scholarly journals Enhanced growth – more than reforestation – counteracted biomass carbon emissions (1990-2020)

Author(s):  
Julia Le Noe ◽  
Karl-Heinz Erb ◽  
Sarah Matej ◽  
Andreas Magerl ◽  
Manan Bhan ◽  
...  

Abstract Understanding the carbon (C) balance in global forest biomass is key for climate change mitigation. However, land-use and environmental drivers affecting forest C fluxes remain poorly isolated and quantified. Following a counterfactual modelling approached based on global Forest Resource Assessments, we show that in the hypothetical absence of changes in forest (i) area, (ii) harvest or (iii) burnt area, global forest biomass would reverse from an actual cumulative net C source of c. 2.4 GtC to a net C sink of 23.6, 2.7 and 5.2 GtC, respectively in 1990–2020. In contrast, cumulative emissions would be 12.9 GtC, i.e. 6 times higher, in the absence of forest growth changes. A typology systematically assessing C flux drivers reveals that enhanced growth, more than reforestation, counteracted C emissions. This sink function may, however, be discontinued in the future, thus alerting to the need for safer strategies to effectively preserve or enhance C sequestration.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Julia Le Noë ◽  
Karl-Heinz Erb ◽  
Sarah Matej ◽  
Andreas Magerl ◽  
Manan Bhan ◽  
...  

AbstractUnderstanding the carbon (C) balance in global forest is key for climate-change mitigation. However, land use and environmental drivers affecting global forest C fluxes remain poorly quantified. Here we show, following a counterfactual modelling approach based on global Forest Resource Assessments, that in 1990–2020 deforestation is the main driver of forest C emissions, partly counteracted by increased forest growth rates under altered conditions: In the hypothetical absence of changes in forest (i) area, (ii) harvest or (iii) burnt area, global forest biomass would reverse from an actual cumulative net C source of c. 0.74 GtC to a net C sink of 26.9, 4.9 and 0.63 GtC, respectively. In contrast, (iv) without growth rate changes, cumulative emissions would be 7.4 GtC, i.e., 10 times higher. Because this sink function may be discontinued in the future due to climate-change, ending deforestation and lowering wood harvest emerge here as key climate-change mitigation strategies.


2015 ◽  
Vol 12 (12) ◽  
pp. 9587-9612 ◽  
Author(s):  
P. Li ◽  
J. Zhu ◽  
H. Hu ◽  
Z. Guo ◽  
Y. Pan ◽  
...  

Abstract. Forests play a leading role in regional and global terrestrial carbon (C) cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area) and forest growth (increase in biomass density). Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms that control forest C sinks and is helpful for developing sustainable forest management policies in the face of climate change. Using the Forest Identity concept and forest inventory data, this study quantified the spatial and temporal changes in the relative contributions of forest areal expansion and increased biomass growth to China's forest C sinks from 1977 to 2008. Over the last 30 years, the areal expansion of forests was a larger contributor to C sinks than forest growth for all forests and planted forests in China (74.6 vs. 25.4 % for all forests, and 62.4 vs. 37.8 % for plantations). However, for natural forests, forest growth made a larger contribution than areal expansion (60.4 vs. 39.6 %). The relative contribution of forest growth of planted forests showed an increasing trend from an initial 25.3 to 61.0 % in the later period of 1998 to 2003, but for natural forests, the relative contributions were variable without clear trends owing to the drastic changes in forest area and biomass density over the last 30 years. Our findings suggest that afforestation can continue to increase the C sink of China's forests in the future subject to persistently-increasing forest growth after establishment of plantation.


2020 ◽  
Author(s):  
Ali Feizi ◽  
Bahar Razavi

<p>Climate change represents a key challenge to the sustainability of global ecosystems and human prosperity in the twenty-first century. The impacts of climate change combined with natural climate variability are predominantly adverse, and often exacerbate other environmental challenges such as degradation of ecosystems, loss of biodiversity, and air, water and land pollution. Besides, rapid industrialization and increasing adaption of agrochemical based crop production practices since green revolution have considerably increased the heavy metal contaminations in the environment.</p><p>Assessing the impacts of climate change on our planet and addressing risks and opportunities is essential for taking decisions that will remain robust under future conditions, when many climate change impacts are expected to become more significant.</p><p>Here, we established a review survey to assess the impact of biochar amendment and agroforstry system on CO<sub>2</sub> sequestration and methaloid remediation.</p><p>Our data base showed that Agroforestry-based solutions for carbon dioxide capture and sequestration for climate change mitigation and adaptation in long-term is more practical and realistic options for a sustainable ecosystem and decreasing negative effect of climate change. This was more supported in arid and semi-arid regions as well as area with saline and alkaline soil (20%).</p><p>From a soil remediation standpoint, the general trend has been shifting from reduction of the total concentration to reduction of the physic-chemically and/or biologically available fractions of metals. This regulatory shift represents a tremendous saving in remediation cost. While metals are not degradable, their speciation and binding with soil through biochar amending reduced their solubility, mobility, and bioavailability. While agroforestry showed high efficiency in C sequestration (32%), biochar amendment raveled significant mitigation in heavymetals bioavailability (42%). However, studies which coupled both approaches are limited. Thus, we conclude that combined Agroforestry and biochar amendment regulates C sequestration and metalloids remediation more efficiently.</p>


2016 ◽  
Vol 13 (2) ◽  
pp. 375-388 ◽  
Author(s):  
P. Li ◽  
J. Zhu ◽  
H. Hu ◽  
Z. Guo ◽  
Y. Pan ◽  
...  

Abstract. Forests play a leading role in regional and global terrestrial carbon (C) cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area) and forest growth (increase in biomass density). Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms that control forest C sinks and it is helpful for developing sustainable forest management policies in the face of climate change. Using the Forest Identity concept and forest inventory data, this study quantified the spatial and temporal changes in the relative contributions of forest areal expansion and increased biomass growth to China's forest biomass C sinks from 1977 to 2008. Over the last 30 years, the areal expansion of forests has been a larger contributor to C sinks than forest growth for planted forests in China (62.2 % vs. 37.8 %). However, for natural forests, forest growth has made a larger contribution than areal expansion (60.4 % vs. 39.6 %). For all forests (planted and natural forests), growth in area and density has contributed equally to the total C sinks of forest biomass in China (50.4 % vs. 49.6 %).The relative contribution of forest growth of planted forests showed an increasing trend from an initial 25.3 % to 61.0 % in the later period of 1998 to 2003, but for natural forests, the relative contributions were variable without clear trends, owing to the drastic changes in forest area and biomass density over the last 30 years. Our findings suggest that afforestation will continue to increase the C sink of China's forests in the future, subject to sustainable forest growth after the establishment of plantations.


2021 ◽  
Author(s):  
Alex Appiah Mensah ◽  
Hans Petersson ◽  
Göran Berndes ◽  
Gustaf Egnell ◽  
David Ellison ◽  
...  

<p>Long-standing debates over the benefits of forest conservation vs. those of substitution and forest resource use continue to occupy attention in Europe and beyond. Moreover, many argue the carbon sequestration benefits of standing forest are greater than those from forest resource use and replanting. To study this question, we generate long-term scenario analyses based on different forest management strategies in Sweden, in particular comparing increasing forest use and increasing land set-asides over 100, 200 and 500 year cycles. We find that the cost of increasing land set-asides is reflected in a significant loss of the carbon benefits created by forest use (substitution and carbon sequestration). We explain this outcome through the loss of additional growth that occurs as forest in land set-asides matures and eventually reaches a steady state. For the Swedish forest, these costs are significant and may amount to the loss (lost opportunity) of annually providing and additional -14 MtCO2e in net annual removals. The EU-based LULUCF carbon accounting framework, however, does not recognize this benefit and thus may effectively encourage land set-asides at the expense of real, measurable forest and forest resource-based climate change mitigation.</p>


2015 ◽  
Vol 153 (7) ◽  
pp. 1151-1173 ◽  
Author(s):  
S. MANGALASSERY ◽  
S. SJÖGERSTEN ◽  
D. L. SPARKES ◽  
S. J. MOONEY

SUMMARYThe benefits of reduced and zero-tillage systems have been presented as reducing runoff, enhancing water retention and preventing soil erosion. There is also general agreement that the practice can conserve and enhance soil organic carbon (C) levels to some extent. However, their applicability in mitigating climate change has been debated extensively, especially when the whole profile of C in the soil is considered, along with a reported risk of enhanced nitrous oxide (N2O) emissions. The current paper presents a meta-analysis of existing literature to ascertain the climate change mitigation opportunities offered by minimizing tillage operations. Research suggests zero tillage is effective in sequestering C in both soil surface and sub-soil layers in tropical and temperate conditions. The C sequestration rate in tropical soils can be about five times higher than in temperate soils. In tropical soils, C accumulation is generally correlated with the duration of tillage. Reduced N2O emissions under long-term zero tillage have been reported in the literature but significant variability exists in the N2O flux information. Long-term, location-specific studies are needed urgently to determine the precise role of zero tillage in driving N2O fluxes. Considering the wide variety of crops utilized in zero-tillage studies, for example maize, barley, soybean and winter wheat, only soybean has been reported to show an increase in yield with zero tillage (7·7% over 10 years). In several cases yield reductions have been recorded e.g. c. 1–8% over 10 years under winter wheat and barley, respectively, suggesting zero tillage does not bring appreciable changes in yield but that the difference between the two approaches may be small. A key question that remains to be answered is: are any potential reductions in yield acceptable in the quest to mitigate climate change, given the importance of global food security?


Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1294
Author(s):  
Asif Raihan ◽  
Rawshan Ara Begum ◽  
Mohd Nizam Mohd Said ◽  
Joy Jacqueline Pereira

Malaysia has a large extent of forest cover that plays a crucial role in storing biomass carbon and enhancing carbon sink (carbon sequestration) and reducing atmospheric greenhouse gas emissions, which helps to reduce the negative impacts of global climate change. This article estimates the economic value of forest carbon stock and carbon value per hectare of forested area based on the price of removing per ton CO2eq in USD from 1990 to 2050. The economic value of biomass carbon stored in the forests is estimated at nearly USD 51 billion in 2020 and approximately USD 41 billion in 2050, whereas carbon value per hectare forest area is estimated at USD 2885 in 2020 and USD 2388 in 2050. If the BAU scenario of forest loss (converting forests to other land use) continues, the projected estimation of carbon stock and its economic value might fall until 2050 unless further initiatives on proper planning of forest management and ambitious policy implementation are taken. Instead, Malaysia’s CO2 emission growth started to fall after 2010 due to rising forest carbon sink of 282 million tons between 2011 and 2016, indicating a huge potential of Malaysian forests for future climate change mitigation. The estimated and projected value of carbon stock in Malaysian forest biomass, annual growth of forest carbon, forest carbon density and carbon sink would be useful for the better understanding of enhancing carbon sink by avoiding deforestation, sustainable forest management, forest conservation and protection, accurate reporting of national carbon inventories and policy-making decisions. The findings of this study could also be useful in meeting emission reduction targets and policy implementation related to climate change mitigation in Malaysia.


2021 ◽  
Author(s):  
David Ellison ◽  
Johannes Breidenbach ◽  
Hans Petersson ◽  
Kari T. Korhonen ◽  
Helena Henttonen ◽  
...  

<div> <p>The announced goal of reversing the European trend toward a declining land carbon sink has garnered much ink. Words can, however, be misleading. Annual additions/contributions (sinks) to the land carbon sink (stocks) from growing forest and increasing forest cover have slowed marginally in recent years. However, the existing European land forest sink (stocks) has (have) expanded continuously across most or all of the 20<sup>th</sup> century and on into the 21<sup>st</sup>. More importantly perhaps, EU Member states with significant long-term investments in the forestry sector have historically witnessed strong forest expansion and <em>not</em>merely with the initiation of international attention to climate change mitigation through the UNFCCC negotiating and climate commitment framework. In this context, frequent assaults on forestry from multiple directions are cause for some bewilderment. We first highlight weaknesses in claims of increased forest use intensity and illustrate that forestry in the Nordic countries has a remarkably small and stable footprint over the 20<sup>th</sup> and 21<sup>st</sup> centuries. Addressing the second problem, however, understanding why such attacks occur in the first place, is more complex. Methodologically speaking, challenges to forestry should presumably be balanced by an understanding of the many human welfare benefits forests and the practice of forestry currently provide, as well as the costs of relinquishing those practices. Perhaps due to strong preferences among NGO’s and in parts of the academic community for natural, untouched, biodiverse forests, the benefits of forestry and forest resource use are consistently under-appreciated. Striking a balance between the desire for natural and biodiverse-rich forest environments on the one hand, and the climate change mitigation (and adaptation) benefits of forestry, forest resource use and substitution on the other is presumably a political and socio-economic necessity. The real question may be to what extent bias in favor of the “<em>natural</em>” may ultimately disrupt real, measurable progress toward effective climate change mitigation? Continuous, positive mitigation-related contributions to the growing European land cover sink (stocks), as well as to the global carbon budget (through annual net removals and substitution), have been and should remain the norm. These goals ultimately require an aggressive EU LULUCF strategy capable of fully mobilizing forest and forest resource use in favor of the goal of climate change mitigation (and adaptation).</p> </div>


Forests ◽  
2017 ◽  
Vol 8 (11) ◽  
pp. 455 ◽  
Author(s):  
Tarit Baul ◽  
Ashraful Alam ◽  
Antti Ikonen ◽  
Harri Strandman ◽  
Antti Asikainen ◽  
...  

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