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Emission targets for avoiding dangerous climate change Niel Bowerman Supervisors: Prof. Myles Allen, Prof. David Frame and Dr. Jason Lowe Word Count: 4,578 words plus 10,047 word peer-‐reviewed paper Date: 18 August 2011

A t m o s p h e r i c , O c e a n i c & P l a n e t a r y P h y s i c s , D e p a r t m e n t o f P h y s i c s , U n i v e r s i t y o f O x f o r d , P a r k s R o a d , O x f o r d O X 1 3 P U , U K

Confirmation of Status Report 2

08 Fall


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Table of contents Table of contents ...................................................................................................................... 3 1 Overview ............................................................................................................................ 4 2 Progress report ................................................................................................................... 6 2.1 Progress of projects .................................................................................................... 6 2.1.1 Cumulative emission targets, rates of warming and emission floors ......... 6 2.1.2 Allowable emissions in 2020 and 2050 to stay below 2°C ............................. 6 2.1.3 The impact of short-‐‑ and long-‐‑lived forcing agents on peak warming ....... 6 2.1.4 Forecasting emissions ......................................................................................... 6 2.1.5 Trading short-‐‑ and long-‐‑lived forcing agents ................................................. 7 2.1.6 Updating Allen et al. (2009) ................................................................................ 7 2.1.7 Does climate uncertainty mean we will need large scale air capture? ........ 7

2.2 Progress chart ............................................................................................................. 8 2.3 Gantt chart ................................................................................................................... 9

3 The impact of short-‐‑ and long-‐‑lived forcing agents on peak warming ................... 11 3.1 Preamble .................................................................................................................... 11 3.2 Impact of short-‐‑lived forcing agents? .................................................................... 11 3.3 References .................................................................................................................. 12 3.4 Figures ........................................................................................................................ 13

References ............................................................................................................................... 14 Appendix A: Book chapter on cumulative emissions ................................................... 17 Appendix B: MPhys project .............................................................................................. 19 Appendix C: Poster on the climatic implications of using large scale air capture ... 21 Appendix D: Bowerman et al. (2011) ............................................................................... 23 Appendix E: Poster on comparing the impact of forcing agents ................................ 25

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1 Overview A substantial fraction of the carbon dioxide (CO2) released into the atmosphere by human activity remains there, in effect, for centuries to millennia. Changes in ocean chemistry, which can be described through the Revelle buffer factor (Archer 2005) limit oceanic removal of CO2 (Solomon, et al. 2009) while the potential for terrestrial vegetation to take up CO2 is also predicted to fall as the climate warms (Cox, et al. 2000), although the size of this feedback is uncertain (Friedlingstein, et al. 2006). Complete removal requires geological timescales, (Le Quere, et al. 2009) or assistance from large-‐‑scale air capture technologies (e.g. Lackner and Brennan 2009; Nikulshina, et al. 2009; Pielke 2009).

This feature of the climate implies that bringing future emissions to zero would not reduce temperatures except in the very long term, but would rather hold temperatures almost steady (Matthews and Caldeira 2008; Lowe, et al. 2009; Matthews and Weaver 2010). Several recent studies have sought to exploit this observation in order to provide a simple link between levels of cumulative emissions and future warming (Allen, et al. 2009a; Matthews, et al. 2009; Meinshausen, et al. 2009; Zickfeld, et al. 2009).

This simple link between cumulative emissions of carbon and future warming is causing policymakers to rethink the way that emission targets are set. Policies are starting to move away from the former target in a single year approach (e.g. G8 2008, UNFCCC 1997) and towards setting cumulative ‘budgets’ over a fixed timespan (e.g. Kallbekken, et al. 2009; WBGU 2009; UKCCC 2010). My thesis aims to refine and extend the scientific underpinnings of this new approach to setting emission targets for avoiding dangerous climate change.

The first paper of my DPhil, which appears in Appendix D, showed that the spread of possible temperatures after meeting a conventional carbon emissions target in a given year is much wider than the spread of resultant temperatures from meeting a cumulative carbon budget (Bowerman, et al. 2011). It also illustrates that the possibility of having a future floor in emissions is not incompatible with a cumulative budget approach. It uses emission floors to show that it is cumulative emissions to roughly 2200 that control peak warming, not cumulative emissions to 2500 (as suggested by Allen, et al. 2009) or 2050 (as implied by Meinshaussen, et al. 2009). I have also written this work up in a book chapter on ‘the importance of limiting cumulative emissions’, which was commissioned by Springer as part of a book titled ‘Can we still avoid dangerous climate change?’

Thus far we have considered only peak warming as an indicator of dangerous climate change, however another key indicator is the rate of global warming (Root, et al. 2003). The first paper of my DPhil, labelled P1 in Section 2, shows that the peak rate of CO2-‐‑induced warming is controlled by the peak rate of CO2 emissions (Bowerman, et al. 2011), contrary to a suggestion by Kallbekken, et al. (2009) that it is controlled by the cumulative emissions between 2010 and 2030.

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The examples above illustrate how the cumulative budgets approach works well for the CO2-‐‑only case (e.g. Raupach, et al. 2011), however several recent papers have highlighted the problems with incorporating non-‐‑CO2 greenhouse gases into this framework (e.g. Cox & Jeffrey 2010; Arora et al. 2011). During my DPhil I hope to illustrate two possible methods of incorporating non-‐‑CO2 forcings into the cumulative emissions framework. The first of these methods assumes constant non-‐‑CO2 forcings that are not time-‐‑dependent, and will be discussed in Smith, et al. (in prep.). The other uses time-‐‑evolving non-‐‑CO2 forcings and will be discussed in detail in this report and in a future paper, labelled P3 in Section 2 (Bowerman, et al. in prep. a). Based on the insights of Hahn (1989) and Mann & Richels (2001), this time-‐‑evolving framework can be used to trade between greenhouse gases in a real-‐‑world market, which will be outlined briefly in this report and explored in more detail in a future paper, labelled P5 in Section 2 (Hahn et al. in prep.).

Recently there have been a series of papers proposing to help tackle climate change by cutting short-‐‑lived forcing agents (e.g. Molina, et al. 2009; UNEP 2011). In this report I will illustrate why delaying the implementation of the measures suggested in these papers until after carbon emissions have peaked, rather than implementing them now, will have little impact on peak warming (Bowerman, et al. in prep. a a.k.a. P3). I also hope to show that the proposed measures cannot be used as an alternative to cutting emissions of CO2 if the aim is to reduce peak global warming (Bowerman, et al. in prep. a a.k.a. P3).

The data used to tune the model utilised in this report, and by both Allen, et al. (2009) and Bowerman, et al. (2011) is now several years out of date and needs to be updated. This will allow me to update the conclusions of Allen et al. (2009) in time for the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) deadline. I hope to do this in a second future paper labelled P6 in Section 2 (Bowerman et al. in prep. b).

Finally, if time allows, I would like to explore the implications of our learning about the climate system on emission targets, as inspired by Allen & Frame (2007) and my Masters project. If in the future the scientific community finds that the climate sensitivity is higher than previously estimated, it seems likely that policymakers would set lower future carbon emission targets, and vice versa. We use this idea to consider future emissions pathways in which learning occurs over time using ideas from basic control theory. We find that it is likely that society would have to employ large scale air capture technology (e.g. Lackner and Brennan 2009; Nikulshina, et al. 2009; Pielke 2009) to remove CO2 from the atmosphere if we learn in the future that climate sensitivity is higher than expected and want to keep temperatures from rising by more than 2°C (Bowerman et al. in prep. c). This would be written up in an additional paper, labelled P7 in Section 2, if time allows.

In summary, over the course of my DPhil, I hope to refine the scientific underpinnings of the link between cumulative carbon emissions targets and peak global warming, as well as extending the concept to include non-‐‑CO2 forcing agents. Over the course of this work, I hope to improve our understanding of the emission targets required to avoid dangerous climate change.

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2 Progress report As I approach the two-‐‑thirds mark in my DPhil I am moving from performing mostly analysis and doing some writing, to doing mostly writing and performing bits of analysis where necessary.

The activities that I have carried out, the progress I have made, and my estimates of what I hope to do over the coming year, are all displayed in the Gantt chart in Table 2. My progress in each of the projects that I am working is illustrated in Table 1, and is described on briefly below. The labelling in brackets in the text below refers to the labels given to projects in the Gantt chart and progress chart.

2.1 Progress of projects

2.1.1 Cumulative emission targets, rates of warming and emission floors This paper (P1) has been published by Philosophical Transactions of the Royal Society A, and is included in Appendix D. It is described briefly in Section 1.

2.1.1.1 Book chapter on cumulative emissions targets This book chapter (B1) is included in Appendix A in the form in which it was submitted to reviewers. It was commissioned by Springer as part of a book titled ‘Can we still avoid dangerous climate change?’, and is based on my published paper P1. It will be published alongside other chapters from members of the AVOID project, which employed me during Michaelmas Term 2009. It is being coordinated in part by the Met Office, which is my CASE sponsor.

2.1.2 Allowable emissions in 2020 and 2050 to stay below 2°C Jason Lowe started this paper (P2) during Michalemas Term 2009. He later handed it over to Chris Huntingford, one of the original co-‐‑authors, who is not leading it. I drafted some of more policy-‐‑oriented parts of the paper, and I am now helping with editing and references.

2.1.3 The impact of short-‐ and long-‐lived forcing agents on peak warming The ideas contained within this paper (P3) are described in Section 1, and are included in this report in draft form in Section 3. It is a collaboration with Drew Shindell, and is in part a response to Molina, et al. (2009) and UNEP (2011). It will be submitted alongside another paper by Steve Smith at the UK Climate Change Committee on comparing the impacts of short-‐‑ and long-‐‑lived species, which describes an alternative metric to the conventional Global Warming Potential. Steve Smith’s paper is discussed briefly in Section 1. A poster displaying some of our early results on this topic is presented in Appendix E.

2.1.4 Forecasting emissions Corinne Le Quéré has developed a method of forecasting emissions over the next few decades based on historic emission trends. We add to her analysis by estimating the range of the CO2-‐‑induced warming that would be likely to occur as a result of her emission projections. Corinne Le Quéré is drafting this paper (P4) at the moment.

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2.1.5 Trading short-‐ and long-‐lived forcing agents In this paper (P5) we hope to extend the analysis presented in paper P3 in collaboration with Robert Hahn, who created the successful sulphur dioxide trading scheme in USA under President George Bush Senior. Myles Allen and I will be providing the science to this project, and Robert Hahn and David Frame will be contributing the economics. The proposed contents of this paper are discussed briefly in Section 1.

2.1.6 Updating Allen et al. (2009) This paper (P6) aims to update the conclusions of Allen et al. (2009) by redoing the analysis with recently published input data. This paper is discussed briefly in Section 1.

2.1.7 Does climate uncertainty mean we will need large scale air capture? This paper (P7) will only written if time allows. The paper would include and extend the results of my Masters project, which is included in Appendix B. Some of the recent extensions to this work are included in the poster presented in Appendix C.


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2.2 Progress chart

Code Paper Lead Author

Activity

Notes

Mod

ellin

g

Plottin

g

Drafting

Editing

Subm

itted

to re

view

ers

Reviewers’

commen

ts

Subm

itted

for

publishing

Publishe

d

P1 Cumulative emissions N. Bowerman

B1 Book chapter N. Bowerman

P2 2020 & 2050 targets C. Huntingford

P3 Short-‐‑ and long-‐‑lived gases N. Bowerman

P4 Forecasting emissions C. Le Quéré

P5 Emissions trading R. Hahn

P6 Updating Allen et al. (2009) N. Bowerman

P7 Air capture N. Bowerman P7 will only be written if time allows

T1 DPhil Thesis N. Bowerman

Table 1: A chart illustrating my progress in each of the projects that I am working on. Solid blue sections represent activities that have been completed, and diagonal shading represents activities that are partially completed. The air capture paper (P7) will only be completed if time allows.

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2.3 Gantt chart

Gantt Chart 1st Year 2nd Year 3rd Year 4th Year

Activity

Cod

e

Experiment or Task Micha

elmas

2009

Hila

ry 2010

Trinity

2010

Micha

elmas

2010

Hila

ry 2011

Trinity

2011

Micha

elmas

2011

Hila

ry 2012

Trinity

2012

Micha

elmas

2012

E1 Simple model comparison E1 Target comparison E1 Cumulative with floors E1 Likelihood with floors P1 Writing targets and floors paper B1 Writing book chapter on

cumulative emissions targets

P2 Contributing to 2020 & 2050 targets paper

E3 Creating multi-‐‑gas model E3 Comparing the impact of short-‐‑

and long-‐‑lived species

E3 Analysis of Molina and UNEP proposals

P3 Writing short-‐‑ vs long-‐‑lived paper E4 Producing warming forecasts for

emissions forecasts paper

P4 Contributing to emissions forecasts paper

Continued on next page…

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Gantt Chart 1st Year 2nd Year 3rd Year 4th Year Activity

Cod

e

Experiment or Task Micha

elmas

2009

Hila

ry 2010

Trinity

2010

Micha

elmas

2010

Hila

ry 2011

Trinity

2011

Micha

elmas

2011

Hila

ry 2012

Trinity

2012

Micha

elmas

2012

E5 Comparison of gases for trading paper

P5 Contributing to trading paper E6 Updating Allen et al. (2009) P6 Write updated Allen et al. paper T1 DPhil thesis first draft T2 DPhil thesis final draft T3 DPhil viva

The following activities will be completed if time allows E7 Air capture and precipitation P7 Air capture paper

Table 2: A Gantt chart illustrating the project schedule. Darker solid colours represent periods when experiments (or vivas) are to be carried out. Diagonal shading depicts periods when writing up will be carried out. The time allocated for paper writing extends to when the final manuscript is handed to the editors once the peer-‐‑review process is complete. The tasks below the dotted lines will only be completed if time allows.

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3 The impact of short-‐ and long-‐lived forcing agents on peak warming

3.1 Preamble The following text may be appropriate for submission as a brief correspondence arising from a Nature review paper published on 4 August 2011, once it has been edited by co-‐‑authors. The review paper implies that reductions in short-‐‑lived greenhouse gases today would reduce peak radiative forcing, which we argue is not the case. The paper in question is: Montzka, S. A., E. J. Dlugokencky & J. H. Butler. Non-‐‑CO2 greenhouse gases and climate change. Nature 476, 43-‐‑50 (2011).

Please note that the plots presented here have been produced with the model outlined in Bowerman, et al. (2011) plus a simplistic exponential-‐‑decay treatment of non-‐‑CO2 greenhouse gases. As such they are not suitable for publication, and will be redone before submission, for example with the simplified NASA GISS model or other simple model. I do not expect the conclusions of the plots to change and thus I include them below.

3.2 Impact of short-‐lived forcing agents? Emissions of both carbon dioxide (CO2) and other greenhouse gases are contributing to global warming. Reducing emissions of non-‐‑CO2 greenhouse gases (GHGs) such as methane and nitrous oxide will help mitigate climate change via global radiative forcing or climate forcing, which controls the magnitude of global warming. Montzka, Dlugokencky and Butler1 imply that reductions in short-‐‑lived GHGs emitted today will reduce peak radiative forcing, which even on the most optimistic mitigation scenarios, will occur in several decades’ time. However, short-‐‑lived GHGs remain in the atmosphere for only a few years2, so emissions of these gases over the coming decade cannot substantially affect either peak radiative forcing, or consequently the magnitude of peak warming, under scenarios in which temperatures peak around 2oC above pre-‐‑industrial such as those consistent with the aspirations espoused in the Copenhagen Accord. Current emissions of short-‐‑lived gases have even less impact on peak temperatures under scenarios in which temperatures peak later and higher. Rather, it is emissions of short-‐‑lived GHGs near the time of peak radiative forcing that significantly affect that peak in radiative forcing and subsequently peak warming3. Short-‐‑lived GHGs emitted today can indirectly affect peak warming through carbon-‐‑cycle feedbacks, but this is a secondary effect, as shown in Figure 1.

Figure 1 shows the contribution to peak GHG-‐‑induced warming from various GHGs (and other short-‐‑lived forcing agents such as black carbon) as a function of decade of emission, calculated simply by omitting the relevant decade’s emissions of a particular gas and computing the resulting change in peak warming. While CO2

emissions are dominant initially, their importance declines as CO2 emissions decline in these two scenarios, and the importance of short-‐‑lived agents increases significantly near the time of peak warming. We use two emissions scenarios,

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RCP3PD and RCP4.5, which we find cause global mean temperatures to peak at roughly 2oC and 3oC respectively with the most likely values of model parameters. Though the details change between scenarios, the qualitative result remains the same: in terms of current emissions, CO2 has a far greater impact on peak radiative forcing and peak warming than short-‐‑lived GHGs for any plausible emissions scenario.

Short-‐‑lived forcing agents emitted today raise global temperatures temporarily, causing increased emission of CO2 from the biosphere via carbon-‐‑cycle feedback mechanisms4. Through this carbon-‐‑cycle feedback, today’s emissions of short-‐‑lived GHGs can impact peak forcing, and in turn peak warming. However, this is a secondary effect that has a much smaller impact in any given decade than the influence of emissions of short-‐‑lived forcing agents near the time of peak forcing.

It has been suggested5 that cuts in short-‐‑lived radiative forcing agents can “buy time” to make more difficult cuts in CO2 emissions. While there are many reasons for reducing short-‐‑lived climate forcings1, our results suggest that the impact on peak temperatures is not one of them. Even the complete elimination of black carbon emissions in the 2020s would have less impact on peak temperatures than the reduction of CO2 emissions envisaged between the 2010s and 2020s under the very optimistic RCP3PD scenario, and almost no impact under the RCP4.5 scenario. Until significant cuts in CO2 emissions occur, radiative forcing from CO2 and hence global temperatures will continue to rise. Emissions of short-‐‑lived radiative forcing agents only affect peak temperatures under circumstances in which global emissions of long-‐‑lived agents are already low and falling.

3.3 References 1. Montzka, S. A., E. J. Dlugokencky & J. H. Butler. Non-‐‑CO2 greenhouse gases and

climate change. Nature 476, 43-‐‑50 (2011). 2. Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey, J.

Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. Prinn, and M. S. a. R. V. D. G. Raga. Changes in Atmospheric Constituents and in Radiative Forcing. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller, Cambridge University Press (2007)

3. Shine, K. P., T. K. Berntsen, J. S. Fuglestvedt, R. Bieltvedt Skeie and N. Stuber. Comparing the climate effect of emissions of short-‐‑ and long-‐‑lived climate agents. Phil. Trans. R. Soc. A 365, 1903-‐‑1914 (2007)

4. Gillett, N. P. & H. D. Matthews. Accounting for carbon cycle feedbacks in a comparison of the global warming effects of greenhouse gases. Environ. Res. Lett. 5, 034011 (2010)

5. Cox, P. M. & H. A. Jeffery. Methane radiative forcing controls the allowable CO2 emissions for climate stabilization. Curr Opin Environ Sustain. 2, 404–408 (2010)

6. Solomon, S., et al. (2009). Irreversible climate change due to carbon dioxide emissions. Proc. Natl Acad. Sci. USA 106(6): 1704-‐‑1709.

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3.4 Figures

Figure 1: Contribution of decade’s emissions to peak warming for two different emissions scenarios. Panel a) uses RCP 3PD, an emissions scenario causing warming to peak at X.X°C relative to pre-‐‑industrial in 2XXX with the most likely values of model parameters. Panel b) uses RCP 4.5, an emissions scenario leading to warming peaking at X.X°C in 2XXX with the most likely values of model parameters. To create these plots we have removed the emissions of a given greenhouse gas in a given decade from a model run and calculated the resulting impact of these emissions on peak global warming.

-‐‑0.05

0

0.05

0.1

0.15

0.2

0.25

2000s 2020s 2040s 2060s 2080s 2100s

Contribution of decade'ʹs emissions to

peak global warming (°C)

Decade

a) RCP 3PD

Black Carbon

Trop. Ozone

(H)CFCs

CH4

N2O

CO2

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

2000s 2050s 2100s 2150s 2200s

Contribution of decade'ʹs emissions to

peak global warming (°C)

Decade

b) RCP 4.5

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Allen, M. and W. Ingram (2002). "ʺ Constraints on future changes in climate and the hydrologic cycle."ʺ Nature 419, 224-‐‑232. Allen, M. R., D. Frame, K. Frieler, W. Hare, C. Huntingford, C. Jones, R. Knutti, J.

Lowe, M. Meinshausen, N. Meinshausen and S. Raper (2009b). "ʺThe exit strategy."ʺ Nature Reports Climate Change 3: 56-‐‑58.

Allen, M. R., D. J. Frame, et al. (2009a). "ʺWarming caused by cumulative carbon emissions towards the trillionth tonne."ʺ Nature 458(7242): 1163-‐‑1166.

Anderson, K. and A. Bows (2008). "ʺReframing the climate change challenge in light of post-‐‑2000 emission trends."ʺ Phil. Trans. Roy. Soc. A 366: 2862-‐‑2883.

Archer, D. (2005). "ʺFate of fossil fuel CO2 in geologic time."ʺ Journal of Geophysical Research-‐‑Oceans 110(C9): -‐‑.

Chakravarty, S., A. Chikkatur, et al. (2009). "ʺSharing global CO2 emission reductions among one billion high emitters."ʺ Proceedings of the National Academy of Sciences of the United States of America 106(29): 11884-‐‑11888.

Cox, P. M., R. A. Betts, et al. (2000). "ʺAcceleration of global warming due to carbon-‐‑cycle feedbacks in a coupled climate model (vol 408, pg 184, 2000)."ʺ Nature 408(6813): 750-‐‑750.

Cox, P. and D. Stephenson (2007). "ʺA changing climate for prediction."ʺ Science 317: 207-‐‑208.

den Elzen, M. and M. Meinshausen (2006). "ʺMeeting the EU 2 degrees C climate target: global and regional emission implications."ʺ Climate Policy 6(5): 545-‐‑564.

den Elzen, M., M. Meinshausen, et al. (2007). "ʺMulti-‐‑gas emission envelopes to meet greenhouse gas concentration targets: Costs versus certainty of limiting temperature increase."ʺ Global Environmental Change-‐‑Human and Policy Dimensions 17(2): 260-‐‑280.

Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey, J. Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. Prinn, and M. S. a. R. V. D. G. Raga (2007). Changes in Atmospheric Constituents and in Radiative Forcing. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller, Cambridge University Press.

Friedlingstein, P., P. Cox, et al. (2006). "ʺClimate-‐‑carbon cycle feedback analysis: Results from the (CMIP)-‐‑M-‐‑4 model intercomparison."ʺ Journal of Climate 19(14): 3337-‐‑3353.

G8 (2008). G8 Hokkaido Toyako Summit Leaders Declaration. G8 (2009). Declaration of the Leaders The Major Economies Forum on Energy and

Climate. Huntingford, et al. (2010). "ʺIMOGEN: an intermediate complexity model to evaluate

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Le Quere, C., M. R. Raupach, et al. (2009). "ʺTrends in the sources and sinks of carbon dioxide."ʺ Nature Geoscience 2(12): 831-‐‑836.

Lowe, J., C. Huntingford, L. Gohar, M. Allen, N. Bowerman (2010). "ʺThe relation between constraining global warming below two degrees and emissions in years 2020 and 2050."ʺ in prep.

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UNFCCC (2009). Copenhagen Accord. WBGU (2009). Solving the climate dilemma: The budget approach. Zickfeld, K., M. Eby, et al. (2009). "ʺSetting cumulative emissions targets to reduce the

risk of dangerous climate change."ʺ Proceedings of the National Academy of Sciences of the United States of America 106(38): 16129-‐‑16134.

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Appendix A: Book chapter on cumulative emissions

Niel H.A. Bowerman, David J. Frame, Chris Huntingford, Jason A. Lowe, Laila Gohar & Myles R. Allen

Cumulative emissions budgets and their implications

Commissioned by Springer as a chapter in a book titled “Can we still avoid dangerous climate change?”

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Appendix B: MPhys project

Niel H. A. Bowerman, Myles R. Allen, David J. Frame, and Nick Jelley

Modelling the behaviour of the coupled carbon cycle-‐‑climate system

Presented to University of Oxford Physics in April 2009 as an MPhys Project

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Appendix C: Poster on the climatic implications of using large scale air capture

Niel H. A. Bowerman, Myles R. Allen, David J. Frame

Does climate uncertainty mean we will need large scale air capture?

Displayed as a poster at European Geoscience Union (EGU) 2010

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Appendix D: Bowerman et al. (2011)

Niel H. A. Bowerman, David J. Frame, Chris Huntingford, Jason A. Lowe and Myles R. Allen

Cumulative carbon emissions, emissions floors

and short-‐‑term rates of warming: implications for policy

Phil. Trans. R. Soc. A 2011 369, 45-‐‑66 doi: 10.1098/rsta.2010.0288

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Appendix E: Poster on comparing the impact of forcing agents

N. H. A. Bowerman, D. J. Frame, C. Huntingford, J. A. Lowe, S. M. Smith & M. R. Allen

Comparing the impacts of different greenhouse gases on peak global warming and

the rate of warming

Displayed as a poster at European Geoscience Union (EGU) 2011

2! · 4! 1 Overview! Asubstantial!fraction!of!the!carbon!dioxide!(CO...

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