Ocean iron fertilization An ‘early promise’ negative emission technology Phil Williamson (NERC/UEA) p.williamson@uea.ac.uk Environmental Sustainability KTN : NET Brokerage Event, London 13 March 2013

“In what way, according to Plymouth Marine Laboratory, might iron, if scattered on the sea’s surface, slow down global warming?” Based on media coverage of presentation by PW at 1990 British Association for Advancement of Science meeting, Swansea

together with emission reduction The challenge for NETs together with emission reduction Global CO2 emissions since 2000 match IPCC ‘worse case’ scenario. 1990 Peters et al (2012) The challenge to keep global warming below 2⁰C. Nature Climate Change (online 2 Dec)

together with emission reduction The challenge for NETs together with emission reduction Global CO2 emissions since 2000 match IPCC ‘worse case’ scenario. 1990 Peters et al (2012) The challenge to keep global warming below 2⁰C. Nature Climate Change (online 2 Dec)

Effectiveness, affordability, safety and timeliness of 12 climate geoengineering techniques assessed by the Royal Society (2009) 2009 THE ROYAL SOCIETY

Effectiveness, affordability, safety and timeliness of 12 climate geoengineering techniques assessed by the Royal Society (2009) Ocean fertilization Effectiveness: medium Affordabillity: medium Safety: low Timeliness: slow 2009 THE ROYAL SOCIETY

issues applicable to all NET options “Could we?” Is it technically possible to slow the rate of global warming by increasing ocean carbon uptake? Effectiveness and permanence Verification (for C accounting) Unintended side-effects Control/reversibility issues applicable to all NET options

issues applicable to all NET options “Could we?” Is it technically possible to slow the rate of global warming by increasing ocean carbon uptake? “Should we?” Is that a step human society ought to take? Effectiveness and permanence Verification (for C accounting) Unintended side-effects Control/reversibility Cost effectiveness Benefits v risks (equity) “Treadmill” (exit strategy) Who pays - and how? Who decides? (governance/ethics) issues applicable to all NET options

Ocean fertilization: background total 730 Gt C atmosphere: total 730 Gt C ~50 times more carbon in the ocean than in the atmosphere . ocean: total 38,000 Gt C

90.0 Gt C per year 92.2 Gt C per year Ocean fertilization: background ~50 times more carbon in the ocean than in the atmosphere Large annual fluxes across the sea surface, with net uptake ~2.2 Gt C pa . 90.0 Gt C per year 92.2 Gt C per year Global net total of 2.2 Gt C pa = mean of ~6 tonnes per sq km

. . . Ocean fertilization: background ~50 times more carbon in the ocean than in the atmosphere Large annual fluxes across the sea surface, with net uptake ~2.2 Gt C pa Increased iron inputs, via dust, raised ocean productivity and CO2 uptake by ~5% during glacial cycles . . . Global net total of 2.2 Gt C pa = mean of ~6 tonnes per sq km

. . . Ocean fertilization: background ~50 times more carbon in the ocean than in the atmosphere Large annual fluxes across the sea surface, with net uptake ~2.2 Gt C pa Increased iron inputs, via dust, raised ocean productivity and CO2 uptake during glacial cycles . . . If other nutrients available, adding 10g iron could (in theory) 'fix' 1 tonne carbon. Hence <0.05% of total iron mined might be enough to totally offset societal carbon emissions

Experimental evidence 13 iron addition experiments ( ), two commercial trials ( ) and two phosphate addition experiments ( ) have been carried out to date, at scale of 10-100 km2. Most induced a phytoplankton bloom, but only four conclusively demonstrated increased carbon export to deeper water. Map background: Satellite-based ocean primary production Small images: Examples of experimentally-induced blooms. Cloud cover is white in top image, black in lower ones

. Key uncertainties for ocean fertilization CO2 CO2 How much carbon is removed from the atmosphere, for how long? CO2

. Key uncertainties for ocean fertilization CH4 N2O CO2 CO2 How much carbon is removed from the atmosphere, for how long? How much extra methane and N2O might be produced in anoxic mid-waters? CO2

. pH ↓ Key uncertainties for ocean fertilization CH4 N2O CO2 CO2 How much carbon is removed from the atmosphere, for how long? How much extra methane and N2O might be produced in anoxic mid-waters? What would be the impacts of increased ocean acidification in mid/deep water? CO2 pH ↓

. pH ↓ Key uncertainties for ocean fertilization CH4 N2O CO2 CO2 How much carbon is removed from the atmosphere, for how long? How much will methane and N2O production increase in anoxic mid-waters? What would be the impacts of increased ocean acidification in mid/deep water? CO2 pH ↓ To answer these questions, experiments at scale of 1000-10,000 km2 over time period of months-years are required.

. pH ↓ Key uncertainties for ocean fertilization CH4 N2O CO2 CO2 How much carbon is removed from the atmosphere, for how long? How much might methane and N2O production increase in anoxic mid-waters? What would be the impacts of increased ocean acidification in mid/deep water? CO2 pH ↓ To answer these questions, experiments at scale of 1000-10,000 km2 over time period of months-years are required. These would require an impact assessment and formal approval to comply with recent CBD and LC/LP decisions CBD: Convention on Biological Diversity LC/LP London Convention & London Protocol

Governance of ocean fertilization CBD: Convention on Biological Diversity Moratorium on ocean fertilization activities until adequate scientific basis, with global regulatory mechanism... (exception for “small-scale studies in coastal waters”) COP Decision IX/16, May 2008 Governance of ocean fertilization LC/LP: London Convention & Protocol No ocean fertilization except legitimate scientific research LC/LP to develop regulatory mechanism, including framework for assessment LC/LP COP, Oct 2008

Governance of ocean fertilization CBD: Convention on Biological Diversity Moratorium on ocean fertilization activities until adequate scientific basis, with global regulatory mechanism... (exception for “small-scale studies in coastal waters”) COP Decision IX/16, May 2008 Scientific Summary for Policymakers by IOC/UNESCO (Intergovernmental Oceanographic Commission) and SOLAS/IGBP (Surface Ocean - Lower Atmosphere Study/International Geosphere-Biosphere Programme) Wallace et al. 2010 Governance of ocean fertilization LC/LP: London Convention & Protocol No ocean fertilization except legitimate scientific research LC/LP to develop regulatory mechanism, including framework for assessment LC/LP COP, Oct 2008

Main conclusions Effectiveness: field experiments show CO2 uptake can be enhanced – but with high variability Permanence: most of the extra carbon uptake will be returned to the atmosphere within a few months Verification: it will be challenging (=expensive) to quantify carbon sequestration and unintended impacts Political acceptability: concerns on unintended impacts: large scale studies may fail ‘precautionary principle’ Ocean fertilization: a scientific summary for policy makers Wallace et al, 2010

Modelling results before and after field experiments Southern Ocean 6 months 20% ocean 15 times per yr global continuous (2 estimates) l Global cumulative CO2 drawdown after 100 yr of ocean fertilization (Gt carbon) 1990 1995 2000 2005 2010 global continuous 200 150 100 50 Reduction in estimated maximum CO2 drawdown Greatest effect in Southern Ocean

Modelling results before and after field experiments Southern Ocean 6 months 20% ocean 15 times per yr global continuous (2 estimates) l Global cumulative CO2 drawdown after 100 yr of ocean fertilization (Gt carbon) 1990 1995 2000 2005 2010 global continuous 200 150 100 50 Estimated annual max. global carbon drawdown (average over 100 years) 1.0 Gt C pa 0.5 Gt C pa Reduction in estimated maximum CO2 drawdown Greatest effect in Southern Ocean If Southern Ocean excluded, maximum benefit <0.2 Gt C pa Does not take account of possible increased release of CH4 and N2O

‘unused’ phosphate in upper ocean The Southern Ocean: where ocean fertilization could be most effective ‘unused’ nitrate in upper ocean ‘unused’ phosphate in upper ocean

‘unused’ phosphate in upper ocean The Southern Ocean: where ocean fertilization could be most effective Projected increases (red, orange and yellow) and decreases (blue) in vertically integrated primary productivity (gC/m2/yr) after 100 years of global iron fertilization. ‘unused’ nitrate in upper ocean ‘unused’ phosphate in upper ocean Aumont & Bopp (2006)

‘unused’ phosphate in upper ocean The Southern Ocean: where ocean fertilization could be most effective Projected increases (red, orange and yellow) and decreases (blue) in vertically integrated primary productivity (gC/m2/yr) after 100 years of global iron fertilization. ‘unused’ nitrate in upper ocean ‘unused’ phosphate in upper ocean Area of special environmental protection under Madrid Protocol (Antarctic Treaty) Also a particularly difficult region for logistics, verification and monitoring

Projected increases (red, orange and yellow) and decreases (blue) in vertically integrated primary productivity (gC/m2/yr) after 100 years of global iron fertilization Area of special environmental protection under Madrid Protocol (Antarctic Treaty) Also a particularly difficult region for logistics, verification and monitoring

Two (relatively) recent publications 1. Ianson D, Völker C, Denman K, Kunze E & Steiner N (2012) “The effect of vertical and horizontal dilution on fertilized patch experiments” Global Biogeochemical Cycles 26, GB3002 2. Smetacek V & 29 others (2012) “Deep carbon export from a Southern Ocean iron-fertilized diatom bloom” Nature 487, 313-319 Main findings: Increase in size of (iron-)fertilized patch area will result in a relative decrease in carbon drawdown – due to reduced lateral supply of other nutrients, particularly silicate. Order of magnitude decrease in drawdown at large patch sizes (at 1000 km scale) Main findings: (Re-)analysis of 2004 EIFEX iron addition experiment indicated that “at least half the bloom biomass sank far below a depth of 1,000 metres and that a substantial portion is likely to have reached the sea floor”

Smetacek V & 29 others (2012) “Deep carbon export from a Southern Ocean iron-fertilized diatom bloom” Nature 487, 313-319

Smetacek V & 29 others (2012) “Deep carbon export from a Southern Ocean iron-fertilized diatom bloom” Nature 487, 313-319 Fertilization site Eddy structure

Smetacek V & 29 others (2012) “Deep carbon export from a Southern Ocean iron-fertilized diatom bloom” Nature 487, 313-319 Fertilization site Eddy structure “If OF were to be a viable carbon sequestration method it would need to function in more than just a handful of mature, stable mesoscale eddies that were fertilized in the later part of the growing season. The EIFEX study is an example of the exception that proves the rule – in this case, that OF using Fe is not a viable approach to long term carbon sequestration”

And a recent news event: Nature 25 October 2012

And a recent news event: Nature 25 October 2012 Not (strictly-speaking) illegal – but did it really cause the effect that has been claimed?

In conclusion: The potential benefits of ocean iron fertilization are relatively modest Impacts (+ve and –ve) occur over large spatial and timescales, and hence many inherent 'management' uncertainties Governance problematic due to special status of Southern Ocean

Thanks for your attention! p.williamson@uea.ac.uk Environmental Sustainability KTN : NET Brokerage Event, London 13 March 2013