Starting climate policies early in order to reach long-term climate targets is... as cumbersome

Starting climate policies early

in order to reach long-term climate targets is...

as cumbersome

yet as neccessary

...as getting out of bed early enough to climb a mountain

following C. Schär (2003)

Malti-gas emission profiles to mitigate dangerous climate change.

Malte Meinshausen, malte.meinshausen@env.ethz.ch, 17. February 2004, RIVM Photo courtesy Leila Mead, IISD.ca;

Where do we want to go?

1. Introduction

2. Methods

3. Limitations

4. Results

Introduction

A work-in-progress report

Objective: Multi-gas emission profiles to limit global mean temperatures, radiative forcing, CO2 concentrations etc.

Possible methods for non-CO2: ‚one size fits all‘ scaling to (fossil) CO2 source-specific reduction potentials for all gases

(IMAGE) cost-optimisations (TIMER/FAIR) and ...

The ‘multi-gas meta approach’ motivation: ‘Peaking’ and ‘temperature’ related profiles Dealing ‘consistently’ with non-CO2 gases Building on pluralism of existing work to derive a

continuous set of mitigation profiles

Methods I: World per-capita emissions

Methods II: The ‚distribution of possible emission levels‘

Methods III: Going along equal percentiles

Methods IV: Overview

Limitations

1. Throwing garbage in a blender? Underestimation of non-CO2 /

landuse reduction potentials?

Limitations

1. Throwing garbage in a blender? Underestimation of non-CO2 /

landuse reduction potentials? Comparison with IMAGE EMF21

profiles shows rough consistency for non-CO2 gases – despite lack of fully elaborated scenarios in the underlying pool of scenarios.

2. Or blending everything into garbage? Not respecting anti-correlations in

scenarios? Ranking correlation analysis

Limitations II: Ranking Correlations

~0 ~0>0 >0 >0 >0 >0

Limitations

1. Throwing garbage in a blender?

2. Or blending everything into garbage? Not respecting anti-correlations in

scenarios? Ranking correlation analysis

3. Does the methodology assume a certain probability of the underlying SRES scenarios? Yes, but robust to different probabilities.

Results / ‚Found again‘

Multi-gas CO2 scenarios have substantially less overall forcing. Comparison CO2-only WRE450 and multi-gas S450C.

Results / ‚Found again‘

Multi-gas CO2 scenarios have substantially less overall forcing. Comparison CO2-only WRE450 and multi-gas S450C.

Under default assumptions, to stay below 2°C requires, atmospheric concentrations to peak below 420 ppmv CO2 or 490 ppmv CO2 equivalence

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results II: Comparison to long-term pledges

Results / ‚Found again‘

Multi-gas CO2 scenarios have substantially less overall forcing. Comparison CO2-only WRE450 and multi-gas S450C.

Under default assumptions, to stay below 2°C requires, atmospheric concentrations to peak below 420 ppmv CO2 or 490 ppmv CO2 equivalence

Long-term pledges of EU countries roughly consistent with derived emission reduction necessities for Annex I countries (Sweden/UK pledges for 2050 on the higher end, though)

Looking forward to another 3 ½ months here... Thanks!