Reframing climate change: from long-term targets to short-term action Dr Alice Bows Lecturer in Energy & Climate Change Sustainable Consumption Institute & Tyndall Centre Challenges in the Transition to a low-carbon society, Warwick, July 2009
Talk outline What is dangerous climate change? Reframing the debate - cumulative emissions Global greenhouse gas emission pathways Implications for policy
What is dangerous climate change? UK & EU define this as 2 C Links to total quantity of CO 2 e in atmosphere - measured in parts-per-million by volume (ppmv) Currently 386ppmv (CO 2 alone) & increasing ~2ppmv each year - 280ppmv before industrial revolution
The UK & EU s targets 2 C: historically, correlated with 550ppmv CO 2 eq Vostok Record IPCC IS92a Scenario Law Dome Record Mauna Loa Record CO 2 Concentration in Ice Core Samples Projections for Next 100 Years Projected (2100) 700 650 600 550 500 Now more closely linked to 450 ppmv CO 2 eq 2008 Current (2001) 450 400 350 300 250 200 400,000 300,000 200,000 100,000 0 150 Years Before Present
What are likely impacts at 2 C? Destruction of the vast majority of coral reefs Hundreds of millions of people exposed to increased water stress 30% of species at increasing risk of extinction Land moves to become a carbon source Cereal productivity to starts to cease in low latitudes Millions more people experience coastal flooding Tipping points? (IPCC Fourth Assessment Report, 2008. Impacts, adaptation & vulnerability )
Emission-reduction targets for 2 C UK, EU & Global - long term reduction targets - UK s 80% reduction in CO 2 e by 2050 - EU 60%-80% reduction in CO 2 e by 2050 - Bali 50% global reduction in CO 2 e by 2050 But CO 2 stays in atmosphere for approx. 100years Hence, today s emissions add to yesterdays & will be added to by tomorrows Focus on long-term targets is very misleading
Put bluntly the final % reduction in carbon has little relevance to avoiding dangerous climate change (e.g. 2 C) What is important are the cumulative emissions of carbon & other greenhouse gases (i.e. the carbon budget)
Linking science to policy How do global temperatures link to global and national carbon budgets & from there to emission-reduction pathways?
Linking science to policy Temperature threshold science/modelling GHG concentration science/modelling Global cumulative emission budget Apportionment regime National cumulative emission budget 2000-2008 emissions + short-term projections Global emission pathway National emission pathway
Illustrative carbon budget & pathway 5000 Carbon dioxide emission ns (MtCO2) 4000 3000 2000 1000 0 1990 2000 2010 2020 2030 2040 2050
Illustrative carbon budget & pathway 5000 Carbon dioxide emissions (MtCO2) 4000 3000 2000 1000 450ppmv Low 450ppmv High 0 1990 2000 2010 2020 2030 2040 2050
Illustrative carbon budget & pathway 5000 Carbon dioxide emissions (MtCO2) 4000 3000 2000 1000 Empirical data Cumulative emissions already spent 450ppmv Low 450ppmv High 0 1990 2000 2010 2020 2030 2040 2050
Illustrative carbon budget & pathway Carbon dioxide emissions (MtCO2) 5000 450ppmv Low 450ppmv High 4000 3000 Empirical data 2000 Cumulative emissions already spent The future carbon budget available 1000 0 1990 2000 2010 2020 2030 2040 2050
Global emission scenarios (CO2e) What are the latest CO2 emission trends? What are implications of factoring in: - land-use & forestry? - non-co2 greenhouse gas emissions? When will global CO2e emissions peak? How much CO2 space left for energy & process emissions?
The latest global CO2 emission trends ~ 2.7% p.a. last 100yrs ~ 3.5% p.a. in last 7 years
Fossil Fuel Emissions: Actual vs. IPCC Scenarios CO2 Emissions (GtC y-1) 10 9 8 7 Actual emissions: CDIAC Actual emissions: EIA 450ppm stabilisation 650ppm stabilisation A1FI (Avgs.) A1B A1T A2 B1 B2 2007 SRES (2000) aver. growth rates in % y -1 for 2000-2010: 2008 2006 A1B: 2.42 A1FI: 2.71 A1T: 1.63 A2: 2.13 B1: 1.79 B2: 1.61 2005 Observed 2000-2007 3.5% 6 5 1990 1995 2000 2005 Raupach et al 2007, PNAS; Global Carbon Project 2009 2010
Emissions of CO2 from land-use change 7 by deforestation) - Represents 12%-25% of total global greenhouse gas emissions in 2000 - Two Tyndall scenarios with different carbon-stock levels remaining: 70% & 80% - Optimistic compared with Forest Resource Assessment Emissions of CO2 (MtCO2) - Characterised by high uncertainty (principally driven 6 5 4 3 2 1 0 2000 2020 2040 2060 Year 2080 2100
Emissions of non-co2 greenhouse gases - Short-term EPA estimates - Characterised by considerable tail due to emissions associated with food production - Represents ~20-23% of total global greenhouse gas emissions in 2000 - Three scenarios with different peak dates Emissions of non-co2 ghg (GtCO2e) 14 12 10 8 6 4 Early action Mid action Late action 2 0 2000 2020 2040 2060 Year 2080 2100
Suggested CO2e emissions peak Bush - USA - 2025 Stern Global aim - 2015 Tyndall - 2015, 2020, 2025
450ppmv greenhouse gas emission pathways
450ppmv CO2e budget We know from the science how much CO2e we can emit between 2000-2100 (the emission budget)
Global budget For a 50% (450ppmvCO2e) chance of avoiding dangerous climate change the global budget is ~ 490 billion tonnes of carbon equivalent between 2000-2100
2015 peak 60 40 20 0 2000 2020 2040 2060 Year 2080 2100 2020 peak Emissions of greenhouse gases (GtCO2e) 80 Emissions of greenhouse gases (GtCO2e) Emissions of greenhouse gases (GtCO2e) Total greenhouse gas emission pathways 80 60 40 20 0 2000 2020 2040 2060 Year 2080 2100 2025 peak 80 Low DL 60 Low DH Medium DL Medium DH High DL 40 High DH 20 0 2000 2020 2040 2060 2080 Year Anderson, K., and Bows, A., 2008, Philosphical Transactions of the Royal Society A, 366, 3863-3882 2100
Emissions of greenhouse gases (GtCO2e) What does all this imply for a 450ppmvCO2escenarios future? 450ppm v cum ulative em ission peaking in 2020 80 Unprecedented Low A annual Low B M edium A reductions B (~10% M paedium globally, A even for High 2020 peak) High B 60 40 20 0 2000 2020 2040 2060 Year 2080 2100
Emission-space remaining for energy CO2 60 2015 peak Medium D L 2015 peak High D L - Removed pathways Emissions of CO2 alone (GtCO2) impossible 2015 peak High D H 50 40 30 20 10 0 2000 2020 2040 2060 Year 2080 2100
Emission-space remaining for energy CO2 60 2015 peak Medium D L 2015 peak High D L - Removed pathways - Complete global decarbonisation 2027-2062 Emissions of CO2 alone (GtCO2) impossible 2015 peak High D 2020 peak High D 50 2020 peak High D H L H 40 30 20 10 0 2000 2020 2040 2060 Year 2080 2100
For 450ppmv CO2e (50:50 of 2 C) Only possible with IPCC upper cumulative emission estimate 70-80% of current forestry carbon stock must remain Peak in GHG emissions in 2015 4% reduction p.a. in CO2e 7% reduction in CO2 from energy Halving carbon intensity of food production between 2015 & 2050
550 & 650 ppmv greenhouse gas emission pathways
Suggested CO2e emissions peak? Bush - USA - 2025 Stern Global aim - 2015 Tyndall - 2015, 2020, 2025
550 & 650 ppmv For 550ppmv CO2e with emissions peaking by 2020: 6% annual reductions in CO2e 9% annual reductions in CO2 from energy For 650ppmv CO2e with emissions peaking by 2020: 3% annual reductions in CO2e 3.5% annual reductions in CO2 from energy
What are the precedents for such reductions? Annual reductions of greater than 1% p.a. have only been associated with economic recession or upheaval Stern 2006 UK gas & French 40x nuclear ~1% p.a. reductions (ex. aviation & shipping) Collapse Soviet Union economy ~5% p.a. reductions
So where does this leave us? Even assuming: an unprecedented step change in mitigating emissions stabilising at 650ppmv CO2e appears increasingly to be the best we can expect i.e. human-induced climate change of ~4 C or more
Reframe the debate We need to urgently reframe the climate change debate: For mitigation 2 C should remain the driver of policy For adaptation 4 C should become the driver of policy
Where does this leave us? Carbon dioxide emissions (MtCO2) 5000 450ppmv Low 450ppmv High 4000 3000 2000 1000 0 1990 2000 2010 2020 2030 2040 2050
Where does this leave us? Carbon dioxide emissions (MtCO2) 5000 450ppmv Low 450ppmv High 4000 demand 3000 2000 supply & demand 1000 0 1990 2000 2010 2020 2030 2040 2050
The example of domestic lighting Light 10 Electricity Consumption Transmission Powerstation 50 54 120 Fuel Production, Extraction &Transport 133 carbon reductions from reducing demand could dwarf reductions from low-carbon supply in all but the long term!
Conclusions Can not afford for emissions to remain high Must seek solutions that deliver radical emission reductions in the short-term Not currently on track to avoid dangerous climate change UK Climate Change Act put is a welcome a starting point