Part #2: An introduction to GHG mitigation

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Part #2: An introduction to GHG mitigation

Roland Séférian

Centre National de Recherches Météorologiques (CNRM), Université de Toulouse, Météo- France, CNRS, Toulouse, France

[email protected] @RolandSeferian

Toulouse Business School- Climate Action Plan - Toulouse – 18 Mars 2021

General Context and introduction to climate policy

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1. Intro : Global context

2. Routes for climate action

3. Major Organizations/Institutions involved in climate policies/actions

4. Major Climate Policy Deals

5. Carbon budgets: a geophysical tool to inform mitigation strategies

6. Mitigation pathways compatible with the remaining carbon budget for 1.5 C (or 2 C)

7. Translation of scientific knowledge in climate policies 8. Application in local/national policy

9. Outtro: Climate policies and post-COVID recovery plans

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Global context

(4)

Rising airborne fraction of carbon dioxide (CO

₂

) is one of the most impressive changes of the Anthroposphere

Changes over the lifetime of the Y generation (my case) :

1982 : 339.95 ppm 2018 : 405.52 ppm Þ ~+20% in 36 years

2021 : about +50% increase

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11.6 GtCO 29%

₂

/yr

Source: CDIAC; NOAA-ESRL; Houghton and Nassikas 2017; Hansis et al 2015; Le Quéré et al 2018;Global Carbon Budget 2018

8.9 GtCO 22%

₂

/yr

1.9 GtCO

5%

₂/yr

Budget Imbalance:

(the difference between estimated sources & sinks)

17.3 GtCO

₂

/yr

44%

Variations in anthropogenic CO

₂

emissions

The source of CO₂ are tightly linked to the economic growth (including global financial crisis)

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Where are we ?

Since the industrial area, human-activity and human-induced emissions has caused a global warming of 1.1 C

• With the current pace of global warming, 1,5 C will be reached between 2030 et 2052

• Past emissions do not bring use above 1,5 C

IPCC SR15 (2018)

Global Warming

( C rel. to 1850-1900)

• We can observe the impacts of climate change in multiple domains

Rising airborne fraction of carbon dioxide (CO

₂

) drives the current

warming trend and deeply alters our environment

(7)

(8)

IPCC SROCC (2019)

Acidification

Desoxygenation

Loss of sea-ice over Ocean

Rising airborne fraction of carbon dioxide (CO

₂

) drives the current

warming trend and deeply alters our environment

(9)

SPM approved draft

Land use and observed climate change

IPCC SRCCL

1 2 3

Prevalence of overweight + obese 4 Prevalence of underweight

Total calories per capita Population

CHANGE in emissions rel. to 1961

B. GHG emissions

An estimated 23% of total anthropogenic greenhouse gas emissions (2007-2016) derive from Agriculture, Forestry and Other Land Use (AFOLU).

E. Food demand

Increases in production are linked to consumption changes.

F. Desertification and land degradation

Land-use change, land-use intensification and climate change have contributed to desertification and land degradation.

CHANGE in % rel. to 1961 and 1970 CHANGE in % rel. to 1961 and 1975

1 2

3 Inland wetland extent

Dryland areas in drought annually

Population in areas experiencing desertification 1

2 3

CHANGE in % rel. to 1961 1

2

3 Irrigation water volume

4 Total number of ruminant livestock Cereal yields

Inorganic N fertiliser use

Intensive pasture 2%

12% (12 - 14%)

1% (1 - 1%) 37% (30 - 47%) 22% (16 - 23%) 28% (24 - 31%)

Used savannahs and shrublands 16%

Plantation forests 2%

Forests managed for timber and other uses 20%

Irrigated cropland 2%

Infrastructure 1%

Non-irrigated cropland 10%

Unforested ecosystems with minimal human use 7%

Forests (intact or primary) with minimal human use 9%

Other land (barren, rock) 12%

Global ice-free land surface 100% (130 Mkm2)

0

10

20

30 Net CO2 emissions from FOLU (Gt CO2/yr)

N2O emissions from Agriculture (Gt CO2eq/yr) CH4 emissions from Agriculture (Gt CO2eq/yr)

A. Observed temperature change relative to 1850-1900

Since the pre-industrial period (1850-1900) the observed mean land surface air

temperature has risen considerably more than the global mean surface (land and ocean) temperature (GMST).

C. Global land use in circa 2015

The barchart depicts shares of different uses of the global, ice-free land area. Bars are

ordered along a gradient of decreasing land-use intensity from left to right.

Extensive pasture 19%

D. Agricultural production

Land use change and rapid land use intensification have supported the

increasing production of food, feed and fibre. Since 1961, the total production of food (cereal crops) has increased by 240%

(until 2017) because of land area

expansion and increasing yields. Fibre production (cotton) increased by 162%

(until 2013).

2 1

3

%

50

-50 150 250

100

0 200

%

50

-50 150 250

100

0 200 1

2 3 4 4

1

2 3

1850 1880 1900 1920 1940 1960 1980 2000 2018

2 0 4 6

1 2 3 0.5

1.5 1

0 -0.5 2

CHANGE in TEMPERATURE rel. to 1850-1900 (°C)

Change in surface air temperature over land (°C) Change in global (land-ocean) mean surface temperature (GMST) (°C)

Gt CO2eq/yr

1961 1980 2000 2016

1961 1980 2000 2017

50

-50 150 250 300700

100

0 200

1961 1980 2000 2017

800

IPCC SRLCC (2019)

Rising airborne fraction of carbon dioxide (CO

₂

) drives the current warming trend and deeply alters our environment

Changes relative to 1961 and 1970

SPM approved draft

Land use and observed climate change

IPCC SRCCL

1 2 3

Prevalence of overweight + obese 4 Prevalence of underweight

Total calories per capita Population

CHANGE in emissions rel. to 1961

B. GHG emissions

An estimated 23% of total anthropogenic greenhouse gas emissions (2007-2016) derive from Agriculture, Forestry and Other Land Use (AFOLU).

E. Food demand

Increases in production are linked to consumption changes.

F. Desertification and land degradation

Land-use change, land-use intensification and climate change have contributed to desertification and land degradation.

CHANGE in % rel. to 1961 and 1970 CHANGE in % rel. to 1961 and 1975

1 2

3 Inland wetland extent

Dryland areas in drought annually

Population in areas experiencing desertification 1

2 3

CHANGE in % rel. to 1961 1

2

3 Irrigation water volume

4 Total number of ruminant livestock Cereal yields

Inorganic N fertiliser use

Intensive pasture 2%

12% (12 - 14%)

1% (1 - 1%) 37% (30 - 47%) 22% (16 - 23%) 28% (24 - 31%)

Used savannahs and shrublands 16%

Plantation forests 2%

Forests managed for timber and other uses 20%

Irrigated cropland 2%

Infrastructure 1%

Non-irrigated cropland 10%

Unforested ecosystems with minimal human use 7%

Forests (intact or primary) with minimal human use 9%

Other land (barren, rock) 12%

Global ice-free land surface 100% (130 Mkm2)

0

10

20

30 Net CO2 emissions from FOLU (Gt CO2/yr)

N2O emissions from Agriculture (Gt CO2eq/yr) CH4 emissions from Agriculture (Gt CO2eq/yr)

A. Observed temperature change relative to 1850-1900

Since the pre-industrial period (1850-1900) the observed mean land surface air

temperature has risen considerably more than the global mean surface (land and ocean) temperature (GMST).

C. Global land use in circa 2015

The barchart depicts shares of different uses of the global, ice-free land area. Bars are

ordered along a gradient of decreasing land-use intensity from left to right.

Extensive pasture 19%

D. Agricultural production

Land use change and rapid land use intensification have supported the

increasing production of food, feed and fibre. Since 1961, the total production of food (cereal crops) has increased by 240%

(until 2017) because of land area

expansion and increasing yields. Fibre production (cotton) increased by 162%

(until 2013).

2 1

3

%

50

-50 150 250

100

0 200

%

50

-50 150 250

100

0 200 1

2 3 4 4

1

2 3

1850 1880 1900 1920 1940 1960 1980 2000 2018

2 0 4 6

1 2 3 0.5

1.5 1

0 -0.5 2

CHANGE in TEMPERATURE rel. to 1850-1900 (°C)

Change in surface air temperature over land (°C) Change in global (land-ocean) mean surface temperature (GMST) (°C)

Gt CO2eq/yr

1961 1980 2000 2016

1961 1980 2000 2017

50

-50 150 250 300700

100

0 200

1961 1980 2000 2017

800

over Land

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Lenton et al. (2019)

… leading to abrupt or irreversible changes in the Earth system

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vs

Let’s summarize the problem

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Routes for climate action

an introduction to mitigation

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Climate change for dummies

CO

₂

emissions Climate Change Impacts

Vulnerability

(14)

CO

₂

emissions Climate Change Impacts Vulnerability

mitigation adaptation

(-) (-) (-)

Climate change for dummies

(15)

CO

₂

emissions Climate Change Impacts Vulnerability

No mitigation Insuficient

adaptation

(+) (+) (+)

Climate change for dummies

(16)

CO

₂

emissions Climate Change Impacts Vulnerability No mitigation

(+) (-) (assumed to be small)

Geoengineering

Solar Radiation Management Climate intervention

Insuficient adaptation

Climate change for dummies

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Mitigation— a definition

Mitigation (of climate change)

A human intervention to reduce emissions or enhance the sinks of greenhouse gases.

Questions:

Þ Scale of mitigation ?

Þ What kind of mitigation can be put in place ?

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Mitigation— a definition

Questions:

Þ Scale of mitigation ?

Þ What kind of mitigation can be put in place ?

Mitigation measures

In climate policy, mitigation measures are technologies, processes or practices that contribute to mitigation, for example, renewable energy (RE) technologies, waste

minimization processes and public transport commuting practices. See also Mitigation option, and Policies (for climate change mitigation and adaptation).

Mitigation behaviour

Human actions that directly or indirectly influence mitigation.

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Mitigation— a definition

Mitigation measures

In climate policy, mitigation measures are technologies, processes or practices that contribute to mitigation, for example, renewable energy (RE) technologies, waste

minimization processes and public transport commuting practices. See also Mitigation option, and Policies (for climate change mitigation and adaptation).

Sources de CO₂

Puits de CO₂

Réduire les sources (-)

Renforcer les puits (+)

Mitigation Exemple:

SNBC en France

Source: Carbone 4

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Mitigation behaviour Human actions that directly or indirectly influence mitigation.

Mitigation— a definition

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Major Organizations/Institutions

involved in climate policies/actions

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Some key institutions involved in climate action

United Nations Environment Program (UNEP, PNUE)

• depends directly upon UN

• coordinating United Nations activities in the field of the environment

• Support/assist countries in the implementation of environmental policies

• Generates reports (UNEP gap report)

World Meteorological Organization (WMO, OMM)

• Depends directly upon UN but it is an non-governmental institution

• Provide standards and recommendations to facilitate the consideration of meteorological, climatic and hydrological factors in all human activities

• Ultimate goal is the preservation of people and property, transport (especially air transport), agriculture, water resource assessment, dissemination of information through the media.

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Some key institutions involved in climate action

United Nations Framework Convention on Climate Change (UNFCCC, CCNUCC)

• Free-standing entity

• ultimate objective is the 'stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic human-induced interference with the climate system

• Its supreme body is the Conference of the Parties (COP)

Intergovernmental Panel on Climate Change (IPCC, GIEC)

• Provides objective and scientific information on the understanding, the impacts and the risk of human-induced climate change and the possible response options (e.g., mitigation)

• Produces reports that contribute to the work of the UNFCCC.

Þ Question: Which was created first ?

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Climate policies in timeframe

IPCC SR15 (2018)

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UN General assembly

WMO UNEP

UNFCCC

IPCC

Institutional framework for Climate Action (1)

Active since March 1994

Continuous dialogue

propose/create Nov 1988

Regular interactions/dialogues

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How IPCC works ?

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Chiffres clés

91 auteurs de 40 pays

3 groupes du GIEC

6000 publications 1 113 relecteurs

42 001 commentaires

133 contributeurs

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How the COP works ?

• Conference of the Parties (COP) is a conference established in accordance with Article 7 “CONFERENCE OF THE PARTIES” under UNFCCC as the supreme body of this Convention to assess in dealing with climate change.

• COP is organized annually since 1995.

• There are 42 parties listed in Annex-I parties to convention, 152 parties including 49 latest developing countries (LDC) listed in Non Annex-I parties to convention.

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Institutional framework for Climate Action (2)

UNFCCC secretariat Conference of the Parties (COP)

Subsidary Body for Implementation

(SBI)

Subsidary Body for Scientific and Technoloigical Advice

(SBSTA)

IPCC

(32)

Climate Action/Negociations in timeframe

IPCC SR15 (2018)

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Major Climate Policy Deals

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Kyoto protocol (Dec 1997)= COP3

The main goal of the Kyoto Protocol is to control human-induced emissions of the main greenhouse gases (GHGs) considering national differences in GHG emissions, wealth, and capacity to make the reductions

Some of the principal concepts of the Kyoto Protocol are below:

• It establishes legally binding commitments to reduce emissions of greenhouse gases for Annex I Parties. The commitments were based on the Berlin Mandate, which was a part of UNFCCC negotiations leading up to the Protocol.

• It sets implementation requirements to prepare policies and measures for the reduction of greenhouse gases in their respective countries. In addition, they are required to increase the absorption of these gases and utilize all mechanisms

available, such as joint implementation, the clean development mechanism and emissions trading, in order to be rewarded with credits that would allow more greenhouse gas emissions at home.

• It establishes and adaptation fund for minimizing the impacts of climate change on Developing Countries.

• It set and ‘Accounting, Reporting and Review’ procedure in order to ensure the integrity of the Protocol.

• It establishes a Compliance Committee to enforce compliance with the commitments under the Protocol.

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Copenhagen Accord (Dec 2009)=COP15

The main goal of the Copenhagen accord is to endorses the continuation of the Kyoto protocol. It also reinforced the role of the scientific knowledge in climate negociations.

Key elements of this accord are below:

• It underlines that climate change is one of the greatest challenges of our time and emphasises a "strong political will to urgently combat climate change in accordance with the principle of common but differentiated responsibilities and respective

capabilities ».

• It recognizes "the scientific view that the increase in global temperature should be below 2 degrees Celsius", in a context of sustainable development to combat climate change.

• It recognizes "the critical impacts of climate change and the potential impacts of response measures on countries particularly vulnerable to its adverse effects" and stresses "the need to establish a comprehensive adaptation programme including international support"

• Recognizes that "deep cuts in global emissions are required according to science » (AR4) and agrees cooperation in peaking global and national greenhouse gas

emissions "as soon as possible" and that "a low-emission development strategy is indispensable to sustainable development »

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Copenhagen Accord (Dec 2009)=COP15

The Copenhagen accord also established several funds:

Þ Agrees that developed countries would raise funds of $30 billion from 2010–2012 of new and additional resources

Þ Agrees a "goal" for the world to raise $100 billion per year by 2020, from "a wide variety of sources", to help developing countries cut carbon emissions (mitigation).

Þ Agrees on a new multilateral funding for adaptation with a governance structure.

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Paris Agreement (Dec 2015)=COP21

The main goal of the Paris Agreement is established a novel

multilateral comprehensive accord to fight climate change with a novel bottom up approach.

The objectives of this accord is established in the Article 2:

1. Limit Global warming well below 2 C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 C above pre- industrial levels.

2. Increase the ability to adapt to the adverse impacts of climate change

3. Make finance flows consistent with a pathway towards low greenhouse gas emissions.

Key elements/dates:

• Adopted in Dec 2015 at COP21 by 191 over 196

• Signed in 2016

• Enter into force the 4th November 2016

• Composed with 29 Articles including goals and monitoring revision verification mechanism

• Facilitating dialogue kicked off in 2018

• Ratched mechanisms in Dec 2020

• Global stocktake planned for Dec 2023

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Paris Agreement (Dec 2015)=COP21

Can be found here: https://unfccc.int/fr/processus-et-reunions/l-accord- de-paris/l-accord-de-paris

Science

Adaptation Mitigation

Finance

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Paris Agreement (Dec 2015)=COP21

Key Articles: https://unfccc.int/fr/processus-et-reunions/l-accord-de- paris/l-accord-de-paris

Principle of the global mitigation

Linkage withNDCs and Art. 3

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Paris Agreement (Dec 2015)=COP21

Key Articles: https://unfccc.int/fr/processus-et-reunions/l-accord-de- paris/l-accord-de-paris

Principle OfNDCs

Climate Education

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Top-down approach

Bottom-up approach

Why Paris Agreement such a big change ?

IPCC SR15 (2018)

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What INDCs/NDCs consists in ?

Countries’ NDC are available on

https://www4.unfccc.int/sites/NDCStaging/Pages/All.aspx

Questions:

Þ Have a look at the [first or updated/revised] NDC of some countries ? Þ What kind of emissions reduction measures are considered ?

Þ Are they comparable between each other ?

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More info on http://unfccc.int/focus/indc_portal/items/8766.php

UE28:

- at least 40% of domestic GHG emissions by 2030 compared to 1990 3206 MtCO2eq with LULUCF (-277 MtCO2eq)

Deals with 7 GHGs=CO2, CH4,N20,4 HFCs

USA:

- 26-28% of GHG emissions reduction below its 2005 level in 2025 4599-4735 MtCO2eq with LULUCF (- 420 MtCO2eq)

Deals with 7 GHGs=CO2, CH4,N20,4 HFCs

China:

-Peak in ~2030

- reduce the GHG emissions per unit of GDP (carbon intensity) by 60-65% from the 2025 level - increase non-fossil energy by 20%

- increase forest stock by 4.5 Mm3 from the 2005 level 13 481 – 16 043 MtCO2 with LULUCF (-292 MtCO2eq) Deals with 3 GHGs

Exemple de Contributions Nationales

INDCs/NDCs

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Aggregating INDCs in emission is challenging

∆T = warming deduced from cumulative aggregated emissions

BAU = 63-72 GtCO2eq

INDCs = 55-63 GtCO2eq (GICN)

Source: GICN 2015

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Climate Action Tracker (PIK+NGOs)

Climate Interactive (MIT+NGOs)

Exemple de projections

Warming projections assumed with INDCs

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Global Warming of 1.5 C

An IPCC special report on the impacts of global warming of 1.5 C above pre-

industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global

response to the threat of climate change, sustainable development, and

efforts to eradicate poverty.

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Carbon budgets: a geophysical tool to inform

mitigation strategies

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IPCC SR15 (2018)

How defining feasibility ?

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IPCC SR15 (2018)

How defining feasibility ?

(50)

TS

0 500 1000 1500 2000 2500

0 1 2 3 4 5

Cumulative total anthropogenic CO₂emissions from 1870 (PgC)

Temperature anomaly relative to 1861-1880 (°C)

RCP2.6 Historical 1% CO₂runs

RCP4.5 RCP6.0

RCP8.5 RCP8.5 rangeRCP6 rangeRCP4.5 rangeRCP2.6 range 1% CO₂runs TCRE assessment

0 500 1000 1500 2000 2500

1.5 2 2.5 3

Consistent cum. total anthropogenic CO₂emissions given warming by all forcers in RCP8.5 (PgC)

Peak warming limit (°C)

90% of models 66% of models 50% of models 33% of models 10% of models

Cumulative emissions estimate 1870-2011

Temperature anomaly relative to 1861-1880 [C]

Cumulative carbon emissions [PgC]

Total emissions Warming

IPCC 2013, Simplified version of Figure 1 TFE.8

The transient climate response to cumulative

CO ₂ emissions: an emerging properties

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Drivers of this near-linear relationship (MacDougall & Friedlingstein 2015):

(1) the diminishing radiative forcing from CO

₂

per unit mass is

compensated by the diminishing ability of the ocean to take up heat and carbon.

(2) This relationship is maintained as long as the ocean carbon uptake remains the dominant driver of the change in

atmospheric CO

₂

(3) Climate-carbon cycle feedbacks play a smaller role except when CO

₂

emissions decline

Þ Ocean Heat and Carbon uptake are the main players of the Transient Climate response to cumulative emissions (TCRE)

The transient climate response to cumulative

CO ₂ emissions: an emerging properties of ESMs

(52)

TS

0 500 1000 1500 2000 2500

0 1 2 3 4 5

Cumulative total anthropogenic CO₂ emissions from 1870 (PgC)

Temperature anomaly relative to 1861-1880 (°C)

RCP2.6 Historical 1% CO₂runs

RCP4.5 RCP6.0

RCP8.5 RCP8.5 rangeRCP6 rangeRCP4.5 rangeRCP2.6 range 1% CO₂runs TCRE assessment

0 500 1000 1500 2000 2500

1.5 2 2.5 3

Consistent cum. total anthropogenic CO₂emissions given warming by all forcers in RCP8.5 (PgC)

Peak warming limit (°C)

90% of models 66% of models 50% of models 33% of models 10% of models

Cumulative emissions estimate 1870-2011

Temperature anomaly relative to 1861-1880 [C]

Cumulative carbon emissions [PgC]

Total emissions Warming

IPCC 2013, Simplified version of Figure 1 TFE.8

An introduction to the carbon budget concept

Remaining carbon budget for 2 ºC warming from 2018 (50%) IPCC AR5 = 230 GtC

IPCC SR15= 410 GtC

Why ?

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Remaining budget 1.5 ºC

Rogelj et al. 2019

A new framework to determine carbon budgets

lim lim hist nonCO₂ ZEC Esfb

feedback

Cumulative CO₂emissions from today (Gt CO₂) 0

TCRE

Temperature increase since preindustrial period (°C)

Remaining carbon budget Global warming limit of interest

0

2

Total carbon budget

1.5 ºC

^TCRE

(54)

Historical warming

• Uncertainty in the observed warming measurement ( 43%)

Rogelj et al. 2019

A new framework to determine carbon budgets

lim lim hist nonCO₂ ZEC Esfb

Historical human-induced warming

Unrepr feedback

TCRE

0

2

Remaining carbon budget

Remaining warming

1.5 ºC

^TCRE

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Historical human-induced warming

ÞParis agreement and carbon budget concept make the use of human-induced warming ÞDetection and Attribution methods helps to decompose the human-induced warming

from the total externally-forced warming

Þ+1.15 C 0.15 C in 2020 (from Ribes et al. 2020)

IPCC SR15 (2018)

2010-2019 1.03 C (Ribes et al. 2021)

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lim lim hist nonCO₂ ZEC Esfb Historical

human-induced warming

Unrepr feedback

TCRE

0

Zero emission commitment Non-CO₂

Remaining warming

1.5 ºC

^TCRE

Zero Emission Committed warming

• Often assumed to be negligible

• knowledge gap at multi-decadal time scale How much warming can we expect

once emissions are stopped or reach a net-zero level?

(Jones at al. 2019; MacDougall et al. 2019) Rogelj et al. 2019

A new framework to determine carbon budgets

(57)

Zero emission committment

0 20 40 60 80 100

Time (year)

−120

−100

−80

−60

−40

−20 0

Δ Atmospheric CO 2 (ppm)

CanESM5 GFDL ESM2M CESM2 ACCESS-ESM1.5 MIROC-ES2L

UKESM1 MPI-ESM1.2 NorESM2 CNRM-ESM2

0 20 40 60 80 100

Time (year)

−1.00

−0.75

−0.50

−0.25 0.00 0.25 0.50 0.75 1.00

ZEC (o C)

0 20 40 60 80 100

Time (year)

−120

−100

−80

−60

−40

−20 0

Δ Atmospheric CO 2 (ppm)

UVic ESCM 2.10 LOVECLIM 1.2 MIROC-lite DCESS CLIMBER-2

MESM PLASIM-GENIE Bern3D-LPX IAPRAS

0 20 40 60 80 100

Time (year)

−1.00

−0.75

−0.50

−0.25 0.00 0.25 0.50 0.75 1.00

ZEC (o C)

ESMs EMICs

(a) (b)

(c) (d)

ÞCharacterize the response of the Earth system to emission cessation

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Zero emission committment

ÞCharacterize the response of the Earth system to emission cessation

models GFDL-ESM2M UKESM1 CNRM-ESM2-1

∆T_ZEC -0.05 °C +0.5 °C +0.25°C

Change in Carbon budget (TCRE=0.4°C per 1000 GtCO₂)

+ 125 GtCO₂ - 1250 GtCO₂ -625 GtCO₂

∆T_ZECfor a carbon budget compatible with 2 C (3670 GtCO₂)

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Unrepr feedback

TCRE

0 Remaining allowable warming

Zero emission commitment Non-CO₂ contribution

Remaining warming

1.5 ºC

^TCRE

• Earth system response to forcing (-69% to +34 %)

• Future scenario uncertainty ( 43%) Remaining budget

1.5 ºC

Non-CO₂ forcing

Rogelj et al. 2019

A new framework to determine carbon budgets

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Contribution of non-CO ₂

2020 2040 2060 2080 2100

0.00.51.0

Time [years]

non−CO2 warming contribution [°C]

Below 1.5°C 50th(a)

Return 1.5°C 66th Return 1.5°C 50th Below 2°C 66th Below 2°C 50th Above 2°C

0.1 0.2 0.3 0.4 0.5 0.6

40060080010001200

non−CO₂ contribution at time of [°C]

Carbon Budget for 1.5°C [GtCO2 rel. to 2016]

(b) (c)

−1540

GtCO₂ °C^-1

−1540

GtCO₂ °C^-1

●

Threshold Return Budget Threshold Peak Budget ÞWarming contribution ~0.5C at the peak of warming

ÞLarge uncertainty associated with technological/infrastructure choices

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Unrepr feedback

TCRE

Remaining warming

1.5 ºC

TCRE distribution

• Observation contrained TCRE

• Distribution of the TCRE remains poorly constrained

A new framework to determine carbon budgets

(62)

IPCC SR15 2018

(63)

Matthews et al. (2021)

Transient Climate response

to Cumulative CO ₂ emissions

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Unrepresented Earth system feedback

TCRE

Remaining warming

1.5 ºC

Unrepresented Earth System Feedbacks

• e.g. permafrost carbon cycle feedbacks (- 17%)

• Reductions of carbon budgets due to permafrost carbon cycle feedbacks

(Gasser et al., 2017; MacDougall et al., 2016).

Rogelj et al. 2019

A new framework to determine carbon budgets

(65)

Updated from Arneth et al. (2010)

Unrepresented Earth system feedbacks

ÞUncertain, poorly understood

ÞPermafrost carbon feedback remains the prominent contributor of the carbon budget reduction

ÞMay reduce remaining carbon budget by 100 GtCO2

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Carbon budgets compatible with 1.5C or 2C

IPCC SR15 (2018), Chap 2 page 108

(67)

Mitigation pathways compatible with the

remaining carbon budget for 1.5 C (or 2 C)

(68)

• In order to hold global warming below 1.5 C, CO₂ emission should be reduced by 45% in 2030 with respect to 2010 level

• In order to hold global warming below

1.5 C, CO₂ emission shoud be “net zero” by 2050

• Reduction in other (non CO₂) greenhouse gases and aerosols will have immediated impact on health

20% for 2 C

By 2075 for 2 C

Mitigation pathways compatible with 1.5-2 C

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Paris Agreement NDCs

Mitigation pathways compatible with 1.5-2 C

20% for 2 C

By 2075 for 2 C

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Nexus of forthcoming Climate negociations

Mitigation pathways compatible with 1.5-2 C

20% for 2 C

By 2075 for 2 C

(71)

Associated warming projections by 2100

Our ambition to reduced human-induced greenhouse gases emission drive the likelihood to halt global warming below 1.5 C

(72)

Associated warming projections by 2100

Our ambition to reduced human-induced greenhouse gases emission drive the likelihood to halt global warming below 1.5 C:

Þ Carbon Neutrality in 2055 + emission cuts for CH4, N2O, CFCs

(73)

Associated warming projections by 2100

Þ Carbon Neutrality in 2055 + emission cuts for CH4, N2O, CFCs Þ The timing of carbon neutrality increase this likelihood

(74)

Þ Carbon Neutrality in 2055 + emission cuts for CH4, N2O, CFCs Þ The timing of carbon neutrality increase this likelihood

Þ Emission cuts for CH₄, N₂O, CFCs are required to halt warming below 1.5 C

Associated warming projections by 2100

(75)

Translation of scientific knowledge

in climate policies

(76)

UNEP, Gap Report 2019

Are we on track ? Is there an emission gap ?

(77)

Þ 32 GtCO2 pour 1,5 C

15 GtCO2 pour 2 C Þ Déclin de 7.6%/an de

émissions de CO2 pour revenir sur la

bonne trajectoire Þ Emission liée à la

COVID-19 au niveau global ~-6.7%

Are we on track ? Is there an emission gap ?

consequence on the remaining carbon budget

(78)

Ambitious climate policies implemented so far

(79)

Comitted structural changes compliant with

ambitious climate target

(80)

Ratchet mechanism

Revised/Updated NDCs are available on

https://www4.unfccc.int/sites/ndcstaging/Pages/LatestSubmissions.aspx

Questions:

Þ How many countries have revised their NDCs ? Paris agreement Art. 4 3^rd paragraph:

(81)

Net Zero Policy global map (Nov 2020)

Source: Climate Analytics

(82)

Source: Climate Analytics

(83)

Application in local/national policy

Cas de la France

(84)

Fossil fuel emission from IAE

Relative to 2000- 2005

Le Quéré et al. (2019) Top 12

0.3 GtCO2/an

Top 2 5.5 GtCO2/an

Several countries show emission reduction

Þ Reduction is CO2 emission in several countries

Þ Emission cut-off is largely driven by an increase of the energy-to-carbon intensity

(85)

Case for 30 Chinese provinces

Fang et al. (2019)

Top 1 emitter 9.2 GtCO2 y-1

Þ China’s CO2 emissions are projected by peak in 2030

Þ But lock-in in energy-to-carbon intensity may lead to a plateau in 2030…

(86)

Stratégie national bas carbone:

Ambition neutralité carbone en 2050

ÞAtténuation des principaux poles d’émissions de CO₂ (transport et bâtiments)

ÞRenforcement des puits de carbone (naturel et artificiels via CCS

ÞCompatibilité de cette trajectoire par rapport au budget carbone restant planétaire ?

Source: Carbone 4

(87)

Réconsilier les allocations nationales avec le budget Mondial

-un enjeu majeur-

(88)

0 100 200 300 400 500 600

1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 2065 2070 2075 2080 2085 2090 2095 2100 2105 Mt CO2e

Emissions GES avec UTCAF 1,5°C sans incertitude 2°C sans incertitude

Principes appliqués au budget carbone de la France

Granfathering= prorata des émissions de la France par rapport aux émissions mondiales

Belaunde and Bueb (2019)

(89)

0 100 200 300 400 500 600

1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 2065 2070 2075 2080 2085 2090 2095 2100

MtCO2e Emissions GES avec UTCAF

1,5°C (dépassement) 2°C

Principes appliqués au budget carbone de la France

Égalité= ponderation par rapport aux indices de développement comme l’indice de Gini

(90)

0 100 200 300 400 500 600

1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 2065 2070 2075 2080 2085 2090 2095 2100

MtCO2e

Emissions GES avec UTCAF

1,5°C 2°C

Principes appliqués au budget carbone de la France

Approche combinée= integration de tous les critères dans la determination des trajectoires vers la neutralité

(91)

Quid de l’empreinte ?

0 100 200 300 400 500 600 700 800

1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 2065 2070 2075 2080 2085 2090 2095 2100

MtCO2e

Empreinte avec UTCAF Emissions territoriales avec UTCAF

1,5°C en territorial 2°C en territorial 1,5°C en empreinte 2°C en empreinte

+300 MtCO2

(92)

Climate policies and post-COVID recovery plans

(93)

Andrijevic et al. 2021

Þ 20 additional billion USD per year = 0.2% of the total fund