An International Legal Framework
for Geoengineering

Geoengineering provides new possibilities for humans to deal with dangerous climate change and its effects but at the same time creates new risks to
the planet. This book responds to the challenges geoengineering poses to
international law by identifying and developing the rules and principles that
are aimed at controlling the risks to the environment and human health arising from geoengineering activities, without neglecting the contribution that
geoengineering could make in preventing dangerous climate change and its
impacts. This book first investigates international laws and principles that apply
to geoengineering in general and to six specific geoengineering techniques
respectively. Then, this book compares different governance approaches and
predicts the short-, mid- and long-term scenarios of the international governance of geoengineering. In the end, in order to balance the positive and
negative dimensions of geoengineering, this book proposes an assessment
framework and a tailored implementation of the precautionary approach.
Haomiao Du is a post-doctoral researcher at the University of Twente,
the Netherlands.


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International Legal Framework for Geoengineering
Managing the Risks of an Emerging Technology
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An International
Legal Framework
for Geoengineering

Managing the Risks of an Emerging
Technology
Haomiao Du



First published 2018
by Routledge
2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN
and by Routledge
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Routledge is an imprint of the Taylor & Francis Group, an informa business
© 2018 Haomiao Du
The right of Haomiao Du to be identified as author of this work has been
asserted by her in accordance with sections 77 and 78 of the Copyright,
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British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library
Library of Congress Cataloging-in-Publication Data
Names: Du, Haomiao, author.
Title: An international legal framework for geoengineering : managing
the risks of an emerging technology / Haomiao Du.
Description: New York, NY : Routledge, 2018. | Series: Routledge
research in international environmental law | Includes bibliographical
references and index.
Identifiers: LCCN 2017031665 | ISBN 9781138744615 (hbk)
Subjects: LCSH: Environmental geotechnology—Law and legislation. |

Global warming—Law and legislation. | Environmental engineering—
Law and legislation. | Technology and law. | Climatology.
Classification: LCC K3585.5 .D8 2018 | DDC 344.04/63—dc23
LC record available at />ISBN: 978-1-138-74461-5 (hbk)
ISBN: 978-1-315-17975-9 (ebk)
Typeset in Galliard
by Apex CoVantage, LLC


Contents

List of figures and tables
List of acronyms
Preface
Introduction

ix
xi
xiii
xv

PART I

Background

1

1 Political and scientific aspects of geoengineering
1.1 Introduction 3
1.2  International background of geoengineering  4

1.2.1  Changes in the climate system  4
1.2.2  Attribution of climate change  5
1.2.3  Emission reduction – target and gap  6
1.2.4  A complement to traditional mitigation methods  6
1.3 Definitions 7
1.3.1  The definition of geoengineering  7
1.3.2  The definition of CDR  9
1.3.3  The definition of SRM  10
1.3.4  Difference between CCS and geoengineering  11
1.3.5 Difference between geoengineering and
mitigation and adaptation  12
1.4  Scientific aspects of CDR and SRM techniques  13
1.4.1 CDR 13
1.4.2 SRM 20
1.5 A description of adverse impacts of geoengineering
activities on the environment and the climate  21
1.5.1 The ocean 22
1.5.2 The land 23
1.5.3 The atmosphere 24
1.5.4 The biosphere 25
1.5.5 The climate 26

3


vi Contents
1.6 The status of research on and testing of different
geoengineering methods  27
1.7 Conclusion 28
PART II


Applying contemporary international law to geoengineering
2Contemporary international law and
geoengineering – a general approach
2.1 Introduction 43
2.2  The international climate change regime  44
2.2.1 UNFCCC 44
2.2.2 Kyoto Protocol 45
2.2.3  Decisions of COP and CMP  46
2.2.4 Paris Agreement 46
2.3  The ENMOD Convention  48
2.4 Prevention and precaution – coping with
environmental harm, the risk of harm
and uncertainty  49
2.4.1 Coping with environmental harm
and the risk of harm – the prevention principle  49
2.4.2 Addressing uncertain risks – the
precautionary approach  66
2.5 Conclusion 79
3Contemporary international law and geoengineering –
a technique-by-technique approach
3.1 Introduction 95
3.2 Ocean fertilization 96
3.2.1  Ocean fertilization and the marine environment  96
3.2.2  Ocean fertilization and the climate change regime  103
3.2.3  The scale and purpose of ocean fertilization activities  104
3.2.4 Synthetic consideration 107
3.3 Ocean upwelling 107
3.3.1 The legal status of ocean pipes and ocean
upwelling activities  108

3.3.2  Rights and duties in the conduct of ocean upwelling  109
3.3.3  Ocean upwelling and the marine environment  114
3.3.4 Synthetic consideration 115
3.4  Ocean alkalinity addition  115
3.4.1 Alkalinity addition and the obligation to
prevent marine pollution  116

41

43

95


Contents  vii
3.4.2 Introduction of alkaline substances and
the rules of “dumping”  117
3.4.3  Potential impacts and relevant conventions  119
3.4.4 Synthetic consideration 119
3.5  Marine cloud whitening (MCW)  120
3.5.1  MCW and the UNCLOS  121
3.5.2  MCW and air-related conventions  123
3.5.3 Synthetic consideration 125
3.6 BECCS 125
3.6.1 Biomass plantation under the coverage of the
biodiversity regime  125
3.6.2  Bioenergy production and air pollution  126
3.6.3 International legal regimes relating to
CO2 transportation and sequestration  127
3.6.4 Synthetic consideration 131

3.7  Stratospheric Aerosols Injection (SAI)  132
3.7.1 The legality of exercising injection activities
in the stratosphere  133
3.7.2 The obligations to prevent adverse impacts
on the environment  134
3.7.3 Synthetic consideration 140
3.8 Conclusion 141
PART III

Towards better governance

155

4 Main scenarios of the future of geoengineering governance
4.1 Introduction 157
4.2 Unilateralism 158
4.2.1  A brief introduction to unilateralism  158
4.2.2  Unilateralism and geoengineering  159
4.3 Minilateral governance 159
4.3.1  The emergence of minilateralism  159
4.3.2  The legitimacy and feasibility of minilateralism  160
4.3.3  Minilateralism and geoengineering  162
4.4 Multilateral governance 162
4.4.1  Geoengineering and equity concerns  163
4.4.2 International institutions 165
4.4.3  The proper form  167
4.5  A non-state governance approach  170
4.6 Some reflections on the international governance of
geoengineering 170


157


viii Contents
4.6.1 Short-term scenario 171
4.6.2 Mid-term scenario 172
4.6.3 Long-term scenario 177
4.7 Conclusion 178
5Balancing the risk of climate change against
geoengineering – controlling environmental risk and
coping with scientific uncertainty
5.1 Introduction 185
5.2 Designing a framework for balancing the
risk of climate change against geoengineering  185
5.3  Main factors relating to the balancing of risks  186
5.3.1  Target risk vs. countervailing risk  186
5.3.2 Scientific uncertainty 187
5.3.3 Various interests 189
5.3.4 Categories 189
5.4  The assessment framework for geoengineering  192
5.4.1 Environmental Impact Assessment (EIA)
and geoengineering  194
5.4.2  Monitoring geoengineering projects  200
5.4.3  Strategic Environmental Assessment (SEA)  201
5.5 Implementing the precautionary approach for
geoengineering 202
5.5.1  Clarifying the scope of application  203
5.5.2 Flexible thresholds of triggering the
precautionary approach  204
5.5.3 Proportionate actions 205

5.5.4  The burden of proof  207
5.6  Seeking a balance  209
5.7 Conclusion 211
Conclusion
Appendix
References
Index

185

219
225
231
255


List of figures and tables

Figures
  1.1
  1.2
  5.1
  5.2

Solar radiation management techniques
FECCS and BECCS
Categories of geoengineering activities
EIA process of a geoengineering project

11

18
190
196

Tables
  1.1 Carbon dioxide removal methods
  5.1 Categories of geoengineering activities
  5.2Flexible thresholds of triggering the
precautionary approach

10
191
204



Acronyms

AR5Fifth Assessment Report of the Intergovernmental Panel on
Climate Change
ASEAN
Association of Southeast Asian Nations
BECCS
Bioenergy with Carbon Capture and Sequestration
CBD
Convention on Biological Diversity
CCAMLRConvention on the Conservation of Antarctic Marine Living
Resources
CDR
Carbon Dioxide Removal

CLRTAP
Convention on Long-Range Transboundary Air Pollution
CMAConference of Parties serving as the meeting of the Parties to
the Paris Agreement
CMPConference of the Parties serving as the meeting of the Parties
to the Kyoto Protocol
CMSConvention on the Conservation of Migratory Species of Wild
Animals
COP
Conference of the Parties
DAC
Direct Air Capture
EEC
Exclusive Economic Zone
ENMODConvention on the Prohibition of Military or Any Hostile Use
of Environmental Modification Techniques
Fossil-fuel Energy with Carbon Capture and Storage
FECCS
International Law Association
ILA
ILC
International Law Commission
IMO
International Maritime Organization
Intended Nationally Determined Contribution
INDC
IOC
Intergovernmental Oceanographic Commission
Intergovernmental Panel on Climate Change
IPCC

International Tribunal for the Law of the Sea
ITLOS
Kyoto Protocol
KP
LCLondon Convention, namely Convention on the Prevention
of Marine pollution by Dumping of Wastes and Other Matter
Protocol of the London Convention
LP
MCW
Marine Cloud Whitening


xii Acronyms
MEA
Multilateral Environmental Agreement
MODUs
Mobile Offshore Drilling Units
NDC
Nationally Determined Contribution
NETs
Negative Emissions Technologies
OSPARConvention for the Protection of the Marine Environment of
the North-East Atlantic
PA
Paris Agreement
SAI
Sulphate Aerosol Injection
IPCC Second Assessment Report
SAR
SBI

Subsidiary Body for Implementation
SBSTA
Subsidiary Body for Scientific and Technological Advices
Solar Radiation Management
SRM
TAR
IPCC Third Assessment Report
UNCEDUnited Nations Conference on Environment and
Development
UNCLOS United Nations Convention on the Law of the Sea
UNEA
United Nations Environmental Assembly
UNECE
United Nations Economic Commission for Europe
UNEP
United Nations Environment Programme
UNESCOUnited Nations Educational, Science and Cultural
Organization
UNFCCC United Nations Framework Convention on Climate Change
WG
IPCC Working Group
World Meteorological Organization
WMO


Preface

The present book titled An International Legal Framework for Geoengineering –
Managing the Risks of an Emerging Technology is a revised version of my dissertation. Geoengineering, or climate engineering, has been exposed to the
international community as an emerging technology to deal with anthropogenic climate change and its impact. Geoengineering provides new possibilities for humans to deal with dangerous climate change and its effects, on the

one hand, and creates new risks to the planet, on the other hand. Scientific
uncertainties contained in such novel techniques and their impacts bring
challenges to environmentalists, politicians as well as lawyers.
In response to the challenges posed by geoengineering to international
law, this book aims to identify and develop international rules and principles
that minimize or control the risks arising from geoengineering activities to
the environmental and human health without neglecting the contribution
that some geoengineering techniques could make in preventing serious or
irreversible climate change and its impacts.
I would not have completed this book without support from great people.
First and foremost, my PhD supervisor René Lefeber has been the most significant guide. I feel so grateful that he never restricts my thoughts, and
always quickly clears up my confusions and points out my mistakes, preventing me from going astray. I also appreciate very much the supervision from
my co-supervisor Jesse Reynolds. His expertise on geoengineering, in particular from the perspective of political science and international relations,
broadened my horizon and effectively complemented my legal research.
Also, I would like to express my gratitude to my internship supervisor
Maria Socorro Manguiat, the former legal officer at the secretariat of the
United Nations Framework Convention on Climate Change (UNFCCC),
for her kindness, patience and strictness. I learned from her how to transfer
my ivory-tower ideas to realistic proposals and to present them in a professional manner.
Special appreciation goes to Alexander Proelß, professor of public international and European law from Trier University, Germany, for his valuable
comments on my dissertation as well as the present book.
Haomiao Du
March 2017 in Eindhoven, The Netherlands



Introduction

Since the beginning of the Industrial Revolution, the world has entered into
the epoch of the Anthropocene, in which the traditional relationship between

nature and humankind has shifted. A man-made world challenges the natural environment as well as human society. Geoengineering has emerged in
the Anthropocene: human beings are attempting to counter anthropogenic
global warming and its effects by manipulating the planetary environment.
Main geoengineering methods can be divided into two categories: sequestering CO2 from the atmosphere (carbon dioxide removal, CDR) and modifying solar radiation coming to the atmosphere and land surface (solar radiation
management, SRM). The emerging ideas include, for instance, injecting a
layer of sulphate aerosols in the upper atmosphere to reflect more solar radiation, adding iron particles into the ocean to increase the rate of photosynthesis, and installing huge mirrors in outer space to block sunlight. These
novel techniques provide new possibilities for humans to deal with dangerous
climate change and its effects, on the one hand, and create new risks to the
planet, on the other hand. It may be the first time for humankind to think
about this question: can we and should we save the planet by intervening/
manipulating it?
Geoengineering has raised debates in various disciplines. Environmentalists have identified the adverse impacts arising from different geoengineering
methods on the environment as well as on human health. The knowledge
about the feasibility of these novel methods and the potential impacts on the
environment and human health are far from fully available; Ethicists have
identified the problem called “moral hazards”, which implies that geoengineering would entice people to maintain their high-carbon lifestyle; Politicians have identified potential conflicts in geopolitics: the focus of climate
negotiations would be deviated from emissions reduction, and there would
be a risk that some developed countries use geoengineering as a means to
escape from their mitigation obligations. More problematically, the implementation of geoengineering techniques can be exercised by one single
country or a small group of countries, but the impacts, both beneficial and
adverse ones, would be uneven and affect a wide range of countries.
Geoengineering also poses challenges to the development, interpretation
and application of international environmental law. First, SRM techniques


xvi Introduction
may force legal scholars to examine the implication of new responses more
than mitigation and adaption to combating global warming on the climate
change regime, inter alia, the United Nations Framework Convention on
Climate Change (UNFCCC). Second, as geoengineering can bring both

opportunities and challenges to the environment, international environmental law needs to provide methods to balance the benefits and risks. Third,
geoengineering is not a single technique; different techniques and different
scales of activities contain different types and levels of risks and uncertainties. Were geoengineering to be implemented, either for research studies or
real deployment, international law needs to govern different geoengineering
techniques in a tailored manner. The specific challenge would be: how to
properly, sufficiently and proportionately govern the implementation of geoengineering by, among others, choosing the proper governing institutions
and applying rules and mechanisms under treaties, customary international
law and non-binding legal instruments.
The main body of this book consists of five chapters:
Chapter 1 introduces the political and scientific aspects of geoengineering techniques, attempting to find out which geoengineering techniques need to be addressed in an international context. The priority
of international legal analysis should be given to the techniques that
are designed to be deployed transnationally or in the areas of global
commons, and the techniques of which the deployment may cause
transboundary interferences to environmental media and the climate
system. In view of this, six geoengineering methods merit further
examination in subsequent chapters. Four CDR techniques (ocean
fertilization, ocean upwelling, ocean alkalinity addition, bioenergy and
carbon capture and storage (BECCS)) and two SRM techniques (sulphate aerosol injection (SAI) and marine cloud whitening (MCW))
are selected.
Chapter 2 examines contemporary international legal rules and principles
that are applicable to the six geoengineering techniques. This chapter
first examines the climate change regime, including the UNFCCC,
the Kyoto Protocol, the Paris Agreement and several decisions made
by the Conference of Parties (COP) and the Conference of Parties
serving as the meeting of the Parties to the Kyoto Protocol (CMP).
This chapter then examines the Convention on the Prohibition of Military or Any Hostile Use of Environmental Modification Techniques
(the ENMOD Convention). Regarding customary international law,
the prevention principle is applicable to geoengineering activity for the
purpose of preventing significant harm or controlling the risk of significant harm to another state or in the global commons. In addition,
the precautionary approach, taking into account the controversy with

respect to its customary legal status, serves as a significant tool to deal
with scientific uncertainties contained in geoengineering techniques
and their impacts on the environment.


Introduction  xvii
Chapter 3 addresses contemporary international rules and principles
that are applicable to each of the six geoengineering techniques. Via a
technique-by-technique approach, two main issues are examined: one
is the lawfulness of undertaking a geoengineering activity or the use
of materials in a technique; the other is whether a technique breaches
the obligations to protect the environment and to preserve natural
resources due to the resulting adverse impacts and, consequently,
whether such a technique is allowed or largely restricted. When examining the lawfulness of conducting a marine geoengineering activity,
the analysis is divided based on the location of the activity – i.e. the
territorial sea, the exclusive economic zone (EEZ) and the high seas.
Chapter 4 attempts to find the most appropriate approach to regulate
geoengineering techniques. The criteria for the most appropriate
approach are applied: such an approach should be able to provide
inclusive, transparent, responsive, adaptive and effective governance
of various geoengineering techniques. It should also avoid over- and
under-governance of geoengineering. While responding to the risk of
causing significant harm resulting from geoengineering to the environment and human health, it should also avoid impeding the appropriate development of geoengineering technology.
Chapter 5 attempts to deal with the issue of balancing the risk of climate
change against the risk created by the implementation of geoengineering techniques. This chapter proposes an assessment framework
by applying the procedural obligations under the prevention principle,
among others, the obligation to conduct an environmental impact
assessment. This chapter also proposes a mechanism to implement
the precautionary approach for each proposed geoengineering project
in a tailored manner by establishing flexible thresholds for triggering

the precautionary approach and applying proportionate precautionary
measures.



Part I

Background



1 Political and scientific aspects of
geoengineering

1.1 Introduction
On 8 November 2013, three days before the opening of the Warsaw Climate
Change Conference (UNFCCC COP19/CMP9), Super Typhoon Haiyan
slammed into the Philippines, killing 6,021 individuals, destroying more
than one million houses, and resulting in colossal damages to agriculture and
infrastructure.1 Haiyan was reported as the strongest typhoon that has ever
made landfall in recorded history. On 11 November 2013, at the COP 19
opening ceremony, the emotional speech from the Philippines’ chief negotiator, Yeb Sano, moved the plenary to tears and reminded the international
community of the great urgency to tackle climate change.
There is a broad scientific consensus on the link between typhoon strength
and sea temperature: When the temperatures of surface water and deep sea
water rise, huge quantities of energy are stored up and integrated with the
water column fuelling the storm.
The Fifth Assessment Report (AR5) of the Intergovernmental Panel on
Climate Change (IPCC) Working Group I concludes that “it is extremely
likely that human influence has been the dominant cause of the observed

warming since the mid-20th century”. Climate scientists assert that anthropogenic global warming causes rising ocean temperatures, which may
increase energy in oceans and create stronger and more frequently extreme
climate events. Although no clear causal relationship between global warming and extreme climate events has yet been built, the disaster from Haiyan
could be seen as a reminder for the parties to take actions on controlling
anthropogenic climate change.
This chapter begins by describing anthropogenic climate change, which
leads to discussions on geoengineering. The projection of a dangerous peaking point of global average temperature has urged humans to find a rapid
solution. At the crucial point, geoengineering may be a set of promising technologies to efficiently and effectively cope with global warming. This chapter
then addresses the definition of geoengineering, emphasizing that geoengineering cannot be simply categorized into either of the two primary and
fundamental options to combat global warming: mitigation or adaptation.


4 Background
Then, this chapter briefly demonstrates the science of each geoengineering technique,2 in particular elucidating the adverse transboundary impacts
of them on environmental media, including the oceans, the land, the atmosphere and the biosphere, as well as the adverse impacts on the climate.
Finally, this chapter provides an overview of the current development of different geoengineering methods.

1.2  International background of geoengineering
1.2.1  Changes in the climate system
“Climate change is no longer an environmental or political issue; it is a borderless human security issue”, said Deputy Prime Minister Vete Palakua
Sakaio of Tuvalu, a low-lying country of atolls in the direct line of threats
from rising oceans.3 Regardless of whether it is called an environmental,
political or a security issue, climate change has been a globally significant
topic for several decades. This significance is reflected in the establishment
of the IPCC, the publishing of reports related to climate change, and more
importantly, the UN Conference on Environment and Development and its
resulting documents.
In 1988, the IPCC was established by the United Nations Environment
Programme (UNEP) and the World Meteorological Organization (WMO)
to provide the world with a clear scientific view on the current state of knowledge relevant to climate change as well as its potential and socio-economic

impacts.4 The IPCC is the leading scientific and intergovernmental body for
the assessment of climate change. Thousands of scientists from all over the
world voluntarily contribute to the work of the IPCC; 195 countries are currently members. Its special nature has enabled the IPCC to provide rigorous,
neutral and thus authoritative reports.
Since 1990, the IPCC has published five assessment reports. The latest one
is the AR5, comprising Working Group (WGI II and III) Assessment Reports
and the Synthesis Report approved by the IPCC in 2013 and 2014.5 According to the AR5, warming of the climate system is unequivocal. From 1880
to 2012, the globally averaged combined land and ocean surface temperature data, as calculated by a linear trend, show a warming of 0.85 °C. Since
1950, a wide range of climate changes have been observed: the atmosphere
and oceans have been warmed, ice sheets and snow cover have diminished,
the sea level has risen, and the atmospheric concentration of carbon dioxide,
methane and nitrous oxide have increased to unprecedented levels. Due to
these changes, oceans have been acidified, and biodiversity is under threat.
In 1992, the UN Conference on Environment and Development, known
as the Earth Summit, was unprecedented for a UN conference and notably
a milestone for the international governance of climate change.6 The Earth
Summit resulted in five documents,7 among which was the UN Framework
Convention on Climate Change (UNFCCC), which symbolized the commencement of international cooperation on limiting the on-going increase


Political and scientific aspects  5
in global average temperature and the resulting changes to the climate. The
ultimate objective of the UNFCCC is to stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.8 Based on the UNFCCC, the
annual climate change conferences have become the most important event
for international climate change negotiation.
In 2015, the UN General Assembly adopted the 2030 Agenda for Sustainable Development, which includes taking urgent action to combat climate
change and its impacts as one of the seventeen sustainable development goals.9
Paragraph 31 of the agenda “calls for the widest possible international cooperation aimed at accelerating the reduction of global greenhouse gas emissions and addressing adaptation to the adverse impacts of climate change”.
A host of intergovernmental and non-governmental organizations concerned about climate change issues have produced various reports as well.
For instance, the UNEP Emissions Gap Report has been published annually

since 2010. This report highlights the emissions gap between the ambition
of reduction and the reality, and suggests options to bridge the gap. Moreover, the World Economic Forum began to publish the Global Risk Network
Report in 2006. In the Global Risks Report of 2006, risks stemming from
climate change were considered an “emerging risk” and were predicted to be
moved to the global agenda.10 One year later in the Global Risks Report of
2007, climate change was identified as one of the core environmental risks.11
More recently, in the Global Risks Report of 2014, “failure of climate change
mitigation and adaptation” was ranked as the fifth-highest concerned global
risk. Another influential report concerning climate change, Turn Down the
Heat: Why a 4°C Warmer World Must be Avoided, was published by the World
Bank in 2012. This report provides a devastating scenario of a 4 °C warmer
world, including extreme weather and climate events, a dramatic change
in landscape and profound consequences for food, water, ecosystems and
human health.
1.2.2  Attribution of climate change
Both natural and anthropogenic substances and processes can alter Earth’s
radiation budget, producing a radiative forcing (RF) that brings about
changes in the climate.12 RF is a measure of the net change in the energy
balance in response to an external perturbation. Positive RF leads to surface
warming, while negative RF leads to surface cooling. Some drivers of RF
alteration are changes in the solar irradiance and changes in atmospheric trace
gases and aerosol concentrations.13 Observational and model studies show
that the total RF since 1750 is positive, and the increase in CO2 concentration by anthropogenic carbon emissions makes the largest contribution to
the total RF production. Thus, the increase in anthropogenic CO2 concentration, or the growth of carbon emissions, results in global warming as well
as other changes in climate.14


6 Background
Pursuant to AR5, it is extremely likely that human influence has been the
dominant cause of the observed warming since the mid-20th century.15

Human activities have contributed to the increase of the global average temperature, the shrinking of glaciers, the rise of the mean sea level and perhaps
stronger extreme weather events. The necessity of controlling global warming from anthropogenic sources is beyond scientific doubt, which requires
substantial and sustained strategies.
1.2.3  Emission reduction – target and gap
In 2010, the parties to the UNFCCC agreed to a concrete target of limiting
the increase in global average temperature to 2 °C compared to pre-industrial
levels.16 In 2015, the Paris Agreement reiterated the 2 °C target and recognized that the efforts to limit the temperature increase to 1.5 °C above preindustrial levels would significantly reduce the risks and impacts of climate
change.1718 In 2014, total GHG emissions amounted to about 52.7 GtCO2e
(range: 47.9–57.5), and the amount of GHG emissions is not expected to
peak before 2020.19 The median emission level in 2030 in scenarios that have
a >66% chance of keeping global mean temperature increase below 2 °C by
the end of the century is 42 GtCO2e (range: 37–44).20 The similar level for a
1.5 °C target is 39 GtCO2e (range: 31–44) per year.21
In order to accomplish at least the 2 °C goal, pledges and commitments
should be made by every state. Taking enhanced early actions (pre-2020), as
compared to the current pledges by 2020, would facilitate the transition to
the stringent, long-term emission reductions required for the 2 °C and 1.5
°C targets, and would reduce the costs of emission reductions, avoid lock-in
of carbon and energy intensive infrastructure, and decrease the risks associated with climate change.22 Regarding the post-2020 commitments, the
implementation of intended nationally determined contributions (INDCs)
will be the new approach to close the emissions gap.23 As of 12 December 2015, 160 INDCs were submitted, covering emissions of 187 parties to
the UNFCCC. However, the emissions gap between the full implementation
of the conditional INDCs24 and the least-cost emission level25 for a pathway
to stay below 2 °C is estimated to be 12 GtCO2e in 2030.26
1.2.4  A complement to traditional mitigation methods
In addition to the initiatives in the areas of energy efficiency and renewable
energy, negative emission technologies are required to bridge the emissions
gap.27 It is estimated that scenarios in line with the 2 °C target require net
zero CO2 emissions around 2075, and the scenarios that keep global warming to below 1.5 °C require net zero CO2 emissions around 2050.28 In most
scenarios, global net zero and negative emissions are achieved by the use

of negative emissions technologies on a large scale. Such technologies and
methods, including massive afforestation and reforestation, bioenergy with
carbon capture and storage (BECCS), and carbon capture and storage (CCS)