The economically optimal warming limit of the planet

Ueckerdt, Falko; Frieler, Katja; Lange, Stefan; Wenz, Leonie; Luderer, Gunnar; Levermann, Anders

doi:https://doi.org/10.5194/esd-10-741-2019

Articles | Volume 10, issue 4

https://doi.org/10.5194/esd-10-741-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/esd-10-741-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 10, issue 4

Research article

|

18 Nov 2019

Research article |

| 18 Nov 2019

The economically optimal warming limit of the planet

Falko Ueckerdt, Katja Frieler, Stefan Lange, Leonie Wenz, Gunnar Luderer, and Anders Levermann

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Final revised paper (published on 18 Nov 2019)
Preprint (discussion started on 16 Nov 2018)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Reviewer Comments', Frances Moore, 30 Jan 2019
- AC1: 'Reply reviewer #1', Anders Levermann, 04 Jun 2019
RC2: 'Reviewer Comments', Anonymous Referee #2, 06 Feb 2019
- AC2: 'Reply reviewer #2', Anders Levermann, 04 Jun 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (26 Jul 2019) by Richard Betts

AR by Anders Levermann on behalf of the Authors (26 Jul 2019) Author's response

ED: Referee Nomination & Report Request started (04 Sep 2019) by Richard Betts

RR by Frances Moore (15 Sep 2019)

Suggestions for revision or reasons for rejection

I thank the authors for detailed discussion and replies to my original comments. I appreciate the additional information on the specification of mitigation costs in the REMIND model and the discussion of the importance of the persistence (or lack thereof) of temperature effects on GDP. Although the challenges associated with a partial coupling between the damages and mitigation cost estimates in this framework are substantial (particularly with respect to inconsistent GDP growth estimates and temperature trajectories), I believe these are clearly communicated in the current manuscript. The paper provides an important contribution, which can be built on and developed to address these issues in the future.

I have two small points that should be clarified:
1) the manuscript (and appendix) repeatedly revers to the Burke et al. main specification as a "one year growth rate effect". This is misleading since, as is described carefully in the appendix discussion, the main Burke et al regression specification is not able to distinguish between a one year growth effect, a one year level effect, and a longer-term growth effect. The casual reader will come away with the impression that the Burke et al paper presents evidence for growth effects, when in fact it does not because it cannot distinguish between these models. I appreciate and agree with the discussion on the current evidence for and against growth effects and the fact that this is so far inconclusive. In referring to their chosen specification regarding persistence of damages therefore, the language should make clear that these are assumptions, not the results of any particular empirical specification. I'm specifically referring to language such as "(main specification in Burke et al., 2015)" in the abstract, page 2, and page 4, as well as some language in the appendix.

2) The authors should more precise in distinguishing between economic costs (i.e. anything that affects human welfare) and market costs (i.e. as captured in production as measured by GDP). All current IAM damages acknowledge the importance of non-market costs of climate change (particularly mortality and losses of biodiverisity). Effects of climate change on GDP are known to be at best a partial measure of the full economic costs of climate change and an imperfect measure of welfare. The manuscript currently uses these interchangeably in a manner that is confusing.

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ED: Publish subject to technical corrections (27 Sep 2019) by Richard Betts

Dear Anders

Your revised manuscript has undergone further review, and I will be happy to accept the paper if the following further minor review comments are addressed:

1) the manuscript (and appendix) repeatedly revers to the Burke et al. main specification as a "one year growth rate effect". This is misleading since, as is described carefully in the appendix discussion, the main Burke et al regression specification is not able to distinguish between a one year growth effect, a one year level effect, and a longer-term growth effect. The casual reader will come away with the impression that the Burke et al paper presents evidence for growth effects, when in fact it does not because it cannot distinguish between these models. I appreciate and agree with the discussion on the current evidence for and against growth effects and the fact that this is so far inconclusive. In referring to their chosen specification regarding persistence of damages therefore, the language should make clear that these are assumptions, not the results of any particular empirical specification. I'm specifically referring to language such as "(main specification in Burke et al., 2015)" in the abstract, page 2, and page 4, as well as some language in the appendix.

2) The authors should more precise in distinguishing between economic costs (i.e. anything that affects human welfare) and market costs (i.e. as captured in production as measured by GDP). All current IAM damages acknowledge the importance of non-market costs of climate change (particularly mortality and losses of biodiverisity). Effects of climate change on GDP are known to be at best a partial measure of the full economic costs of climate change and an imperfect measure of welfare. The manuscript currently uses these interchangeably in a manner that is confusing.

Following further consultation with one of the reviewers, I am happy that the earlier suggestion of a sensitivity analysis to the rich/poor country threshold is not necessary and would add little to the paper, so this will not be a condition of acceptance.

Best regards

Richard

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AR by Anders Levermann on behalf of the Authors (04 Oct 2019) Author's response Manuscript

Short summary

We compute the global mean temperature increase at which the costs from climate-change damages and climate-change mitigation are minimal. This temperature is computed robustly around 2 degrees of global warming across a wide range of normative assumptions on the valuation of future welfare and inequality aversion.