TY  - JOUR
A1  - Döbbeling-Hildebrandt, Niklas
A1  - Miersch, Klaas
A1  - Khanna, Tarun M.
A1  - Bachelet, Marion
A1  - Bruns, Stephan B.
A1  - Callaghan, Max
A1  - Edenhofer, Ottmar
A1  - Flachsland, Christian
A1  - Forster, Piers M.
A1  - Kalkuhl, Matthias
A1  - Koch, Nicolas
A1  - Lamb, William F.
A1  - Ohlendorf, Nils
A1  - Steckel, Jan Christoph
A1  - Minx, Jan C.
T1  - Systematic review and meta-analysis of ex-post evaluations on the effectiveness of carbon pricing
JF  - Nature communications
N2  - Today, more than 70 carbon pricing schemes have been implemented around the globe, but their contributions to emissions reductions remains a subject of heated debate in science and policy. Here we assess the effectiveness of carbon pricing in reducing emissions using a rigorous, machine-learning assisted systematic review and meta-analysis. Based on 483 effect sizes extracted from 80 causal ex-post evaluations across 21 carbon pricing schemes, we find that introducing a carbon price has yielded immediate and substantial emission reductions for at least 17 of these policies, despite the low level of prices in most instances. Statistically significant emissions reductions range between –5% to –21% across the schemes (–4% to –15% after correcting for publication bias). Our study highlights critical evidence gaps with regard to dozens of unevaluated carbon pricing schemes and the price elasticity of emissions reductions. More rigorous synthesis of carbon pricing and other climate policies is required across a range of outcomes to advance our understanding of “what works” and accelerate learning on climate solutions in science and policy.
KW  - carbon and energy
KW  - climate-change mitigation
KW  - climate-change policy
KW  - economics
Y1  - 2024
U6  - https://doi.org/10.1038/s41467-024-48512-w
SN  - 2041-1723
VL  - 15
IS  - 1
PB  - Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Kikstra, Jarmo S.
A1  - Nicholls, Zebedee R. J.
A1  - Smith, Christopher J.
A1  - Lewis, Jared
A1  - Lamboll, Robin D.
A1  - Byers, Edward
A1  - Sandstad, Marit
A1  - Meinshausen, Malte
A1  - Gidden, Matthew J.
A1  - Rogelj, Joeri
A1  - Kriegler, Elmar
A1  - Peters, Glen P.
A1  - Fuglestvedt, Jan S.
A1  - Skeie, Ragnhild B.
A1  - Samset, Bjørn H.
A1  - Wienpahl, Laura
A1  - van Vuuren, Detlef P.
A1  - van der Wijst, Kaj-Ivar
A1  - Al Khourdajie, Alaa
A1  - Forster, Piers M.
A1  - Reisinger, Andy
A1  - Schaeffer, Roberto
A1  - Riahi, Keywan
T1  - The IPCC Sixth Assessment Report WGIII climate assessment of mitigation pathways
BT  - from emissions to global temperatures
JF  - Geoscientific model development
N2  - While the Intergovernmental Panel on Climate Change (IPCC) physical science reports usually assess a handful of future scenarios, the Working Group III contribution on climate mitigation to the IPCC's Sixth Assessment Report (AR6 WGIII) assesses hundreds to thousands of future emissions scenarios. A key task in WGIII is to assess the global mean temperature outcomes of these scenarios in a consistent manner, given the challenge that the emissions scenarios from different integrated assessment models (IAMs) come with different sectoral and gas-to-gas coverage and cannot all be assessed consistently by complex Earth system models. In this work, we describe the “climate-assessment” workflow and its methods, including infilling of missing emissions and emissions harmonisation as applied to 1202 mitigation scenarios in AR6 WGIII. We evaluate the global mean temperature projections and effective radiative forcing (ERF) characteristics of climate emulators FaIRv1.6.2 and MAGICCv7.5.3 and use the CICERO simple climate model (CICERO-SCM) for sensitivity analysis. We discuss the implied overshoot severity of the mitigation pathways using overshoot degree years and look at emissions and temperature characteristics of scenarios compatible with one possible interpretation of the Paris Agreement. We find that the lowest class of emissions scenarios that limit global warming to “1.5 ∘C (with a probability of greater than 50 %) with no or limited overshoot” includes 97 scenarios for MAGICCv7.5.3 and 203 for FaIRv1.6.2. For the MAGICCv7.5.3 results, “limited overshoot” typically implies exceedance of median temperature projections of up to about 0.1 ∘C for up to a few decades before returning to below 1.5 ∘C by or before the year 2100. For more than half of the scenarios in this category that comply with three criteria for being “Paris-compatible”, including net-zero or net-negative greenhouse gas (GHG) emissions, median temperatures decline by about 0.3–0.4 ∘C after peaking at 1.5–1.6 ∘C in 2035–2055. We compare the methods applied in AR6 with the methods used for SR1.5 and discuss their implications. This article also introduces a “climate-assessment” Python package which allows for fully reproducing the IPCC AR6 WGIII temperature assessment. This work provides a community tool for assessing the temperature outcomes of emissions pathways and provides a basis for further work such as extending the workflow to include downscaling of climate characteristics to a regional level and calculating impacts.
Y1  - 2022
U6  - https://doi.org/10.5194/gmd-15-9075-2022
SN  - 1991-959X
SN  - 1991-9603
VL  - 15
IS  - 24
SP  - 9075
EP  - 9109
PB  - Copernicus
CY  - Katlenburg-Lindau
ER  -