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

2. “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

3. 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)

4. 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)

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

6. 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

7. 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

8. 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

9. 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

10. 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 .
Gt C per year
Gt C per year
Global net total of 2.2 Gt C pa = mean of ~6 tonnes per sq km

11. . . . 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

12. . . . 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

13. Experimental evidence
13 iron addition experiments ( ), two commercial trials ( ) and two phosphate addition experiments ( ) have been carried out to date, at scale of 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

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

15. . 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

16. . 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 ↓

17. . 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 ,000 km2 over time period of months-years are required.

18. . 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 ,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

19. 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

20. 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

21. 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

22. 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)
global
continuous
200
150
100 50
Reduction in estimated maximum CO2 drawdown
Greatest effect in Southern Ocean

23. 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)
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

24. ‘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

25. ‘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)

26. ‘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

27. 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

28. 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,
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”

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

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

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

32. And a recent news event:
Nature 25 October 2012

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

34. 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

35. Thanks for your attention!
Environmental Sustainability KTN : NET Brokerage Event, London 13 March 2013