CO2 emissions threaten ocean crisis

A major report warns life in the seas will be irreversibly changed unless CO2 emissions from industrial society are drastically cut
Roger Harrabin BBC 3 Jul 15;

Scientists have warned that marine life will be irreversibly changed unless CO2 emissions are drastically cut.

Writing in Science, experts say the oceans are heating, losing oxygen and becoming more acidic because of CO2.

They warn that the 2C maximum temperature rise for climate change agreed by governments will not prevent dramatic impacts on ocean systems.

And they say the range of options is dwindling as the cost of those options is skyrocketing.

Twenty-two world-leading marine scientists have collaborated in the synthesis report in a special section of Science journal. They say the oceans are at parlous risk from the combination of threats related to CO2.

They believe politicians trying to solve climate change have paid far too little attention to the impacts of climate change on the oceans.

It is clear, they say, that CO2 from burning fossil fuels is changing the chemistry of the seas faster than at any time since a cataclysmic natural event known as the Great Dying 250 million years ago.

They warn that the ocean has absorbed nearly 30% of the carbon dioxide we have produced since 1750 and, as CO2 is a mildly acidic gas, it is making seawater more acidic.

It has also buffered climate change by absorbing over 90% of the additional heat created by industrial society since 1970. The extra heat makes it harder for the ocean to hold oxygen.

'Radical change'

Several recent experiments suggest that many organisms can withstand the future warming that CO2 is expected to bring, or the decrease in pH, or lower oxygen… but not all at once.

Jean-Pierre Gattuso, lead author of the study, said: “The ocean has been minimally considered at previous climate negotiations. Our study provides compelling arguments for a radical change at the UN conference (in Paris) on climate change”.

They warn that the carbon we emit today may change the earth system irreversibly for many generations to come.

Carol Turley, of Plymouth Marine Laboratory, a co-author, said: “The ocean is at the frontline of climate change with its physics and chemistry being altered at an unprecedented rate so much so that ecosystems and organisms are already changing and will continue to do so as we emit more CO2.

“The ocean provides us with food, energy, minerals, drugs and half the oxygen in the atmosphere, and it regulates our climate and weather.

“We are asking policy makers to recognise the potential consequences of these dramatic changes and raise the profile of the ocean in international talks where, up to now, it has barely got a mention.”

The scientists say ocean acidification is likely to impact reproduction, larval survival and feeding, and growth rates of marine organisms - especially those with calcium carbonate shells or skeletons.

Dangerous path

The authors say when the multiple stressors work together they occasionally cancel each other out, but more often they multiply negative effects.

The experts say coastal protection, fisheries, aquaculture and human health and tourism will all be affected by the changes.

They warn: “Immediate and substantial reduction of CO2 emissions is required in order to prevent the massive and effectively irreversible impacts on ocean ecosystems and their services”.

Professor Manuel Barange, director of science at the Plymouth Marine Laboratory, said: “Climate change will continue to affect ocean ecosystems in very significant ways, and society needs to take notice and respond.

“Some ecosystems and their services will benefit from climate change, especially in the short term, but overall the impacts are predominately negative.

“Negative impacts are particularly expected in tropical and developing regions, thus potentially increasing existing challenges in terms of food and livelihood security.

"We are allowing ourselves to travel a uniquely dangerous path, and we are doing so without an appreciation for the consequences that lie ahead."

World must cut pollution to save marine life, study warns
Kerry Sheridan AFP Yahoo News 3 Jul 15;

Miami (AFP) - If left unchecked, global warming will cause irreversible damage to marine life in the world's oceans, forcing fish to search for cooler waters and destroying valuable coral reefs, an international study said Thursday.

Keeping global average temperatures within two degrees Celsius above pre-industrial temperatures is the only way to stave off the worst effects of climate change on the Earth's oceans, which provide 90 percent of the planet's habitable space, said the study in the journal Science.

The findings are based on the Ocean 2015 Initiative, which examined the latest studies on how climate change is projected to affect oceans, marine life and hundreds of billions of dollars in goods and services they provide each year.

"All the species and services we get from the ocean will be impacted," said co-author William Cheung, associate professor at the University of British Columbia.

The team considered a business-as-usual scenario, and compared that to the effect of introducing big cuts in carbon dioxide emissions in order to keep temperature rise below two degrees Celsius by 2100, as outlined by the Copenhagen accord.

"The condition of the future ocean depends on the amount of carbon emitted in the coming decades," said the study.

"Immediate and substantial reduction of CO2 emissions is required in order to prevent the massive and effectively irreversible impacts on ocean ecosystems and their services that are projected" with business-as-usual scenarios.

Unless changes are made, "fish will migrate away from their current habitats 65 percent faster, resulting in changes to biodiversity and ecosystem functions," said the study, led by Jean-Pierre Gattuso of the French National Center for Scientific Research.

Over time, the ocean will become less capable of absorbing carbon emissions from the burning of fossil fuels.

Such pollution leads to rising acidification and harms marine life.

Sea level rise, loss of oxygen in the waters and disease are also top threats linked to pollution.

Even though recent research has suggested certain types of corals may be able to adapt to warming waters, the study said it was "doubtful that corals will be able to adapt quickly enough to maintain populations under most emissions scenarios, especially where temperature keeps increasing over time."

Researchers said their findings should help inform the global climate talks being held in Paris later this year.

According to Phillip Williamson, science coordinator of the UK Ocean Acidification (UKOA) research program, the paper gives a "powerful and succinct summary" of science that is already well known to experts, "but it's good to have the evidence brought together."

Williamson, who was not involved in the study, pointed out that even the two-degree Celsius scenario was not a cure for the world's waters.

"Even the stringent emissions scenario for carbon dioxide and other greenhouse gases is not without risks," he said.

"Knowing that such risks might only be 'moderate' rather than 'severe', still gives considerable cause for concern."

Ocean life facing a corrosive future - new report
IUCN Press Release 2 Jul 15;

The ocean moderates human-induced global warming but at the cost of profound alterations to its physics, chemistry, ecology and ecosystems services. These are the findings of a report published today in Science by the Oceans 2015 Initiative and co-authored by IUCN World Commission on Protected Areas Marine Vice Chair, Dan Laffoley.

The report evaluates and compares two scenarios under two potential carbon dioxide emissions pathways over this century. Both carry high risks to vulnerable ecosystems, such as warm-water corals and mid-latitude bivalve species (molluscs), but a business-as-usual scenario was projected to be particularly devastating with a high risk of widespread species mortalities.

Lead author, Jean-Pierre Gattuso, Senior Scientist at CNRS (Centre National de la Recherche Scientifique, France), hopes that the findings of the report will generate the political will to enforce meaningful cuts in carbon dioxide emissions, stating "The oceans have been minimally considered at previous climate negotiations; our study provides compelling arguments for a radical change at COP21 (the UN climate summit in Paris in December)".

Driven by 40% increases in atmospheric carbon dioxide (CO2), the oceans have already undergone a series of major environmental changes in terms of ocean warming, ocean acidification and sea level rise. Whilst the report finds that emissions cuts in line with the Copenhagen Accord target of less than 2 degrees temperature rise by 2100 would ensure moderate impacts to all but the most vulnerable of species, failure to achieve this goal would lead to high impacts on all the marine organism groups considered. These include high-value species such as corals and finfish as well as pteropods (shell-bearing zooplankton) and krill that form the base of the oceanic food chain.

The report singles out ocean acidification as one of the highest risks with the biggest impacts; shellfish, corals and zooplankton are particularly at risk. "Signs of ocean acidification have now been detected in both hemispheres," warns Carl Gustaf Lundin, Director of IUCN's Global Marine and Polar Programme. "Once thought to be a problem for the future, acidification is already having economic repercussions today and, if carbon emissions continue to grow, these are set to grow rapidly."
What can be done?

Beyond the stringent emissions cuts needed to meet the Copenhagen Accord target, the authors stress the need for recognition of the ocean's important role in climate regulation and acknowledgement of its particular vulnerability. "Any new climate regime that fails to minimise ocean impacts will be seen as incomplete and inadequate,” says Laffoley. "Implementation of further Marine Protected Area networks and investment in coastal ecosystem restoration are two important ways to ensure the ocean can remain resilient and can continue to regulate the Earth's climate."