cup 2015: Tournament runs riot to make the event more hit than miss...

Cricket World Cup runs riot to make the event more hit than miss...

The tournament has reached its halfway mark and scores of 300 and amazing catches abound. One thing never changes, though – everyone loves beating England
Katarina Johnson-Thompson: Heptathlete ready to jump at first major title

Katarina Johnson-Thompson: Ready to jump at first major title

After her 2014 was ruined by injury, 21-year-old Briton is leading pentathlete going into this week’s European Indoors. Now she intends to turn form into gold
Syrian conflict is the world's first 'climate change war', say scientists, but it won't be the last one

Climate change key in Syrian conflict

And it will trigger more war in future
How I outwitted the Gestapo

How I outwitted the Gestapo

My life as a Jew in wartime Berlin
The nation's favourite animal revealed

The nation's favourite animal revealed

Women like cuddly creatures whilst men like creepy-crawlies
Is this the way to get young people to vote?

Getting young people to vote

From #VOTESELFISH to Bite the Ballot