RIVM (the Netherlands) and ETH (Switzerland) 1 Emission implications of long-term climate targets - a work-in-progress report - Michel den Elzen (RIVM,

RIVM (the Netherlands) and ETH (Switzerland) 1

Emission implications of long-term climate targets - a work-in-progress report -

Michel den Elzen (RIVM, the Netherlands)

Malte Meinshausen (ETH Zurich, Switzerland)

Side Event COP-10

13th December 2004

Buenos Aires


Introduction

Part 1: Why 2°C ? What CO2 level corresponds with a 2°C target?

Part 2: The method to derive emission pathways with cost-effective multi-gas mixes of reductions.

Part 3:What are the (regional) emission reduction targets?

Part 4: What is the impact of further delay?


Part 1:Why 2°C?

What equilibrium CO2-equivalent level corresponds with 2oC?


EU’s 2°C target

“[...] the Council believes that global average temperatures should not exceed 2 degrees above pre-industrial level and that therefore concentration levels lower than 550 ppm CO2 should guide global limitation and reduction efforts. [...]”(1939th Council meeting, Luxembourg, 25 June 1996)

“REAFFIRMS that, with a view to meeting the ultimate objective of the United Nations Framework Convention on Climate Change [...] to prevent dangerous anthropogenic interference with the climate system, overall global annual mean surface temperature increase should not exceed 2°C above pre-industrial levels in order to limit high risks, including irreversible impacts of climate change; RECOGNISES that 2°C would already imply significant impacts on ecosystems and water resources [...]” (2610th Council

Meeting, Luxembourg, 14 October 2004 Council 2004, 25-26 March 2004)


Temperature increase higher over land


Reasons for Concern (IPCC TAR WGII)


Millions at Risk (Parry et al., 2001)


Expected warming for ~550ppm CO2eq

Climate Sensitivity ...

... summarizes key uncertainties in climate science

... is the expected average warming of the earth’s surface for a doubling of CO2 concentrations (about 550 ppm CO2)


Background: Difference between CO2 and CO2equivalence

Conversion Table for > 2100

CO2 (ppmv)

+ other GHG + aerosols

CO2eq(ppmv)

350 + other ≈ 400

390 + other ≈ 450

470 + other ≈ 550

550 + other ≈ 650

“CO2equivalence” summarizes the climate effect (‘radiative forcing’) of all human-induced greenhouse-gases and aerosols, as if we only changed the atmospheric concentrations of CO2.

Like “bread exchange” units for food or “tonnes oil equivalent (toe)” for energy sources.


Expected warming for ~550ppm CO2eq New research cannot exclude very high warming levels (e.g. >

4.5°C) for stabilization of greenhouse gases at 550ppm CO2–eq. “The fact that we are uncertain may actually be a reason to act

sooner rather than later” (Eileen Claussen)


The risk to overshoot 2°C


The Risk to overshoot 2°C


Conclusions Part 1

550 ppm CO2 equivalence is “unlikely” to meet the 2°C target

The risk to overshoot 2°C can be substantially reduced for lower stabilization levels.

There is about a fifty:fifty chance to meet 2°C by stabilizing at 450ppm

There is a “likely” achievement of the 2°C target for stabilization at 400ppm CO2eq (risk to overshoot 2°C is about 25%).

Dependent on climate sensitivity PDF


Part 2: The method to calculate emission

pathways


Method: FAIR-SiMCaP FAIR (RIVM)

Calculates the emission allowances and abatement costs of post-2012 regimes

Here we use the cost-model: cost-optimal mixes of greenhouse gas for total reductions (6

GHGs) every 5 year periodsleast costs approach using on MAC curves Not over time

SiMCaP (ETH Zurich)calculates parameterised emission pathways to achieve predefined

climate targets, like 400ppm CO2eqClimate calculations by simple climate model


Method: FAIR-SiMCaP


Basic assumptions

Three baseline scenarios: IMAGE-B1 (IPCC B1, MACs B1 & LUCF: B1) CPI (middle IPCC, MACs CPI & LUCF: CPI) CPI+tech (MACs additional technological

improvements) & LUCF: B1)

Rationale behind CPI+tech:1. Current studies show more abatements are possible

2. More optimistic, simple assumptions for the MACs (e.g. energy CO2 MACs now additional improvement of

0.2%/year)


Basic assumptions (continued) In order to avoid global emission reduction rates exceeding

3%/year, the default scenarios assume early reductions. Peak of global emissions in 2015-2020

Early peaking is technically feasible, costs not too high, but … political willingness?

Focus on CO2-equivalent concentration stabilisation levels of 400, 450, 500 and 550 ppm

The lower concentration levels include overshooting: Stabilisation at 400 ppm: Peaking at 480 ppm; Stabilisation at 450 ppm: Peaking at 500 ppm; Stabilisation at 500 ppm: Peaking at 525 ppm;


CO2-eq. emissions in GtC-eq

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1995 2020 2045 2070 2095


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1995 2020 2045 2070 2095

baseline CPI

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1995 2020 2045 2070 2095

Sinks

F-gasses

N2O

CH4

CO2

profile

Cost-optimal reduction over GHGs

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1995 2020 2045 2070 2095

IM A-B1

450

baseline B1


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450

CP I-tech

baseline CPI Main focus on

energy-related CO2 reductions

In short terms, potentially large incentives for sinks and non-CO2 GHGs (cheap options)

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1995 2020 2045 2070 2095

Sinks

F-gasses

N2O

CH4

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profile


Fossil CO2 emissions


Other Greenhouse gas Emissions


Greenhouse gas Concentrations


Contribution GHGs to net radiative forcing


Presented multi-gas scenarios are roughly within the range of existing mitigation scenarios.

The applied method reflects the existing policy-framework and assumes cost-minimizing achievements of targets in each 5 year period: This results in near-term incentives for non-CO2 reductions and

for sinks But in the long-term the focus has to be on reductions in CO2

emissions

Conclusions Part 2


Part 3:What are the (regional) emission

reduction implications?


Emission pathways with different baselines


The default emission pathways


In 2020, global emissions may increase from 10-25% above 1990 levels (400-450ppm).

In 2050, the emissions have to be reduced by 30-60%

Change of global GHG emissions (incl. LUCF CO2 emissions) compared to 1990 level (in %)

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010203040

2050

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2020

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OECD90

400ppm

450ppm

500ppm

550ppm


Change of global GHG emissions (excl. LUCF CO2 emissions) compared to 1990 level (in %)

If landuse CO2 emissions decrease, then reduction needs for the Kyoto gas emissions only (without landuse CO2) are relaxed by about 10%-15%.

By 2050, 20-45% below 1990 levels (400-450ppm).

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2050

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2020

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OECD90

400ppm

450ppm

500ppm

550ppm


Change emissions compared to 1990 level in 2020 excl. LUCF CO2 for Multi-Stage regime (%)

-40

-30

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Annex I

-40

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FSU & E. Eur

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OECD90

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Non-Annex I

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Africa & Lat. Am

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Asia

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OECD90

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550ppm

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global


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Annex I

Change emissions compared to 1990 level in 2050 excl. LUCF CO2 for Multi-Stage regime (%)

-100

-80

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40

FSU & E.Eur

-100

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OECD90

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Non-Annex I

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Africa & Lat. Am

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Asia

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Global

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OECD90

400ppm

450ppm

500ppm

550ppm


Overall global emissions (Kyoto gas emissions + landuse CO2):

400ppm CO2eq: 50% to 60% below 1990 by 2050


Assuming landuse CO2 emission decrease as specified, needed global Kyoto gas emissions reductions are less: 400ppm CO2eq: 35% to 45% below 1990 by 2050


Conclusions Part 3 (Global)


Focusing on Kyoto gas emissions excluding landuse emissions: In 2020, Annex I emissions need to be reduced ~

30% below 1990 levels for 400ppm, and ~15% 450ppm.

The reductions are differentiated amongst the Parties, Annex I takes the lead, followed by the more advance developing countries, and then the low-income countries.

For meeting the lower concentration levels major developing countries have to participate in the reductions between 2015 and 2025

Conclusions Part 3 (Regional)


Part 4:What is the impact of further delay


The effect of delay: 450ppm






A delay of global action of just five years matters.

Global emissions will have to peak in 10 to 15 years to limit the risk of overshooting 2°C to reasonable levels.

The consequence of delay are: Lower absolute emissions after around 2040 Steeper maximal reduction rates already from 2020 /

2025

“Delaying action for a decade, or even just years, is not a serious option” (Sir David King, Sience,9 January 2004)

Conclusions Part 4


Overall conclusions


Overall conclusions Multi-gas mitigation pathways

550 ppm CO2 eq. is “unlikely” to meet the 2°C target

Limiting the risk to overshoot 2°C to less then 33% requires stabilization at approximately 400ppm.

It seems necessary, that global emissions peak before 2020 to achieve 400 or 450ppm stabilization levels. Cost of delay potentially very high.

This is followed by reductions in the order of 30% to 60% (incl. land use CO2 emissions) in 2050 compared to 1990 levels (450/400ppm CO2eq).


Overall conclusions (continued)

Regional emission reductions depend on: emissions growth in the baseline allocation scheme for differentiated commitments abatement potential and reduction costs

In 2020, Annex I emission need to be approximately 30% below 1990 levels for 400ppm, and approximately 20% lower for 450ppm stabilization.

For meeting the lower concentration levels, major developing countries have to participate in the reductions between 2015 and 2025


Reminder - Disclaimer

The presented work is part of a longer term project. Cost estimates, in particular non-fossil CO2, will be

explored in more detail (implementation barriers). Cost of delayed pathways will be explored with dynamic

energy model TIMER (inertia, technological improvements, forgone learning effects)

Work in progress


Thank you!

Contact: [email protected]@ethz.ch

Presentation will be made available from www.rivm.nl/ieweb/www.simcap.org

RIVM (the Netherlands) and ETH (Switzerland) 1 Emission implications of long-term climate targets - a work-in-progress report - Michel den Elzen (RIVM,

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