RE: [geo] Making ice (change of thread title)
A few comments. First, I think it is important to be cautious about concluding that anything is unworkable when it is in the early conceptual stage; important not to discourage idea building that sometimes leads to novel places. That said: I think of the thermal diode as a means of enhancing heat transfer to the atmosphere, and eventually to space. One application of this is to simply increase the rate of cooling of ocean water, independent of ice formation. Some years back a student and I pondered what humans might do if ice melting reduced the strength of the Gulf Stream. (The Gulf Stream is the replacement current for sinking North Atlantic Deep Water, NADW, a 15 Sverdrup downwelling of cold salty water in the Greenland/ Iceland/ Norway (GIN) area. The irony is that the consequence of excessive fresh melt water in the North Atlantic during warm periods is that northern Europe plunges into a deep freeze because NADW, a density driven current, slows or stops. This occurred about 12,000 years ago, for 1300 years, in a period known as the Younger Dryas when glacial Lake Agassiz flowed into the North Atlantic.) Our conceptual scheme for enhancing NADW was supplementing ice formation in the winter by pumping water to surface (we noted that this would only work if salt was trapped in the ice formed on the surface). It would be interesting to see if long thermal diodes might be an alternate scheme for generating cold downwelling water. But this need not focus on NADW: if the goal is to cool the earth or stop the thermal expansion of the ocean, get more heat out of it. The key engineering question would be, I think, the magnitude of heat transfer from diodes compared to that from the ocean surface itself: how much enhancement takes place. I think it is harder to conceptualize thickening sea ice with a thermal diode. If the diode is in the ice itself it will subcool the ice substantially, getting around the self-insulating property of ice. However, the diode gets farther away from sea water as ice forms at the bottom of the sheet. If the diode is below the ice sheet one wonders if the chilled water would sink away from the bottom of the ice sheet. This is not a problem for a thick glacier, which is riding on a lubricating layer of water: could one pin the glacier in place by freezing the bottom layer in winter, subcooling it enough to last through the summer season, since the insulating property of ice would now work in the opposite direction? Andrew's observation that open ice behind ice breakers quickly freezes over in cold weather is intriguing. Might one herd ice south from the Arctic Ice sheet, time and again, to increase the area of annual ice formation? The question of salt disposition if one thickens ice by pumping water on top of it is a persistent unknown. How I would love to see a test of this; as Ron points out, a submarine could easily be equipped to do a small scale test. Does the salt stay in the ice on the surface, or does brine find a way down to the sea, through microchannels. If the salt does stay, what is the impact in the spring. Peter Flynn Peter Flynn, P. Eng., Ph. D. Emeritus Professor and Poole Chair in Management for Engineers Department of Mechanical Engineering University of Alberta peter.fl...@ualberta.ca cell: 928 451 4455 -Original Message- From: Doug MacMartin [mailto:macma...@cds.caltech.edu] Sent: January-15-14 5:36 PM To: andrew.lock...@gmail.com; 'Ronal Larson' Cc: 'Keith Henson'; 'Geoengineering'; 'John Nissen'; 'Peter Flynn'; 'RAU greg' Subject: RE: [geo] Making ice (change of thread title) The only advantage is the disposition of the salt - making ice thicker at the bottom ensures that the salt stays in the water, not the ice. As has been pointed out before, we don't know what happens with the salt if you flood the ice from the top, nor whether higher-salinity ice creates a problem by melting earlier. However, given that the oil industry seems to use this approach regularly, it seems like it ought to be relatively straightforward for the right person to actually collect some data rather than simply trading hypotheses. (The right person almost certainly isn't me, much though I'd love the excuse to head up to the Beaufort sea.) -Original Message- From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] On Behalf Of Andrew Lockley Sent: Wednesday, January 15, 2014 4:24 PM To: Ronal Larson Cc: Keith Henson; Geoengineering; John Nissen; Peter Flynn; RAU greg Subject: Re: [geo] Making ice (change of thread title) Personally, I can't see these thermal diodes being at all practical. Far cheaper and simpler to just break up the ice, or pump water on top of it. The maths is pretty simple. The thermal diode can only be at a temperature of the water, at a maximum. It's heat transfer is a function of the surface area exposed to the air. This heat exchanger is a manufactured item, and thus expensive, with a small surface area.
[geo] IPCC: CDR must be considered
This is apparently from the upcoming IPCC Mitigation volume, or something else? CDRer's mount up? Greg http://www.brisbanetimes.com.au/environment/climate-change/sucking-co2-from-atmosphere-may-be-only-way-to-meet-climate-goals-un-report-says-20140116-30vnr.html Sucking CO2 from atmosphere may be only way to meet climate goals, UN report says Published: January 16, 2014 - 5:51AM Advertisement Governments may have to extract vast amounts of greenhouse gases from the air by 2100 to achieve a target for limiting global warming, backed by trillion-dollar shifts towards clean energy, a draft U.N. report showed on Wednesday. A 29-page summary for policymakers, seen by Reuters, says most scenarios show that rising world emissions will have to plunge by 40 to 70 per cent between 2010 and 2050 to give a good chance of restricting warming to U.N. targets. The report, outlining solutions to climate change, is due to be published in Germany in April after editing by the Intergovernmental Panel on Climate Change (IPCC). It will be the third in a series by the IPCC, updating science from 2007. It says the world is doing too little to achieve a goal agreed in 2010 of limiting warming to below 2 degrees above pre-industrial times, seen as a threshold for dangerous floods, heatwaves, droughts and rising sea levels. To get on track, governments may have to turn ever more to technologies for carbon dioxide removal (CDR) from the air, ranging from capturing and burying emissions from coal-fired power plants to planting more forests that use carbon to grow. Most projects for capturing carbon dioxide from power plants are experimental. Among big projects, Saskatchewan Power in Canada is overhauling its Boundary Dam power plant to capture a million tonnes of carbon dioxide a year. And, if the world overshoots concentrations of greenhouse gases in the atmosphere consistent with the 2C goal, most scenarios for getting back on track deploy CDR technologies to an extent that net global carbon dioxide emissions become negative before 2100, it says. Temperatures have already risen by 0.8C since the Industrial Revolution. Bioenergy To limit warming, the report estimates the world would have to invest an extra $US147 billion ($164 billion) a year in low-carbon energies, such as wind, solar or nuclear power from 2010 to 2029. At the same time, investments in fossil fuel energy would have to be reduced by $US30 billion annually. And several hundred billion dollars a year would have to go on energy efficiency in major sectors such as transport, buildings and industry. By contrast, it said that global annual investments in the energy system are now about $US1.2 trillion. And it says there are huge opportunities for cleaning up, for instance by building cities that use less energy for a rising world population. Most of the world's urban areas have yet to be constructed, it says. Overall, the report estimates that the costs of combating global warming would reduce global consumption of goods and services by between 1 and 4 per cent in 2030, 2-6 per cent in 2050 and 2-12 per cent in 2100, compared to no action. The IPCC said in September that it is at least 95 per cent probable that human activities, led by the burning of fossil fuels, are the dominant cause of global warming since the 1950s, up from 90 per cent in a 2007 assessment. The world has agreed to work out a global U.N. deal by the end of 2015, entering into force from 2020, to fight climate change. But progress has been sluggish. Global greenhouse gases have risen more rapidly between 2000 and 2010, the draft says, with greater reliance on coal than in previous decades. China, the United States and the European Union are the top emitters. The IPCC cautioned that the findings in the draft, dated Dec. 17, were subject to change. This is a work in progress which will be discussed and revised in April, said Jonathan Lynn, spokesman for the IPCC in Geneva. The report adds many details to earlier drafts. The IPCC's credibility suffered in 2007 after one of its reports wrongly said that Himalayan glaciers could all melt by 2035, centuries earlier than experts reckon. The draft says that only the most radical curbs outlined in an IPCC report in September would give a better than 66 per cent chance of keeping temperature rises below 2C. The scenario corresponds to greenhouse gas concentrations of 430 to 480 parts per million in the atmosphere - up from about 400 now. Reuters This story was found at: http://www.brisbanetimes.com.au/environment/climate-change/sucking-co2-from-atmosphere-may-be-only-way-to-meet-climate-goals-un-report-says-20140116-30vnr.html -- You received this message because you are subscribed to the Google Groups geoengineering group. To unsubscribe from this group and stop receiving emails from it, send an email to geoengineering+unsubscr...@googlegroups.com. To post to this group, send email
Re: [geo] IPCC: CDR must be considered
Al Gore weighs in on the IPCC's new change of heart: Geoengineering 'Insane, Utterly Mad and Delusional'. http://www.commondreams.org/headline/2014/01/16 Don't sugar coat it, Al. On the other hand Nature will perform her own geoengineering over the next 100 kyrs in consuming all of the CO2 we end up emitting. How delusional is it to think we might able to engineer a speedup of this process and alleviate at least some of the suffering in the interim? Call me mad, but considering how well cap and trade, the Kyoto Protocol, and the COP process have gone, it would seem rather reckless to dismiss the possibility/necessity of post-emissions remediation of the CO2 problem without further study. Greg From: Rau, Greg r...@llnl.gov To: geoengineering@googlegroups.com geoengineering@googlegroups.com Sent: Thursday, January 16, 2014 9:18 AM Subject: [geo] IPCC: CDR must be considered This is apparently from the upcoming IPCC Mitigation volume, or something else? CDRer's mount up? Greg http://www.brisbanetimes.com.au/environment/climate-change/sucking-co2-from-atmosphere-may-be-only-way-to-meet-climate-goals-un-report-says-20140116-30vnr.html Sucking CO2 from atmosphere may be only way to meet climate goals, UN report says Published: January 16, 2014 - 5:51AM Advertisement Governments may have to extract vast amounts of greenhouse gases from the air by 2100 to achieve a target for limiting global warming, backed by trillion-dollar shifts towards clean energy, a draft U.N. report showed on Wednesday. A 29-page summary for policymakers, seen by Reuters, says most scenarios show that rising world emissions will have to plunge by 40 to 70 per cent between 2010 and 2050 to give a good chance of restricting warming to U.N. targets. The report, outlining solutions to climate change, is due to be published in Germany in April after editing by the Intergovernmental Panel on Climate Change (IPCC). It will be the third in a series by the IPCC, updating science from 2007. It says the world is doing too little to achieve a goal agreed in 2010 of limiting warming to below 2 degrees above pre-industrial times, seen as a threshold for dangerous floods, heatwaves, droughts and rising sea levels. To get on track, governments may have to turn ever more to technologies for carbon dioxide removal (CDR) from the air, ranging from capturing and burying emissions from coal-fired power plants to planting more forests that use carbon to grow. Most projects for capturing carbon dioxide from power plants are experimental. Among big projects, Saskatchewan Power in Canada is overhauling its Boundary Dam power plant to capture a million tonnes of carbon dioxide a year. And, if the world overshoots concentrations of greenhouse gases in the atmosphere consistent with the 2C goal, most scenarios for getting back on track deploy CDR technologies to an extent that net global carbon dioxide emissions become negative before 2100, it says. Temperatures have already risen by 0.8C since the Industrial Revolution. Bioenergy To limit warming, the report estimates the world would have to invest an extra $US147 billion ($164 billion) a year in low-carbon energies, such as wind, solar or nuclear power from 2010 to 2029. At the same time, investments in fossil fuel energy would have to be reduced by $US30 billion annually. And several hundred billion dollars a year would have to go on energy efficiency in major sectors such as transport, buildings and industry. By contrast, it said that global annual investments in the energy system are now about $US1.2 trillion. And it says there are huge opportunities for cleaning up, for instance by building cities that use less energy for a rising world population. Most of the world's urban areas have yet to be constructed, it says. Overall, the report estimates that the costs of combating global warming would reduce global consumption of goods and services by between 1 and 4 per cent in 2030, 2-6 per cent in 2050 and 2-12 per cent in 2100, compared to no action. The IPCC said in September that it is at least 95 per cent probable that human activities, led by the burning of fossil fuels, are the dominant cause of global warming since the 1950s, up from 90 per cent in a 2007 assessment. The world has agreed to work out a global U.N. deal by the end of 2015, entering into force from 2020, to fight climate change. But progress has been sluggish. Global greenhouse gases have risen more rapidly between 2000 and 2010, the draft says, with greater reliance on coal than in previous decades. China, the United States and the European Union are the top emitters. The IPCC cautioned that the findings in the draft, dated Dec. 17, were subject to change. This is a work in progress which will be discussed and revised in April, said Jonathan Lynn, spokesman for the IPCC in Geneva. The report adds many details to earlier drafts
