Climate change threatens the stability of the Earth's oceans
The dangers posed by global warming to the Earth’s oceans have been investigated by a group of marine research scientists. They insist on the role of the planet’s biggest ecosystem, since it is largely ignored at UN climate talks. The scientists are connected with the French research vessel Tara, which is completing a three-and-a-half year exploration where information has been gathered across the globe in the largest ever study of plankton. Plans are made to make their appeal at the UN climate change conference in Paris this December.
The scientific team, discovered thousands of new plankton species, sampling the seas and oceans at depths up to 500 metres from the poles to the tropics and from east to west. They applied DNA analysis techniques on around 35,000 samples. A next step will be to study the samples more closely using powerful microscopes. Above 90% of species identified are new to science and hence, the team could not determine their different characteristics and properties.
Chris Bowler, one of the scientists leading the expedition stated that a huge effort will have to be made to characterise all these new species. Plankton represents about 95% of biomass in oceans and phytoplankton is a vital starting point of the marine food chain. It is found that much of what makes up the matrix of microscopic organisms is still a mystery. One of the surprises for the team was that the largest diversity found among specimen is in middle-sized organisms. Another key finding was how large an effect sea surface temperature (SST) can have on organisms like those under study. Temperature determines which species are present and where, which is pretty relevant in the context of climate change,” according to Bowler.
In addition the Earth's oceans act as enormous carbon and heat sinks and hence play an important role in the absorbtion of radiation and atmospheric carbon dioxide. Carbon dioxide absorption is slowly turning oceanic alkaline salt water (pH larger than 7) into acidic salt water (pH smaller than 7). This acidification of the world oceans has severe implications on marine life.
For oceanic ecosystems, the additional warming humans induce (Climate Change) can trigger a huge change according to Eric Karsenti, director of Tara Oceans, a French environmental NGO. One of the discoveries striking the researchers strongly is how interconnected the organisms they found were. Only 20% of the organisms exclude each other according to Karsenti. The majority is tied in a complex web of prey/predator, parasitic and mutually dependent relationships. Hence, disruptions in one part of the oceanic ecosystem can have vast repercussions across the food chain.
Tara, a schooner is currently moored on the Thames in London and will be taken back to France in time for the Paris meeting, which starts late November. The Tara scientists hope to collect at least 100,000 signatures for a petition they will present at the Paris Climate conference, calling for more attention for the fate of the Earth's oceans. They fear that it is likely that the text of a possible Paris climate agreement will include not more than a glancing reference to the issue of climate impacts on world oceans. They are are hopeful though that future revisions will remedy this. They have been encouraged by the willingness of the Intergovernmental Panel on Climate Change (IPCC), an International Panel of experts on Climate Change convened by the UN, to include much more detail on oceanic science in its future reports.
Question is if any scientist has made estimates of when world oceans might turn from alkalinic into acidic, and what impact this may have on the oceanic food chains?
Anyone wants to have a go at this issue?
This is really scary!
what is needed to reverse the situation? or at least keep it as it is?
I's it time to discuss the oxidation sequence of methane to answer these questions??Recently Elizabeth Kolbert stated in an article on climate change: the amount of water on earth is fixed. This is only true if methane levels remain the same as they have been in known times.
Methane after a quick oxidation to methanol converts to water vapor and formaldehyde, and twenty-five percent of it winds up as carbon dioxide.
I have read about the massive leaks of methane into our seas, but no one has said exactly what the amount of leakage in them is. Does anyone know? If we knew, the math would be simple, and then we would know to the day when our oceans would become too acidic to support the sea life we know. As methane also uses the sea's oxygen to reduce itself, we could also calculate when we run out of the oxygen algae produces, which is the main source of of our human supply. Plants on earth are of a higher order and take back the oxygen they produce in respiration to preform the transpiration process, leamving net 0 for human use. We also could see what part methane oxidation is playing on sea level ride as the main sequence is to water and formaldehyde. We should also know the formaldehyde level in our seas in areas of leakage, especially in warm areas. formaldehyde resists further oxidation in warm air and known warmer waters.
Doesanyone know the amount of methane leaking into our seas and what portion escapes to the air? It would be more than important to know.
Thanks Ahmad and Andrea for your concern.
I have a question for Andrea. We know that methane is also on the rise in the Earh's atmosphere at rate comparable to that of CO2. My question is, is methane oxidized into CO2 in the global atmosphere and then dissolved in the oceans or is it oxidized when methane is dissolved in the oceans? Not so clear to me.
Natural sinks of atmospheric methane
Most natural sinks occur as a result of chemical reactions in the atmosphere as well as oxidation by methane consuming bacteria in the Earth’s soils.
Methanotrophs in soils
Soils act as a major sink for atmospheric methane through the methanotrophic bacteria that reside in them. This occurs for two different types of bacteria. "High capacity-low affinity" methanotrophic bacteria grow in areas of high methane concentration, such as waterlogged soils in wetlands and other moist environments.
In areas of low methane concentration, "low capacity-high affinity" methanotrophic bacteria make use of methane in the atmosphere to grow, rather than relying on methane in their immediate environment.
Forest soils act as sinks for atmospheric methane because soils are optimally moist for methanotroph activity, and the movement of gases between soil and atmosphere (soil diffusivity) is high. With a lower water table, any methane in the soil has to make it past the methanotrophic bacteria before it can reach the atmosphere. Wetland soils, however, are often sources of atmospheric methane rather than sinks because the water table is (much) higher, oxygen content low and then methane can be diffused fairly easily into the atmosphere without having to compete with the soil’s methanotrophs.
Troposphere
The most effective reagent acting as a sink for atmospheric methane is the hydroxyl radical in the troposphere the lowest 10 km of thje Earth’s atmosphere. As methane reaches higher heighets in the aatmosphere, it reacts with the hydroxyl radical to create water vapor and carbon dioxide. The lifespan of methane in the atmosphere is estimated to be 9.6 years as estimated for the year 2001. However, increasing emissions of methane over time reduce the concentration of the hydroxyl radical in the atmosphere. Hence, With less OH˚ to react with, the lifespan of methane increases, resulting in higher concentrations of atmospheric methane (see the added graph)
Stratosphere
Even if methane is not destroyed in the troposphere, methane can usually only last 12 years before it is eventually destroyed in Earth’s next atmospheric layer: the stratosphere above 10 km height. Destruction in the stratosphere occurs the same way as it does in the troposphere: methane is oxidized producing carbon dioxide and water vapor.
Reaction with free chlorine
But methane also reacts with natural chlorine gas in the atmosphere to produce chloromethane and hydrochloric acid (HCl). This process is known as free radical halogenation.
CH4 + Cl2 → CH3Cl + HCl of which CH3Cl is chloroform and HCl is a strong acid, which may be a cause for ocean acidification as well besides increasing CO2 concentrations. Though scientists know for decades that ocean acidification occurs since CO2 increases in the atmosphere, the consequences to marine life have not been described until about 10 years ago. At that time, biologists discovered that ocean acidification impacte don the ability of many marine organisms to form their shells or skeletons. Since then, many more effects of ocean acidification have been found to influence a wide array of organisms and marine processes. Because the scientific process relies on formal research protocols, peer-review, and publishing, it takes time for new findings to be verified and accepted by the scientific community.
However, sufficient evidence about ocean acidification existed largely since in 2007 the IPCC Fourth Assessment Report on Climate Change stated in the Summary for Policy Makers, that, “The progressive acidification of the oceans due to increasing atmospheric carbon dioxide is expected to have negative impacts on marine shell-forming organisms (e.g. corals) and the species dependent on them.” Ocean acidification and its effects have now been documented to the point that they are widely accepted by the scientific community and it will be seriously addressed by the Fifth Assessment Report of the IPCC. In fact, ocean acidification is a major topic of discussion at side events such as Oceans Day at the December 2009 COP15 Climate Change negotiations in Copenhagen even though specific considerations about oceans had typically little or no mention in the text of the proposed agreement.
One of the lead conveners at the CFCC15 sessions, Jean-Pierre Gattuso of France’s CNRS-UPMC, Laboratoire d'Océanographie, outlines what the conference can expect to hear. “The Ocean is critical to life on Earth through its regulation of atmospheric gases, stabilisation of planetary heat, and provision of food and resources to well over 3 billion people worldwide. Despite its importance, however, our understanding of impacts of key climate change drivers such as ocean warming and acidification has been relatively limited. The recent consensus report from WGII of the IPCC AR5 addresses this deficit by including a number of ocean focused chapters for the first time ever. AR5 identified serious risks to marine ecosystems, fisheries, and coastal ecosystems.
The sessions at CFCC15 provide an integrated and updated perspective on the changes, risks and projections for both natural and human systems. The ensuing discussions will facilitate the construction of key messages for the COP21 negotiation process on the Oceans and associated issues.
On the opening day of Conference, on July 7, 2014, a large session presenting the latest assessments of ocean impacts and feedbacks was held. Marine species are shifting their living ranges, the state of fisheries and threats to food security are imminent, not mentioning the fast emptying of oceans by industrila fishery. Regional challenges for people, industry and ecosystems in a rapidly warming and acidifying ocean come on the agenda. A more in depth look at ocean changes including those affecting coral reef systems, and a session focussing on the specific challenges facing the Mediterranean were held.The Mediterranean is one of the world’s iconic - and most overfished - seas which is confronted with a wide range of challenges induced by climatic change: extreme events, sea-level change, ocean acidification, and significant risks for food production, water availability, biodiversity and other impacts.
It is believed that the focus on oceans underlines the critical importance of their role in regulating many of the the Earth's bio-geophysical as well as meteorological systems and the risks humanity faces in losing vital services is not to be underestimted. However, despite the ocean’s critical role in global ecosystem processes and services, international climate negotiations have only minimally touched on ocean impacts.
Some key ocean statistics and Information presented in the IPCC 5th assessment report in 2014 are the follwoing:
• Oceans cover more than 70% of the planet;
• Half (yep half!) of the production of oxygen of the earth system takes palce in its oceans. this puts terretrial oxygen in its true perspective.
• Oceans provide 20% of animal proteins which are consumed by 3 billion people!
• Climate change causes oceans to warm up and stratify (where the naturally occurring different layers of warmer and colder and more or less salt water does not effectively mix, disrupting a normal supply of nutrients for marine species and to causes the sea level to rise, as well as during the Arctic summer the sea ice to shrink, probably till the Arctic is ice -free during summer. Ice-bears will be banned to live on and area's and cill come in competition with other wildlife to survive.
• Ocean warming accounts for more than 90% of the energy accumulated in the climate system. Poroabaly the El Nino is in some way coupled with the process of energy accumualtion in a cyclic mode of 4 to 10 years.
• Warming causes oceans to lose oxygen overall and during an expansion of hypoxic (depleted oxygen) water layers as well. Without oxygen phytoplankton may not be able to survice the night since it needs oxygen to respire.
• The accumulation of anthropogenic CO2 in ocean surface waters disturbs water chemistry with is its major effect,... the increase of ocean acidification.
• Ocean warming has caused geographical shifts in the distribution of marine species, with some migrating further north, further away from equatorial waters.
Finally methane not only is a more potent greenhous gas than CO2, but is converted in CO2 as well after a residence time in the atmopshere of about 9 years. Is this 9 years cycle in some way related to the El Nino effect which in 2015 - 2016 e.g. now reaches a very high maximum with strong effects on the Earth's climate. 2015 - 2016 is an all-time climate record breaking year.
Again therefore my question, are we slowly approaching a runaway phase of the Earth's climate? If so, then drastic measures will have to be taken to stop the runaway process and stabilize the bio-geosphere and climate as well. I guess there is not so much time left to waste.
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