Challenges and Opportunities for Integrated Modeling of Climate Engineering

Abstract

The Paris Agreement has set stringent temperature targets to limit global warming to 2°C above preindustrial level, with efforts to stay well below 2°C. At the same time, its bottom-up approach with voluntary national contributions makes the implementation of these ambitious targets particularly challenging. Climate engineering -both through carbon dioxide removal (CDR) and solar radiation management (SRM) -is currently discussed to potentially complement mitigation and adaptation. Results from integrated assessment models already suggest a significant role for some forms of climate engineering in achieving stringent climate objectives 1 . However, these estimates and their underlying assumptions are uncertain and currently heavily debated [2][3][4] . By reviewing the existing literature and reporting the views of experts, we identify research gaps and priorities for improving the integrated assessment of climate engineering. Results point to differentiated roles of CDR and SRM as complementary strategies to the traditional ones, as well as diverse challenges for an adequate representation in integrated assessment models. We identify potential synergies for model development which can help better represent mitigation and adaptation challenges, as well as climate engineering. Motivation

Negative emissions and international climate goals—learning from and about mitigation scenarios

“…23 Canadell and Raupach (2008), Strengers et al (2008), Edmonds et al (2013), Fuss et al (2013, Kriegler et al (2013a), Tavoni and Socolow (2013), Bibas and Méjean (2014), Blanford et al (2014a), Kriegler et al (2014), Popp et al (2014), Selosse and Ricci (2014), Vaughan and Gough (2016), Gambhir et al (2017), Marcucci et al (2017, Mintenig et al (2017), Tavoni et al (2017, Holz et al (2018), Obersteiner et al (2018, Sanchez et al (2018), Séférian et al (2018), Strefler et al (2018, Vaughan et al (2018) Others O7…”

“…2014),Humpenöder et al (2014),Kober et al (2014),Popp et al (2014),Selosse and Ricci (2014),,van Sluisveld et al (2013),Eom et al (2015),Leibowicz et al (2016),Mouratiadou et al (2016),Calvin et al (2017),Marcucci et al (2017),Tavoni et al (2017),Sanchez et al (2018),Séférian et al (2018), Vaughan et al reductions rates have been scarcely reported in the past but remain central to climate action. Mid-term gross CO2 emission reduction rates envisaged in scenarios have no historical precedence.…”

“…Azar et al (2006),Klein et al (2011), van Vuuren et al (2013,Koelbl et al (2014),Luderer et al (2016b),Manoussi et al (2017),Mintenig et al (2017),Tavoni et al (2017),Holz et al (2018),Kober et al (2018),Lehtilä and Koljonen (2018),Luderer et al (2018),Rickels et al (2018) Mitigation costsC1Lower_costsThe availability and use of NET lower carbon prices and so decrease aggregated discounted mitigation costs. Any techno-economic limitations of NETs would result in an increase of mitigation costs (e.g.…”

“…Chen and Tavoni et al (2013),Fuss et al (2013),Tavoni and Socolow (2013),van Vuuren et al (2013),Blanford et al (2014b),Manoussi et al (2017),Tavoni et al (2017),Keller et al (2018),Obersteiner et al (2018),Rickels et al (2018) Earth System/NET interactionsE4 Tipping_points Temperature overshoot associated with NET deployments increasing the risks of triggering climate tipping points. High temperature overshoot decreases the probability of meeting climate targets.…”

The role of large—scale BECCS in the pursuit of the 1.5°C target: an Earth system model perspective

“…BECCS has furthermore been much discussed as a policy option in the integrated assessment modelling (IAM) literature (e.g. Fuss et al 2014, Azar et al 2013, Smith et al 2016, Klein et al 2014, Tavoni et al 2017. Vaughan and Gough (2016) found, however, that assumptions concerning the availability of BECCS in future IAM scenarios are too optimistic according to expert judgment, and this could indeed lead to overshoot of temperature targets with a substantial bearing on near-term mitigation options.…”