TY  - JOUR
A1  - Warszawski, Lila
A1  - Kriegler, Elmar
A1  - Lenton, Timothy M.
A1  - Gaffney, Owen
A1  - Jacob, Daniela
A1  - Klingenfeld, Daniel
A1  - Koide, Ryu
A1  - Costa, María Máñez
A1  - Messner, Dirk
A1  - Nakicenovic, Nebojsa
A1  - Schellnhuber, Hans Joachim
A1  - Schlosser, Peter
A1  - Takeuchi, Kazuhiko
A1  - van der Leeuw, Sander
A1  - Whiteman, Gail
A1  - Rockström, Johan
T1  - All options, not silver bullets, needed to limit global warming to 1.5 °C
BT  - a scenario appraisal
JF  - Environmental research letters
N2  - Climate science provides strong evidence of the necessity of limiting global warming to 1.5 °C, in line with the Paris Climate Agreement. The IPCC 1.5 °C special report (SR1.5) presents 414 emissions scenarios modelled for the report, of which around 50 are classified as '1.5 °C scenarios', with no or low temperature overshoot. These emission scenarios differ in their reliance on individual mitigation levers, including reduction of global energy demand, decarbonisation of energy production, development of land-management systems, and the pace and scale of deploying carbon dioxide removal (CDR) technologies. The reliance of 1.5 °C scenarios on these levers needs to be critically assessed in light of the potentials of the relevant technologies and roll-out plans. We use a set of five parameters to bundle and characterise the mitigation levers employed in the SR1.5 1.5 °C scenarios. For each of these levers, we draw on the literature to define 'medium' and 'high' upper bounds that delineate between their 'reasonable', 'challenging' and 'speculative' use by mid century. We do not find any 1.5 °C scenarios that stay within all medium upper bounds on the five mitigation levers. Scenarios most frequently 'over use' CDR with geological storage as a mitigation lever, whilst reductions of energy demand and carbon intensity of energy production are 'over used' less frequently. If we allow mitigation levers to be employed up to our high upper bounds, we are left with 22 of the SR1.5 1.5 °C scenarios with no or low overshoot. The scenarios that fulfil these criteria are characterised by greater coverage of the available mitigation levers than those scenarios that exceed at least one of the high upper bounds. When excluding the two scenarios that exceed the SR1.5 carbon budget for limiting global warming to 1.5 °C, this subset of 1.5 °C scenarios shows a range of 15–22 Gt CO2 (16–22 Gt CO2 interquartile range) for emissions in 2030. For the year of reaching net zero CO2 emissions the range is 2039–2061 (2049–2057 interquartile range).
KW  - climate change
KW  - emissions scenarios
KW  - 1.5 ◦C
KW  - negative emissions
Y1  - 2021
U6  - https://doi.org/10.1088/1748-9326/abfeec
SN  - 1748-9326
N1  - Corrigendum: 10.1088/1748-9326/acbf6a
VL  - 16
IS  - 6
PB  - IOP Publishing
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Schultes, Anselm
A1  - Piontek, Franziska
A1  - Soergel, Bjoern
A1  - Rogelj, Joeri
A1  - Baumstark, Lavinia
A1  - Kriegler, Elmar
A1  - Edenhofer, Ottmar
A1  - Luderer, Gunnar
T1  - Economic damages from on-going climate change imply deeper near-term emission cuts
JF  - Environmental research letters
N2  - Pathways toward limiting global warming to well below 2 ∘C, as used by the IPCC in the Fifth Assessment Report, do not consider the climate impacts already occurring below 2 ∘C. Here we show that accounting for such damages significantly increases the near-term ambition of transformation pathways. We use econometric estimates of climate damages on GDP growth and explicitly model the uncertainty in the persistence time of damages. The Integrated Assessment Model we use includes the climate system and mitigation technology detail required to derive near-term policies. We find an optimal carbon price of $115 per tonne of CO2 in 2030. The long-term persistence of damages, while highly uncertain, is a main driver of the near-term carbon price. Accounting for damages on economic growth increases the gap between the currently pledged nationally determined contributions and the welfare-optimal 2030 emissions by two thirds, compared to pathways considering the 2 ∘C limit only.
KW  - climate change
KW  - climate mitigation
KW  - climate impacts
KW  - integrated assessment
Y1  - 2021
U6  - https://doi.org/10.1088/1748-9326/ac27ce
SN  - 1748-9326
VL  - 16
IS  - 10
PB  - IOP Publishing
CY  - Bristol
ER  -