" '…if controversies were to arise, there would be no more need of disputation between two philosophers than between two calculators. For it would suffice for them to take their pencils in their hands and to sit down at the abacus, and say to each other […]: Let Us Calculate.'
I share that vision. TABULA is my 21st-century abacus – my 2-cents contribution to its fulfilment. " That is a good goal, as long as one keeps in mind that models are models and avoids potential traps (e.g., to claim that regarding this or that topic "the science is settled"). On Sat, Jun 15, 2019 at 3:25 AM Ian Clark <[email protected]> wrote: > Thank you, Donna. There is material here I can use in additional case > studies to exhibit TABULA in action. > > Yes, I'm using out-of-date figures, but they're nicely rounded figures, > which make it easier to see what's going on in the model. Even if I used > up-to-date figures (…and I was aware of them), they'd go out of date by > next year. Things are beginning to move fast. > > But one of my points of concern was checking primary sources for the input > figures to the model. If these figures show different values to the ones > I've used, e.g. 415 ppm as against my >400, then should I use actual > figures, or nice tidy ones that make for an uncluttered display? I haven't > come to a decision about this. There are arguments both ways. > > It's no big deal to extend the model to estimate the number of plants that > Carbon Engineering would have to build, and the fact that SAMPLE9 doesn't > do that is arguably an omission. But to calculate it I'd need to pluck a > figure out of the air for a completion date for the project. The UK has > just committed to becoming carbon neutral by 2050. Is that a figure I > should challenge? No, because it's in print from official sources and > easily checked. But if one were to ask: is that a reliable figure to plan > on, I have my doubts, because pressure is already growing to bring the date > forward by two or three decades. > > So the region of doubt is so large that maybe it's best to leave that > particular calculation out of SAMPLE9. After all, I'm not proposing to use > it to advise the British government. I'm proposing to use it to teach > 14-18-year-olds what mathematical modelling is all about and how to use > TABULA for this sort of thing. Here simplicity scores over accuracy. > Refining the model is an exercise left to the reader. > > A UK Treasury official told me once they had a saying: figures can't lie, > but lies can figure. I'm leaning over backwards *here* (and I stress > "here") to avoid muddying the clear waters of mathematical modelling with > preaching, or anything that could be mistaken for it. Gottfried Leibnitz > had a vision of a world in which debates on public policy would not be > conducted in an atmosphere of passion and ignorance, where nobody could > distinguish evidence from prejudice. Instead he foresaw… "…if > controversies > were to arise, there would be no more need of disputation between two > philosophers than between two calculators. For it would suffice for them to > take their pencils in their hands and to sit down at the abacus, and say to > each other […]: Let Us Calculate." > > I share that vision. TABULA is my 21st-century abacus – my 2-cents > contribution to its fulfilment. > > That's not to say we shouldn't start another thread on the topic of global > warming and have a good sound-off about it. But others might reasonably ask > whether that debate isn't better conducted on other platforms, such as > Nature https://www.nature.com/npjclimatsci/ > > Meanwhile I've appealed to the collective wisdom of the J community for > their views on the way I've chosen to promote TABULA. In particular the > models I've chosen as mini case studies. I badly need its answers, and hope > to use them. It's a big question I've asked, but a restricted one. I'm keen > to focus on the topic (in this thread) because I'm afraid that bringing in > wider issues will either derail the proceedings or dilute them and make it > hard to recognise answers I can use. > > The updated figures you've kindly provided don't make a lot of difference > to the "bottom line", if we can call item {13} that. What I'm afraid of are > factors of 10 or 100 creeping in. The great thing about published estimates > for the things I'm calculating is: if they're the same order of magnitude > then it's some assurance that TABULA itself isn't injecting gross errors > into the estimate. > > > > On Sat, 15 Jun 2019 at 01:53, Donna Y <[email protected]> wrote: > > > > I'd be happy if I could establish the model as at > > > least being a start in the direction of accurately costing the carbon > in > > > the atmosphere. > > > > > > > > https://code.jsoftware.com/wiki/TABULA/samples/cost_to_capture_atmospheric_CO2 > > < > > > https://code.jsoftware.com/wiki/TABULA/samples/cost_to_capture_atmospheric_CO2 > > > > > > > > Atmospheric CO2 concentration has been rising steadily since 1960, when > > it > > > first began to be measured regularly at Mauna Loa, HI. At that time it > > > stood at <320 ppm (parts-per-million). Now it stands at >400 ppm, an > > > increase of over 80 ppm. > > > > Yes my comment was about what you said you wanted to model and not > TABULA. > > > > > > This April, the concentration of carbon dioxide in the atmosphere hit 415 > > parts per million for the first time. It’s the highest level in human > > history. > > > > Current emissions are around 40 giga-tons a year. > > > > So far – we got a free ride--forests and oceans mop up more than half our > > carbon waste. > > > > To reduce levels the best thing would be to curb carbon emissions now. > > > > To model CO2 in the atmosphere you need to account for ongoing sources > and > > sinks—its not static, it's a carbon cycle. > > > > In terms of sinks, someone mentioned forests, someone mentioned > > phytoplankton in the ocean, and I mentioned coastal habitats (see Blue > > Carbon). Mounting CO2 in the atmosphere mopped up by the ocean is making > > large sections of the ocean anoxic—these are not bottomless sinks. > > > > It's acceptable to use Mauna Loa data as a proxy for global CO2 levels > > since CO2 mixes well throughout the atmosphere. The trend in Mauna Loa > CO2 > > (1.64 ppm per year) is statistically indistinguishable from the trend in > > global CO2 levels (1.66 ppm per year). There is a history of atmospheric > > CO2, derived from the Mauna Loa observations back to 1958. > > > > Annual CO2 levels from Mauna Loa--60 data points (that would seem easy to > > cross check) > > > > With ice core, data goes back to year 900. > > > > Longer history of atmospheric CO2 was reconstructed from studies of > > deep-sea sediments > > > > To find atmospheric CO2 levels equivalent to the present, we have to go > > back 2.5 million years > > > > 1 ppmv of CO2= 2.13 Gt of carbon > > > > Enough direct air capture to remove current emissions would take 40,000 > > large Carbon Engineering plants that they say will capture 500,000 tons > of > > CO2 annually. > > > > Carbon Engineering published a paper saying that it had dropped costs to > > around $94 to $232 a ton. That assumes selling the CO2—it can be sold for > > as much as $350 a ton in niche applications, like remote soda bottling > > plants—the market would quickly be saturated. Your $100 cost is a net > cost > > assuming the CO2 can be sold. It does not include the cost of carbon > > storage. > > > > Clean Power Plan (US EPA 2015) $11 per ton CO2—would have resulted in > > large emissions reductions for a cost far below the $100 in your model. > > > > Example Carbon sinks: > > > > 83% of the global carbon cycle is circulated through the ocean. > > > > Coastal habitats account for approximately half of the total carbon > > sequestered in ocean sediments. > > > > Forests and oceans both draw in carbon dioxide from the atmosphere, > > —reforestation—$ 1—$10 per ton CO2 > > > > Paradox: Three billion years ago, the sun was only about 70 percent as > > bright as it is today. Earth should have frozen over, but it didn’t. Why > > not? > > Because greenhouse gases in the atmosphere, mainly methane and carbon > > dioxide, trapped enough of the sun’s heat to keep temperatures above > > freezing. When photosynthetic organisms produced enough oxygen it reacted > > with the methane in the atmosphere, transforming it forever. About two > > billion years ago, the methane haze cleared and the sky turned blue. > > > > > > > > In the world of a Pigouvian tax (cost imposed on activities that create > > social harms), markets sort out the most cost-effective ways to reduce > > emissions > > > > > > > > Blending corn ethanol into gasoline up to a 10 percent ratio provides > > essentially costless emissions reductions (replacing more expensive > octane > > booster) > > Replacing coal-fired electricity generation with natural gas > > Using an electric vehicle in a region in which electricity is generated > by > > coal has approximately the same CO2 footprint a gas fuelled vehicle. > > > > Aim to minimize the cost of mitigation both today and into the future, > > recognizing that actions taken today can influence future costs. > > > > > Some groups have taken a stab at calculating what climate change will > > cost the world, or conversely, how much humanity would save by becoming > > more sustainable. Earlier this month, the Global Commission on the > Economy > > and Climate < > > > https://www.vox.com/energy-and-environment/2018/9/5/17816808/sustainability-26-trillion-global-commission-economy-climate > > > > tallied the number at a truly massive $26 trillion in savings by 2030. > > > > > Critically, it’s also the foundation of US climate policies, including > > the Clean Power Plan < > > > https://www.vox.com/2018/8/21/17763916/epa-clean-power-plan-affordable-clean-energy > >. > > Revising this number down has been a key part of the Trump > administration’s > > strategy to roll back environmental rules < > > > https://www.vox.com/energy-and-environment/2018/1/29/16684952/epa-scott-pruitt-director-regulations > >. > > Under Obama, the social cost of carbon < > > > https://19january2017snapshot.epa.gov/climatechange/social-cost-carbon_.html > > > > was set at $45 per ton < > > > https://blogs.wsj.com/experts/2017/11/15/trump-vs-obama-on-the-social-cost-of-carbon-and-why-it-matters/ > > > > of carbon dioxide; under Trump, it’s as little as $1. > > > > > > Donna Y > > > > [email protected] > > > > > > > On Jun 9, 2019, at 11:15 PM, Ian Clark <[email protected]> wrote: > > > > > > Sorry, Donna & Greg, off-topic. I didn't want to start a disputation > > about > > > climate science per-se. If I didn't make that clear, I'm really sorry. > > > > > > This thread's for mathematical modelling with sufficiently transparent > > and > > > trusty software; TABULA in particular; plus suggestions for how to > > provide > > > assurance that it is to be trusted. > > > > > > Or alternatively, establish that it isn't. > > > > > > Then there's how much trust to place in the model itself, but that's a > > > different issue -- a colossal one. Maybe that needs a thread of its own > > too. > > > > > > Except that the 11 built-in models are part of the TABULA release, so > > maybe > > > we need some assurance about those, or at least a clear statement of > > their > > > assumptions and limitations. > > > > > > > > > > > > On Sun, 9 Jun 2019 at 23:35, Donna Y <[email protected] <mailto: > > [email protected]>> wrote: > > > > > >>> The ocean acts as a carbon sink and covers 71% of the earth’s surface > > >> (and is 270 times greater in mass than the atmosphere > > >>> > > >>> coastline is extensive enough to wrap around the earth almost fifteen > > >> times (372,000 miles!). The study found that annually, such ecosystems > > >> could trap and store 2 to 35 times more carbon than even ocean > > phytoplankton > > >> > > >> Donna Y > > >> [email protected] > > >> > > >> > > >>> On Jun 7, 2019, at 2:28 PM, greg heil <[email protected]> wrote: > > >>> > > >>>> If good/cheap/big/fast carbon sinks are up for discussion i would > > >> recommend phytoplankton... Salmon are tasty too, but that is a side > > dish. > > >>> > > >>> > > >> > > > https://www.vox.com/the-highlight/2019/5/24/18273198/climate-change-russ-george-unilateral-geoengineering > > >> < > > >> > > > https://www.vox.com/the-highlight/2019/5/24/18273198/climate-change-russ-george-unilateral-geoengineering > > < > > > https://www.vox.com/the-highlight/2019/5/24/18273198/climate-change-russ-george-unilateral-geoengineering > > > > > >>> > > >>> > > >>> ~greg > > >>> http://krsnada <http://krsnada/> <http://krsnadas.org/ < > > http://krsnadas.org/>> > > >> ---------------------------------------------------------------------- > > >> For information about J forums see > http://www.jsoftware.com/forums.htm > > <http://www.jsoftware.com/forums.htm> > > >> > > > ---------------------------------------------------------------------- > > > For information about J forums see http://www.jsoftware.com/forums.htm > < > > http://www.jsoftware.com/forums.htm> > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
