Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Oct 6;10(5):20190129.
doi: 10.1098/rsfs.2019.0129. Epub 2020 Aug 14.

Climate change mitigation potential of wetlands and the cost-effectiveness of their restoration

Pierre Taillardat  1 , Benjamin S Thompson  2   3 , Michelle Garneau  1 , Karelle Trottier  1 , Daniel A Friess  4
Affiliations

Climate change mitigation potential of wetlands and the cost-effectiveness of their restoration

Pierre Taillardat et al. Interface Focus. .

Abstract

The cost-effective mitigation of climate change through nature-based carbon dioxide removal strategies has gained substantial policy attention. Inland and coastal wetlands (specifically boreal, temperate and tropical peatlands; tundra; floodplains; freshwater marshes; saltmarshes; and mangroves) are among the most efficient natural long-term carbon sinks. Yet, they also release methane (CH4) that can offset the carbon they sequester. Here, we conducted a meta-analysis on wetland carbon dynamics to (i) determine their impact on climate using different metrics and time horizons, (ii) investigate the cost-effectiveness of wetland restoration for climate change mitigation, and (iii) discuss their suitability for inclusion in climate policy as negative emission technologies. Depending on metrics, a wetland can simultaneously be a net carbon sink (i.e. boreal and temperate peatlands net ecosystem carbon budget = -28.1 ± 19.13 gC m-2 y-1) but have a net warming effect on climate at the 100 years time-scale (i.e. boreal and temperate peatland sustained global warming potential = 298.2 ± 100.6 gCO2 eq-1 m-2 y-1). This situation creates ambivalence regarding the effect of wetlands on global temperature. Moreover, our review reveals high heterogeneity among the (limited number of) studies that document wetland carbon budgets. We demonstrate that most coastal and inland wetlands have a net cooling effect as of today. This is explained by the limited CH4 emissions that undisturbed coastal wetlands produce, and the long-term carbon sequestration performed by older inland wetlands as opposed to the short lifetime of CH4 in the atmosphere. Analysis of wetland restoration costs relative to the amount of carbon they can sequester revealed that restoration is more cost-effective in coastal wetlands such as mangroves (US$1800 ton C-1) compared with inland wetlands (US$4200-49 200 ton C-1). We advise that for inland wetlands, priority should be given to conservation rather than restoration; while for coastal wetlands, both conservation and restoration may be effective techniques for climate change mitigation.

Keywords: Paris agreement; blue carbon; carbon dioxide removal; ecological restoration; nature-based solutions; peatland.

PubMed Disclaimer

Conflict of interest statement

We declare we have no competing interests.

Figures

Figure 1.
Figure 1.
Conceptual model of the NECB that summarizes ecosystem carbon inputs and outputs. Note that if a stream is crossing a wetland (rather than taking its source within it), the import of allochthonous carbon has to be deducted.
Figure 2.
Figure 2.
Global distribution of the studies that assessed the net carbon budget by accounting for CO2, CH4 (and aquatic lateral export when available) in filled circles and wetland restoration cost in open circles with a cross.
Figure 3.
Figure 3.
Boxplots for mangrove and inland wetlands presenting (a) annual NECB and (b) SGWP based on the studies selected for our meta-analysis. Boxes span the interquartile range (25–75% quartiles), whiskers 5–95% of observations, horizontal lines are the medians and circle points represent the outliers. Letters indicate significant differences between wetlands with an n > 2 (non-parametric Van der Warden test, p < 0.05). *Value for mangrove is not from a particular study site but from a global synthesis from Rosentreter et al. [28].
Figure 4.
Figure 4.
(a) Instantaneous radiative effect of CH4 following a 1 kg CH4 pulse addition, and CO2 following 1 kg CO2 pulse uptake at time 0 and the decay of each gas over a 500-year period. The remainder of the figure shows a radiative effect due to sustained CH4 emissions or sustained CO2 uptake. The CH4 curve includes any radiative effect by CO2 that was produced from the oxidation of atmospheric CH4. Note the logarithmic scale on the y-axes. fW = 10−15W. Adapted from Neubauer & Megonigal [11]. (b) Cumulative radiative perturbation of the integrated lifetime result of warming caused by CH4 emissions (in kg CH4) and cooling due to long-term CO2 sequestration (in kg CO2). For all the seven scenarios, CH4 emissions were set at 1 kg CH4 m−2 y−1 while CO2 uptake was modelled from 1 kg CO2 m−2 y−1 to 50 kg CO2 m−2 y−1. pW refers to picowatts (10−12 W). The red background is where the simulation produces a warming effect, the blue background is where the simulation produces a cooling effect. Adapted from Neubauer & Verhoeven [37].
Figure 5.
Figure 5.
(a) Radiative effect of wetlands from our meta-analysis using their radiative balance (kgCO2:kgCH4) and age, adapted from figure 4b. (a) Restored wetlands over a time-scale from 0 to 100 years; and (b) the undisturbed wetlands over a time-scale from 0 to 12 500 years.
Figure 6.
Figure 6.
Boxplot of the switchover time when a wetland changes from having a net warming to a net cooling effect. Note that some studies that had a positive NEE (CO2 emission > CO2 uptake) were not considered in this model as they cannot have a negative radiative balance. Also note that two outliers from the peatland boxplot are not presented in this figure as their values were 10 608 and 16 354 years.
Figure 7.
Figure 7.
Boxplot of restoration cost per wetland type in (a) US$ ha−1 y−1; (b) US$ ton C−1; and (c) US$ ton CO2eq 100 SGWP−1. Note that for (a) one outlier from the freshwater marsh (1 733 632 US$ ha−1 y−1) and two from mangrove (828 033 and 692 814 US$ ha−1 y−1) are not presented in this figure. Also note that the lower samples size for (c) is because only sites with a negative SGWP-100y could be considered. Letters indicate significant differences between ecosystems (non-parametric Van der Warden test, p < 0.05). Values at the bottom of the lower boxplots indicate the sample size for each wetland type.
See this image and copyright information in PMC

References

    1. IPCC. 2018. Special report. Global warming of 1.5° C (SR15).
    1. Griscom BW, et al. 2017. Natural climate solutions. Proc. Natl Acad. Sci. USA. 114, 11 645–11 650. ( 10.1073/pnas.1710465114) - DOI - PMC - PubMed
    1. Minx JC, et al. 2018. Negative emissions—part 1: research landscape and synthesis. Environ. Res. Lett. 13, 063001 ( 10.1088/1748-9326/aabf9b) - DOI
    1. Fuss S, et al. 2018. Negative emissions—part 2: costs, potentials and side effects. Environ. Res. Lett. 13, 063002 ( 10.1088/1748-9326/aabf9f) - DOI
    1. Taillardat P, Friess DA, Lupascu M. 2018. Mangrove blue carbon strategies for climate change mitigation are most effective at the national scale. Biol. Lett. 14, 20180251 ( 10.1098/rsbl.2018.0251) - DOI - PMC - PubMed

LinkOut - more resources