Microsoft Word - PRES22_0064.docx
DOI: 10.3303/CET2294092
Paper Received: 26 June 2022; Revised: 03 July 2022; Accepted: 03 July 2022
Please cite this article as: Wang X.-C., Dong X., Klemeš J.J., Varbanov P.S., 2022, Overview of the Linkages between Land-Based Sectors and
Climate Change towards Carbon Emissions Neutrality, Chemical Engineering Transactions, 94, 553-558 DOI:10.3303/CET2294092
A publication of
CHEMICAL ENGINEERING TRANSACTIONS
VOL. 94, 2022 The Italian Association
of Chemical Engineering
Online at www.cetjournal.it
Guest Editors: Petar S. Varbanov, Yee Van Fan, Jiří J. Klemeš, Sandro Nižetić
Copyright © 2022, AIDIC Servizi S.r.l.
ISBN 978-88-95608-93-8; ISSN 2283-9216
Overview of the Linkages between Land-Based Sectors and
Climate Change towards Carbon Emissions Neutrality
Xue-Chao Wanga,b,*, Xiaobin Donga,b, Jiří Jaromír Klemešc, Petar Sabev Varbanovc
aState Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal
University, Beijing, 100875, China
bSchool of Natural Resources Science and Technology, Faculty of Geographical Science, Beijing Normal University, Beijing
100875, China
cSustainable Process Integration Laboratory - SPIL, NETME Centre, Faculty of Mechanical Engineering, Brno University of
Technology - VUT Brno, Technická 2896/2, 616 69, Brno, Czech Republic
xcwang@bnu.edu.cn
Land-based sectors play significant roles in carbon emissions, and removals, including agriculture, forestry,
other land uses (AFOLU), as well as land use and cover change (LUCC). More than 20 % of carbon emissions
globally are from land-based sectors. It is increasingly crucial to identify and model the relationship between
land-based sectors and climate change, especially toward the carbon emissions neutrality target or net-zero
emission goal. However, few works so far were systematically and comprehensively designed for this topic. The
boundary of land-based sectors is not clearly defined, and the linkages between land-based sectors and carbon
emissions are not well identified. This paper overviewed the relationship between land-based sectors and
climate change toward the carbon emissions neutrality goal to narrow the research gaps. The AFOLU-related
greenhouse gas (GHG) emissions were identified, the implications for land-based emissions reduction were
discussed, and the potential priority action areas were summarised. This study provides a better understanding
of the relationship between land use and climate change.
1. Introduction
Increasing GHG emissions, along with sequence global warming, have been the main challenge worldwide.
Fossil fuel consumption and generation, as well as relevant economic activities, are the crucial contributors to
GHG emissions (Wang et al., 2022). It has been promised that 137 countries have committed to carbon
emissions neutrality targets, and 73 % of global emissions are currently covered by the net-zero emission goal
(Content, 2021). However, only six countries have passed their carbon neutrality targets into law, and only 24
countries have their targets set as an official policy (Content, 2021). Increasing effort and activities should be
put into practice to mitigate GHG emissions. Global GHG emissions are mainly from energy, especially fossil
fuel, and consumption-related activities. However, there is an increasing interest in that land-based sectors
account for significant GHG emissions, which contribute to 23 % of the whole figure, including Agriculture,
Forestry, and Other Land Uses (AFOLU) (Wang et al., 2019). The AFOLU sector encompasses managed
ecosystems and offers significant mitigation opportunities while delivering food, wood and other renewable
resources as well as biodiversity conservation, provided the sector adapts to climate change.
However, the relevant topics haven’t been thoroughly studied. Based on the most recent Sixth Assessment
Report released by the Working Group Ⅲ of the Intergovernmental Panel on Climate Change (IPCC), the
measures of land-based GHG emissions mitigation represent some of the most important options currently
available (IPCC, 2022a). The land-based sectors encompass managed ecosystems and offer significant
mitigation opportunities while delivering food, wood and other renewable resources as well as biodiversity
conservation, provided the sector adapts to climate change. They can both deliver carbon dioxide removal
(CDR) and substitute for fossil fuels, thereby enabling emissions reductions in other sectors. The rapid
deployment of AFOLU measures is essential in all pathways to staying within the limits of the remaining budget
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for a 1.5 ℃ target (Roe et al., 2019). Based on the contribution of Wang et al. (2019), AFOLU account for around
14 % - 20 % of all GHG emissions. However, the above number is possibly underestimated. Dynamic global
vegetation model simulations suggest that GHG emissions from land-use change have been substantially
underestimated because processes such as tree harvesting and land clearing from shifting cultivation have not
been considered (Arneth et al., 2017). According to the study by Roe et al. (2019), the transformation of the
land sector and measures deployment in agriculture, forestry, wetlands and bioenergy would significantly
contribute to about 30 % of the global GHG emissions mitigation for achieving the goal of 1.5 °C by 2050, which
would be around 15 Gt of CO2 equivalent (CO2-eq) per year. However, it would require substantially more effort
than the 2 °C targets. Human beings must take much more serious carbon emissions mitigation measures,
especially focusing on the land-based sectors, AFOLU. However, there is few studies have been systematically
designed and conducted, despite some of them already made contributions to this topic.
According to the contribution by Wang et al. (2019), AFOLU accounts for a significant part of global GHG
emissions, including CO2 emissions, and especially methane emissions. Tian et al. (2021) studied that carbon
emissions from land use and land-use change are an important part of anthropogenic carbon emissions.
However, the size and location still need more in-depth exploration. The relationship between AFOLU and GDP
remains partial and uncertain. It is quantified that the carbon emissions directly caused by the land-use change
from 1992 to 2015 were 26.54 Pg C, which was 1.15 Pg C/y (Tian et al., 2021).
The carbon emissions embodied in the inter-regional trade are also remarkable from the consumption side.
Inter-regional trade makes goods and services produced in one country to be consumed elsewhere, separating
consumption from its environmental impacts. Based on the most recent study by Hong et al. (2022), international
trade separates the consumption of goods from related environmental impacts, including GHG emissions from
agriculture and land-use change. They used the new emissions estimates and a multiregional input-output
model and evaluated the land-use emissions embodied in global trade from 2004 to 2017. They found that
annually 27 % of land-use emissions and 22 % of agricultural land are related to agricultural products ultimately
consumed in a different region from where they were produced, and roughly three-quarters of embodied
emissions are from land-use change, with the largest transfers from lower-income countries (Hong et al., 2022).
Methane is one other important GHG, accounting for about 20 % of the warming induced by long-lived GHG
since pre-industrial times. Kirschke et al. (2013) assessed the global methane sources and sinks of the past
three decades, revealing that a rise in natural wetland emissions and fossil fuel emissions probably accounts
for the renewed increase in global methane levels after 2006, although the relative contribution of these two
sources remains uncertain. Land-based sectors, especially agriculture, are the key methane emitters as well.
Jackson et al. (2020) pointed out that increasing anthropogenic methane emissions arise equally from
agricultural and fossil fuel sources.
Although the land-based sectors have been drawing increasing attention in terms of carbon emissions, previous
works haven’t clearly understood the linkages between land use and carbon emissions. For example, what
exactly number of carbon emissions are from land use? What are the proportions of carbon emissions from
natural land-use change processes, human land-use activities or relevant energy consumption? How do mitigate
the carbon emissions from land-based sectors, including agriculture and forest? What measures should be
taken when cooperating with other sectors to achieve carbon emissions neutrality? To better answer those
questions, this paper aims to review the relationship between land-based sectors and climate change, especially
regarding the carbon emissions neutrality target. The following sections are arranged: section 2 reviews the
linkages between AFOLU and GHG emissions; section 3 concludes the approaches used for assessing or
modelling AFOLU-related GHG emissions; section 4 presents discussions and Implications for the carbon
emissions neutrality target, and section 5 is the conclusions section.
2. Linkages between AFOLU and GHG emissions
The role of AFOLU activities in the mitigation of GHG emissions and climate change has long been recognised.
Human activities affect changes in carbon stocks between the carbon pools of the terrestrial ecosystem and
between the terrestrial ecosystem and the atmosphere (UNFCCC, 2022).
The land is a critical resource of carbon emissions, according to the IPCC report. The land is already under
growing human pressure, and climate change is adding to these pressures. As shown in Figure 1, GHG
emissions from AFOLU showed an increasing trend during the past few decades. Keeping global warming to
well below 2 ºC can be achieved only by reducing GHG emissions from all sectors, including land and food
(IPCC, 2022b). Agriculture, forestry and other types of land use account for 23 % of human GHG emissions,
including CO2, CH4 and NOx combined as CO2 equivalents in 2007 – 2016 (IPCC, 2020). Natural land processes
absorb carbon dioxide equivalent to almost a third of carbon dioxide emissions from fossil fuels and industry
(IPCC, 2022b). The linkages between land and carbon emissions are quite complicated. When land is degraded,
it becomes less productive, restricting what can be grown and reducing the soil’s ability to absorb carbon. This
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exacerbates climate change, while climate change, in turn, exacerbates land degradation in many different
ways. Coordinated action to address climate change can simultaneously improve land, food security and
nutrition and help to end hunger. The most recent IPCC report highlights that climate change is affecting all four
pillars of food security: availability (yield and production), access (prices and ability to obtain food), utilisation
(nutrition and cooking), and stability (disruptions to availability) (IPCC, 2022a).
Policies that are outside the land and energy domains, such as on transport and the environment, can also
make a critical difference in tackling climate change. Acting early is more cost-effective as it avoids losses.
There is real potential here through more sustainable land use, reducing over-consumption and waste of food,
eliminating the clearing and burning of forests, preventing over-harvesting of fuelwood, and reducing GHG
emissions, thus helping to address land-related climate change issues.
*FOLU: Forestry and Other Land Uses, exclude agriculture.
Figure 1: GHG emissions changes from AFOLU, 1961-2016, adapted from (IPCC,2020)
The role of AFOLU activities in the mitigation of climate change has long been recognised. It is revealed that
taking precedence act on land-based sectors can significantly contribute to cutting down a third of the GHG
emissions that are needed to achieve the goal of below 1.5°C increase, which is additional to the 30 % of carbon
emissions that land already sequesters naturally (United Nation, 2019). Human activities affect changes in
carbon stocks between the carbon pools of the terrestrial ecosystem and between the terrestrial ecosystem and
the atmosphere. Mitigation can be achieved through activities in the land use, land use change and forestry
(LULUCF) sector that increase the removals of GHG from the atmosphere or decrease emissions by halting the
loss of carbon stocks.
It is predicted that, between 2020 and 2050, mitigation measures in forests and other natural ecosystems
provide the largest share of the economic AFOLU mitigation potential, followed by agriculture and demand-side
measures (IPCC, 2022c).
Figure 2: AFOLU sector GHG emissions and removals in the EU, by main land use category. Developed from
(European Environment Agency, 2022c)
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As shown in Figure 2, AFOLU sectors contribute to a huge amount of GHG emissions, fortunately, which
removes more than emits. Through its LULUCF activities, the EU currently removes a net total of 249 Mt CO2eq
from the atmosphere every year, equivalent to 7 % of its annual GHG emissions (European Environment
Agency, 2022).
3. Assessing/modelling AFOLU-related GHG emissions
GHG emissions and removals from AFOLU sectors place significant roles in the mitigation of global climate
change. It is crucial to precisely assess or model the AFOLU-relevant GHG emissions. Increasingly works have
been focusing on this topic and several different methods are used in the assessing processes. The most
important process is to identify the boundary of the assessment. GHG emissions from land-based sectors are
shown in Table 1, which is modified based on the study of Hong et al. (2021). The land-based GHG emissions
sources mainly include land-use emissions, land-use change emissions and agricultural emissions.
Table 1: GHG emissions from AFOLU
GHG emissions sources, level 1 GHG emissions sources, level 2
Land-use emissions 1. CO2 emissions from transitions in land use (which could include,
for example, the clearing of native habitat for agriculture or
changes in agricultural use), harvesting of forest products, peat
drainage and peat burning;
2. uptake of CO2 from regrowth of forests and recovery of abandoned
agricultural land (that is, negative emissions);
3. N2O released from soils related to the application of nitrogenous
fertiliser, manure applied to soils, manure left on pasture, and
agricultural residues left on pasture;
4. CH4 from enteric fermentation of livestock;
5. CH4 and N2O from manure management;
6. CH4 from rice cultivation;
7. CH4 and N2O from burning of agricultural residues.
Land-use change emissions 1. Conversion of natural land to cropland;
2. Conversion of natural land to pasture;
3. Harvest of forest products;
4. Recovery and abandonment of cropland or pasture.
Agricultural emissions 1. CH4 emissions from enteric fermentation of livestock and rice
cultivation;
2. N2O emissions from synthetic fertilisers;
3. manure applied to soils;
4. Manure left on pasture;
5. Agricultural residues left on pasture;
6. CH4 and N2O emissions from manure management and burning of
agricultural residues.
The impact of land-use changes within terrestrial ecosystems on carbon balance has been a focus of global
change research in recent decades. Several studies have researched the disturbance of carbon pools by human
activities using bookkeeping models, which track changes in the areas of different land-use types and use
standard growth and decomposition curves to calculate changes in carbon pools (Lai et al., 2016). Life cycle
assessment (LCA), Input-Output (IO) model, etc., were also widely used for assessing GHG emissions.
4. Discussions and Implications
Several strategies, targets and policies have been set up and revolve around GHG mitigation and improving
energy efficiency, especially raising the share of renewable energy. AFOLU is of global importance, with
significant implications for changes in GHG emissions, removals and carbon storage. It is quite complicated to
identify the boundary of land-based sectors. In addition to the widely researched land-use types of forest,
grassland, and agriculture, other significant kinds of land-use should be more seriously considered, including
water area, built-up land, unexploited land, and other land uses. A comprehensive assessment covering all
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kinds of land use is mandatory for more precisely evaluating the contribution from land-based sectors to global
climate change.
Although energy-relevant activities are the main contributors to GHG emissions, those emitted from land-based
sectors have been drawing increasing attention. Different regions, countries, and governments take measures
and make policies to assess, model, and mitigate the GHG emissions from AFOLU parts. The European Union
(EU) set a good example on this topic. Under current EU legislation, EU Member States must ensure that
accounted GHG emissions from land use, land-use change or forestry are balanced by at least an equivalent
accounted removal of CO2 from the atmosphere in the period 2021 to 2030. It is in line with its more ambitious
target of achieving net emission reductions of at least 55 % by 2030, compared to the level in 1990 (European
Commission, 2022).
AFOLU mitigation measures have been well understood for decades, but deployment remains slow, and
emissions trends indicate unsatisfactory progress despite beneficial contributions to global emissions reduction
from forest-related options. More serious actions worldwide should be increasingly put forward, based on the
guide of the Paris Agreements. The potential priority actions areas might include:
(i). Reducing deforestation, peatland drainage and burning, and mangrove conversion;
(ii). Enhancing soil carbon sequestration in agriculture across all agricultural countries;
(iii). Restoring forests, drained peatlands, and coastal mangroves;
(iv). Improving forest management and agroforestry;
(v). Reducing consumer food waste in developed and emerging countries;
(vi). Shifting people to primarily plant-based diets;
(vii). Reducing fertiliser consumption in agriculture.
The situation and linkages among different land-based sectors and economic activities are getting more
complicated under the impacts of COVID-19. The economic activities are significantly influenced by the
pandemic. The embodied energy transmission pattern is instability, especially for the agriculture relevant trades
and energy consumption by land-use change activities. Consequently, the caused carbon emission
transmissions network is getting complicated as well. It poses new challenges to the formulation of carbon
emissions neutrality strategies. It would further complicate the sectoral, regional, national and global linkages
and interdependencies, which would be taken into consideration in the following parts of this research moving
forward.
5. Conclusions
This paper overviewed the linkages between land-based sectors and climate change toward the carbon
emissions neutrality target. The AFOLU-related GHG emissions were identified, including the emissions from
land-use emissions, land-use change emissions and agricultural. The implications for land-based emissions
reduction were discussed, and the potential priority action areas were summarised. Agriculture, forestry and
other types of land use account for 23 % of human GHG emissions. GHG emissions from AFOLU showed an
increasing trend during the past 50 y. Keeping global warming to well below 2ºC can be achieved only by
reducing GHG emissions from all sectors, which must include the land-based parts. At the same time, natural
land processes absorb a large number of CO2, which is equal to a third of CO2 emissions from fossil fuels and
industry. Human beings must take more serious actions, including legislation and carbon emission policy-
making, more focusing on reducing deforestation, protecting wetlands, reducing food waste and reducing
fertiliser utilisation.
Acknowledgements
This study is supported by the Fundamental Research Funds for the Central Universities (310421102), and the
EU project “Sustainable Process Integration Laboratory – SPIL”, project No.
CZ.02.1.01/0.0/0.0/15_003/0000456 funded by EU “CZ Operational Programme Research, Development and
Education”, Priority 1: Strengthening capacity for quality research under the collaboration with Beijing Normal
University.
References
Arneth A., Sitch S., Pongratz J., Stocker B.D., Ciais P., Poulter B., Bayer A.D., Bondeau A., Calle L., Chini L.P.,
Gasser T., Fader M., Friedlingstein P., Kato E., Li W., Lindeskog M., Nabel J.E.M.S., Pugh T. a. M.,
Robertson E., Viovy N., Yue C., Zaehle S., 2017, Historical carbon dioxide emissions caused by land-use
changes are possibly larger than assumed, Nature Geosci 10, 79–84. DOI: 10.1038/ngeo2882.
Content S., 2021, Race to Net Zero: Carbon Neutral Goals by Country. accessed 1.6.22.
557
European Commissions, 2022, Land Use, Forestry and Agriculture,
accessed 6.24.22.
European Environment Agency, 2022, Greenhouse gas emissions from land use, land use change and forestry,
accessed 6.24.22.
Hong C., Burney J.A., Pongratz J., Nabel J.E.M.S., Mueller N.D., Jackson R.B., Davis S.J., 2021, Global and
regional drivers of land-use emissions in 1961–2017, Nature 589, 554–561. DOI: 10.1038/s41586-020-
03138-y.
Hong C., Zhao H., Qin Y., Burney J.A., Pongratz J., Hartung K., Liu Y., Moore F.C., Jackson R.B., Zhang Q.,
Davis S.J., 2022, Land-use emissions embodied in international trade, Science 376, 597–603. DOI:
10.1126/science.abj1572.
IPCC, AR6 Climate Change 2022: Mitigation of Climate Change, 2022a, accessed 4.12.22.
IPCC, Climate Change 2022: Mitigation of Climate Change, 2022b,
accessed 5.22.22.
IPCC, Land is a Critical Resource, IPCC report says — IPCC, 2020, accessed 6.10.22.
IPCC, Special Report on Climate Change and Land — IPCC, 2022c, accessed
6.10.22.
Jackson R.B., Saunois M., Bousquet P., Canadell J.G., Poulter B., Stavert A.R., Bergamaschi P., Niwa Y.,
Segers A., Tsuruta A., 2020, Increasing anthropogenic methane emissions arise equally from agricultural
and fossil fuel sources, Environ. Res. Lett., 15, 071002. DOI: 10.1088/1748-9326/ab9ed2.
Kirschke S., Bousquet P., Ciais P., Saunois M., Canadell J.G., Dlugokencky E.J., Bergamaschi P., Bergmann
D., Blake D.R., Bruhwiler L., Cameron-Smith P., Castaldi S., Chevallier F., Feng L., Fraser A., Heimann M.,
Hodson E.L., Houweling S., Josse B., Fraser P.J., Krummel P.B., Lamarque J.-F., Langenfelds R.L., Le
Quéré C., Naik V., O’Doherty S., Palmer P.I., Pison I., Plummer D., Poulter B., Prinn R.G., Rigby M., Ringeval
B., Santini M., Schmidt M., Shindell D.T., Simpson I.J., Spahni R., Steele L.P., Strode S.A., Sudo K., Szopa
S., van der Werf G.R., Voulgarakis A., van Weele M., Weiss R.F., Williams J.E., Zeng G., 2013, Three
decades of global methane sources and sinks, Nature Geosci. 6, 813–823. DOI: 10.1038/ngeo1955
Lai L., Huang X., Yang H., Chuai X., Zhang M., Zhong T., Chen Z., Chen Y., Wang X., Thompson J.R., 2016,
Carbon emissions from land-use change and management in China between 1990 and 2010, Science
Advances 2, e1601063. DOI: 10.1126/sciadv.1601063.
Roe S., Streck C., Obersteiner M., Frank S., Griscom B., Drouet L., Fricko O., Gusti M., Harris N., Hasegawa
T., Hausfather Z., Havlík P., House J., Nabuurs G.-J., Popp A., Sánchez M.J.S., Sanderman J., Smith P.,
Stehfest E., Lawrence D., 2019, Contribution of the land sector to a 1.5 °C world. Nat. Clim. Chang. 9, 817–
828. DOI: 10.1038/s41558-019-0591-9
Study Knowledge Hub, Transforming land use can make world carbon neutral by 2040,
accessed 6.24.22.
Tian S., Wang S., Bai X., Luo G., Li Q., Yang Y., Hu Z., Li C., Deng Y., 2021, Global patterns and changes of
carbon emissions from land use during 1992–2015, Environmental Science and Ecotechnology 7, 100108.
DOI: 10.1016/j.ese.2021.100108
UNFCCC, Land Use, Land-Use Change and Forestry (LULUCF), accessed 6.10.22.
Wang X.-C., Klemeš J.J., Dong X., Fan W., Xu Z., Wang Y., Varbanov P.S., 2019, Air pollution terrain nexus: A
review considering energy generation and consumption, Renewable and Sustainable Energy Reviews 105,
71–85. DOI: 10.1016/j.rser.2019.01.049
Wang X.-C., Yang L., Wang Y., Klemeš J.J., Varbanov P.S., Ouyang X., Dong X., 2022, Imbalances in virtual
energy transfer network of China and carbon neutrality implications, Energy 124304. DOI:
10.1016/j.energy.2022.124304
558