Ocean fertilization. An overview of an early promise geoengineering technique for carbon dioxide reduction. Phil Williamson

Transcription

1 Ocean fertiization An overview of an eary promise geoengineering technique for carbon dioxide reduction Phi Wiiamson UNFCCC SBSTA Bonn 2 June 2011

2 Issues appicabe to a CDR geoengineering options Coud we? Is it technicay possibe to sow the rate of goba warming by enhancing carbon remova processes? Shoud we? Is that a step human society ought to take?

3 Issues appicabe to a CDR geoengineering options Coud we? Is it technicay possibe to sow the rate of goba warming by enhancing carbon remova processes? Effectiveness and permanence of carbon sequestration Verification (how much?) Unintended side-effects Contro/reversibiity Shoud we? Is that a step human society ought to take?

4 Issues appicabe to a CDR geoengineering options Coud we? Is it technicay possibe to sow the rate of goba warming by enhancing carbon remova processes? Effectiveness and permanence of carbon sequestration Verification (how much?) Unintended side-effects Contro/reversibiity Shoud we? Is that a step human society ought to take? Cost effectiveness ($) Benefits v risks (equity) Treadmi (exit strategy) Who pays - and how? Who decides? (governance)

5 Ocean fertiization: background ~50 times more carbon in the ocean than in the atmosphere tota 730 Pg C tota 38,000 Pg C

6 Ocean fertiization: background ~50 times more carbon in the ocean than in the atmosphere Large annua fuxes across the sea surface, with net uptake ~22 Pg C pa 900 Pg C per year tota 730 Pg C 922 Pg C per year tota 38,000 Pg C

7 Ocean fertiization: background ~50 times more carbon in the ocean than in the atmosphere Large annua fuxes across the sea surface, with net uptake ~22 Pg C pa Increased iron inputs, via dust, raised ocean productivity and CO 2 uptake during gacia cyces Current goba net tota of 22 Pg C pa = annua mean of 6 tonnes per sq km Coud that be doubed?

8 Ocean fertiization: background ~50 times more carbon in the ocean than in the atmosphere Large annua fuxes across the sea surface, with net uptake ~22 Pg C pa Increased iron inputs, via dust, raised ocean productivity and CO 2 uptake during gacia cyces Current goba net tota of 22 Pg C pa = annua mean of 6 tonnes per sq km Coud that be doubed? If other nutrients avaiabe, adding 10g iron coud (in theory) sequester 1 tonne carbon Hence <005% of tota iron mined might be enough to totay offset societa carbon emissions

9 13 iron addition experiments ( ), two commercia trias ( ) and two phosphate addition experiments ( ) have been carried out to date, at scae of km 2 Most induced a phytopankton boom, but ony three concusivey demonstrated increased carbon export to deeper water Map background: Sateite-based ocean primary production Sma images: Exampes of experimentay-induced booms Coud cover is white in upper images, back in ower ones

10 Unresoved issues for ocean fertiization How much carbon is removed from the atmosphere, for how ong?

11 Unresoved issues for ocean fertiization How much carbon is removed from the atmosphere, for how ong? How much might methane and N 2 O production increase in anoxic mid-waters?

12 Unresoved issues for ocean fertiization How much carbon is removed from the atmosphere, for how ong? How much might methane and N 2 O production increase in anoxic mid-waters? ph What wi be the impacts of increased ocean acidification in mid/deep water?

13 Unresoved issues for ocean fertiization How much carbon is removed from the atmosphere, for how ong? How much wi methane and N 2 O production increase in anoxic mid-waters? ph What woud be the impacts of increased ocean acidification in mid/deep water? To answer these questions, experiments at scae of ,000 km 2 over time period of months-years are required

14 Unresoved issues for ocean fertiization How much carbon is removed from the atmosphere, for how ong? How much might methane and N 2 O production increase in anoxic mid-waters? ph What woud be the impacts of increased ocean acidification in mid/deep water? To answer these questions, experiments at scae of ,000 km 2 over time period of months-years are required These woud require an impact assessment and internationa approva to compy with recent CBD and LC/LP decisions

15 CBD: Convention on Bioogica Diversity Moratorium on ocean fertiization activities unti adequate scientific basis, with goba reguatory mechanism (exception for sma-scae studies in coasta waters ) COP Decision IX/16, May 2008 LC/LP: London Convention & Protoco No ocean fertiization except egitimate scientific research LC/LP wi deveop reguatory mechanism, incuding framework for assessment LC/LP COP, Oct 2008

16 Modeing studies are sti possibe goba continuous Southern Ocean 6 months 20% ocean 15 times per yr goba continuous (2 estimates) Reduction in estimated scae of geoengineering benefits since 1991 Greatest effect in Southern Ocean If Southern Ocean excuded, maximum benefit <02 Pg C pa Does not take account of possibe increased reease of CH 4 and N 2 O

17 Modeing studies are sti possibe goba continuous Southern Ocean 6 months 20% ocean 15 times per yr goba continuous (2 estimates) Estimated max goba carbon drawdown over 100 years 10 Pg C pa 05 Pg C pa Reduction in estimated scae of geoengineering benefits since 1991 Greatest effect in Southern Ocean If Southern Ocean excuded, maximum benefit <02 Pg C pa Does not take account of possibe increased reease of CH 4 and N 2 O

18 CBD: Convention on Bioogica Diversity Moratorium on ocean fertiization activities unti adequate scientific basis, with goba reguatory mechanism (exception for sma-scae studies in coasta waters ) COP Decision IX/16, May 2008 LC/LP: London Convention & Protoco No ocean fertiization except egitimate scientific research LC/LP wi deveop reguatory mechanism, incuding framework for assessment LC/LP COP, Oct 2008

19 CBD: Convention on Bioogica Diversity Moratorium on ocean fertiization activities unti adequate scientific basis, with goba reguatory mechanism (exception for sma-scae studies in coasta waters ) COP Decision IX/16, May 2008 Scientific Summary for Poicymakers by IOC/UNESCO (Intergovernmenta Oceanographic Commission) and SOLAS/IGBP (Surface Ocean - Lower Atmosphere Study/Internationa Geosphere-Biosphere Programme) Waace et a 2011 LC/LP: London Convention & Protoco No ocean fertiization except egitimate scientific research LC/LP wi deveop reguatory mechanism, incuding framework for assessment LC/LP COP, Oct 2008

20 Ocean fertiization: a scientific summary for poicy makers The geoengineering technique we know most about but sti with many uncertainties Effectiveness: fied experiments (at scae of km 2 ) show CO 2 uptake can be enhanced but with high variabiity Permanence: most of the extra carbon uptake wi be returned to the atmosphere within a few months Goba net maximum < 05 Pg C pa? Verification: it wi be chaenging (=expensive) to quantify carbon sequestration and unintended impacts, and hence net cimatic benefit Poitica acceptabiity: concerns on unintended impacts currenty imit research Large scae studies may fai precautionary principe