Cumulative carbon and its implications: the case for mandatory sequestration

Transcription

1 Cumulative carbon and its implications: the case for mandatory sequestration Myles Allen School of Geography and the Environment/ECI & Department of Physics University of Oxford

2 A career in climate research Matriculation

3 A career in climate research Awarded DPhil

4 A career in climate research IPCC Author

5 A career in climate research Lectureship

6 A career in climate research Chair

7 What happens to the carbon we dump into the atmosphere?

8 Understanding the carbon cycle A popular myth: About half the carbon we dump in the atmosphere is taken up by the oceans and biosphere, so if we reduce emissions by 50%, concentrations will stop rising. Right? Sadly, wrong. Additional CO 2 is rapidly mixed between the atmosphere, near-surface oceans and biosphere, but concentrations are rising in all three pools. Fraction removed by permanent carbon sinks is very small.

9 How various greenhouse gases behave after emissions cease

10 So fossil carbon accumulates in the climate system, and temperatures keep rising

11 And most of the warming over the past 50 years is attributable to rising greenhouse gases Humaninduced warming

12 And the solution is

13

14 Stock of cumulative CO2 emissions are the principal determinant of peak warming

15 Which is not the topic of climate change negotiations What they obsess over

16 Which is not the topic of climate change negotiations What actually matters

17 Does this mean we can relax? The risk of dangerous climate change is principally driven by cumulative emissions of CO 2. To limit warming to 2 o C, we need to limit the total stock of carbon released to about 1TtC. Reducing the rate of flow doesn t help unless it is a means of limiting the total stock. Emissions from fossil fuels and deforestation since 1750 are about 0.5TtC. On current trends, emissions reach 1TtC in 2040s. So, we ve got 30 years to relax?

18 Sadly, no: because CO 2 accumulates, and can t be switched off, delay actually does matter

19 Impact of delay in reducing CO2 emissions Global emissions, fossil & land-use, (GtC/yr) Committed CO 2 -induced warming at 2 o C/TtC Rate of decline after peak: 1.1%/yr 3.0 o C 5.4 o C 5.0 o C 4.6 o C 4.2 o C 3.8 o C 3.4 o C Year

20 There is plenty of fossil carbon down there Past emissions, Conventional and fossil oil oil, and unconventional and gas gas land-use coal change reserves

21 Can we actually stop people from using fossil fuels? And do we have any right to anyway? With apologies to Charlton Heston

22 The problem with the Kyoto/Copenhagen shortterm emission budget approach Emission rates in 2020 do not determine peak warming. Cheapest technologies for getting emissions down in the short term may crowd out measures required to limit cumulative emissions. Kyoto and Wallace s Technotrousers: Prins & Rayner, 2008

23 Climate Mitigation with No New Taxes: SAFE carbon Sequestered Adequate Fraction of Extracted (SAFE) carbon: carbon from a supply that ensures we never exceed the atmospheric capacity. So, what is an Adequate Fraction? S = net carbon sequestered / carbon extracted In the very long term, S 100%. At present, S=0%. Simplest option: specify S=C/C 0 : C = Cumulative emissions from the time policy is adopted. C 0 = Atmospheric capacity at the time policy is adopted. If all carbon sources were SAFE, we would never exceed the atmospheric capacity.

24 Getting from A to B B A

25 Why carbon taxes are not the answer: waiting for a high enough carbon price for CCS to be viable IWG Theatre Guild

26 Suppose the fossil fuel industry decides to defend its share of world energy supply

27 But paying for all that sequestration implies a carbon price, passed on to consumers

28 So they might consume less, making the carbon price lower but without compromising policy

29 Comparing SAFE carbon with IEA BLUE Map scenario S=40% in 2050 under IEA BLUE Map scenario

30 We could start with an optimistic (high) budget, and adjust when warming reaches 1.5 o C. 1.0 a) SAFE carbon pathways 20 b) High consumption scenario 20 c) Low consumption scenario Sequestered fraction %/10GtC 1.2%/10GtC GtC per year GtC per year Emissions to date (TtC) Year Year

31 Mandatory sequestration works Gorgon gas project, Western Australia

32 Policy implications Simple climate policy goal: to achieve 100% net sequestration before we release the trillionth tonne. Purpose is clear. Progress is verifiable. Complex energy strategy response: Rapid and immediate large-scale development of CCS. Cost of carbon determined by cost of CCS, not by politics. Potential windfall for owners of large point sources of CO 2. Prepare for rising cost of carbon by phasing out fossil subsidies, deploying renewables, nuclear, efficiency etc. One policy, one outcome, no new taxes.

33 IT S CUMULATIVE CARBON, STUPID