Our Common Future Under Climate Change

International Scientific Conference 7-10 JULY 2015 Paris, France

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Wednesday 8 July - 15:00-16:30 UPMC Jussieu - ROOM 101 - Block 24/34

2202 - Turn down the Heat: Climate Change Impacts, Development and Lock-in

Parallel Session

Lead Convener(s): C. Reyer (Potsdam Institute for Climate Impact Research, Potsdam, Germany)

Convener(s): N. Arnell (University of Reading, Reading, United Kingdom), E. Critchley (Grantham Institute, Imperial College London, London, United Kingdom), J. Dangerman (Potsdam Institute for Climate Impact Research, Potsdam, Germany), B. Hare (Climate Analytics, Berlin, Germany), K. Kumari (World Bank, Washington D.C., United States of America), J. Lowe (Met Office, Exeter, United Kingdom), O. Serdecny (Climate Analytics, Berlin, Germany), H.J. Schellnhuber (Potsdam Institute for Climate Impact Research, Potsdam, Germany), D. Urge-Vorsatz (Center for Climate Change and Sustainable Energy Policy (3CSEP), Budapest, Hungary), R. Warren (Tyndall Centre, University of East Anglia, Norwich, United Kingdom)


Development and the New Climate Normal

M. Fay (World Bank, -, United States of America), R. Kyte (World Bank, Washington D.C., United States of America)

Abstract details
Development and the New Climate Normal

R. Kyte (1)
(1) World Bank, Washington D.C., United States of America

Abstract content

As the planet warms, heat and other weather extremes which occur once in hundreds of years, if ever, and considered highly unusual or unprecedented today would become the “new climate normal” as we approach 4°C. Ending poverty, increasing global prosperity and reducing global inequality, already difficult, will be much harder with 2°C warming, but at 4°C there is serious doubt whether this can be achieved at all. The urgency for action is even more critical, with growing evidence that warming close to 1.5°C above pre-industrial levels is locked-in to the Earth’s atmospheric system.

The consequences for development would be severe as crop yields decline, water resources change, diseases move into new ranges, and sea levels rise. This presentation will look at the consequences of increased warming for the key geographic regions that the World Bank Group is engaged in, and action areas which are urgently needed to confront the development challenge.  [A new global climate agreement in Paris this year needs to speak as loudly of economic transformation as it does of carbon emissions target.  2015 is a critical year for countries to re-think the way they manage their economies]. It’s increasingly clear that smart policy choices can deliver economic, health and climate benefits. Come hear how the Bank is working with client counties to address this unprecedented challenge.


The implications of climate mitigation policy for the impacts of climate change

N. Arnell (University of Reading, Reading, United Kingdom)

Abstract details
The implications of climate mitigation policy for the impacts of climate change

N. Arnell (1)
(1) University of Reading, Walker institute, Reading, United Kingdom

Abstract content

The broad aim of climate mitigation policy is to avoid the dangerous impacts of climate change. The definition of ‘dangerous’ is of course contested, and there are many potential definitions. The Copenhagen Accord states the aspiration of limiting the increase in global mean temperature to 2oC above pre-industrial levels, and other groups are urging lower temperature targets. Meanwhile, existing and new pledges for future emissions will imply different – and probably larger – increases in global temperature. Most attention is given to the economic, technical, political and social implications of achieving specific emissions reductions, but it is also necessary to assess the impacts that are avoided or delayed by mitigation policies. This is partly because it helps define the benefits of climate mitigation, and partly because it highlights the impacts that remain: this helps inform national and international adaptation policies.

This keynote talk will present results from the UK AVOID programme, which is concerned with both identifying and quantifying impacts of climate change under different potential emissions pathways and assessing the technical and economic feasibility of these pathways. The focus of this presentation is on the impacts avoided and delayed by climate mitigation. It considers global and regional impacts on a range of sectors including water resources, flooding, agriculture and energy demand, and evaluates how these impacts are affected – globally and regionally – under different mitigation pathways. The effects of climate change and mitigation policy are expressed in terms of the magnitude of impact and the risks of impacts exceeding specific thresholds.

The presentation concludes by reviewing the key issues involved in assessing the implications of climate mitigation policy for impacts, which include the representation of adaptation within global-scale impact assessments, the treatment of uncertainties, and the presentation of results in terms meaningful to climate policymakers and negotiators.


[Keynote for 2202 - Visions of Global Responses to Climate Change] - Unlocking the lock-in

D. Urge-Vorsatz (Central European University, Budapest, Hungary), J. Dangerman (Potsdam Institute for Climate Impact Research, Potsdam, Germany)

Abstract details
[Keynote for 2202 - Visions of Global Responses to Climate Change] - Unlocking the lock-in

J. Dangerman (1)
(1) Potsdam Institute for Climate Impact Research, Potsdam, Germany

Abstract content

This keynote will discuss the central dynamics of complex systems that determine change and lack of change. Or, in more specific terms, that determine transformation and lock-in. It will also present a case that illustrates these dynamics and their effects in practice.

Important portions of yesterday's and today’s socio-technological-political decisions extrapolate the past into the future and thereby profoundly constrain the possibilities of important systems to transform themselves non-catastrophically so that they can help mitigate their current and future effect on climate change and the ensuing impacts on nature and humanity. The transpiring rigidification of these systems is eminent from essential perspectives and in fact provides grounds for structural alternative decisions. However, the constraints caused are often underestimated and misinterpreted and the accompanying alternative decisions are frequently not so profoundly breaking with the past. The development of a key actor in climate change, the global energy system, provides ample examples of these instances and on a macro-scale shows the ensuing lock-in patterns.

This keynote therefore provides a simple and stylised view on the universal workings of the fundamental dynamics that determine the behavior of evolving complex systems, such as cells, the human brain, organisms, organisations, technologies, societies and economies. It uses the concepts of effectiveness & efficiency and chaos & organisation in the context of the cyclical and periodical behaviour of these systems to explain the dynamics of both transformation and lock-in.

It ends with a discussion of a research case about the role of energy efficiency policies in the building industry (called "Best Practice Policies for Low Carbon & Energy Buildings Based on Scenario Analysis, authored by the Center For Climate Change And Sustainable Energy Policy, Central European University) to elucidate the lock-in dynamics, their consequences and their implications for policy making. Three scenarios explain the potential for the buildings sector to mitigate energy consumption in China, the EU, India and the USA. The most ambitious scenario shows the benefit and necessity of taking today’s best practice to a global scale.


Hydrological variability, transboundary floods and institutions: an exploration of tomorrow's bottlenecks

M. Bakker (Utrecht University, Utrecht, Netherlands), J. Duncan, (University of Vermont, Vermont, United States of America)

Abstract details
Hydrological variability, transboundary floods and institutions: an exploration of tomorrow's bottlenecks

M. Bakker (1) ; J. Duncan, (2)
(1) Utrecht University, Utrecht, Netherlands; (2) University of Vermont, Vermont, United States of America

Abstract content

Floods are among the world’s most frequent and damaging types of disasters and annually affect the lives of millions all over the globe. Over time, human exposure and vulnerability to floods has increased with a growing and increasingly urbanized population. The projected effects of climate change on hydrology, aggravated by a range of social, economic and political processes will continue to increase this vulnerability. Nonetheless, vulnerability of societies and their institutions to floods remains poorly understood.


Using global data, we examine the nexus of transboundary flood events and social vulnerability: which international river basins (IRBs) have experienced transboundary floods, i.e. floods that affect two or more countries, in the past, and which are forecast to experience increased hydrological variability in the future, but lack institutional provisions, i.e. river basin organizations and/or treaties, to deal with these shared events?


Current data and research on institutional capacity deriving from treaties as listed in the Transboundary Freshwater Dispute Database (Yoffe, Ward and Wolf, 2000; De Stefano et al. 2012) will be refined by looking more specifically at the roles that river basin organization functioning and treaty composition play in flood management. IRBs will be stratified by the type of climate-related stress they may face in terms of hydrological change and the aspects of society most affected by flooding. Then, this updated information will be merged and weighted to produce a vulnerability ranking specific to floods and the institutions designed to manage them.

Results and conclusions

A global vulnerability ranking of IRBs and cities when it comes to transboundary floods, climate-driven hydrological variability and institutional capacity.

Societal relevance

The findings of this research will significantly increase our current knowledge on transboundary flood events, projected variability regimes related to the shared waters between countries, and flood-related international institutional capacity. These insights will help policy-makers of tomorrow identify and evaluate potential tipping points related to transboundary river floods.


Past and future weather-induced risk in agriculture

J. Elliott (University of Chicago, Chicago, United States of America), C. Müller (Potsdam Institute for Climate Impact Research, Potsdam, Germany)

Abstract details
Past and future weather-induced risk in agriculture

J. Elliott (1) ; C. Müller (2)
(1) University of Chicago, Chicago, United States of America; (2) Potsdam Institute for Climate Impact Research, Potsdam, Germany

Abstract content

The global food system has seen increased volatility in recent years, with spiking food prices blamed for civil unrest on several continents. Rising prices for global commodity products like maize, soy, meat and palm are increasingly driving deforestation around the globe, and with agriculture increasingly interconnected to global food and energy markets, weather-related risk and supply-side shocks have become a key issue of concern for governments and businesses alike. Speculation about the risk of future large-scale extremes have led some authors to contend that more people will suffer in future from large-scale drought and heat events than any other climate-change-related disaster. 

Using best-available archives of global crop and climate models from the Agricultural Model Intercomparison and Improvement Project (AgMIP) and the Intersectoral Impact Model Intercomparison (ISI-MIP), we look first at the impacts of 65 years of continental and global extreme events using observation-driven models and data. We identify the most severe historical events in caloric terms at national to global scales and evaluate the ability of models and model ensembles to identify weather-induced extreme years, correctly assess the magnitude of large-scale extreme events, reproduce historical country-level variability, and reproduce spatial patterns of losses under extreme drought.

We next consider these global crop models driven with large ensembles of climate model output (both under historical forcing and with future scenarios) to characterize present day risk and the extent of non-stationary risk in global crop production. We find increasing, and in many cases accelerating risk, of extreme global loss events even in scenarios with little to no climate-induced long-term mean changes. In some cases, global-scale production loss events that would have recently been called 1-in-100 year events are estimated to occur every 30 years by mid-century, and ever 10-20 years by end-of-century.

We present these scenarios and consider regional and global protective measures that might be introduced, including increased trade, stock-hoarding, crop breeding, and improved forecasts, monitoring, and modeling. We also consider the extent to which aggressive carbon mitigation may decrease the risk of extreme loss events in future. 


Climate indicators of pace and perception of changes over the 21st century

Y. Chavaillaz (LSCE-IPSL, Gif-sur-Yvette, France), S. Joussaume (LSCE-IPSL, Gif-sur-Yvette, France), S. Bony (LMD-IPSL, Paris, France), P. Braconnot (LSCE-IPSL, Gif-sur-Yvette, France), R. Vautard (LSCE-IPSL, Gif-sur-Yvette, France)

Abstract details
Climate indicators of pace and perception of changes over the 21st century

Y. Chavaillaz (1) ; S. Joussaume (1) ; S. Bony (2) ; P. Braconnot (1) ; R. Vautard (1)
(1) LSCE-IPSL, Gif-sur-Yvette, France; (2) LMD-IPSL, Paris, France

Abstract content

In most studies, climate change is approached by focusing on the evolution between a fixed current baseline and a future period. They emphasize stronger warming and increasingly modified precipitation patterns as we move further from the current climate. This long-term vision is adopted in order to characterize quantitatively the magnitude and expected effects of mitigation policies across the globe, but is not well suited to discuss coming generations’ experience. In this study, we propose an alternative approach that considers indicators of pace and perception of changes using projections of a General Circulation Model ensemble. It first consists in tracking statistics and their projected changes with a 20-year running baseline, defining the time evolution of the pace at which climate changes on the scale of a generation. Then, distributions of the following and previous 20 years are compared for each year to theoretically assess the perception of changes. We focus here on the annual and seasonal evolution of surface air temperature and precipitation.

Under the strongest emission pathway (RCP8.5), the warming rate and its perception become far stronger over the 21st century, with a maximum reached around 2060. While northern high-latitudes witness a higher temperature rise, all other latitudes highlight at least a doubling in the warming rate and indicators of perception are at their highest value in the tropics, especially in West Africa and South-East Asia.

As for precipitation under the same pathway, moistening and drying rates strongly increase at global scale. Regions with significant rate of change expand more and more over the 21st century. Moreover, rate patterns tend to spatially stabilize, making them persistent in some regions that also exhibit the largest rates and the largest increases of rate by 2080: e.g. the Mediterranean Sea, Central America, South Asia and the Arctic.

These trends are already visible in the current period, but could almost disappear if strong mitigation policies were quickly implemented. Only the strongest mitigation pathway (RCP2.6) leads to a global return to historical regime. This approach shows that, under strong emissions, one should be prepared for higher adaptation rates in the coming decades regarding temperature and precipitation change.