OCEAN CARBON SEQUESTRATION and Geo-Engineering Should we attempt to engineer the planet?
Today: If we can t (= won t) stop burning carbon.. Are there other things we CAN do? And should we try? CO 2 Atm CO 2 already above ~ last million years of planetary history..
What is geo-engineering?
What is geo-engineering? 1) Approaches that attempt to diminish effects or concentrations of greenhouse gases Or more broadly: 2) deliberately manipulating physical, chemical, or biological aspects of the Earth system
Currently becoming hot topic Example: Recent conference down the road at Asilomar (~ Monterey) brought together scientists from 14 countries
Also an extremely contentious topic Dueling Editorials after Asilomar Conf.
Also an extremely contentious topic *Organizer has advisory links to commercial company ( Climos ; Fe fertilization) * Issue of Priorities: should it be on reducing carbon, not new global manipulations?
Reply by a scientist *Silly to dismiss possible mitigation ideas without even testing or thinking seriously about them * A lot of research is really basic climate/ C-cycle researchwill help us understand systems..
Two basic kinds of approaches are being discussed: 1) Remove CO 2 (from atm or from power plants) and put it somewhere else*. *but where? 2) Reduce amount of sunlight (heat) that makes it to the earth s surface
Two basic approaches: SRM (Solar radiation management) increase with Albedo CDR (Carbon Dioxide Removal) decrease with the greenhouse
CO 2 removal (CDR) is thing most actively being worked on *Some CDR versions are actually now being tested * Most CDR ideas (but not all..) are less controversial.. CDR Options SRM CDR (Carbon Dioxide Removal) decrease the greenhouse SRM (solar radiation management) increase with Abedo
SRM options are currently closer to science fiction *highly controversial: due to unknown feedbacks, law of unintended consequences *seen by many as last resort CDR Options SRM CDR (Carbon Dioxide Removal) decrease the greenhouse SRM (solar radiation management) increase with Abedo
Schema of some approaches proposed:
Weighing Approaches: Cooling influence Cost Readiness RISKS? All are judged to need further research before testing
Weighing Approaches: What Criteria would you use? Soundness of the mitigation method Technical challenges Time and spatial scales required Advertent and inadvertent consequences? Reversibility Political viability Cost (fiscal and other resources)
Today: Focus on CDR (CO 2 removal)- closest to reality - 1.Sequestration: a. Geological (reservoirs and new minerals?) b. In the Ocean 2. Removal: Ocean Fertilization and similar ideas. 3. Engineering a cooler Climate? 4.Local slant: A UCSC alumni s great idea?
1. Physical Carbon Sequestration* *The state of being Set apart, or Secluded, From Latin sequestrare to hand something over to a trustee
Human C- emissions Without changing these uses at all, can you GRAB the CO2, and store it?
Non-biological sequestration 1) Put CO2 somewhere directly ( as liquid or solid) 2) Turn it into another form, and store that..
1) Carbon Capture and Storage a) CAPTURE CO 2 from smokestacks or atmosphere directly Then: 1) Geological storage? 2) Ocean CO 2 storage? 3) Mineral carbonation?
capture There are lots of chemical ways you can strip CO 2 out of a gas stream (or the air!) and concentrate it as ~ pure CO 2 - all cost $.
Geological Storage Simulation of injection of CO2 in a reservoir in Algerian oil field. Pump liquid CO 2 in existing geological formations either on land or under seafloor
Or: Pump CO 2 offshore, then into depleted seafloor oil reservoirs
Large Project in Norway, already doing it
1) Geological Storage Positives: *Ready to go now uses off the shelf oil field technology Can be meshed directly into oil removal operations Negatives: How stable is the storage..really? How many areas have the correct sort of reservoir to hold CO 2? (possibly huge transport problems..)
2) Deep Ocean Storage Pump liquid CO 2 (or drop solid CO2) into the deep ocean
CO 2 physical form changes with depth: gas vs. rising liquid vs. sinking liquid vs. solid: all depends on DEPTH (temp and pressure) If You put it > 3km deep, turns in liquid CO2 lakes on bottom of sea floor
Ocean Storage: upside Positives: * easy can put in deep ocean in many places, get similar effect Models suggest at least several hundred years sequestration maybe a lot more
Ocean Storage: downside Negatives: 1) TEMPORARY.. It will be back..
Recall: Global Ocean Conveyor Belt circulation
Recall: total turnover time of ocean = 1000 years Surface Ocean residence time = 100 years Upwelling Deep Water Formation Deep Cold Ocean residence time ~ 1000 years Recall: Residence time is the average amount of time a substance (in this case water) spends in a reservoir
Ocean Storage: downside More Negatives: 2) Toxicity to ocean life: as it mixes into ocean, huge plumes of very acidic water..
3) Mineral Carbonation A Calcite (CaCO3) crystal Use CO 2 to create carbonate minerals.. Then put them someplace...
Natural Mineral Carbonation Examples of some natural carbonate minerals formed When rocks that have Mg or Ca weather (naturally) they take up CO 2 to form new carbonate minerals (new kinds of rocks)
Question: can you speed up natural process enough? 1) where would you get all the silicate rocks? 2) Where would you PUT all the new rocks?
Another option: in-situ carbonationuses natural reactions that occur in volcanic rocks (basalt) Places in world (red) where basalt volcanic rocks exist on land where you might pump in CO2
Test of in-situ basalt carbonation now going on in Iceland
Overall: Mineral carbonation Positives: *Stable once you make mineral, CO 2 is gone forever ( ~geologic time scales) Negatives: Lots of development/ research needed May be very expensive Generate huge amounts of new carbonate rocks.. Have to go somewhere..
2. Biological Carbon Sequestration: focus on ocean fertilization
Recall Biological pump (role of oceans in CO 2 adsorption)
Recall: 1) Autotrophs: Fixation of C into organic matter 2) Heterotrophs: oxidize C - returns to geosphere via breakdown of organic matter Inorganic matter (oxidized carbon) CO 2 autotrophs heterotrophs Organic matter (reduced carbon) CHO
CO 2 Biological Pump Plankton SURFACE OCEAN Sinking Organic matter (reduced carbon) CHO Heterotrophic bacteria CO 2 DEEP OCEAN
Biological Pump C removed on time scale of plankton bloom (=weeks) C Stays down there: time scale of deep ocean circulation (100 s- 1000 yrs..)!
Recall: whatever you put down deep would take on 100 s to 1000 yrs to get back up Surface Ocean residence time = 100 years Upwelling Deep Water Formation Deep Cold Ocean residence time ~ 1000 years
Break?
Ocean uptake 1: Fe Fertilization
Background: Plankton blooms can be enormous, typically associated with upwelled N and P
BUT some large regions of world ocean have lots of N and P.. But low plankton.why? Blue and black regions are high nutrients.. But low plankton
Answer in many places: Trace metal nutrients plants also need trace metal nutrients to grow for example Fe, Mg Cytochrome with Heme group- (Fe) involved in chl manufacture Center of Chlorophyll A (with Mg in center)
IRON Fe is one of key trace nutrients for plankton (and all plants) But in ocean, supply is often VERY limited. DUST is about it in many places
Gulf of Alaska is one such place.. Dust plume carrying critical Fe can only occur in summer..
So..what if you go out and dump a plume of Fe into the ocean.. Will it work? Yes. Up to now, about a dozen experiments already conducted- causes extensive plankton blooms
Give me half a tanker of iron, and I ll give you an ice age John Martin 1 John Martin was one of first to predict this effect. (He was a professor at Moss Landing down the road )
But: Commercial Ocean Fertilization?
Buy Now?
Some Pesky Scientists always will worry..
Problem #1: shifts ecosystem composition.. unknown effects.. `
Problem #2: Will Carbon actually go down deep where you want it? Bottom line: only small fraction actually reaches deep oceanand exactly how much depends on ecosystem structure!
Overall: Most Oceanographers are extremely wary of Fe Fertilization ideas due to these problems.. (And the law of unintended consequences )
However: Artificial upwelling? Lights Please
Artificial upwelling An alternate fertilization approach Mimics the natural process of upwelling Big difference vs. Fe: brings natural nutrient laden water to surface Overall effects?
Some Other Related Ideas: Tube the Ocean? (dude)
Dr. Lovelock strikes again! Similar Idea: * put couple of bzillion plastic tubes in ocean * wave motion + one way valve creates artificial upwelling
Or: Saved by Salps?
Saved by Salps? A Salp is gelatinous zooplankton..but makes largest and fastest sinking fecal pellets known to science..
Recall: The Martin curve Attenuation of sinking Particles (plankton remains ) is approximately exponential with depth POC Attenuation Most organic tissue is converted back into CO 2 by 500m Almost all (>90%) by 1000m
4) Finally: A local slant UCSC Alumni s great idea?
Brent Constanz Calera Inc. Sequestering CO 2 in the Built Environment
(Not to be confused with Calera Winery.. )
The Idea: Green Cement
Basically idea = mineral carbonation, but takes one step further to make cement out of new minerals Idea to make profitable: sell the carbonates as building materials
Demonstration project currently in progress at moss landing up the road
Overall: What do you think? Many, Many questions: Good ideas? Bad ideas, but necessary? Should we continue research on these things? Should we allow commercial companies to do large scale tests? Since sea is international zone, who is to say they can or can t?