• Comment |

    Framing solutions to climate change as natural strongly influences their acceptability, but what constitutes a ‘natural’ climate solution is selected, not self-evident. We suggest that the current, narrow formulation of natural climate solutions risks constraining what are thought of as desirable policy options.

    • Rob Bellamy
    •  & Shannon Osaka
  • Comment |

    A failure to recognize the factors behind continued emissions growth could limit the world’s ability to shift to a pathway consistent with 1.5 °C or 2 °C of global warming. Continued support for low-carbon technologies needs to be combined with policies directed at phasing out the use of fossil fuels.

    • G. P. Peters
    • , R. M. Andrew
    • , J. G. Canadell
    • , P. Friedlingstein
    • , R. B. Jackson
    • , J. I. Korsbakken
    • , C. Le Quéré
    •  & A. Peregon
  • Comment |

    Many recently updated climate models show greater future warming than previously. Separate lines of evidence suggest that their warming rates may be unrealistically high, but the risk of such eventualities only emphasizes the need for rapid and deep reductions in emissions.

    • Piers M. Forster
    • , Amanda C. Maycock
    • , Christine M. McKenna
    •  & Christopher J. Smith
  • Comment |

    Misleading claims about mass migration induced by climate change continue to surface in both academia and policy. This requires a new research agenda on ‘climate mobilities’ that moves beyond simplistic assumptions and more accurately advances knowledge of the nexus between human mobility and climate change.

    • Ingrid Boas
    • , Carol Farbotko
    • , Helen Adams
    • , Harald Sterly
    • , Simon Bush
    • , Kees van der Geest
    • , Hanne Wiegel
    • , Hasan Ashraf
    • , Andrew Baldwin
    • , Giovanni Bettini
    • , Suzy Blondin
    • , Mirjam de Bruijn
    • , David Durand-Delacre
    • , Christiane Fröhlich
    • , Giovanna Gioli
    • , Lucia Guaita
    • , Elodie Hut
    • , Francis X. Jarawura
    • , Machiel Lamers
    • , Samuel Lietaer
    • , Sarah L. Nash
    • , Etienne Piguet
    • , Delf Rothe
    • , Patrick Sakdapolrak
    • , Lothar Smith
    • , Basundhara Tripathy Furlong
    • , Ethemcan Turhan
    • , Jeroen Warner
    • , Caroline Zickgraf
    • , Richard Black
    •  & Mike Hulme
  • Comment |

    Minimizing the adverse consequences of sea-level change presents a key societal challenge. New modelling is necessary to examine the implications of global policy decisions that determine future greenhouse gas emissions and local policies around coastal risk that influence where and how we live.

    • D. J. Wrathall
    • , V. Mueller
    • , P. U. Clark
    • , A. Bell
    • , M. Oppenheimer
    • , M. Hauer
    • , S. Kulp
    • , E. Gilmore
    • , H. Adams
    • , R. Kopp
    • , K. Abel
    • , M. Call
    • , J. Chen
    • , A. deSherbinin
    • , E. Fussell
    • , C. Hay
    • , B. Jones
    • , N. Magliocca
    • , E. Marino
    • , A. Slangen
    •  & K. Warner
  • Comment |

    Though critical to many projected pathways to meet global climate targets, the challenges facing biomass energy with carbon capture and storage have yet to enter the forefront of public dialogue.

    • Christopher S. Galik
  • Comment |

    Concern about the carbon footprint of Bitcoin is not holding back blockchain developers from leveraging the technology for action on climate change. Although blockchain technology is enabling individuals and businesses to manage their carbon emissions, the social and environmental costs and benefits of doing so remain unclear.

    • Peter Howson
  • Comment |

    The publication of the IPCC Special Report on global warming of 1.5 oC paved the way for the rise of the political rhetoric of setting a fixed deadline for decisive actions on climate change. However, the dangers of such deadline rhetoric suggest the need for the IPCC to take responsibility for its report and openly challenge the credibility of such a deadline.

    • Shinichiro Asayama
    • , Rob Bellamy
    • , Oliver Geden
    • , Warren Pearce
    •  & Mike Hulme
  • Comment |

    The Paris Agreement established a global goal on adaptation and invites parties to review the effectiveness of adaptation actions. However, the measurement of adaptation success remains elusive. Focusing on the capabilities of households and governments to pursue a range of adaptation futures provides a more robust foundation.

    • Lisa Dilling
    • , Anjal Prakash
    • , Zinta Zommers
    • , Farid Ahmad
    • , Nuvodita Singh
    • , Sara de Wit
    • , Johanna Nalau
    • , Meaghan Daly
    •  & Kerry Bowman
  • Comment |

    The 2030 Agenda and the Paris Agreement share the purpose of creating a more resilient, productive and healthy environment for present and future generations. Nations must seize the opportunity to raise their ambition, realize synergies and minimize trade-offs.

    • Liu Zhenmin
    •  & Patricia Espinosa
  • Comment |

    Climate-smart food systems are needed to feed growing populations while reducing greenhouse gas emissions and conserving natural resources. However, to be successful, climate-smart agriculture interventions must be equitable and inclusive to overcome trade-offs with other Sustainable Development Goals.

    • Jon Hellin
    •  & Eleanor Fisher
  • Comment |

    Manipulation of European Union emission trading systems (ETS) by the buy, bank, burn program compensates unregulated emissions while regulated sectors carry a large part of the burden. This distorts the balance between regulated firms and non-regulated projects, so parties outside the EU ETS can be virtuous at the cost of others.

    • Reyer Gerlagh
    •  & Roweno J. R. K. Heijmans
  • Comment |

    The #FridaysForFuture campaign has prompted unprecedented numbers of youth to join the climate movement around the world. This growing movement is important beyond its potential impact on climate policy because it is creating a cohort of citizens who will be active participants in democracy.

    • Dana R. Fisher
  • Comment |

    The students striking for action on climate change admirably display civic engagement on a pressing issue. Nevertheless, their movement’s message focuses far too heavily on the need to ‘listen to science’, which is at most a point of departure for answering the ethical and political questions central to climate action.

    • Darrick Evensen
  • Comment |

    Many countries are formulating a long-term climate strategy to be submitted to the United Nations Framework Convention on Climate Change by 2020. Model-based, multi-disciplinary assessments can be a key ingredient for informing policy makers and engaging stakeholders in this process.

    • Matthias Weitzel
    • , Toon Vandyck
    • , Kimon Keramidas
    • , Markus Amann
    • , Pantelis Capros
    • , Michel den Elzen
    • , Stefan Frank
    • , Stéphane Tchung-Ming
    • , Ana Díaz Vázquez
    •  & Bert Saveyn
  • Comment |

    The way in which climate change research funds are managed is shifting dramatically toward investments in large collaborative research networks. This poses significant challenges for researchers, and requires changes from the institutions and funders that support them.

    • G. Cundill
    • , B. Currie-Alder
    •  & M. Leone
  • Comment |

    Climate science celebrates three 40th anniversaries in 2019: the release of the Charney report, the publication of a key paper on anthropogenic signal detection, and the start of satellite temperature measurements. This confluence of scientific understanding and data led to the identification of human fingerprints in atmospheric temperature.

    • Benjamin D. Santer
    • , Céline J. W. Bonfils
    • , Qiang Fu
    • , John C. Fyfe
    • , Gabriele C. Hegerl
    • , Carl Mears
    • , Jeffrey F. Painter
    • , Stephen Po-Chedley
    • , Frank J. Wentz
    • , Mark D. Zelinka
    •  & Cheng-Zhi Zou
  • Comment |

    The current narrow focus on afforestation in climate policy runs the risk of compromising long-term carbon storage, human adaptation and efforts to preserve biodiversity. An emphasis on diverse, intact natural ecosystems — as opposed to fast-growing tree plantations — will help nations to deliver Paris Agreement goals and much more.

    • Nathalie Seddon
    • , Beth Turner
    • , Pam Berry
    • , Alexandre Chausson
    •  & Cécile A. J. Girardin
  • Comment |

    Carbon mitigation efforts often focus on the world’s poorest people, dealing with topics such as food and energy security, and increased emissions potential from projected population, income and consumption growth. However, more policies are needed that target people at the opposite end of the social ladder — the super-rich.

    • Ilona M. Otto
    • , Kyoung Mi Kim
    • , Nika Dubrovsky
    •  & Wolfgang Lucht
  • Comment |

    The tendency of modern science to reduce complex phenomena into their component parts has many advantages for advancing knowledge. However, such reductionism in climate science is also a problem because it narrows the evidence base, limiting visions of possible futures and the ways they might be achieved.

    • Jonathan Rigg
    •  & Lisa Reyes Mason
  • Comment |

    Extensive evidence reveals that Earth’s snow cover is declining, but our ability to monitor trends in mountain regions is limited. New satellite missions with robust snow water equivalent retrievals are needed to fill this gap.

    • Kat J. Bormann
    • , Ross D. Brown
    • , Chris Derksen
    •  & Thomas H. Painter
  • Comment |

    The current focus on the long-term global warming potential in climate policy-making runs the risk of mitigation options for short-lived climate pollutants being ignored, and tipping points being crossed. We outline how a more balanced perspective on long- and short-lived climate pollutants could become politically feasible.

    • Lukas P. Fesenfeld
    • , Tobias S. Schmidt
    •  & Alexander Schrode
  • Comment |

    Indigenous reindeer herding in the circumpolar North is threatened by multiple drivers of environmental and social changes that affect the sustainability of traditional family-based nomadic use of pastures. These impacts are exacerbated by indigenous peoples’ lack of voice in governance strategies, management and adaptation responses.

    • Inger Marie Gaup Eira
    • , Anders Oskal
    • , Inger Hanssen-Bauer
    •  & Svein Disch Mathiesen
  • Comment |

    Bitcoin is a power-hungry cryptocurrency that is increasingly used as an investment and payment system. Here we show that projected Bitcoin usage, should it follow the rate of adoption of other broadly adopted technologies, could alone produce enough CO2 emissions to push warming above 2 °C within less than three decades.

    • Camilo Mora
    • , Randi L. Rollins
    • , Katie Taladay
    • , Michael B. Kantar
    • , Mason K. Chock
    • , Mio Shimada
    •  & Erik C. Franklin
  • Comment |

    Scenarios have supported assessments of the IPCC for decades. A new scenario ensemble and a suite of visualization and analysis tools is now made available alongside the IPCC 1.5 °C Special Report to improve transparency and re-use of scenario data across research communities.

    • Daniel Huppmann
    • , Joeri Rogelj
    • , Elmar Kriegler
    • , Volker Krey
    •  & Keywan Riahi
  • Comment |

    Climate change mitigation scenarios are finding a wider set of users, including companies and financial institutions. Increased collaboration between scenario producers and these new communities will be mutually beneficial, educating companies and investors on climate risks while grounding climate science in real-world needs.

    • Christopher Weber
    • , David L. McCollum
    • , Jae Edmonds
    • , Pedro Faria
    • , Alban Pyanet
    • , Joeri Rogelj
    • , Massimo Tavoni
    • , Jakob Thoma
    •  & Elmar Kriegler
  • Comment |

    Biological communities beneath Antarctic ice shelves remain a mystery, hampering assessment of ecosystem development after ice-shelf collapse. Here we highlight major gaps in understanding of the patterns and processes in these areas, and suggest effective ways to study the ecological impacts of ice-shelf loss under climate change.

    • Jeroen Ingels
    • , Richard B. Aronson
    •  & Craig R. Smith
  • Comment |

    Climate change will almost certainly cause millions of deaths. Climate engineering might prevent this, but benefits — and risks — remain mostly unevaluated. Now is the time to bring planetary health research into climate engineering conversations.

    • Colin J. Carlson
    •  & Christopher H. Trisos
  • Comment |

    The SDGs and CitiesIPCC offer an unprecedented opportunity for urban transformation, but bold, integrated action to address the constraints imposed by economic, cultural and political dynamics is needed. We move beyond a narrow, technocentric view and identify five key knowledge pathways to catalyse urban transformation.

    • Patricia Romero-Lankao
    • , Harriet Bulkeley
    • , Mark Pelling
    • , Sarah Burch
    • , David J. Gordon
    • , Joyeeta Gupta
    • , Craig Johnson
    • , Priya Kurian
    • , Emma Lecavalier
    • , David Simon
    • , Laura Tozer
    • , Gina Ziervogel
    •  & Debashish Munshi
  • Comment |

    Transformation is required for cities to fulfil their leadership potential on climate change. Five action pathways can guide them: integrate mitigation and adaptation; coordinate risk reduction and climate adaptation; cogenerate risk information; focus on disadvantaged populations; and improve governance and knowledge networks.

    • Cynthia Rosenzweig
    •  & William Solecki
  • Comment |

    To realize ambitious climate targets, research should focus more on effective ways to encourage rapid and wide-scale changes in climate mitigation actions, and less on understanding climate change beliefs.

    • Linda Steg
  • Comment |

    With country-specific development objectives and constraints, multiple market failures and limited international transfers, carbon prices do not need to be uniform across countries, but must be part of broader policy packages.

    • Chris Bataille
    • , Céline Guivarch
    • , Stephane Hallegatte
    • , Joeri Rogelj
    •  & Henri Waisman
  • Comment |

    A well-defined relationship between global mean sea-level rise and cumulative carbon emissions can be used to inform policy about emission limits to prevent dangerous and essentially permanent anthropogenic interference with the climate system.

    • Peter U. Clark
    • , Alan C. Mix
    • , Michael Eby
    • , Anders Levermann
    • , Joeri Rogelj
    • , Alexander Nauels
    •  & David J. Wrathall
  • Comment |

    The atmospheric concentration of CO2 at the time of passing 1.5 °C or 2 °C is unknown due to uncertainties in climate sensitivity and the concentrations of other GHGs. Impacts studies must account for a wide range of concentrations to avoid either over- or underestimating changes in crop yields and land and marine biodiversity.

    • Richard A. Betts
    •  & Doug McNeall
  • Comment |

    In key European cities, stabilizing climate warming at 1.5 °C would decrease extreme heat-related mortality by 15–22% per summer compared with stabilization at 2 °C.

    • Daniel Mitchell
    • , Clare Heaviside
    • , Nathalie Schaller
    • , Myles Allen
    • , Kristie L. Ebi
    • , Erich M. Fischer
    • , Antonio Gasparrini
    • , Luke Harrington
    • , Viatcheslav Kharin
    • , Hideo Shiogama
    • , Jana Sillmann
    • , Sebastian Sippel
    •  & Sotiris Vardoulakis
  • Comment |

    Climate change-driven alterations in storminess pose a significant threat to global capture fisheries. Understanding how storms interact with fishery social-ecological systems can inform adaptive action and help to reduce the vulnerability of those dependent on fisheries for life and livelihood.

    • Nigel C. Sainsbury
    • , Martin J. Genner
    • , Geoffrey R. Saville
    • , John K. Pinnegar
    • , Clare K. O’Neill
    • , Stephen D. Simpson
    •  & Rachel A. Turner
  • Comment |

    The benefits of limiting global warming to the lower Paris Agreement target of 1.5 °C are substantial with respect to population exposure to heat, and should impel countries to strive towards greater emissions reductions.

    • Andrew D. King
    • , Markus G. Donat
    • , Sophie C. Lewis
    • , Benjamin J. Henley
    • , Daniel M. Mitchell
    • , Peter A. Stott
    • , Erich M. Fischer
    •  & David J. Karoly
  • Comment |

    Low-probability, high-consequence climate change events are likely to trigger management responses that are based on the demand for immediate action from those affected. However, these responses may be inefficient and even maladaptive in the long term.

    • Sarah E. Anderson
    • , Ryan R. Bart
    • , Maureen C. Kennedy
    • , Andrew J. MacDonald
    • , Max A. Moritz
    • , Andrew J. Plantinga
    • , Christina L. Tague
    •  & Matthew Wibbenmeyer
  • Comment |

    New international governance arrangements that manage environmental risk and potential conflicts of interests are needed to facilitate negative emissions research that is essential to achieving the large-scale CO2 removal implied by the Paris Agreement targets.

    • Kerryn Brent
    • , Jeffrey McGee
    • , Jan McDonald
    •  & Eelco J. Rohling
  • Comment |

    Current and future climate change poses a substantial threat to the African continent. Young scientists are needed to advance Earth systems science on the continent, but they face significant challenges.

    • Victor Nnamdi Dike
    • , Martin Addi
    • , Hezron Awiti Andang’o
    • , Bahar Faten Attig
    • , Rondrotiana Barimalala
    • , Ulrich Jacques Diasso
    • , Marcel Du Plessis
    • , Salim Lamine
    • , Precious N. Mongwe
    • , Modathir Zaroug
    •  & Valentine Khasenye Ochanda
  • Comment |

    Literature reviews can help to inform decision-making, yet they may be subject to fatal bias if not conducted rigorously as ‘systematic reviews’. Reporting standards help authors to provide sufficient methodological detail to allow verification and replication, clarifying when key steps, such as critical appraisal, have been omitted.

    • Neal Robert Haddaway
    •  & Biljana Macura
  • Comment |

    Until recently, national bans on fossil fuel-related activities were a taboo subject, but they are now becoming increasingly common. The logic of appropriateness that underpins such bans is key to understanding their normative appeal, and to explaining and predicting their proliferation.

    • Fergus Green
  • Comment |

    Ambition regarding climate change at the national level is critical but is often calibrated with the projected costs — as estimated by a small suite of energy–economic models. Weaknesses in several key areas in these models will continue to distort policy design unless collectively addressed by a diversity of researchers.

    • Alexander R. Barron
  • Comment |

    China recently announced its national emissions trading scheme, advancing market-based approaches to cutting greenhouse gas emissions. Its evolution over coming years will determine whether it becomes an effective part of China’s portfolio of climate policies.

    • Frank Jotzo
    • , Valerie Karplus
    • , Michael Grubb
    • , Andreas Löschel
    • , Karsten Neuhoff
    • , Libo Wu
    •  & Fei Teng
  • Comment |

    Awareness of the threats to mental health posed by climate change leads to questions about the potential impacts on climate scientists because they are immersed in depressing information and may face apathy, denial and even hostility from others. But they also have sources of resilience.

    • Susan Clayton
  • Comment |

    Research on climate change mitigation tends to focus on supply-side technology solutions. A better understanding of demand-side solutions is missing. We propose a transdisciplinary approach to identify demand-side climate solutions, investigate their mitigation potential, detail policy measures and assess their implications for well-being.

    • Felix Creutzig
    • , Joyashree Roy
    • , William F. Lamb
    • , Inês M. L. Azevedo
    • , Wändi Bruine de Bruin
    • , Holger Dalkmann
    • , Oreane Y. Edelenbosch
    • , Frank W. Geels
    • , Arnulf Grubler
    • , Cameron Hepburn
    • , Edgar G. Hertwich
    • , Radhika Khosla
    • , Linus Mattauch
    • , Jan C. Minx
    • , Anjali Ramakrishnan
    • , Narasimha D. Rao
    • , Julia K. Steinberger
    • , Massimo Tavoni
    • , Diana Ürge-Vorsatz
    •  & Elke U. Weber
  • Comment |

    The new rules of the EU ETS will fundamentally change its character. The long-term cap on emissions will become a function of past and future market outcomes, temporarily puncturing the waterbed and having retroactive impacts on GHG abatement from overlapping policies.

    • Grischa Perino
  • Comment |

    Well-intended climate actions are confounding each other. Cities must take a strategic and integrated approach to lock into a climate-resilient and low-emission future.

    • Diana Ürge-Vorsatz
    • , Cynthia Rosenzweig
    • , Richard J. Dawson
    • , Roberto Sanchez Rodriguez
    • , Xuemei Bai
    • , Aliyu Salisu Barau
    • , Karen C. Seto
    •  & Shobhakar Dhakal