Re: [geo] For the why geoengineering could prove to be vital department...
And some parts of the world; northern Canada, Alaska Northern Europe for example, may prefer some warming and will prosper. - Original Message - From: Russell Seitz russellse...@gmail.com To: geoengineering@googlegroups.com Cc: jrandomwin...@gmail.com, kcalde...@carnegiescience.edu Sent: Wednesday, April 17, 2013 10:50:12 PM Subject: Re: [geo] For the why geoengineering could prove to be vital department... Even before Europeans arrived, the Mayan civilization had begun to collapse thanks to relatively minor climate changes. The classic Maya civilization collapsed late in the 8th century, and all its great urban ceters were abandoned by the end of the first millennium. More inreresting is the role of climate change and migration in the dissapearance of the Olmec civilization that went before, taking much of mesoamerica's neolithic trade network with it- http://www.nytimes.com/2002/05/22/world/in-guatemala-a-rhode-island-size-jade-lode.html?pagewanted=allsrc=pm Wednesday, April 17, 2013 8:15:12 PM UTC-4, Ken Caldeira wrote: I am of the opinion that while climate change may pose an existential threat to those already facing existential threats (i.e., the poor, the marginalized, etc) it is far less clear how large a threat climate change poses to those who live in gated communities. I was quoted in the New Yorker recently (behind a pay wall, but slightly misquoted here): http://stevemasover.blogspot.com/2012/06/human-are-like-rats-and-cockroaches.html I have two perspectives on what this might mean, he said. One says: humans are like rats or cockroaches. We are already living from the equator to the Arctic Circle. The weather has already become .7 degrees warmer, and barely anyone has noticed or cares. And, yes, the coral reefs might become extinct, and people from the Seychelles might go hungry. But they have gone hungry in the past, and nobody cared. So basically we will live in our gated communities, and we will have our TV shows and Chicken McNuggets, and we will be O.K. The people who would suffer are the people who always suffer. There is another way to look at this, though, he said. And that is to compare it to the subprime-mortgage crisis, where you saw that a few million bad mortgages led to a five-per-cent drop in gross domestic product throughout the world. Something that was a relatively small knock to the financial system led to a global crisis. And that could certainly be the case with climate change. http://www.newyorker.com/reporting/2012/05/14/120514fa_fact_specter I think the uninhabitable claim of Hansen is a bit excessive. While such a world might not be very pleasant, I don't see it as threatening fundamental habitability. In the attached Scientific American article, I wrote: We are re-creating the world of the dinosaurs 5,000 times faster [than it was created in the Cretaceous]. What will thrive in this hothouse? Some organisms, such as rats and cockroaches, are invasive generalists, which can take advantage of disrupted environments. Other organisms, such as corals and many tropical forest species, have evolved to thrive in a narrow range of conditions. Invasive species will likely transform such ecosystems as a result of global warming. Climate change may usher in a world of weeds. Human civilization is also at risk. Consider the Mayans. Even before Europeans arrived, the Mayan civilization had begun to collapse thanks to relatively minor climate changes. The Mayans had not developed enough resilience to weather small reductions in rainfall, and the Mayans are not alone as examples of civilizations that failed to adapt to climate changes. Crises provoked by climate change are likely to be regional. If the rich get richer and the poor get poorer, could this set in motion mass migrations that challenge political and economic stability? Some of the same countries that are most likely to suffer from the changes wrought by global warming also boast nuclear weapons. Could climate change exacerbate existing tensions and provoke nuclear or other apocalyptic conflict? The social response to climate change could produce bigger problems for humanity than the climate change itself. On Wed, Apr 17, 2013 at 9:32 AM, David Lewis jrando...@gmail.com wrote: blockquote Jim Hansen is circulating a note calling attention to the Hansen, et.al . near final paper (entitled Climate Sensitivity, Sea Level, and Atmospheric CO2) presently available on arXiv.org, i.e. here . The concluding sentence of the abstract reads: Burning all fossil fuels, we conclude, would make much of the planet uninhabitable by humans , thus calling into question strategies that emphasize adaptation to climate change. Over to those putting forward or supporting the McBurger hypothesis... (The McBurger Hypothesis holds that climate change may only become an issue of secondary importance to those
[geo] Direct air capture of CO2 with chemicals: optimization of a two-loop hydroxide carbonate system using a countercurrent air-liquid contactor | Mazzotti et al | Climatic Change
Direct air capture of CO2 with chemicals: optimization of a two-loop hydroxide carbonate system using a countercurrent air-liquid contactor Marco Mazzotti, Renato Baciocchi, Michael J. Desmond, Robert H. Socolow Abstract Direct Air Capture (DAC) of CO2 with chemicals, recently assessed in a dedicated study by the American Physical Society (APS), is further investigated with the aim of optimizing the design of the front-end section of its benchmark two-loop hydroxide-carbonate system. Two new correlations are developed that relate mass transfer and pressure drop to the air and liquid flow velocities in the countercurrent packed absorption column. These relationships enable an optimization to be performed over the parameters of the air contactor, specifically the velocities of air and liquid sorbent and the fraction of CO2 captured. Three structured Sulzer packings are considered: Mellapak-250Y, Mellapak-500Y, and Mellapak-CC. These differ in cost and pressure drop per unit length; Mellapak-CC is new and specifically designed for CO2 capture. Scaling laws are developed to estimate the costs of the alternative DAC systems relative to the APS benchmark, for plants capturing 1 Mt of CO2 per year from ambient air at 500 ppm CO2 concentration. The optimized avoided cost hardly differs across the three packing materials, ranging from $518/tCO2 for M-CC to $568/tCO2 for M-250Y. The $610/tCO2 avoided cost for the APS-DAC design used M-250 Y but was not optimized; thus, optimization with the same packing lowered the avoided cost of the APS system by 7 % and improved packing lowered the avoided cost by a further 9 % The overall optimization exercise confirms that capture from air with the APS benchmark system or systems with comparable avoided costs is not a competitive mitigation strategy as long as the energy system contains high-carbon power, since implementation of Carbon Capture and Storage, substitution with low-carbon power and end-use efficiency will offer lower avoided-cost strategies. -- 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 to geoengineering@googlegroups.com. Visit this group at http://groups.google.com/group/geoengineering?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
[geo] Re: Direct air capture of CO2 with chemicals: optimization of a two-loop hydroxide carbonate system using a countercurrent air-liquid contactor | Mazzotti et al | Climatic Change
Apologies - link was missing http://rd.springer.com/article/10.1007/s10584-012-0679-y On 19 April 2013 01:57, Andrew Lockley andrew.lock...@gmail.com wrote: Direct air capture of CO2 with chemicals: optimization of a two-loop hydroxide carbonate system using a countercurrent air-liquid contactor Marco Mazzotti, Renato Baciocchi, Michael J. Desmond, Robert H. Socolow Abstract Direct Air Capture (DAC) of CO2 with chemicals, recently assessed in a dedicated study by the American Physical Society (APS), is further investigated with the aim of optimizing the design of the front-end section of its benchmark two-loop hydroxide-carbonate system. Two new correlations are developed that relate mass transfer and pressure drop to the air and liquid flow velocities in the countercurrent packed absorption column. These relationships enable an optimization to be performed over the parameters of the air contactor, specifically the velocities of air and liquid sorbent and the fraction of CO2 captured. Three structured Sulzer packings are considered: Mellapak-250Y, Mellapak-500Y, and Mellapak-CC. These differ in cost and pressure drop per unit length; Mellapak-CC is new and specifically designed for CO2 capture. Scaling laws are developed to estimate the costs of the alternative DAC systems relative to the APS benchmark, for plants capturing 1 Mt of CO2 per year from ambient air at 500 ppm CO2 concentration. The optimized avoided cost hardly differs across the three packing materials, ranging from $518/tCO2 for M-CC to $568/tCO2 for M-250Y. The $610/tCO2 avoided cost for the APS-DAC design used M-250 Y but was not optimized; thus, optimization with the same packing lowered the avoided cost of the APS system by 7 % and improved packing lowered the avoided cost by a further 9 % The overall optimization exercise confirms that capture from air with the APS benchmark system or systems with comparable avoided costs is not a competitive mitigation strategy as long as the energy system contains high-carbon power, since implementation of Carbon Capture and Storage, substitution with low-carbon power and end-use efficiency will offer lower avoided-cost strategies. -- 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 to geoengineering@googlegroups.com. Visit this group at http://groups.google.com/group/geoengineering?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
[geo] Biochar: Downstream effects
Press Release 13-069 Where Does Charcoal, or Black Carbon, in Soils Go? Scientists find surprising new answers in wetlands such as the Everglades [Charred boreal forest after a fire] Charred boreal forest after a fire has raged: where does the charcoal go? Credit and Larger Versionhttp://www.nsf.gov/news/news_images.jsp?cntn_id=127577org=NSF April 18, 2013 Scientists have uncovered one of nature's long-kept secrets--the true fate of charcoal in the world's soils. The ability to determine the fate of charcoal is critical to knowledge of the global carbon budget, which in turn can help understand and mitigate climate change. However, until now, researchers only had scientific guesses about what happens to charcoal once it's incorporated into soil. They believed it stayed there. Surprisingly, most of these researchers were wrong. The findings of a new study that examines the result of charcoal once it is deposited into the soil are outlined in a paper published this week in the journal Science. The international team of researchers was led by scientists Rudolf Jaffe of Florida International University and Thorsten Dittmar of the German Max Planck Society. Most scientists thought charcoal was resistant, says Jaffe. They believed that once it was incorporated into soils, it stayed there. But if that were the case, soils would be black. Charcoal, or black carbon, is a residue generated by combustion including wildfires and the burning of fossil fuels. When charcoal forms, it is usually deposited into the soil. From a chemical perspective, no one really thought it dissolved, but it does, Jaffe says. It doesn't accumulate for a long time. It's exported into wetlands and rivers, eventually making its way to the oceans. It all started with a strange finding in the Everglades. At the National Science Foundation (NSF) Florida Coastal Everglades Long-Term Ecological Research (LTER) site--one of 26 such NSF LTER sites in ecosystems around the worldhttp://www.nsf.gov/cgi-bin/goodbye?http://www.lternet.edu/sites/map--Jaffe studied the glades' environmental chemistry. Dissolved organic carbon is known to be abundant in wetlands such as the Everglades and plays a critical role in the ecology of these systems. Jaffe wanted to learn more about what comprised the organic carbon in the Everglades. He and colleagues discovered that as much as 20 percent of the total dissolved organic carbon in the Everglades is charcoal. Surprised by the finding, the researchers shifted their focus to the origin of the dissolved charcoal. In an almost serendipitous scientific journey, Dittmar, head of the Max Planck Research Group for Marine Geochemistry at the University Oldenburg in Germany, was also tracing the paths of charcoal, but from an oceanographic perspective. To map out a more comprehensive picture, the researchers joined forces. Their conclusion is that charcoal in soils is making its way into the world's waters. This study affirms the power of large-scale analyses made possible through international collaborations, says Saran Twombly, program director in NSF's Division of Environmental Biology, which funded the research along with NSF's Directorate for Geosciences. What started out as a puzzling result from the Florida Everglades engaged scientists at other LTER sites in the U.S., and eventually expanded worldwide, says Twombly. The result is a major contribution to our understanding of the carbon cycle. Fire is probably an integral part of the global carbon cycle, says Dittmar, its effects seen from land to sea. The discovery carries significant implications for bioengineering, the scientists believe. The global carbon budget is a balancing act between sources that produce carbon and sources that remove it. The new findings show that the amount of dissolved charcoal transported to the oceans is keeping pace with the total charcoal generated by fires annually on a global scale. While the environmental consequences of the accumulation of black carbon in surface and ocean waters are currently unknown, Jaffe said the findings mean that greater consideration should be given to carbon sequestration techniques. Biochar addition to soils is one such technique. Biochar technology is based on vegetation-derived charcoal that is added to agricultural soils as a means of sequestering carbon. As more people implement biochar technology, says Jaffe, they should take into consideration the potential dissolution of the charcoal to ensure that these techniques are environmentally friendly. Jaffe and Dittmar agree that there are still many unknowns when it comes to the environmental fate of charcoal, and both plan to move on to the next phase of the research. They've proved where charcoal goes. Now they'd like to answer how that happens, and what the environmental consequences are. The more scientists can understand the process and the environmental factors
