Ironex II - like SOIREE - like data model (Aumont and Bopp, 2006)
(unrealistic) global-scale iron fertilization experiment Method : no more iron limitation for 10 or 100 years Results : - 33 pmm after 100 years - 7 ppm after 10 years, but if stopped, sequestered carbon is lost rapidly non-local effects (on productivity, …)
SOIREE ‘99: EVOLUTION OF DMSP AND DMS IN THE UPPER WATER COLUMN INSIDE AND OUTSIDE THE IRON-ENRICHED PATCH days after start of iron enrichment SUZANNE TURNER DMSP nmol l -1 DMS nmol l -1 DMSP inside DMS inside DMSP outside DMS outside
Other Secondary Effects A)Nutrient robbing B)Cyclones/hurricanes C)Geo-engineering and ocean acidification
SOLAS Position statement on large-scale ocean fertilisation (2007) Large-scale fertilisation of the ocean is being actively promoted by various commercial organisations as a strategy to reduce atmospheric CO 2 levels. However, the current scientific evidence indicates that this will not significantly increase carbon transfer into the deep ocean or lower atmospheric CO 2. Furthermore, there may be negative impacts of iron fertilisation including dissolved oxygen depletion, altered trace gas emissions that affect climate and air quality, changes in biodiversity, and decreased productivity in other oceanic regions. It is then critical and essential that robust and independent scientific verification is undertaken before large-scale fertilisation is considered. Given our present lack of knowledge, the judgement of the SOLAS SSC is that ocean fertilisation will be ineffective and potentially deleterious, and should not be used as a strategy for offsetting CO 2 emissions.
“Give me half a tanker of iron, and I’ll give you an ice age.” Martin, 1988
“Human beings are now carrying out a large scale geophysical experiment (i.e. added CO 2 to the atmosphere) of a kind that could not have happened in the past or be reproduced in the future (Roger Revelle and Hans Suess, 1957). Pilots in the Royal Flying Corps in WWI were not issued with parachutes (nor were they allowed to buy their own) since this “might impair their fighting spirit”. “Only fools find joy in the prospect of climate engineering. It’s foolish to think that risk of significant climate damage can be denied or wished away. Perhaps we can depend on the transcendent human capacity for self-sacrifice when faced with unprecedented shared, long-term risk, and therefore can depend on future reductions in greenhouse gas emissions. But just in case, we’d better have a plan” (Ken Caldeira, 2008). “A focus on tinkering with the entire planetary system is not a dynamic new technological and scientific frontier, but an expression of political despair” (Greenpeace, 2008). The US Presidential Science Advisory Council in 1965 identified geo- engineering as the only response to the CO 2 climate problem, reporting that “The possibilities of deliberately bringing about countervailing climatic changes therefore needs to be deliberately explored” – the possibility of reducing fossil fuel use was not discussed.
Age of scientific innocence is over (Fe fertilisation, CRU) Geo-engineering may be needed if all else fails Research to eliminate unworkable ideas and thoroughly test those that might be useful (including secondary effects and unintended consequences) Favour – carbon capture/removal schemes – reversible – scaleable from small to large Against – large direct schemes (particularly SRM) Governance – legal, political, financial aspects