Seagrass better against climate change than Amazon rainforest ?

[studiot]

Quote

A study published in the Royal Society's flagship biological research journal says seagrasses capture carbon at a rate 35 times quicker than rainforests. If undisturbed, they can hold carbon for thousands of years, far longer than terrestrial plants. They thereby play the role of a natural carbon sink.

https://www.bbc.co.uk/news/world-africa-63901644

[geordief]

Thanks to @TheVat there is this site that addresses the importance of seagrasses

https://www.seagrasswatch.org/seagrassimportance/

 (This came up  in an earlier thread )

 

 

[Ken Fabian]

The moderating effects on atmospheric CO2 of healthy seagrasses are way short of being a global warming solution. Even if losing more of them will add to the climate problem (the loss of them as sink makes them a CO2 source) I'm not sure how we can greatly enhance their habitats and health, even to the point of retaining as sink what exists before it is lost. Preventing further loss seems the clear priority.

Locally as adaptation ( eg to reduce erosion from sea level rise) there may be efforts at enhancing their growth. But climate change itself is probably a negative influence on seagrass health, undermining the likelihood they will "hold carbon for thousands of years". We need more emphasis on emissions reductions through growth of low emissions energy as an element of preserving sea grass health.

Quote

They account for 10% of the ocean's total burial of carbon, despite covering less than 0.2% of the ocean floor, a report in the scientific journal Nature Geoscience said.

Not sure ocean floor coverage gives a valid comparison of seagrass effectiveness, although human intervention may be more effective for enhancing seagrasses than for other things that contribute to carbon sedimentation in oceans - being shallow and coastal vs open ocean.

[studiot]

12 hours ago, Ken Fabian said:

The moderating effects on atmospheric CO2 of healthy seagrasses are way short of being a global warming solution. Even if losing more of them will add to the climate problem (the loss of them as sink makes them a CO2 source) I'm not sure how we can greatly enhance their habitats and health, even to the point of retaining as sink what exists before it is lost. Preventing further loss seems the clear priority.

Locally as adaptation ( eg to reduce erosion from sea level rise) there may be efforts at enhancing their growth. But climate change itself is probably a negative influence on seagrass health, undermining the likelihood they will "hold carbon for thousands of years". We need more emphasis on emissions reductions through growth of low emissions energy as an element of preserving sea grass health.

Not sure ocean floor coverage gives a valid comparison of seagrass effectiveness, although human intervention may be more effective for enhancing seagrasses than for other things that contribute to carbon sedimentation in oceans - being shallow and coastal vs open ocean.

Thanks for the reply, but you seem to have missed the point of the article and my headline question.

The sham they called the recent climate conference (COP27 I think)  produced at least one good result.

Namely that richer nations are putting some resources into helping poorer ones play their part.

To me at any rate an, I would think it would not take much of this money to help extend seagrass and also mangrove margins.

It is also true that the oceans were and still are the largest carbon sinks on the planet, so it make real sense to promote their function.

[Sensei]

14 minutes ago, studiot said:

Seagrass better against climate change than Amazon rainforest ?

Seagrass is better scalable. The Amazon rainforest is limited in area by the size of the country and continent.

Edited December 10, 2022 by Sensei

[studiot]

49 minutes ago, Sensei said:

Seagrass is better scalable. The Amazon rainforest is limited in area by the size of the country and continent.

Nice point +1

[TheVat]

Yes.  And the hope that prawn and fishing industries would have high motivation to pay in to seagrass pasture expansion and mangroves seems well founded.  Potential billions for them.  And IIRC seagrass is fairly hardy and handles water temp rises well.  While land based solutions must also be implemented, they involve plantings that are more vulnerable to shifting rainfall patterns, wind erosions, increased wildfire, etc.  Rainforest, for example, makes its own weather and so when its lost you have areas that no longer have enough rain to readily bring it back.  There you are looking at generations before a forest can come back from scrublands and savannahs, and only with immense effort.

[Sensei]

3 hours ago, Sensei said:

Seagrass is better scalable. The Amazon rainforest is limited in area by the size of the country and continent.

..which does not mean that the rainforests should be cut down, destroyed, erased, from the Earth.. it would have other tragic consequences apart from climate warming..

Some European countries have gone down this road and now have problems.

 

 

[Ken Fabian]

I don't think I am missing the point. Globally, seagrasses appear to be on par with global rainforests in terms of carbon uptake and, like them, are being lost, not gained. Comparison to Amazon alone rather than global rainforest is misleading. Also Carbon going into ocean sediments is relatively small in the global carbon cycle scheme of things.

Carbon going into vegetation, whether on land or marine requires ongoing and enduring gain in biomass; without the assurance it is unduring it remains iffy. I think zero emissions is a prerequisite to the possibility, without assuring it - whilst failure at zero emissions seems likely to assure that it won't stay put. And I don't think it has been shown that enhanced seagrass growth is easier than terrestrial vegetation and soil carbon or that biomass gain wherever it is is a cost effective and scalable way to draw down atmospheric CO2, no matter how tantalising the quoted numbers look.

I see preventing their loss, ie stopping them being an emissions source - as both the higher priority and as the prerequisite to achieving a rebound, as are significant emissions reductions. The changes that global warming are causing represent significant threats to that "thousands of years" of sequestration - e.g. marine heatwaves, which shallow waters, ie seagrasses, are at most risk of, have already seen large areas suffer die-backs that saw years of becoming emissions source before recovery. It isn't clear that the recovery brought them back to net CO2 negative or that their survival as sinks can be counted on.

No matter that in theory they offer opportunity to draw down CO2 I remain doubtful about achieving recovery equal to past losses without success at achieving zero emissions first. Becoming a significant drawdown of CO2 beyond that - becoming an emissions solution that can lessen the requirements for reducing fossil fuel burning - looks unlikely to me, so I am inclined to object when it is presented as a solution. It isn't any more than Amazon re-forestation is a solution.

I see building low/zero emissions energy - emissions reduction - as the most effective action we can take on global warming. It looks  necessary to preventing seagrass ecosystem losses as well as enabling potential for any ongoing draw down.

How to pay for enhancing seagrass ecosystem carbon draw-down?

Mostly emissions offsets are the likely funding source but I am not a fan of carbon offsets; the financing of them, including seagrass management by such means is going to present ongoing challenges starting with preventing abuse of such schemes that includes their role in excusing and justifying ongoing emissions and delay. If we do indeed reach zero emissions other kinds of funding will be needed… well, I don't think we can seriously begin without alternatives to carbon offsets to fund it. It has to be not just subsidised but protected against the variety of human impacts, from inappropriate and excessive fishing to protected against global warming itself that are threatening their viability.

I am doubtful of fishing industries being sufficiently supportive of seagrass protection; it may get in principle support but my observation of industry responses to protected no-fishing zones is that they tend to object, often fiercely, rather than support, irrespective of science based evidence of overall benefits to fish stocks. At the individual fishing business level any reduced access - to prevent damage from trawling, anchoring and overfishing, which rate high as threats - will be opposed; having them pay for managing those areas as well seems even more likely to be opposed.

 This isn't objecting for the sake of argument, it is me attempting to be pragmatic; I am seeing a necessary priority of preventing their degradation and loss and most of all by actual emissions reductions. 

 

[Lady of Elms]

I find plant science to be fascinating. Grasses are probably one of the most important species to humanity and the animal kingdom, so I come bringing more information about seagrasses! 

https://www.seagrasswatch.org/seagrass/

https://ocean.si.edu/ocean-life/plants-algae/seagrass-and-seagrass-beds#:~:text=Seagrasses grow in salty and,where light levels are high. 

Once climate change raises ocean levels, perhaps there will be more places for seagrass to grow.... :/

 

[SohanPerves]

Thank you so much.