Restoring coastal vegetationso called ‘blue carbon’ habitatsmay not function as nature-based climate solution it really is claimed to be, in accordance with a fresh study.
Within their analysis, researchers from the University of East Anglia (UEA), the French Centre National de la Recherche Scientifique (CNRS) and the OACIS initiative of the Prince Albert II of Monaco Foundation challenge the widely held view that restoring areas such as for example mangroves, saltmarsh and seagrass can remove huge amounts of skin tightening and (CO2) from the atmosphere.
The findings of these review, published today in the journal Frontiers in Climate, identify seven explanations why carbon accounting for coastal ecosystems isn’t just extremely challenging but risky.
Included in these are the high variability in carbon burial rates, vulnerability to future climate change, and fluxes of methane and nitrous oxide. The authors, who also viewed info on restoration costs, warn that extra measurements can reduce these risks, but means higher costs.
However, they stress that blue carbon habitats should be protected, and restored where possible, because they have benefits for climate adaptation, coastal protection, food provision and biodiversity conservation.
Lead author Dr. Phil Williamson, honorary reader in UEA’s School of Environmental Sciences, said, “We’ve investigated the processes involved with carbon removal and you can find way too many uncertainties. The expected climate advantages from blue carbon ecosystem restoration could be achieved, yet it appears more likely they’ll fall seriously short.
“If you wish to have extra carbon removal, you will need extra habitat, and the scope for restoration is bound. A number of these sites have already been built on, for coastal settlement, tourism and port development.
“Nevertheless, we think that every effort ought to be designed to halt, and whenever we can reverse the worldwide lack of coastal vegetation. That’s because blue carbon habitats tend to be more than carbon storesthey provide storm protection, support biodiversity and fisheries, and improve water quality.”
The sediments beneath mangrove forests, tidal saltmarshes and seagrass meadows are abundant with organic carbon, accumulated and stored over many more than 100 years.
Many recent studies and reviews have favorably identified the prospect of these coastal blue carbon ecosystems to supply an all natural climate solution in two ways: by conservation, reducing the greenhouse gas emissions due to losing and degradation of such habitats; and by restoration, to improve skin tightening and drawdown and its own long-term storage.
This new review targets the latter, assessing the feasibility of achieving quantified and secure carbon removal (negative emissions) through the restoration of coastal vegetation.
Increasingly businesses and states have pledged to offset their emissions by restoring these ecosystems through carbon credits, assuming reliable knowledge on what much CO2 they’ll remove in future from the atmosphere.
However, Dr. Williamson and co-author Prof. Jean-Pierre Gattuso, of CNRS and the OACIS initiative of the Prince Albert II of Monaco Foundation, say the policy problem is more subtle. That’s, CO2 removal using coastal blue carbon restoration has questionable cost-effectiveness when considered only as a climate mitigation action, either for carbon-offsetting or for inclusion in countries’ Nationally Determined Contributions, which lay out their efforts to lessen emissions and adjust to the impacts of climate change beneath the Paris Agreement.
“If we use these ecosystems for carbon offsets in a significant way, expecting they would remove around, say, 100 gigatons of skin tightening and on the period 2025-2100, but find they only remove 10 or possibly just one single gigaton of CO2, then climate tipping points could possibly be crossed, with sincere about consequences,” said Dr. Williamson.
“If, however, such ecosystems are restored to safeguard biodiversity, and we discover that in addition they remove several gigatons of CO2, then that might be an additional benefit, assuming other means are employed for climate mitigation.
“Restoration should therefore maintain addition tonot as an alternative fornear-total emission reductions. Where coastal blue ecosystems restoration projects are completed primarily for carbon removal, they have to include comprehensive long-term monitoring to verify that the intended climate benefits are increasingly being achieved.”
Prof. Gattuso said, “Many important issues associated with the measurement of carbon fluxes and storage have yet to be resolved, affecting certification and leading to potential over-crediting.
“The restoration of coastal blue carbon ecosystems is nevertheless highly advantageous for climate adaptation, coastal protection, food provision and biodiversity conservation. Such action can therefore be societally justified in lots of circumstances, in line with the multiple benefits that such habitats provide at the neighborhood level.”
More info: Carbon removal using coastal blue carbon ecosystems is uncertain and unreliable, with questionable climatic cost-effectiveness, Frontiers in Climate (2022). www.frontiersin.org/articles/1 lim.2022.853666/full
Citation: Carbon removal using ‘blue carbon’ habitats could be ‘uncertain and unreliable’ (2022, July 28) retrieved 28 July 2022 from https://phys.org/news/2022-07-carbon-blue-habitats-uncertain-unreliable.html
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