Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Greenhouse gases' millennia-long ocean legacy

04.08.2015

Continuing current carbon dioxide (CO2) emission trends throughout this century and beyond would leave a legacy of heat and acidity in the deep ocean. These changes would linger even if the atmospheric carbon dioxide concentration were to be restored to pre-industrial levels at some point in the future, according to a new Nature Climate Change paper from an international team including Carnegie's Ken Caldeira. This is due to the tremendous inertia of the ocean system.


Coral near Tarawa, Kiribati.

Credit: Taken by Linda Wade; Courtesy of NOAA photo library

Greenhouse gases emitted by human activities not only cause rapid warming of the seas, but also an unprecedented rate of ocean acidification. Ocean acidification occurs when atmospheric carbon dioxide is absorbed by the ocean and forms carbonic acid, inhibiting coral reef growth and threatening marine life.

Some experts propose that climate and chemical damage due to high levels of greenhouse gases could be avoided by removing active carbon dioxide from the atmosphere, processes broadly called CDR for carbon dioxide removal. One idea is that fast-growing trees such as poplars, which consume a great deal of carbon dioxide during growth, could be farmed and then burned in bioenergy plants where their carbon dioxide would captured and stored underground instead of released back into the atmosphere. However, none of the proposed removal-and-storage strategies have been proven at an industrial scale yet, and ideas such as poplar farming would have to be carefully balanced against land use for food production.

Using computer modeling to investigate the success of CDR strategies, the team discovered that the clock is ticking for CDR to substantially reduce risks to much marine life. If these processes are applied too late, they might as well not be applied at all, as far as ocean acidification is concerned, the team found.

"Geoengineering measures are currently being debated as a kind of last resort to avoid dangerous climate change--either in the case that policymakers find no agreement to cut CO2 emissions, or to delay the transformation of our energy systems," said lead-author Sabine Mathesius from GEOMAR Helmholtz Centre for Ocean Research Kiel and the Potsdam Institute for Climate Impact Research (PIK). "However, looking at the oceans we see that this approach carries great risks."

As policymakers consider what might occur if various near- to mid-term climate policy targets are not achieved, it becomes increasingly important to understand what happens if society exceeds these targets.

"If we overspend our carbon dioxide emission budget now, can we make up for it by paying back a carbon dioxide debt later?" asked Caldeira, who worked on this issue during a research stay at PIK. "Can later carbon dioxide removal from the atmosphere offset today's emissions?"

The team conducted a computer experiment and simulated different rates of carbon dioxide extraction from the atmosphere. One of these rates, 22 billion tons per year, would remove carbon dioxide at slightly more than half current emission rates. Another was the probably unfeasible rate of more than 90 billion tons per year, which is more than two times today's yearly emissions. The experiment did not account for the availability of technologies for extraction and storage.

"Interestingly, it turns out that after business-as-usual until 2150, even taking such enormous amounts of carbon dioxide from the atmosphere would not help life that exists deep in the ocean very much. After large-scale ocean circulation has transported acidified water to great depths, it is out of reach for many centuries, no matter how much carbon dioxide is removed from the atmosphere," Caldeira said.

The scientists' model also looked at increasing temperatures and decreasing concentrations of dissolved oxygen in the sea. Oxygen is, of course, vital for many creatures. The warming reduces ocean circulation, harming nutrient transport. Together with acidification, these changes put heavy pressures on marine life. Earlier in Earth's history, such changes have led to mass extinctions. However, the combined effect of all three factors has not yet been fully understood.

"In the deep ocean, the chemical echo of this century's CO2 pollution will reverberate for thousands of years," said co-author John Schellnhuber, director of PIK. "If we do not implement emissions reductions measures in line with the 2 degrees Celsius target in time, we will not be able to preserve ocean life as we know it."

Ken Caldeira | EurekAlert!

More articles from Earth Sciences:

nachricht New plate adds plot twist to ancient tectonic tale
15.08.2017 | Rice University

nachricht Global warming will leave different fingerprints on global subtropical anticyclones
14.08.2017 | Institute of Atmospheric Physics, Chinese Academy of Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>