Our Common Future Under Climate Change

International Scientific Conference 7-10 JULY 2015 Paris, France

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Wednesday 8 July - 14:30-16:00 UNESCO Fontenoy - ROOM VI

2204 - A world above 2°C global warming: understanding risks and developing transformative solutions

Parallel Session

Lead Convener(s): D. Murtagh (University of Exeter, Exeter, United Kingdom), B. O'neill (National Center for Atmospheric Research, Boulder, CO, United States of America)

Convener(s): P. Harrison (University of Oxford, Oxford, United Kingdom), J. Rockström (Stockholm Resilience Center, Stockholm, Sweden), R. Betts (University of Exeter, Exeter, United Kingdom)

14:30

Transformative solutions to high-end climate change

D. Tabara (Independent consultant - UAB, Barcelona, Spain), J. Jaeger (Independent Consultant, Vienna, Austria), P. Harrrison (Environmental Change Institute, University of Oxford, Oxford, United Kingdom), I. Holman (Cranfield University, Cranfield, United Kingdom)

Abstract details
Transformative solutions to high-end climate change

D. Tabara (1) ; J. Jaeger (2) ; P. Harrrison (3) ; I. Holman (4)
(1) Independent consultant - UAB, ICTA, Barcelona, Spain; (2) Independent Consultant, Vienna, Austria; (3) Environmental Change Institute, University of Oxford, Oxford, United Kingdom; (4) Cranfield University, Cranfield, United Kingdom

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Current trends in greenhouse gas emissions show that limiting global warming to the international target of 2°C is likely to be difficult. Despite the increasing plausibility of high-end scenarios, there are few studies that assess transformative strategies and solutions to address potential synergies and trade-offs between adaptation, mitigation and sustainable development. The latest IPCC AR5 report defines transformation as ‘a change in the fundamental attributes of natural and human systems […that…] reflects strengthened, altered, or aligned paradigms, goals, or values towards promoting adaptation that supports sustainable development, including poverty reduction’ (IPCC 2014; WGII, SPM p.5). However, the notion and implications of transformation in climate science and policy are poorly understood. On the one hand, transformation is an autonomous dimension which does not depend on, or is not necessarily conditioned by, either mitigation or adaptation strategies. But on the other hand, transformative adaptation and transformative mitigation policies can contribute to the development of decisive systems’ innovations to cope with high-end scenarios, while at the same time fostering sustainable development. To achieve this goal, knowledge and new modelling tools on how to develop and implement ‘global systems of interconnected solutions’ are urgently required. The new emerging Global Systems Science (GSS) is a promising approach which could support Integrated Climate Governance by looking at new modes of science appraisal, global governance arrangements and engagement with stakeholders. In particular, innovative climate strategies and solutions could take advantage of, and support, a number of global transformative forces already evident outside of the strictly climate domain. These include: 1. Increasing interest in the creation of a global citizenship, e.g., to redistribute global climate rights and responsibilities; 2. The development of win-win solutions to generate a global green low-carbon economy, to replace the brown economy; 3. Opening Human Information and Knowledge Systems (HIKS) and coupling them with Social-Ecological Change, to connect knowledge networks and agents globally to deal with specific sustainability needs and problems; and 4. The generation of distributed and conducive conditions for global cooperation and institutional capacity building, to ensure the equitable implementation of transformative strategies and policies in the long-term. This presentation will introduce this cluster of interconnected systems of global solutions, referred to as the ‘Global Transformation Propeller’, and suggest how it could be used to develop and implement transformative responses in the face of high-end scenarios. Our goal is to stimulate an open debate to explore the implications for climate science and policy of existing or potential transformative forces that can be connected to innovative solutions which are able to cope with HES while supporting sustainable development.
14:43

Avoiding the impacts of climate change: Results from the BRACE study

B. O'neill (National Center for Atmospheric Research (NCAR), Boulder, CO, United States of America)

Abstract details
Avoiding the impacts of climate change: Results from the BRACE study

B. O'neill (1)
(1) National Center for Atmospheric Research (NCAR), Boulder, CO, United States of America

Abstract content
Understanding the potential consequences of climate change for ecosystems and society is necessary for an informed response to the climate issue. A particularly important task is improving our understanding of how impacts differ across alternative levels of future climate change. Such understanding can help inform the balancing of the costs of climate change mitigation and adaptation with the benefits of reduced impacts. This talk will present results from a project led by the National Center for Atmospheric Research (NCAR) on the Benefits of Reduced Anthropogenic Climate changE (BRACE), which assesses the differences in impacts between two specific climate futures: those associated with Representative Concentration Pathways (RCPs) 4.5 and 8.5. The latter would lead to a likely global average temperature change of 3.2-5.4 C relative to pre-industrial temperatures by the end of the century, the former to a likely range of 1.7-3.2 C degrees of warming. This project is quantifying avoided impacts in terms of extreme events, health, agriculture, tropical cyclones, and sea level rise. Methodologically, it combines climate modeling, statistical analysis, and impact assessment to examine physical, ecological, and societal impacts, and draws heavily on the use of large initial condition ensembles of climate model simulations in order to better account for internal variability and extreme events and to develop new approaches to pattern scaling techniques. Results show that the benefits of reduced climate change vary substantially across sectors, and depend importantly on assumptions about future societal conditions.
14:56

Understanding and Addressing Infinite and Existential Climate Risks

J. Rockström (Stockholm Resilience Center, Stockholm, Sweden)

Abstract details
Understanding and Addressing Infinite and Existential Climate Risks

J. Rockström (1)
(1) Stockholm Resilience Center, Stockholm university, Stockholm, Sweden

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Scientific evidence indicates humanity has entered a new geological epoch, the Anthropocene, where the world entreprise constitutes the largest driver of change at the planetary scale. Furthermore, we increasingly find evidence that the social and environmental response to rising human pressures on the planet are non-linear, and that the globalized world of the 21st century is associated with rising social-ecological turbulence. This raises the need to better understand risks of facing infinite or existential risks, i.e., risks that may affect a significant proportion of the global population or the entire world community. In this presentation a presentation is made of a scientific methodology to investigate infinite risks, including global climate risks, and a first assessment of global risks is presented, and compared, e.g,. with the WEF global risk report.
15:09

Sensitivity of Amazonia to climate change: the main uncertainties are effects of Drought, Elevated Temperature and Elevated CO2

B. Kruijt (Alterra, wageningen UR, Wageningen, Netherlands), C. Von Randow (Instituto Nacional de Pesquisas Espaciais, Sao Jose dos Campos, SP, Brazil), H. Verbeeck (University of Gent, Gent, Belgium), P. Meir (University of Edinburgh, Edinburgh, United Kingdom), D. H. De (University of Gent, Gent, Belgium), W. Jans (Alterra, wageningen UR, Wageningen, Netherlands), L. Rowland (University of Edinburgh, Edinburgh, United Kingdom), B. Christoffersen (University of Edinburgh, Edinburgh, United Kingdom), D. Galbraith (University of Leeds, Leeds, United Kingdom), A. Rammig (Potsdam Institut fuer Klimaforshung, Potsdam, Germany), C. Seiler (University of Victoria, Victoria, Canada)

Abstract details
Sensitivity of Amazonia to climate change: the main uncertainties are effects of Drought, Elevated Temperature and Elevated CO2

B. Kruijt (1) ; C. Von Randow (2) ; H. Verbeeck (3) ; P. Meir (4) ; DH. De (3) ; W. Jans (1) ; L. Rowland (4) ; B. Christoffersen (4) ; D. Galbraith (5) ; A. Rammig (6) ; C. Seiler (7)
(1) Alterra, wageningen UR, Wageningen, Netherlands; (2) Instituto Nacional de Pesquisas Espaciais, Ccst, Sao Jose dos Campos, SP, Brazil; (3) University of Gent, Gent, Belgium; (4) University of Edinburgh, School of geosciences, Edinburgh, United Kingdom; (5) University of Leeds, Leeds, United Kingdom; (6) Potsdam Institut fuer Klimaforshung, Potsdam, Germany; (7) University of Victoria, Victoria, Canada

Abstract content
Amazonia is under threat of the combined effects of unsustainable regional development and climate change. As summarised in the IPCC reports of 2007 and 2014, studies in the past ten years indicate that these pressures can lead to deforestation, regional and global disturbance of temperatures and the water cycle, as well as causing loss of carbon stocks and biodiversity. In turn, these transitions can result in forest loss, droughts, low river levels, floods, loss of hydropower energy and plenty of other ecosystem services. Even enhanced risk of livestock and human diseases and loss of agricultural productivity are inextricably related to these stressful alterations. Recognising that processes driving land-use change and fire in Amazonia are of overriding importance, here we address three biophysical uncertainties related to the impact of climate change on Amazonia: the effects of drought, elevated temperature and elevated CO2. Model experiments have shown repeatedly that these factors represent the highest uncertainly in projecting climate change impacts.

The EU-FP7 AMAZALERT project has investigated the threats through combining novel field measurements with modelling of feedbacks between Amazonian ecosystems, human-caused land-use change and the climate system. Field measurements indicate that leaf level maximum rate of photosynthesis is not significantly affected by temperature increases. Thus, also with climate change, trees may be well able to maintain high rates of photosynthesis, however, this negative temperature sensitivity is currently overestimated in vegetation models. Data from experimentally droughted forest and of dry years show that in particular large trees of some tree species, are vulnerable to drought, thus potentially risking significant biomass losses. Besides, prolonged (multi-year) drought appears to eventually lead to higher respiration rates, i.e., less efficient growth. However, basin-wide plot measurements indicate that at short timescales (months) forests are able to remain net primary production at constant level during, for example, the 2010 drought but photosynthesis was suppressed, autotrophic respiration decreased and carbon allocation patterns changed potentially leading to increased post-drought forest mortality. Such observations provide important insights for model development at the physiological level. The net effect means that under extended drought and warming, if no fire occurs, a long-term change in the species composition and structure of the forest is likely, together with an increase in the amount of dead and decomposing wood, potentially turning the forest into a carbon source.

The effects of increasing atmospheric CO2 on Amazonian forests can so far only be assessed from theory, which predicts that the forests may become more robust and may even grow through ‘CO2 fertilisation’, but this fertilisation effect is limited by the availability of nutrients such as nitrogen and phosphorus. At the same time, theory and some data sets predict that water use efficiency will increase, which may increase forest resistance but also l decrease water cycling, potentially causing a climate warming feedback. The magnitude of these limiting effects is still uncertain due to poor understanding of soil nutrient dynamics and this must be improved by rigorously combining measurements and new modelling approaches. Altogether, it is clear that new data are needed and it is essential that these processes will be investigated in a new, whole-ecosystem elevated CO2 experiment such as the AMAZON_FACE experiment which is currently being set up in the Amazon basin. These should be combined with other focused research projects further addressing drought and temperature dependence.
15:22

Implications of growing CO2 emissions for staying below the 2°C limit

P. Friedlingstein (University of Exeter, Exeter, United Kingdom)

Abstract details
Implications of growing CO2 emissions for staying below the 2°C limit

P. Friedlingstein (1)
(1) University of Exeter, Exeter, United Kingdom

Abstract content
Efforts to limit climate change below a given temperature level require that global emissions of CO2 cumulated over time remain below a limited quota. This quota varies depending on the temperature level, the desired probability of staying below this level and the contributions of other gases. In spite of this restriction, global emissions of CO2 from fossil fuel combustion and cement production have continued to grow by 2.5% per year on average over the past decade. Two thirds of the CO2 emission quota consistent with a 2 °C temperature limit has already been used, and the total quota will likely be exhausted in a further 30 years at the 2014 emissions rates. I present recent analysis showing that CO2 emissions track the high end of the latest generation of emissions scenarios, due to lower than anticipated carbon intensity improvements of emerging economies and higher global gross domestic product growth. In the absence of more stringent mitigation, these trends are set to continue and further reduce the remaining quota until the onset of a potential new climate agreement in 2020. Breaking current emission trends in the short term is key to retaining credible climate targets within a rapidly diminishing emission quota.
15:35

Panel discussion

R. Betts (University of Exeter, Exeter, United Kingdom), D. Tabara (Independent consultant, Barcelona, Spain), B. O'neill (National Center for Atmospheric Research, Boulder, CO, United States of America), J. Rockström (Stockholm Resilience Centre, Stockholm, Sweden), B. Kruijt (Alterra, wageningen UR, Wageningen, Netherlands)

Abstract details
Panel discussion
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