[geo] IMPORTANT: PLEASE be sure to include Cloud Brightening using Cryogenics as a viable option!!
Some months ago I submitted a patent pending concept for brightening clouds by releasing large amounts of liquefied air or liquid nitrogen (June 12th entry Proposed Method to Offset Global Warming). One aspect of the application would be to increase the number of droplets in clouds to boost their reflectivity. I believe it is imperative that this concept be considered along with those which are being evaluated for the approved list. This concept could be relatively easy to validate, and relatively straightforward to execute unlike many other options being considered. The concept also has several additional applications of great significance, including potentially fighting large wildfires and reducing the severity of destructive weather. It therefore might be used to not only reduce global warming but also reduce some of the natural disasters that may arise due to global warming (including preventing tornados and reducing hurricane strength). The potential multi-use capability of this concept is one unique advantage it has over most other concepts being considered. In terms of feasibility, the Chinese have inadvertently created significant proof of this in trying to prevent rain during the Olympics. Here is a quote from one of the news articles: Finally, any rain-heavy clouds that near the Bird's Nest will be seeded with chemicals to shrink droplets so that rain won't fall until those clouds have passed over. Zhang Qian, head of Beijing's Weather Modification Office, explains, We use a coolant made from liquid nitrogen to increase teh number of droplets while decreasing their average size. As a result, the smaller droplets are less likely to fall, and precipitation can be reduced. The Chinese have therefore given a significant level of proof that cooling of clouds can increase the number of droplets while decreasing their average size. This is exactly the effect that I believe would be desired to brighten clouds. The Chinese are using this to prevent precipitation on a limited scale. I believe this provides proof that large scale cooling using cryogenic liquids could also be used to increase cloud albedo by increasing droplet density. My concept would be scaled much larger than the Chinese by utilizing heavy lift aircraft to release large amounts of liquefied air or liquid nitrogen precisely where it could have maximum effect (i.e. close to the equator and on targeted cloud types), and on a rotating basis to maintain the desired albedo increase. This process may also serve to enlarge existing clouds or create new clouds under the right conditions. One valuable aspect of the concept is that the working fluid would be naturally absorbed by the atmosphere. The process could therefore be safely scaled as large as necessary to obtain the desired result. So most importantly, it should have no adverse effect to the atmosphere, unlike most concepts being considered. This removes an enormous potential roadblock for other concepts, giving this concept a much greater chance of obtaining public support in addition to widespread government approval, which otherwise will be extremely difficult as this is of course an international issue. Another feature of this approach is enabling very large scaling due to the enormous expansion ratio of liquefied air and liquid nitrogen, enabling it to cool very large atmospheric volumes with minimal effort. These liquids expand over 800 times at sea level into their respective gases, and more importantly expand much more than this at higher altitudes. For example, at 40,000 feet these liquids expand over 4,000 times into gaseous air or nitrogen, so that one payload from a 10 foot diameter by 40 foot long tank could cool an atmospheric volume of 6 miles in diameter by 30 miles long. If for example 10 or 20 aircraft were outfitted with cryogenic tanks, one can imagine an almost constant delivery of cryogenic payloads that would expand thousands of times each, to enable the type of scaling that would be required to increase global cloud albedo by 5% (the amount considered in previous scientific reports to offset a doubling of pre-industrial CO2). Testing would need to determine how droplet density will dissipate over time (reducing albedo with time). This effect is actually desired, to ensure that albedo levels stay safely in control. However, this will also determine how often re-treatment is required, and how large the fleet of aircraft will need to be in order to maintain desired overall albedo. I don't believe that this answer can be obtained without running real-world tests at a reasonable scale. In other words, I don't believe this concept can be considered for elimination until real-world tests can be run. My hope is that brightened clouds will remain brighter long enough to allow a global increase of 5% to be obtained with a reasonable amount of aircraft and mission frequency. And in this fashion, allow mankind to reduce global CO2 within a
[geo] Re: Bright Ideas
Re Arctic ice, the issue is not just albedo, but also thermai inertia. The effective heat capacity of the exposed ocean is hugely greater than the ice. Tom. ++ http://www.celsias.com/article/all-about-albedo-lighter-world-cooler-world/ All About Albedo: A Lighter World is a Cooler World Jeremy Williams From the latin ‘albus', meaning ‘white', albedo is an indicator of reflectivity. Bright objects reflect much of the light that reaches them, and have high albedo. Dark objects have low albedo, because they absorb light. If you've ever climbed into a dark-colored car on a hot day, you already understand albedo. It's an unusual word, and an unusual factor in climate change, presenting both dangers and and opportunities. The danger comes primarily from the Arctic, where vast sheets of white ice reflect sunlight away from the earth and have a cooling effect on the atmosphere. Ice is highly reflective, reflecting 80-90% of sunlight (pdf), but seawater is dark blue or green and reflects very little. As Arctic ice melts, seawater takes its place, which absorbs more heat and compounds the melting problem. Loss of albedo in this context becomes an accelerator of climate change. This works in reverse in the case of deforestation, something I learned a few years ago when I had flying lessons in Kenya's Rift Valley. We flew across the transition from forested escarpment to desert valley floor, and the rising heat off the dusty plains created great waves of turbulence that tossed our little plane around. Forests, being dark, absorb 95% of the sunlight that falls across them, whereas cleared land or desert has a higher albedo and beams that light and heat back up. Interestingly, deforestation actually raises the earth's albedo. Before we get the chainsaws out however, we should remember that forests use some of the sunlight in photosynthesis. They also help create clouds, and of course absorb CO2 from the atmosphere. Overall, their net effect is usually cooling. I say usually because research by the Global Carbon Project found that there is in fact a case for deforestation (pdf) to cool the earth in some places. In tropical countries and mid-latitude areas forests have a cooling effect. But high latitude forests have a strong warming influence, largely due to the presence of dark forest canopies in regions that would otherwise be snow covered. As well as giving us some complicating factors in forestation and Arctic ice, albedo presents us with some interesting opportunities. If reflective surfaces have a cooling effect on the earth, can we create some more of them? There are two immediate possibilities. The first of these is the urban environment, which covers around 1% of the earth's surface. In research earlier this year, two scientists at the Lawrence Berkeley National Laboratory in California discovered that whitening our cities (pdf) could have a considerable cooling effect. Increasing urban albedo can result in less absorption of incoming solar radiation by the surface-troposphere system, countering to some extent the global scale effects of increasing greenhouse gas concentrations. It would also cool the air on the ground, reducing the need for air conditioning in the summer. The report estimated that around 40% of the urban environment is pavement and 20-25% is roofs, both of which could be made more reflective. Most pavements and parking lots are laid in Portland cement concrete, which is expensive when totally white, but can be easily made lighter with different aggregates (pdf). White asphalt shingles, corrugated iron, or white acylic tiles can be used for roofing. You can read the maths for yourself, but the authors conclude that whitening the urban environment would offset the equivalent of 44 Gigatonnes of CO2, or 11 years worth of growth in CO2 emissions. That's an offset, so it would not affect climate change in the long term, but it would buy us some time while we bring emissions under control. A second, more radical idea is the Global Albedo Enhancement Project , which suggests we cover large areas of the earth with white polythene film. According to Alvia Gaskill, the originator of the idea, covering a large enough area of the earth could be expected to offset some or all of the projected additional radiative forcing and global warming from 2010 to 2070. Prime locations would be the Sahara, Arabian or Gobi deserts, where thousands of square miles of desert could be covered. As geo-engineering goes, it's a fairly conservative idea, and the plastics technology already exists. On the downside, the cover would kill every living thing in the area, and would need to stay in place for at least a century. Local weather patterns may be affected. Windblown dust may lower the albedo of the plastic as it gets dirty, but Gaskill suggests robotic vacuum cleaners to keep them clean. This may be the more
[geo] arctic engineering needs and sea-ice science
hi all, I consulted with a few sea-ice wizards on the exchanges here related to Arctic trends, and Jennifer Francis at Rutgers weighed in with the following thoughts. Note the importance of the boundary layer changes as well. There are many important factors besides albedo and ocean solar absorption. Winter cloudiness etc important factor. But also note the importance of not over-interpreting short-term wiggles as trends. Much more on Dot Earth and in my earlier coverage of the sea-ice question. This post (shortcut) is a good starting point: http://tinyurl.com/dotIceTrends Here's jennifer's comment (I sent her that sea-ice graph that was making the rounds here) Hi Andy -- The first figure you attached with the extrapolation from the 2007 summer ice loss is very unrealistic, in my opinion. Both the observed record and model simulations of ice extent exhibit a great deal of interannual variability, and most sea ice researchers would expect this behavior to continue superimposed on a continuing downward trend. Some years the decline will be dramatic, as it was in 2007, and some years there will likely be a recovery, as random atmospheric patterns act on the ice cover. What's different now as opposed to 2 decades ago is that the ice is now so thin that any unusual forcing -- be it a persistent wind pattern, cloud cover, heat transfer from lower latitudes -- will have a much bigger effect on the ice, as thin ice is more easily moved by wind and/or melted by increased heating. The small ice cover of recent years allows more solar energy to be absorbed by the open surface during summer, but exactly how that extra heat affects the system over the following months is still being worked out. Some recent research suggests that during falls after low-ice summers the lower atmosphere warms, the atmospheric boundary layer gets deeper, and low clouds increase, all of which tend to retard regrowth of sea ice in the fall and early winter. It also appears there's a large-scale influence on winter weather patterns over much of the northern hemisphere. The reason I'm telling you all this is that it appears there is no obvious mechanism for the ice to rebound significantly unless there is a multi-year period of colder-than-normal temperatures, but this is not likely as greenhouse gases continue to increase at rates even faster than the most pessimistic IPCC scenario. Regarding water temperatures, the main effect is through the added absorption of solar energy in summer, which accelerates the melt during late summer. Warmer winter temperatures in the Atlantic sector also appear to be responsible for most of the retreat of the ice edge during winter in that region, but not on the Pacific side. Maybe this is more info that you needed and much of it you already know, but it's not a simple explanation. Regarding the shipping text you sent, it looks like a bunch of hooey to me. 51 ships in the area will not have a perceptible effect on the clouds. The good low clouds they're talking about are already almost 100% emissive of infrared energy, and adding ship smoke to them is not going to matter. Hope this helps -- Happy New Year!! Jennifer ~~ Jennifer Francis, Ph.D. Institute of Marine and Coastal Sciences, Rutgers University Co-Director of the Rutgers Climate and Environmental Change Initiative 74 Magruder Rd, Highlands NJ 07732 USA -- Tel: (732) 708-1217, Fax: (732) 872-1586 fran...@imcs.rutgers.edu | http://marine.rutgers.edu/~francis/ At 9:14 AM -0700 12/29/08, wig...@ucar.edu wrote: Re Arctic ice, the issue is not just albedo, but also thermai inertia. The effective heat capacity of the exposed ocean is hugely greater than the ice. Tom. ++ -- Andrew C. Revkin The New York Times / Science 620 Eighth Ave., NY, NY 10018 Tel: 212-556-7326 Mob: 914-441-5556 Fax: 509-357-0965 www.nytimes.com/revkin --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~--~~~~--~~--~--~---
[geo] Re: Bright Ideas
. . . . but the latent heat of ice is hugely greater than the specific heat of water. Freezing one metre of ice is like cooling an 80 metre depth of sea by 1 K. Stephen wig...@ucar.edu wrote: Re Arctic ice, the issue is not just albedo, but also thermai inertia. The effective heat capacity of the exposed ocean is hugely greater than the ice. Tom. ++ http://www.celsias.com/article/all-about-albedo-lighter-world-cooler-world/ All About Albedo: A Lighter World is a Cooler World Jeremy Williams From the latin ‘albus', meaning ‘white', albedo is an indicator of reflectivity. Bright objects reflect much of the light that reaches them, and have high albedo. Dark objects have low albedo, because they absorb light. If you've ever climbed into a dark-colored car on a hot day, you already understand albedo. It's an unusual word, and an unusual factor in climate change, presenting both dangers and and opportunities. The danger comes primarily from the Arctic, where vast sheets of white ice reflect sunlight away from the earth and have a cooling effect on the atmosphere. Ice is highly reflective, reflecting 80-90% of sunlight (pdf), but seawater is dark blue or green and reflects very little. As Arctic ice melts, seawater takes its place, which absorbs more heat and compounds the melting problem. Loss of albedo in this context becomes an accelerator of climate change. This works in reverse in the case of deforestation, something I learned a few years ago when I had flying lessons in Kenya's Rift Valley. We flew across the transition from forested escarpment to desert valley floor, and the rising heat off the dusty plains created great waves of turbulence that tossed our little plane around. Forests, being dark, absorb 95% of the sunlight that falls across them, whereas cleared land or desert has a higher albedo and beams that light and heat back up. Interestingly, deforestation actually raises the earth's albedo. Before we get the chainsaws out however, we should remember that forests use some of the sunlight in photosynthesis. They also help create clouds, and of course absorb CO2 from the atmosphere. Overall, their net effect is usually cooling. I say usually because research by the Global Carbon Project found that there is in fact a case for deforestation (pdf) to cool the earth in some places. In tropical countries and mid-latitude areas forests have a cooling effect. But high latitude forests have a strong warming influence, largely due to the presence of dark forest canopies in regions that would otherwise be snow covered. As well as giving us some complicating factors in forestation and Arctic ice, albedo presents us with some interesting opportunities. If reflective surfaces have a cooling effect on the earth, can we create some more of them? There are two immediate possibilities. The first of these is the urban environment, which covers around 1% of the earth's surface. In research earlier this year, two scientists at the Lawrence Berkeley National Laboratory in California discovered that whitening our cities (pdf) could have a considerable cooling effect. Increasing urban albedo can result in less absorption of incoming solar radiation by the surface-troposphere system, countering to some extent the global scale effects of increasing greenhouse gas concentrations. It would also cool the air on the ground, reducing the need for air conditioning in the summer. The report estimated that around 40% of the urban environment is pavement and 20-25% is roofs, both of which could be made more reflective. Most pavements and parking lots are laid in Portland cement concrete, which is expensive when totally white, but can be easily made lighter with different aggregates (pdf). White asphalt shingles, corrugated iron, or white acylic tiles can be used for roofing. You can read the maths for yourself, but the authors conclude that whitening the urban environment would offset the equivalent of 44 Gigatonnes of CO2, or 11 years worth of growth in CO2 emissions. That's an offset, so it would not affect climate change in the long term, but it would buy us some time while we bring emissions under control. A second, more radical idea is the Global Albedo Enhancement Project , which suggests we cover large areas of the earth with white polythene film. According to Alvia Gaskill, the originator of the idea, covering a large enough area of the earth could be expected to offset some or all of the projected additional radiative forcing and global warming from 2010 to 2070. Prime locations would be the Sahara, Arabian or Gobi deserts, where thousands of square miles of desert could be covered. As geo-engineering goes, it's a fairly conservative idea, and the plastics technology already exists. On the downside, the cover would kill every living thing in the area, and would need to stay in place for at
[geo] Re: arctic engineering needs and sea-ice science
I would respond with two hopefully clarifying comments: 1. While there is a lot of focus on when the ice will be gone in summer, this will have little effect on the weather as the surface temperature and water availability are similar for no ice and melting ice. Indeed, more solar is absorbed, but that does not significantly raise ocean temperatures. What really matters is what happens in the fall into winter, because as long as there is no ice or thin ice, there will be a lot of heat transport to the atmosphere and so the near surface air cannot cool to 40 C and so create cold, dense air masses that spread out from the Arctic and influence weather around the midlatitudes. With all the extra heat going up into the atmosphere (the solar heat absorbed during the time with lower albedo), the atmospheric circulation will be altered‹causing, as Jennifer notes, the ³large-scale influence on winter weather patterns over much of the northern hemisphere.² So, while the retreat of summer sea ice is an easy metric, what really affects the weather is the delayed formation of thick ice that can insulate the atmosphere from the heat contained in the ocean. 2. On the characteristics of low clouds, I thought the intent was to raise the albedo when the Sun was out, not to raise the IR emissivity. During the polar summer one wants the clouds with a high albedo (once the surface starts to melt and its albedo comes down to below that of low clouds). Then, during the polar night, one would want to decrease the cloud emissivity so the surface can more rapidly radiate to space (the clouds tend to retard the cooling process that allows ice to form, as Jennifer notes). Mike MacCracken On 12/29/08 11:26 AM, Andy Revkin anr...@nytimes.com wrote: hi all, I consulted with a few sea-ice wizards on the exchanges here related to Arctic trends, and Jennifer Francis at Rutgers weighed in with the following thoughts. Note the importance of the boundary layer changes as well. There are many important factors besides albedo and ocean solar absorption. Winter cloudiness etc important factor. But also note the importance of not over-interpreting short-term wiggles as trends. Much more on Dot Earth and in my earlier coverage of the sea-ice question. This post (shortcut) is a good starting point: http://tinyurl.com/dotIceTrends Here's jennifer's comment (I sent her that sea-ice graph that was making the rounds here) Hi Andy -- The first figure you attached with the extrapolation from the 2007 summer ice loss is very unrealistic, in my opinion. Both the observed record and model simulations of ice extent exhibit a great deal of interannual variability, and most sea ice researchers would expect this behavior to continue superimposed on a continuing downward trend. Some years the decline will be dramatic, as it was in 2007, and some years there will likely be a recovery, as random atmospheric patterns act on the ice cover. What's different now as opposed to 2 decades ago is that the ice is now so thin that any unusual forcing -- be it a persistent wind pattern, cloud cover, heat transfer from lower latitudes -- will have a much bigger effect on the ice, as thin ice is more easily moved by wind and/or melted by increased heating. The small ice cover of recent years allows more solar energy to be absorbed by the open surface during summer, but exactly how that extra heat affects the system over the following months is still being worked out. Some recent research suggests that during falls after low-ice summers the lower atmosphere warms, the atmospheric boundary layer gets deeper, and low clouds increase, all of which tend to retard regrowth of sea ice in the fall and early winter. It also appears there's a large-scale influence on winter weather patterns over much of the northern hemisphere. The reason I'm telling you all this is that it appears there is no obvious mechanism for the ice to rebound significantly unless there is a multi-year period of colder-than-normal temperatures, but this is not likely as greenhouse gases continue to increase at rates even faster than the most pessimistic IPCC scenario. Regarding water temperatures, the main effect is through the added absorption of solar energy in summer, which accelerates the melt during late summer. Warmer winter temperatures in the Atlantic sector also appear to be responsible for most of the retreat of the ice edge during winter in that region, but not on the Pacific side. Maybe this is more info that you needed and much of it you already know, but it's not a simple explanation. Regarding the shipping text you sent, it looks like a bunch of hooey to me. 51 ships in the area will not have a perceptible effect on the clouds. The good low clouds they're talking about are already almost 100% emissive of infrared energy, and adding ship smoke to them is not going to matter. Hope this helps -- Happy New Year!! Jennifer
[geo] COLLECTIVE WISDOM sorry formatting was messed up - now sorted!
1. Taking all factors into account, what do you think of the following geoengineering techniques? (please consider feasibility, cost, side effects, political acceptability, etc.) answered question 4 skipped question 0 Promising as a major solution Promising as a contribution Possibly useful Not promising Don't know Response Count Stratospheric sulphur aerosols 0.0% (0) 25.0% (1) 25.0% (1) 50.0% (2) 0.0% (0) 4 Fake plastic trees (CO2 scrubber) 25.0% (1) 0.0% (0) 0.0% (0) 50.0% (2) 25.0% (1) 4 Ocean Iron Fertilisation 0.0% (0) 0.0% (0) 50.0% (2) 50.0% (2) 0.0% (0) 4 Ocean Urea Fertilisation 0.0% (0) 0.0% (0) 25.0% (1) 50.0% (2) 25.0% (1) 4 Cool roof (white pavements roofs) 0.0% (0) 25.0% (1) 50.0% (2) 25.0% (1) 0.0% (0) 4 Pykrete or other ice stabilisation 0.0% (0) 0.0% (0) 25.0% (1) 50.0% (2) 25.0% (1) 4 Reflective sheets in deserts etc. 0.0% (0) 0.0% (0) 25.0% (1) 75.0% (3) 0.0% (0) 4 Space mirrors 0.0% (0) 25.0% (1) 25.0% (1) 50.0% (2) 0.0% (0) 4 Moon dust in orbit 0.0% (0) 0.0% (0) 0.0% (0) 75.0% (3) 25.0% (1) 4 Nuclear winter 0.0% (0) 0.0% (0) 0.0% (0) 100.0% (4) 0.0% (0) 4 Tropospheric/low stratospheric smoke 0.0% (0) 0.0% (0) 0.0% (0) 75.0% (3) 25.0% (1) 4 Tropospheric sulphur aerosols 25.0% (1) 0.0% (0) 25.0% (1) 50.0% (2) 0.0% (0) 4 Biochar burial 25.0% (1) 25.0% (1) 0.0% (0) 50.0% (2) 0.0% (0) 4 Forestry projects 0.0% (0) 25.0% (1) 50.0% (2) 25.0% (1) 0.0% (0) 4 Biomass Energy with Carbon Capture 0.0% (0) 50.0% (2) 25.0% (1) 25.0% (1) 0.0% (0) 4 Do nothing - emissions cuts only 50.0% (2) 25.0% (1) 0.0% (0) 25.0% (1) 0.0% (0) 4 Seawater spraying 25.0% (1) 0.0% (0) 25.0% (1) 50.0% (2) 0.0% (0) 4 Reflective balloons 0.0% (0) 0.0% (0) 0.0% (0) 75.0% (3) 25.0% (1) 4 Extract hydrochloric acid from seawater 0.0% (0) 0.0% (0) 25.0% (1) 50.0% (2) 25.0% (1) 4 Using lasers to break up CFCs etc. 0.0% (0) 0.0% (0) 0.0% (0) 66.7% (2) 33.3% (1) 3 Burying wood other biomass 0.0% (0) 0.0% (0) 0.0% (0) 75.0% (3) 25.0% (1) 4 Ocean pipes to force nutrient mixing 0.0% (0) 0.0% (0) 50.0% (2) 50.0% (2) 0.0% (0) 4 St. Lawrence dam 0.0% (0) 0.0% (0) 0.0% (0) 75.0% (3) 25.0% (1) 4 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~--~~~~--~~--~--~---
[geo] Re: Bright Ideas
Sea ice acts to insulate the underlying water from the cold atmosphere. In the absence of sea ice, heat fluxes into or out of the surface can easily increase by more than an order of magnitude. ___ Ken Caldeira Carnegie Institution Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA kcalde...@ciw.edu; kcalde...@stanford.edu http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab +1 650 704 7212; fax: +1 650 462 5968 On Mon, Dec 29, 2008 at 8:42 AM, Stephen Salter s.sal...@ed.ac.uk wrote: . . . . but the latent heat of ice is hugely greater than the specific heat of water. Freezing one metre of ice is like cooling an 80 metre depth of sea by 1 K. Stephen wig...@ucar.edu wrote: Re Arctic ice, the issue is not just albedo, but also thermai inertia. The effective heat capacity of the exposed ocean is hugely greater than the ice. Tom. ++ http://www.celsias.com/article/all-about-albedo-lighter-world-cooler-world/ All About Albedo: A Lighter World is a Cooler World Jeremy Williams From the latin 'albus', meaning 'white', albedo is an indicator of reflectivity. Bright objects reflect much of the light that reaches them, and have high albedo. Dark objects have low albedo, because they absorb light. If you've ever climbed into a dark-colored car on a hot day, you already understand albedo. It's an unusual word, and an unusual factor in climate change, presenting both dangers and and opportunities. The danger comes primarily from the Arctic, where vast sheets of white ice reflect sunlight away from the earth and have a cooling effect on the atmosphere. Ice is highly reflective, reflecting 80-90% of sunlight (pdf), but seawater is dark blue or green and reflects very little. As Arctic ice melts, seawater takes its place, which absorbs more heat and compounds the melting problem. Loss of albedo in this context becomes an accelerator of climate change. This works in reverse in the case of deforestation, something I learned a few years ago when I had flying lessons in Kenya's Rift Valley. We flew across the transition from forested escarpment to desert valley floor, and the rising heat off the dusty plains created great waves of turbulence that tossed our little plane around. Forests, being dark, absorb 95% of the sunlight that falls across them, whereas cleared land or desert has a higher albedo and beams that light and heat back up. Interestingly, deforestation actually raises the earth's albedo. Before we get the chainsaws out however, we should remember that forests use some of the sunlight in photosynthesis. They also help create clouds, and of course absorb CO2 from the atmosphere. Overall, their net effect is usually cooling. I say usually because research by the Global Carbon Project found that there is in fact a case for deforestation (pdf) to cool the earth in some places. In tropical countries and mid-latitude areas forests have a cooling effect. But high latitude forests have a strong warming influence, largely due to the presence of dark forest canopies in regions that would otherwise be snow covered. As well as giving us some complicating factors in forestation and Arctic ice, albedo presents us with some interesting opportunities. If reflective surfaces have a cooling effect on the earth, can we create some more of them? There are two immediate possibilities. The first of these is the urban environment, which covers around 1% of the earth's surface. In research earlier this year, two scientists at the Lawrence Berkeley National Laboratory in California discovered that whitening our cities (pdf) could have a considerable cooling effect. Increasing urban albedo can result in less absorption of incoming solar radiation by the surface-troposphere system, countering to some extent the global scale effects of increasing greenhouse gas concentrations. It would also cool the air on the ground, reducing the need for air conditioning in the summer. The report estimated that around 40% of the urban environment is pavement and 20-25% is roofs, both of which could be made more reflective. Most pavements and parking lots are laid in Portland cement concrete, which is expensive when totally white, but can be easily made lighter with different aggregates (pdf). White asphalt shingles, corrugated iron, or white acylic tiles can be used for roofing. You can read the maths for yourself, but the authors conclude that whitening the urban environment would offset the equivalent of 44 Gigatonnes of CO2, or 11 years worth of growth in CO2 emissions. That's an offset, so it would not affect climate change in the long term, but it would buy us some time while we bring emissions under control. A second, more radical idea is the Global Albedo Enhancement Project ,
[geo] Re: arctic engineering needs and sea-ice science
There's an effect which I've not seen discussed here, but without doubt it's important. Ocean NOT covered by sea ice will radiate heat into space far more effectively than will the white ice it replaces. Ocean ice loss is potentially less significant than has been assumed. In fact, if the water uncovered is relatively warm, it could result in a greater loss of heat into space than would otherwise be the case. Can the clever people (or the people with clever computers) estimate the significance of this effect? A 2008/12/29 Mike MacCracken mmacc...@comcast.net: I would respond with two hopefully clarifying comments: 1. While there is a lot of focus on when the ice will be gone in summer, this will have little effect on the weather as the surface temperature and water availability are similar for no ice and melting ice. Indeed, more solar is absorbed, but that does not significantly raise ocean temperatures. What really matters is what happens in the fall into winter, because as long as there is no ice or thin ice, there will be a lot of heat transport to the atmosphere and so the near surface air cannot cool to –40 C and so create cold, dense air masses that spread out from the Arctic and influence weather around the midlatitudes. With all the extra heat going up into the atmosphere (the solar heat absorbed during the time with lower albedo), the atmospheric circulation will be altered—causing, as Jennifer notes, the large-scale influence on winter weather patterns over much of the northern hemisphere. So, while the retreat of summer sea ice is an easy metric, what really affects the weather is the delayed formation of thick ice that can insulate the atmosphere from the heat contained in the ocean. 2. On the characteristics of low clouds, I thought the intent was to raise the albedo when the Sun was out, not to raise the IR emissivity. During the polar summer one wants the clouds with a high albedo (once the surface starts to melt and its albedo comes down to below that of low clouds). Then, during the polar night, one would want to decrease the cloud emissivity so the surface can more rapidly radiate to space (the clouds tend to retard the cooling process that allows ice to form, as Jennifer notes). Mike MacCracken On 12/29/08 11:26 AM, Andy Revkin anr...@nytimes.com wrote: hi all, I consulted with a few sea-ice wizards on the exchanges here related to Arctic trends, and Jennifer Francis at Rutgers weighed in with the following thoughts. Note the importance of the boundary layer changes as well. There are many important factors besides albedo and ocean solar absorption. Winter cloudiness etc important factor. But also note the importance of not over-interpreting short-term wiggles as trends. Much more on Dot Earth and in my earlier coverage of the sea-ice question. This post (shortcut) is a good starting point: http://tinyurl.com/dotIceTrends Here's jennifer's comment (I sent her that sea-ice graph that was making the rounds here) Hi Andy -- The first figure you attached with the extrapolation from the 2007 summer ice loss is very unrealistic, in my opinion. Both the observed record and model simulations of ice extent exhibit a great deal of interannual variability, and most sea ice researchers would expect this behavior to continue superimposed on a continuing downward trend. Some years the decline will be dramatic, as it was in 2007, and some years there will likely be a recovery, as random atmospheric patterns act on the ice cover. What's different now as opposed to 2 decades ago is that the ice is now so thin that any unusual forcing -- be it a persistent wind pattern, cloud cover, heat transfer from lower latitudes -- will have a much bigger effect on the ice, as thin ice is more easily moved by wind and/or melted by increased heating. The small ice cover of recent years allows more solar energy to be absorbed by the open surface during summer, but exactly how that extra heat affects the system over the following months is still being worked out. Some recent research suggests that during falls after low-ice summers the lower atmosphere warms, the atmospheric boundary layer gets deeper, and low clouds increase, all of which tend to retard regrowth of sea ice in the fall and early winter. It also appears there's a large-scale influence on winter weather patterns over much of the northern hemisphere. The reason I'm telling you all this is that it appears there is no obvious mechanism for the ice to rebound significantly unless there is a multi-year period of colder-than-normal temperatures, but this is not likely as greenhouse gases continue to increase at rates even faster than the most pessimistic IPCC scenario. Regarding water temperatures, the main effect is through the added absorption of solar energy in summer, which accelerates the melt during late summer. Warmer winter temperatures in the Atlantic sector also
[geo] Re: hydrological geoengineering - new wiki page
The 'hydrological geoengineering' page title is set, and can only be changed by taking down the whole page. In any event, I think that hydrological is more appropriate, as it includes schemes like glacier seeding which aren't polar I don't know about the pykrete fibre ratio, please feel free to research and correct any mistakes. I think that pykrete has some interesting applications. It could help insulate ice, stabilise ice sheets and may also have engineering benefits for the 'ice road truckers' and suchlike. A 2008/12/29 John Nissen j...@cloudworld.co.uk: Hi Andrew, 1. I think that polar geoengineering might be more appropriate than hydrological geoengineering. Hydrology suggests water resources, but we want to concentrate on critical processes occurring principally in polar regions, because here there are some of the most worrying tipping points (indeed, I fear the Arctic sea ice is already tipping and could be near the point of no return). I'm not sure we need a separate entry for this. Saving the Arctic sea ice is a potential application of geoengineering; similarly dealing with ice sheet meltwater and dealing with methane from permafrost are potential applications of geoengineering. 2. I was fascinated when I heard about pykrete recently, and have been thinking about possible applications for saving the Arctic sea ice. I've added an alternative idea for plugging the moulins, and that is using pykrete, for which there is already a useful wikipedia entry: www.wikipedia.org/wiki/Pykrete Ideally, the pykrete would be sprayed onto existing ice using a mixture of fibrous material (such as sawdust) and near freezing or perhaps supercooled water. It would be interesting to do some experimentation into whether such a process could be developed. This would use a simple device like a snowgun. About Pykrete itself, you say that the fibre/ice ratio is about 1:25, but the pykrete entry says it is 45% fibre, 55% ice by weight. Which ratio is correct? Also the picture of a pykrete block shows the block as dark brown, and not reflecting like ice, as suggested with ref [3]. The advantage of having floating rafts/islands of pykrete is that they would quickly get covered in snow, and only melt slowly from below. Thus they would last throughout the Arctic summer, if made thick enough. (Much of the thinning of the Arctic sea ice is by melting from below.) If ice breakers were to spread sawdust in the freezing water behind them, this might freeze directly into pykrete, and help preserve the ice to increase the proportion of multi-year ice. Again some experimentation would be interesting. There is an idea from Prof John Shepherd, who BTW is leading the RS geoengineering study, to use a large number of ice breakers to plough up the one-year ice, so the ice on either side of the channel left by the ice breaker is thicker, and melts slower in the summer. Perhaps one could combine these ideas, both ploughing up the ice and forming pykrete in the track left by the icebreaker. Cheers, John - Original Message - From: Andrew Lockley andrew.lock...@gmail.com To: Geoengineering geoengineering@googlegroups.com Sent: Sunday, December 28, 2008 3:57 PM Subject: [geo] hydrological geoengineering - new wiki page http://en.wikipedia.org/wiki/Hydrological_geoengineering built by me using material from Alber Kallio Please edit at will --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~--~~~~--~~--~--~---
[geo] new wiki SOLAR RADIATION MANAGEMENT
http://en.wikipedia.org/wiki/Solar_Radiation_Management All the albedo/shade projects are now here, in more detail. Hope people can pitch in with edits and comments. Please keep the SRM section of the main article to a brief summary from now on thanks. A --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~--~~~~--~~--~--~---
[geo] detailing experimental history - ignoramus appeals for help from learned colleagues! :-)
could someone with knowledge of the history of geoeng experiements please detail it on the following liniks: main geoeng page http://en.wikipedia.org/wiki/Geoengineering#Experimentation SRM page http://en.wikipedia.org/wiki/Solar_Radiation_Management#Experimentation Any SULFATE AEROSOL project experiment should added to http://en.wikipedia.org/wiki/Stratospheric_sulfur_aerosols#Scientific_study as applicable Thanks! A --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~--~~~~--~~--~--~---
[geo] Holiday Viewing
No grinch, no football. Just geoengineering. http://www.youtube.com/watch?v=os6lMICqECs World Needs Climate Emergency Backup Plan, Says Expert In submitted testimony to the British Parliament, climate scientist Ken Caldeira of the Carnegie Institution said that while steep cuts in carbon emissions are essential to stabilizing global climate, there also needs to be a backup plan. Geoengineering solutions such as injecting dust into the atmosphere are risky, but may become necessary if emissions cuts are insufficient to stave off catastrophic warming. He urged that research into the pros and cons of geoengineering be made a high priority. http://www.youtube.com/watch?v=v7mWvkBSPio http://www.youtube.com/watch?v=XlxhY1ISb5sfeature=channel Dave Webb: Geo-engineering - Parts 1, 2 and 3, around 28 mins total. Crisis Forum: Climate Change and Violence Workshop Series. Workshop 1: Climate Catastrophe, where are we heading? Friday 14 November 2008 University of Southampton Prof. Dave Webb (Praxis Centre, Leeds Metropolitan University, and Vice Chair CND) 'Geo-engineering and its implications' Gives overview of various geoengineering options, claiming OIF could remove as much as one third of CO2 and between 5 and 30,000 Flettner vessels would be needed. Slides are unreadable. Audio quality varies. Mostly repeating old and in some cases inaccurate information. Part 3 touches on international governance issues. Compares mitigation to the Marshall Plan and geoengineering to the Manhattan Project. How about the TARP? Troubled Atmospheric Remediation Program. http://www.youtube.com/watch?v=ttf8jl6hYUk http://www.youtube.com/watch?v=QwyZPRqQufw http://www.youtube.com/watch?v=ixBxkMyJBW4 http://www.youtube.com/watch?v=XXCzTqZps-c Most of the introductory episode of Discovery Project Earth, presenting an overview of the series. Part 1 was not posted for some reason. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~--~~~~--~~--~--~---
