Monday, May 23, 2022

The Terminal Shock of the MEER Reflection Project and Solar Geoengineering promoted by GEE McFearSun, et. al.

 https://www.theguardian.com/commentisfree/2021/apr/22/climate-crisis-emergency-earth-day

If the world fails to achieve net zero carbon dioxide emissions, then each year’s emissions will add to the stock of atmospheric carbon dioxide, requiring ever-escalating ratcheting up any techno-fix and ever-escalating increase in the damage wrought by termination shock. And meanwhile, other dangerous effects of accumulating carbon pollution, such as ocean acidification, continue to worsen over time.

If the world decarbonizes eventually but only after pumping out so much carbon dioxide that it renders the world lethally hot, then deploying sun-dimming as a survival tactic puts the world in a precarious state, one in which current and future generations would live in perpetual fear of sudden death by termination shock.

Michael Mann and Raymond Pierrehumbert are correct about this.

  I'm just pointing out that you haven't read Raymond Pierrehumbert's argument against solar geoengineering. His point is that the damage from CO2 emissions is WAY WORSE than the opportunity cost of focusing on solar geoengineering. The MEER project needs $50 Billion and that would be double what is currently spent in the U.S. by the government on global warming initiatives. The US military budget is $1.5 trillion a year when you take into account veteran payments and debt payments on past spending. So a basic concept in economics is what is the "opportunity cost" of NOT focusing on reducing CO2 emissions. To say the MEERS project is a band-aid is deceptive because you are calling for a 100% shift in focus AWAY from carbon emission reductions since currently there is the same amount in CO2 emission reductions spent as would be needed for the MEERS project. But the COST of neglecting the reduction of CO2 Emissions has a 1000 year price tag!! So every dollar not spent on CO2 emissions has a "discount value" of negative 1000 years. Economics has a term called "discounting the future" which basically is what the MEERS project is arguing for. The MEERS project is arguing that if we can "delay" the heating of earth then we can "figure out" HOW to solve the global warming crisis. That argument IGNORES the obvious fact that we already know how to solve the crisis - by getting rid of the cause of the crisis. So then the MEERS Project advocates YES but we are NOT getting rid of the problem!! We are only getting WORSE - therefore we should focus on this quick fix "band-aid" as you call it. haha. Don't you see that the MEERS project simply is another step of "engineering" quick Fix DeNile - if the MEERS Project would go forward that would be the equivalent of stealing away 100% of the global warming budget thus far to redirect it away from the CAUSE of the problem. The opportunity cost of STEALING AWAY 100% of the CO2 emission reduction budget is a 1000 year cost as Raymond Pierrehumbert details. Now I knew we were doomed by 1996 - so I realize the problem has just gotten worse. How many times have you been arrested protesting against the evil modern world? haha. How many campaigns have you organized or coalitions? How many activist jobs have you had? blah blah. I've done more than enough - research and activism - such that I knew we were doomed by 1996. NO way am I going to pretend that the MIRRORS or MEERS campaign is going to make anything better. You can't fool me with another TechnoFix Scam.

https://elixirfield.blogspot.com/2022/04/raymond-pierrehumbert-on-why.html 

 "If we emit a trillion tons of carbon in the form of carbon dioxide before we decarbonize the economy (we’ve already emitted more than half that) it will cause about 2 degrees Celsius of warming, and most of that warming will still be around in 10,000 years." Raymond Pierrehumbert

  "What is the morality of committing 10,000 years of future humanity to maintaining an activity year in and year out without fail? What is our track record as a species of maintaining any technological activity for more than a century or two? Oliver Morton, in his thoughtful (but ultimately boosterish) book puts forth the vision of albedo modification as just another stage in the cycle of technological dependencies that make the life of humanity better, rather like the Haber Process for making fertilizer has allowed agriculture to support a much larger population. It’s an interesting point, but there remains the uncomfortable issue of whether a global-scale intervention like albedo modification is really in the same category. 

Or, more broadly, is our ever-expanding wave of technological dependency increasing the resilience of human society or just setting us up for a harder fall when it all becomes unsustainable? Albedo modification is sometimes thought of as something you can do to hold warming in check while “buying time” to decarbonize the economy, but this is a fundamental misconception. Each additional kilogram of carbon dioxide emitted commits the Earth to a certain amount of warming that essentially never goes away (unless we learn how to suck carbon dioxide out of the atmosphere in massive amounts quickly—a very debatable prospect). And so the need for continued geoengineering to counteract that additional warming never goes away—even after carbon dioxide emissions are eventually brought to zero.  

Moreover, because carbon dioxide accumulates inexorably in the atmosphere so long as emissions continue, one cannot even achieve the more modest goal of slowing the rate of warming without inexorably increasing the amount of albedo modification deployed each year. It’s like drinking water contaminated with a poison like mercury that accumulates in your body, but trying to cancel out the effects with ever greater dosages of antidote. So long as there is any poison left in the water, your bodily burden increases and each year you need to take a greater daily dose of antidote. Even if the poison is removed from the drinking water supply, you have to continue taking the antidote for the rest of your life, because of the poison accumulated in your body—unless you undergo some therapy which actively removes the poison from your body, which would be analogous to sucking carbon dioxide out of the air." Raymond Pierrehumbert

 Short-lived climate pollution Authors Ramond T Pierrehumbert Publication date 2014/5/30 Source Annual Review of Earth and Planetary Sciences Volume 42 Pages 341-379 Publisher Annual Reviews Description Although carbon dioxide emissions are by far the most important mediator of anthropogenic climate disruption, a number of shorter-lived substances with atmospheric lifetimes of under a few decades also contribute significantly to the radiative forcing that drives climate change. In recent years, the argument that early and aggressive mitigation of the emission of these substances or their precursors forms an essential part of any climate protection strategy has gained a considerable following. There is often an implication that such control can in some way make up for the current inaction on carbon dioxide emissions. The prime targets for mitigation, known collectively as short-lived climate pollution (SLCP), are methane, hydrofluo-rocarbons, black carbon, and ozone. A re-examination of the issues shows that the benefits of early SLCP mitigation have been greatly exaggerated, largely because of inadequacies in the …

 https://scholar.google.com/citations?view_op=view_citation&hl=en&user=XVwKqOIAAAAJ&cstart=20&pagesize=80&citation_for_view=XVwKqOIAAAAJ:M3NEmzRMIkIC

 @rollinswitch  Short-lived climate pollution Authors Ramond T Pierrehumbert Publication date 2014/5/30 Source Annual Review of Earth and Planetary Sciences Volume 42 Pages 341-379 Publisher Annual Reviews Description Although carbon dioxide emissions are by far the most important mediator of anthropogenic climate disruption, a number of shorter-lived substances with atmospheric lifetimes of under a few decades also contribute significantly to the radiative forcing that drives climate change. In recent years, the argument that early and aggressive mitigation of the emission of these substances or their precursors forms an essential part of any climate protection strategy has gained a considerable following. There is often an implication that such control can in some way make up for the current inaction on carbon dioxide emissions. The prime targets for mitigation, known collectively as short-lived climate pollution (SLCP), are methane, hydrofluo-rocarbons, black carbon, and ozone. A re-examination of the issues shows that the benefits of early SLCP mitigation have been greatly exaggerated, largely because of inadequacies in the …

 @rollinswitch  New use of global warming potentials to compare cumulative and short-lived climate pollutants Authors Myles R Allen, Jan S Fuglestvedt, Keith P Shine, Andy Reisinger, Raymond T Pierrehumbert, Piers M Forster Publication date 2016/8 Journal Nature Climate Change Volume 6 Issue 8 Pages 773-776 Publisher Nature Publishing Group Description Parties to the United Nations Framework Convention on Climate Change (UNFCCC) have requested guidance on common greenhouse gas metrics in accounting for Nationally determined contributions (NDCs) to emission reductions 1. Metric choice can affect the relative emphasis placed on reductions of ‘cumulative climate pollutants’ such as carbon dioxide versus ‘short-lived climate pollutants’(SLCPs), including methane and black carbon 2, 3, 4, 5, 6. Here we show that the widely used 100-year global warming potential (GWP 100) effectively measures the relative impact of both cumulative pollutants and SLCPs on realized warming 20–40 years after the time of emission. If the overall goal of climate policy is to limit peak warming, GWP 100 therefore overstates the importance of current SLCP emissions unless stringent and immediate reductions of all climate pollutants result in temperatures nearing their peak …
 @rollinswitch  Infrared radiation and planetary temperature Authors Raymond T Pierrehumbert Publication date 2011/11/4 Journal AIP Conference Proceedings Volume 1401 Issue 1 Pages 232-244 Publisher American Institute of Physics Description Infrared radiative transfer theory, one of the most productive physical theories of the past century, has unlocked myriad secrets of the universe including that of planetary temperature and the connection between global warming and greenhouse gases.
 @rollinswitch  Abrupt climate change: inevitable surprises Authors Richard B Alley, Jochem Marotzke, William Nordhaus, Jonathon Overpeck, D Peteet, Roger Pielke, Raymond Pierrehumbert, P Rhines, T Stocker, L Talley, JM Wallace Publication date 2002 Publisher National Academy Press Description Abrupt climate change: Inevitable surprises :: MPG.PuRe English Help Privacy Policy Disclaimer Include files Advanced SearchBrowse START BASKET (0)Tools Item ITEM ACTIONSEXPORT Add to Basket Local TagsRelease HistoryDetailsSummary Released Book Abrupt climate change: Inevitable surprises MPS-Authors There are no MPG-Authors in the publication available External Resource http://www.nap.edu/openbook.php?record_id=10136 (Publisher version) Fulltext (public) There are no public fulltexts stored in PuRe Supplementary Material (public) There is no public supplementary material available Citation Committee on Abrupt Climate Change, Alley, R., Marotzke, J., Nordhaus, W., Overpeck, J., Peteet, D., et al. ( Eds. ). (2002). Abrupt climate change: Inevitable surprises. Washington, DC: National Academy Press. Cite as: http://hdl.handle.net/11858/00-001M-0000-0014-3C1F-A Abstract There is no …
 @rollinswitch  Cumulative carbon as a policy framework for achieving climate stabilization Authors H Damon Matthews, Susan Solomon, Raymond Pierrehumbert Publication date 2012/9/13 Journal Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences Volume 370 Issue 1974 Pages 4365-4379 Publisher The Royal Society Publishing Description The primary objective of the United Nations Framework Convention on Climate Change is to stabilize greenhouse gas concentrations at a level that will avoid dangerous climate impacts. However, greenhouse gas concentration stabilization is an awkward framework within which to assess dangerous climate change on account of the significant lag between a given concentration level and the eventual equilibrium temperature change. By contrast, recent research has shown that global temperature change can be well described by a given cumulative carbon emissions budget. Here, we propose that cumulative carbon emissions represent an alternative framework that is applicable both as a tool for climate mitigation as well as for the assessment of potential climate impacts. We show first that both atmospheric CO2 concentration at a given year and the associated temperature change are generally associated with a …
 @rollinswitch  There is no Plan B for dealing with the climate crisis Authors Raymond Pierrehumbert Publication date 2019/9/3 Journal Bulletin of the Atomic Scientists Volume 75 Issue 5 Pages 215-221 Publisher Routledge Description To halt global warming, the emission of carbon dioxide into the atmosphere by human activities such as fossil fuel burning, cement production, and deforestation needs to be brought all the way to zero. The longer it takes to do so, the hotter the world will get. Lack of progress towards decarbonization has created justifiable panic about the climate crisis. This has led to an intensified interest in technological climate interventions that involve increasing the reflection of sunlight to space by injecting substances into the stratosphere which lead to the formation of highly reflective particles. When first suggested, such albedo modification schemes were introduced as a “Plan B,” in case the world economy fails to decarbonize, and this scenario has dominated much of the public perception of albedo modification as a savior waiting in the wings to protect the world against massive climate change arising from a failure to …
 @rollinswitch  The warming papers: The scientific foundation for the climate change forecast Authors David Archer, Raymond Pierrehumbert Publication date 2011/1/18 Publisher John Wiley & Sons Description Chosen for the 2011 ASLI Choice-Honorable Mention (History Category) for a compendium of the key scientific papers that undergird the global warming forecast. Global warming is arguably the defining scientific issue of modern times, but it is not widely appreciated that the foundations of our understanding were laid almost two centuries ago with the postulation of a greenhouse effect by Fourier in 1827. The sensitivity of climate to changes in atmospheric CO2 was first estimated about one century ago, and the rise in atmospheric CO2 concentration was discovered half a century ago. The fundamentals of the science underlying the forecast for human-induced climate change were being published and debated long before the issue rose to public prominence in the last few decades. The Warming Papers is a compendium of the classic scientific papers that constitute the foundation of the global warming forecast. The paper trail ranges from Fourier and Arrhenius in the 19th Century to Manabe and Hansen in modern times. Archer and Pierrehumbert provide introductions and commentary which places the papers in their context and provide students with tools to develop and extend their understanding of the subject. The book captures the excitement and the uncertainty that always exist at the cutting edge of research, and is invaluable reading for students of climate science, scientists, historians of science, and others interested in climate change.
 @rollinswitch  Global warming, convective threshold and false thermostats Authors Ian N Williams, Raymond T Pierrehumbert, Matthew Huber Publication date 2009/11 Journal Geophysical Research Letters Volume 36 Issue 21 Description We demonstrate a theoretically expected behavior of the tropical sea surface temperature probability density function (PDF) in future and past (Eocene) greenhouse climate simulations. To first order this consists of a shift to warmer temperatures as climate warms, without change of shape of the PDF. The behavior is tied to a shift of the temperature for deep convection onset. Consequently, the threshold for appearance of high clouds and associated radiative forcing shifts along with temperature. An excess entropy coordinate provides a reference to which the onset of deep convection is invariant, and gives a compact description of SST changes and cloud feedbacks suitable for diagnostics and as a basis for simplified climate models. The results underscore that the typically skewed appearance of tropical SST histograms, with a sharp drop‐off above some threshold value, should not be taken as evidence for tropical …
 @rollinswitch  Abrupt climate change: inevitable surprises Authors Richard B Alley, Jochem Marotzke, William Nordhaus, Jonathon Overpeck, D Peteet, Roger Pielke, Raymond Pierrehumbert, P Rhines, T Stocker, L Talley, JM Wallace Publication date 2002 Publisher National Academy Press Description Abrupt climate change: Inevitable surprises :: MPG.PuRe English Help Privacy Policy Disclaimer Include files Advanced SearchBrowse START BASKET (0)Tools Item ITEM ACTIONSEXPORT Add to Basket Local TagsRelease HistoryDetailsSummary Released Book Abrupt climate change: Inevitable surprises MPS-Authors There are no MPG-Authors in the publication available External Resource (Publisher version) Fulltext (public) There are no public fulltexts stored in PuRe Supplementary Material (public) There is no public supplementary material available Citation Committee on Abrupt Climate Change, Alley, R., Marotzke, J., Nordhaus, W., Overpeck, J., Peteet, D., et al. ( Eds. ). (2002). Abrupt climate change: Inevitable surprises. Washington, DC: National Academy Press. Cite as: Abstract There is no …
 @rollinswitch  Reconstructing climate from glaciers Authors Andrew N Mackintosh, Brian M Anderson, Raymond T Pierrehumbert Publication date 2017/8/30 Source Annual Review of Earth and Planetary Sciences Volume 45 Pages 649-680 Publisher Annual Reviews Description Glaciers offer the potential to reconstruct past climate over timescales from decades to millennia. They are found on nearly every continent, and at the Last Glacial Maximum, glaciers were larger in all regions on Earth. The physics of glacier-climate interaction are relatively well understood, and glacier models can be used to reconstruct past climate from geological evidence of past glacier extent. This can lead to significant insights regarding past, present, and future climate. For example, glacier modeling has demonstrated that the near-ubiquitous global pattern of glacier retreat during the last few centuries resulted from a global-scale climate warming of ∼1°C, consistent with instrumental data and climate proxy records. Climate reconstructions from glaciers have also demonstrated that the tropics were colder at the Last Glacial Maximum than was originally inferred from sea surface temperature reconstructions …
 @rollinswitch  Feedback temperature dependence determines the risk of high warming Authors Jonah Bloch‐Johnson, Raymond T Pierrehumbert, Dorian S Abbot Publication date 2015/6/28 Journal Geophysical Research Letters Volume 42 Issue 12 Pages 4973-4980 Description The long‐term warming from an anthropogenic increase in atmospheric CO2 is often assumed to be proportional to the forcing associated with that increase. This paper examines this linear approximation using a zero‐dimensional energy balance model with a temperature‐dependent feedback, with parameter values drawn from physical arguments and general circulation models. For a positive feedback temperature dependence, warming increases Earth's sensitivity, while greater sensitivity makes Earth warm more. These effects can feed on each other, greatly amplifying warming. As a result, for reasonable values of feedback temperature dependence and preindustrial feedback, Earth can jump to a warmer state under only one or two CO2 doublings. The linear approximation breaks down in the long tail of high climate sensitivity commonly seen in observational studies. Understanding feedback temperature …
 @rollinswitch  Climate change: A catastrophe in slow motion Authors Raymond T Pierrehumbert Publication date 2005 Journal Chi. J. Int'l L. Volume 6 Pages 573 Description The word catastrophe usually brings to mind phenomena like tsunamis, earthquakes, mudslides, or asteroid impacts--disasters that are over in an instant and have immediately evident dire consequences. The changes in Earth's climate wrought by industrial carbon dioxide emissions do not at first glance seem to fit this mold since they take a century or more for their consequences to fully manifest. However, viewed from the perspective of geological time, humaninduced climate change, known more familiarly as" global warming," is a catastrophe equal to nearly any other in our planet's history. Seen by a geologist a million years from now, the era of global warming will probably not seem as consequential as the asteroid impact that killed the dinosaurs. It will, however, appear in the geological record as an event comparable to such major events as the onset or termination of an ice age or the transition to the hot …
 @rollinswitch  Warming the world Authors Raymond T Pierrehumbert Publication date 2004/12 Journal Nature Volume 432 Issue 7018 Pages 677-677 Publisher Nature Publishing Group Description Jean-Baptiste Joseph Fourier is generally credited with the discovery of the greenhouse effect, whereby the presence of an atmosphere acts to increase a planet's surface temperature. Written in 1827, nearly three-quarters of a century before science advanced to the point where Arrhenius could quantify the phenomenon, how well does Fourier's concept measure up against our current understanding of the greenhouse effect? First, it is important to recognize what Fourier did not do in his 1827 essay. He did not say that the operation of the atmosphere is analogous to that of a greenhouse—the French word serre (greenhouse) does not appear anywhere in the essay—so he should not be blamed for the well known shortcomings of the analogy. Neither did he write down any equations describing the greenhouse effect, nor compute any estimate of planetary temperature.
 @rollinswitch  A simple carbon cycle representation for economic and policy analyses Authors Michael J Glotter, Raymond T Pierrehumbert, Joshua W Elliott, Nathan J Matteson, Elisabeth J Moyer Publication date 2014/10 Journal Climatic Change Volume 126 Issue 3 Pages 319-335 Publisher Springer Netherlands Description Integrated Assessment Models (IAMs) that couple the climate system and the economy require a representation of ocean CO2 uptake to translate human-produced emissions to atmospheric concentrations and in turn to climate change. The simple linear carbon cycle representations in most IAMs are not however physical at long timescales, since ocean carbonate chemistry makes CO2 uptake highly nonlinear. No linearized representation can capture the ocean’s dual-mode behavior, with initial rapid uptake and then slow equilibration over ∽10,000 years. In a business-as-usual scenario followed by cessation of emissions, the carbon cycle in the 2007 version of the most widely used IAM, DICE (Dynamic Integrated model of Climate and the Economy), produces errors of ∽2∘C by the year 2300 and ∽6∘C by the year 3500. We suggest here a simple alternative representation that captures the relevant …
 @rollinswitch  On the Scattering Greenhouse Effect of CO 2 Ice Clouds Authors RT Pierrehumbert, C Erlick Publication date 1998/5 Journal Journal of the atmospheric sciences Volume 55 Issue 10 Pages 1897-1903 Description The authors offer some remarks on the greenhouse effect due to high clouds that reflect thermal infrared radiation, but do not absorb or emit it. Such clouds are an idealization of the CO 2 ice clouds that are thought to have existed early in the history of Mars. Clouds of this type enter also in the ability of Earth to recover from a globally glaciated “cold start” and in the determination of habitable zones of planetary systems. A simplified model of cloud optical effects is used to estimate the effect of high CO 2 ice clouds on the planetary radiation budget in the solar and infrared spectrum. It is argued that the scattering greenhouse effect certainly cancels out a large part of the cooling effect due to the cloud’s visible albedo and in some circumstances may even lead to a net warming as compared to the no-cloud case. Speculative implications for the climate of early Mars are discussed …
 @rollinswitch  Thermodynamic and energetic limits on continental silicate weathering strongly impact the climate and habitability of wet, rocky worlds Authors RJ Graham, Ray Pierrehumbert Publication date 2020/6/18 Journal The Astrophysical Journal Volume 896 Issue 2 Pages 115 Publisher IOP Publishing Description The" liquid water habitable zone"(HZ) concept is predicated on the ability of the silicate weathering feedback to stabilize climate across a wide range of instellations. However, representations of silicate weathering used in current estimates of the effective outer edge of the HZ account for neither the thermodynamic limit on the concentration of weathering products in runoff set by clay precipitation nor the energetic limit on precipitation set by planetary instellation. We find that when the thermodynamic limit is included in an idealized coupled climate/weathering model, the steady-state planetary climate loses sensitivity to silicate dissolution kinetics, becoming sensitive to temperature primarily through the effect of temperature on runoff and to through an effect on solute concentration mediated by pH. This increases sensitivity to land fraction, outgassing, and geological factors such as soil age and lithology, all …
 @rollinswitch  Atmospheric composition, irreversible climate change, and mitigation policy Authors Susan Solomon, Raymond T Pierrehumbert, Damon Matthews, John S Daniel, Pierre Friedlingstein Publication date 2013 Book Climate science for serving society Pages 415-436 Publisher Springer, Dordrecht Description The Earth’s atmosphere is changing due to anthropogenic increases of gases and aerosols that influence the planetary energy budget. Policy has long been challenged to ensure that instruments such as the Kyoto Protocol or carbon trading deal with the wide range of lifetimes of these radiative forcing agents. Recent research has sharpened scientific understanding of how climate system time scales interact with the time scales of the forcing agents themselves. This has led to an improved understanding of metrics used to compare different forcing agents, and has prompted consideration of new metrics such as cumulative carbon. Research has also clarified the understanding that short-lived forcing agents can “trim the peak” of coming climate change, while long-lived agents, especially carbon dioxide, will be responsible for at least a millennium of elevated temperatures and altered climate, even if emissions …
 @rollinswitch  Hot climates, high sensitivity Authors RT Pierrehumbert Publication date 2013/8/27 Journal Proceedings of the National Academy of Sciences Volume 110 Issue 35 Pages 14118-14119 Publisher National Academy of Sciences Description Climate sensitivity is the Holy Grail of climate science; because CO2 is one of the principal control knobs for climate, sensitivity to changes in atmospheric CO2 concentration is of particular interest. This sensitivity is typically characterized by the change in global mean temperature per doubling of concentration. Because the determination of climate sensitivity is plagued by uncertainties about the operation of various feedbacks in the climate system—notably cloud feedback—it is natural to look to the past for clues about how well we can model those feedbacks. The chilly climate of the Last Glacial Maximum has been extensively exploited for this purpose (1), but the high CO2 hothouse climates such as the Pliocene (∼ 5 Mya) or Eocene (∼ 55 Mya) may be better analogs for where we are headed with our present adventure in turning fossil fuels into atmospheric CO2. In this issue, Caballero and Huber (2) throw …
 @rollinswitch  Ice, fire, or fizzle: The climate footprint of Earth's supercontinental cycles Authors AM Jellinek, A Lenardic, RT Pierrehumbert Publication date 2020/2 Journal Geochemistry, Geophysics, Geosystems Volume 21 Issue 2 Pages e2019GC008464 Description Supercontinent assembly and breakup can influence the rate and global extent to which insulated and relatively warm subcontinental mantle is mixed globally, potentially introducing lateral oceanic‐continental mantle temperature variations that regulate volcanic and weathering controls on Earth's long‐term carbon cycle for a few hundred million years. We propose that the relatively warm and unchanging climate of the Nuna supercontinental epoch (1.8–1.3 Ga) is characteristic of thorough mantle thermal mixing. By contrast, the extreme cooling‐warming climate variability of the Neoproterozoic Rodinia episode (1–0.63 Ga) and the more modest but similar climate change during the Mesozoic Pangea cycle (0.3–0.05 Ga) are characteristic features of the effects of subcontinental mantle thermal isolation with differing longevity. A tectonically modulated carbon cycle model coupled to a one‐dimensional energy …
 @rollinswitch  Comment on ‘unintentional unfairness when applying new greenhouse gas emissions metrics at country level' Authors Michelle Cain, Keith Shine, David Frame, John Lynch, Adrian Macey, Ray Pierrehumbert, Myles Allen Publication date 2021/6/7 Journal Environmental Research Letters Volume 16 Issue 6 Publisher IOP Description Cain, M. ORCID: Shine, K. ORCID: Frame, D. ORCID: , Lynch, J. ORCID:, Macey, A., Pierrehumbert, R. ORCID: and Allen, M. ORCID: (2021) Comment on ‘unintentional unfairness when applying new greenhouse gas emissions metrics at country level'. Environmental Research Letters, 16 (6). 068001. ISSN 1748-9326 doi: Available at
 @rollinswitch  Indicate separate contributions of long-lived and short-lived greenhouse gases in emission targets Authors Myles R Allen, Glen P Peters, Keith P Shine, Christian Azar, Paul Balcombe, Olivier Boucher, Michelle Cain, Philippe Ciais, William Collins, Piers M Forster, Dave J Frame, Pierre Friedlingstein, Claire Fyson, Thomas Gasser, Bill Hare, Stuart Jenkins, Steven P Hamburg, Daniel JA Johansson, John Lynch, Adrian Macey, Johannes Morfeldt, Alexander Nauels, Ilissa Ocko, Michael Oppenheimer, Stephen W Pacala, Raymond Pierrehumbert, Joeri Rogelj, Michiel Schaeffer, Carl F Schleussner, Drew Shindell, Ragnhild B Skeie, Stephen M Smith, Katsumasa Tanaka Publication date 2022/1/28 Journal NPJ climate and atmospheric science Volume 5 Issue 1 Pages 1-4 Publisher Nature Publishing Group Description As researchers who have published over recent years on the issue of comparing the climate effects of different greenhouse gases, we would like to highlight a simple innovation that would enhance the transparency of stocktakes of progress towards achieving any multi-decade-timescale global temperature goal. In addition to specifying targets for total CO2-equivalent emissions of all greenhouse gases, governments and corporations could also indicate the separate contribution to these totals from greenhouse gases with lifetimes around 100 years or longer, notably CO2 and nitrous oxide, and the contribution from Short-Lived Climate Forcers (SLCFs), notably methane and some hydrofluorocarbons. This separate indication would support an objective assessment of the implications of aggregated emission targets for global temperature, in alignment with the UNFCCC Parties’ Decision (4/CMA. 1) 1 to provide …
 @rollinswitch  Earth's supecontinental climate control Authors A Mark Jellinek, Adrian Lenardic, Raymond Pierrehumbert Publication date 2021/4 Journal EGU General Assembly Conference Abstracts Pages EGU21-3461 Description Supercontinent assembly and breakup can influence the rate and global extent to which insulated and relatively warm subcontinental mantle is mixed globally, potentially introducing lateral oceanic-continental mantle temperature variations that regulate volcanic and weathering controls on Earth's long-term carbon cycle for a few hundred million years. In this talk we explore some remarkable consequences of this class of mantle climate control consistent with varied observational constraints. Whereas the relatively unchanging and ice sheet-free climate of the Nuna supercontinental epoch (1.8-1.3 Ga) is an expected consequence of thorough mantle thermal mixing, the extreme cooling-warming climate variability of the Neoproterozoic Rodinia episode (1-0.63 Ga), marked by discontinuous periods of global glaciation (snowball Earth), is a predicted effect of protracted subcontinental mantle thermal isolation.
 @rollinswitch  Data discrepancies in solar-climate link Authors Raymond T Pierrehumbert Publication date 2008/5/9 Journal Science Volume 320 Issue 5877 Pages 746-746 Publisher American Association for the Advancement of Science Description Contrary to the impression given in J. Pasotti's News of the Week story (“Daggers are drawn over revived cosmic ray-climate link,” 11 January, p. 144), neither I nor any of the other climate scientists quoted in the story seek “to strangle the hypothesized climate-geomagnetism connection in its crib.” However, it is not unreasonable to expect that a hypothesis that neglects well-established greenhouse gas and aerosol radiative forcings should at least be based on appropriate and accurately described data. Courtillot and co-workers (1) made two errors that exaggerate the solar-climate correlation (2, 3). First, they showed only the most recent 50 years of a solar irradiance proxy; application of the same data analysis to the readily available full-century record causes the apparent correlation to fall apart. Second, the temperature record used as a basis of comparison was not a global mean temperature or any of the other …
 @rollinswitch  Plant power: Burning biomass instead of coal can help fight climate change—but only if done right Authors Raymond Pierrehumbert Publication date 2022/5/4 Journal Bulletin of the Atomic Scientists Volume 78 Issue 3 Pages 125-127 Publisher Routledge Description Burning of biomass such as wood pellets for energy has the potential to contribute to the portfolio of solutions to the climate crisis. Considered over a time span of a few decades, sustainably sourced biofuels can be considered a renewable energy source, with net zero associated emissions of carbon dioxide. However, whether or not biofuels realize this potential depends very much on the way they are sourced, and this involves an intricate and difficult accounting of full lifecycle carbon emissions. More stringent policies and carbon accounting methods need to be put in place in order to assure that biofuels come close to the ideal of being a net-zero emitter. It also needs to be recognized that increased exploitation of biofuels can come into conflict with other environmental or societal goals, including biodiversity preservation and indigenous rights.
 @rollinswitch  Use of CO2-warming-equivalence to assess progress towards the Paris Agreement temperature goal Authors Michelle Cain, Stuart Jenkins, Nicholas Leach, John Lynch, Raymond Pierrehumbert, David J Frame, Jan S Fuglestvedt, Adrian H Macey, Myles Robert Allen Publication date 2019/12 Journal AGU Fall Meeting Abstracts Volume 2019 Pages GC32B-08 Description The Paris Agreement temperature goals could be achieved either by temperature stabilization, or a peak and decline in temperature. For either of these outcomes to be efficiently achieved, decisions must be made on how to reduce emissions not only to minimise costs, but also to avoid adverse trade-offs. If the aim is to limit global warming (as per the headline goal of the Paris Agreement) then we propose that the benefits of proposed policies are best expressed as avoided warming.
 @rollinswitch  Responding to Climate Change at the Poles: Findings from the National Research Council's Reports on Climate Intervention Authors LM Russell, MK McNutt, W Abdalati, K Caldeira, SC Doney, PG Falkowski, S Fetter, JR Fleming, S Hamburg, G Morgan, J Penner, R Pierrehumbert, PJ Rasch, JT Snow, J Wilcox Publication date 2015/12 Journal AGU Fall Meeting Abstracts Volume 2015 Pages GC14C-03 Description Earlier this year the National Research Council of the US National Academy of Sciences released a pair of reports on two strategies of climate intervention in order to reduce the risks of negative impacts from climate change. The first of the pair of reports discusses the opportunities and challenges in carbon capture and long-term, safe sequestration. The second report discusses several approaches to reflecting sunlight to cool Earth, including the risks, time scales, costs, and socio-economic, and political considerations. The primary conclusion from these pair of reports is that mitigation and adaptation are still our best choices in terms of cost and low risk for reducing harmful effects from climate change: there is no" silver bullet." Given that the polar regions of the planet are the most sensitive to climate change, the reports also touched on the potential for regional climate intervention. The majority of the methods that …
 @rollinswitch  On Reducing the Uncertainty of High Climate Sensitivity Authors Jonah Bloch-Johnson, Raymond Pierrehumbert Publication date 2014/12 Journal AGU Fall Meeting Abstracts Volume 2014 Pages A14A-07 Description Physical modelling and observational studies sometimes suggest there is a nonnegligible probability that the Earth's equilibrium climate sensitivity is greater than 4.5 ºC, the upper end of the IPCC range of likely values. Such worst case scenarios warrant special scrutiny, and there has been much discussion of the methods, and even the feasibility, of reducing our uncertainty of their likelihood. We present a brief review of high sensitivity outcomes and what gives them such high values, highlighting which mechanisms suggest reasonable future pathways for the Earth. In particular, we highlight the role of low cloud feedbacks. We illustrate that the assumption of linearity often used in analysis of climate feedbacks becomes increasingly likely to break down for high sensitivity Earths, and show in a simple thought experiment how the true climate sensitivity can become decorrelated from the one predicted by linear …
 @rollinswitch  Climate Intervention: Reflecting Sunlight to Cool the Earth-Report from the National Research Council Authors Marcia K McNutt, Waleed Abdalati, Ken Caldeira, Scott C Doney, Paul G Falkowski, Steven Fetter, James Rodger Fleming, Steve Hamburg, JE Penner, Granger Morgan, Raymond Pierrehumbert, Philip J Rasch, Lynn M Russell, John T Snow, David Titley, Jennifer Wilcox Publication date 2014/12 Journal AGU Fall Meeting Abstracts Volume 2014 Pages GC13I-0771 Description A committee of the National Research Council was charged with performing a technical evaluation of several potential technologies for geoengineering Earth's climate system. This presentation will summarize the committee's report concerning potential methods for changing Earth's albedo in order to cool the planet. Scientific information concerning albedo modification could prove useful in making decisions to take action to potentially offset some of the worst consequences of climate change should efforts at greenhouse gas mitigation and climate adaptation prove inadequate. For several albedo modification methods, the committee has discussed what is currently known about the science, including potential risks and consequences, the technical readiness for deployment, and future research directions. Governance and legal frameworks that could pertain to research-level experiments in order to better …
 @rollinswitch  Cumulative Carbon and Anthropocene Climate Authors D Matthews, R Pierrehumbert, S Solomon Publication date 2010/12 Journal AGU Fall Meeting Abstracts Volume 2010 Pages B43B-0456 Description In this presentation we will highlight a few of the key findings of the recently completed National Research Council Study Climate Stabilization Targets: Emissions, Concentrations and Impacts over Decades to Millennia (NRC, 2010), and discuss their implications for planetary stewardship. A synthesis of published results shows that the single number which most characterizes the magnitude of the human imprint on the climate of the coming millennia is the net amount of carbon released as CO2 by fossil fuel burning and land use changes during the time over which humanity continues such activities. Details of emissions scenarios are not important; rather it is the net carbon released by the time the emissions have been brought to essentially zero that controls long-term climate changes. In this report, we estimate that global temperatures increase by about 1 degree for approximately every 570 Pg of carbon emitted …
 @rollinswitch  IPCC errors: facts and spin Authors G Schmidt, M Mann, C Ammann, R Benestad, R Bradley, Stefan Rahmstorf, E Steig, D Archer, R Pierrehumbert, T de Garidel, J Bouldin Publication date 2010 Publisher Science Communication Network
 @rollinswitch  Silicate weathering and dry vs. wet runaway greenhouse scenarios Authors R Pierrehumbert Publication date 2008/12 Journal AGU Fall Meeting Abstracts Volume 2008 Pages U42B-01 Description One of the key habitability crises faced by a rocky or icy planet is the possibility of a runaway greenhouse. While the runaway greenhouse threshold is primarily governed by water vapor thermodynamics and radiative properties, the extent of irreversible loss of water can be strongly affected by the amount of CO2 that builds up in the atmosphere. In the" wet runaway" scenario, liquid water persists at the planet's surface, which means that if silicates are present in the planet's crust, there is the possibility of CO2 drawdown due to silicate weathering. I will discuss the problem of silicate weathering on a hot wet-runaway planet, and the factors governing the amount of CO2 that remains in the atmosphere. If large amounts of CO2 remain in the atmosphere, the affect on the cold trap concentration can strongly inhibit water loss. Recent planetary formation calculations suggest that rocky planets can form with a much greater …
 @rollinswitch  Flexible climate modeling systems: Lessons from Snowball Earth, Titan and Mars Authors RT Pierrehumbert Publication date 2007/12 Journal AGU Fall Meeting Abstracts Volume 2007 Pages A22B-10 Description Climate models are only useful to the extent that real understanding can be extracted from them. Most leading-edge problems in climate change, paleoclimate and planetary climate require a high degree of flexibility in terms of incorporating model physics--for example in allowing methane or CO2 to be a condensible substance instead of water vapor. This puts a premium on model design that allows easy modification, and on physical parameterizations that are close to fundamentals with as little empirical ad-hoc formulation as possible. I will provide examples from two approaches to this problem we have been using at the University of Chicago. The first is the FOAM general circulation model, which is a clean single-executable Fortran-77/c code supported by auxiliary applications in Python and Java. The second is a new approach based on using Python as a shell for assembling building blocks in compiled-code …
 @rollinswitch  Water vapor feedback and climate change in the tropical free troposphere. Authors Hélène Brogniez, Raymond T Pierrehumbert Publication date 2007 Journal Proceedings of the National Academy of Sciences of the United States of America Pages A25-185 Description Water vapor feedback and climate change in the tropical free troposphere. - Archive ouverte HAL Accéder directement au contenu Accéder directement à la navigation Toggle navigation CCSD HAL HAL HALSHS TEL MédiHAL Liste des portails AURéHAL API Data Documentation Episciences.org Episciences.org Revues Documentation Sciencesconf.org Support HAL - Archives Ouvertes Accueil Dépôt Consultation Les derniers dépôts Par type de publication Par discipline Par année de publication Par structure de recherche Les portails de l'archive Recherche Documentation hal-00159816, version 1 Article dans une revue Water vapor feedback and climate change in the tropical free troposphere. Hélène Brogniez 1 Raymond T. Pierrehumbert Détails 1 CETP - Centre d'étude des environnements terrestre et planétaires Type de document : Article dans une revue Domaine : Planète et Univers [physics] / Océan, …
 @rollinswitch  Analysis of the influence of a climate change on the free tropospheric water vapor over mid-latitude areas in GCMs Authors H Brogniez, RT Pierrehumbert Publication date 2005/12 Journal AGU Fall Meeting Abstracts Volume 2005 Pages A13B-0914 Description The representation of the mid-tropospheric water vapor over a mid-latitude area is analyzed for two General Circulation Models. We use a lagrangian approach to study the effect of a climate change on the distribution of the water vapor content of the free troposphere. For this purpose, different kind of reconstruction of the water vapor field at 500mb were carried out, hence allowing to study the effects of changes in the structure of the temperature field and of changes in the trajectory statistics. The results show the lack of representation of the driest relative humidity values in the studied GCMs. They also highlight the importance of both dynamic and thermodynamic when analyzing the role of a climate change on the water vapor distribution of the free troposphere.
 @rollinswitch  Flexible Environments for Grand-Challenge Simulation in Climate Science Authors R Pierrehumbert, M Tobis, J Lin, C Dieterich, R Caballero Publication date 2004/12 Journal AGU Fall Meeting Abstracts Volume 2004 Pages SF31A-0714 Description Current climate models are monolithic codes, generally in Fortran, aimed at high-performance simulation of the modern climate. Though they adequately serve their designated purpose, they present major barriers to application in other problems. Tailoring them to paleoclimate of planetary simulations, for instance, takes months of work. Theoretical studies, where one may want to remove selected processes or break feedback loops, are similarly hindered. Further, current climate models are of little value in education, since the implementation of textbook concepts and equations in the code is obscured by technical detail. The Climate Systems Center at the University of Chicago seeks to overcome these limitations by bringing modern object-oriented design into the business of climate modeling. Our ultimate goal is to produce an end-to-end modeling environment capable of configuring anything from a simple single …
 @rollinswitch  Water vapour, atmospheric dynamics and the greenhouse effect Authors R Caballero, M Huber, R Pierrehumbert Publication date 2003/12 Journal AGU Fall Meeting Abstracts Volume 2003 Pages PP21B-1167 Description Unlike other greenhouse gases, water vapour concentration is not limited by availability (given the infinite source in the oceans) but by saturation vapour pressure, which increases exponentially with temperature. The resulting positive``water vapour feedback''acts as a strong amplifier of climate change. Just how strong the amplification is, however, depends on a host of mechanisms in which dynamics play a key role. Atmospheric moisture decreases roughly exponential with height, and vertical motion induced by horizontal temperature gradients will therefore moisten ascending regions and dry out subsiding ones. Vertical motion also affects moist convection, an important source of atmospheric moisture. Over Earth's history, changes in mean temperature have generally been accompanied by changes in gradients. Understanding the evolution of Earth's greenhouse effect therefore requires a detailed …
 @rollinswitch  Risk and reason: Safety, law, and the environment Authors RT Pierrehumbert Publication date 2003/3/20 Source NATURE Volume 422 Issue 6929 Pages 263-263 Publisher NATURE PUBLISHING GROUP
 @rollinswitch  Counting the cost Authors Raymond T Pierrehumbert Publication date 2003/3 Journal Nature Volume 422 Issue 6929 Pages 263-263 Publisher Nature Publishing Group Description How much would you pay to save an isopod? What's that, you say, they're slimy little devils that you'd rather see exterminated? Keep your pencils sharp, because your answers to this and a few thousand other questions (how much would we have to pay you to let us expose your children to malaria?) will be used to determine whether it's worthwhile trying to halt global warming. Oh, and by the way, please let us know how you think the next hundred generations of your descendants will value these things, too. Risk and Reason—a rather sprawling book by legal scholar Cass Sunstein—covers a lot of interesting territory pertinent to environmental regulation. The main theses are that people can't be trusted to judge rationally the risks they face, and that the answer to this problem is a priesthood of government technocrats who carry out cost–benefit analysis (CBA) insulated from judicial review and pressure by advocacy …
 @rollinswitch  CLIMATE Abrupt Climate Change Authors RB Alley, J Marotzke, WD Nordhaus, JT Overpeck, DM Peteet, RA Pielke, RT Pierrehumbert, PB Rhines, TF Stocker, LD Talley Publication date 2003 Journal SCIENCE-NEW YORK THEN WASHINGTON- Pages 2005-2005 Publisher AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE
 @rollinswitch  Climate change and the tropical Pacific: The sleeping dragon wakes Authors Raymond T Pierrehumbert Publication date 2000/2/15 Journal Proceedings of the National Academy of Sciences Volume 97 Issue 4 Pages 1355-1358 Publisher National Academy of Sciences Description The unusually steady climate of the past 10,000 years, after the ultimate recovery from the Younger Dryas cold reversion, has provided a congenial home for the rise of civilization. This era contrasts with the Last Glacial Maximum and other cold periods of the Pleistocene, which were beset by erratic, rapid, and large-amplitude climate reorganizations with no obvious astronomical pacemaker. The mechanism of these millennial scale climate changes is not known (see ref. 1 for some current thinking on the matter); given that we don’t know what accounts for the unusual stability of the recent climate, we don’t know what it would take to break it. This thought is unsettling in a world seemingly committed to substantial warming from anthropogenic CO2 increases in the next 2 centuries. Attention has focused on the Atlantic thermohaline circulation (THC) as the ‘‘Achilles heel’’of climate, primarily because many of the abrupt …
 @rollinswitch  Abrupt Climate Change Authors R. B. Alley, J. Marotzke, J. T. Nordhaus, W. D. , Overpeck, D. M. Peteet, R. A. Pielke Jr., R. T. Pierrehumbert, P. B. Rhines, T. F. Stocker, L. D. Talley, J. M. Wallace Publication date 2003/3/28 Journal Science Volume 299 Issue 5615 Pages 2005-2010 Publisher American Association for the Advancement of Science Description Large, abrupt, and widespread climate changes with major impacts have occurred repeatedly in the past, when the Earth system was forced across thresholds. Although abrupt climate changes can occur for many reasons, it is conceivable that human forcing of climate change is increasing the probability of large, abrupt events. Were such an event to recur, the economic and ecological impacts could be large and potentially serious. Unpredictability exhibited near climate thresholds in simple models shows that some uncertainty will always be associated with projections. In light of these uncertainties, policy-makers should consider expanding research into abrupt climate change, improving monitoring systems, and taking actions designed to enhance the adaptability and resilience of ecosystems and economies.
 @rollinswitch  Principles of planetary climate Authors Raymond T Pierrehumbert Publication date 2010/12/2 Publisher Cambridge University Press Description This book introduces the reader to all the basic physical building blocks of climate needed to understand the present and past climate of Earth, the climates of Solar System planets, and the climates of extrasolar planets. These building blocks include thermodynamics, infrared radiative transfer, scattering, surface heat transfer and various processes governing the evolution of atmospheric composition. Nearly four hundred problems are supplied to help consolidate the reader's understanding, and to lead the reader towards original research on planetary climate. This textbook is invaluable for advanced undergraduate or beginning graduate students in atmospheric science, Earth and planetary science, astrobiology, and physics. It also provides a superb reference text for researchers in these subjects, and is very suitable for academic researchers trained in physics or chemistry who wish to rapidly gain enough background to participate in the excitement of the new research opportunities opening in planetary climate.
 @rollinswitch  Thermostats, radiator fins, and the local runaway greenhouse Authors R Thermostates Pierrehumbert Publication date 1995/5/15 Journal Journal of the atmospheric sciences Volume 52 Issue 10 Pages 1784-1806 Publisher American Meteorological Society Description The author has reconsidered the question of the regulation of tropical sea surface temperature. This has been done in general terms through consideration of the tropical beat budget and in specific terms through consideration of an idealized radiative-dynamic model of the tropical general circulation. It is argued that evaporation on its own cannot provide an effective regulating mechanism. Clouds cannot serve as regulators unless there are substantial departures from the observed cancellation between cloud greenhouse and cloud albedo effects. In particular, it is shown that the prediction by Ramanathan and Collins of highly stable tropical climates is based on an inconsistent set of assumptions about the behavior of the atmospheric heat transports. When the heat transports are treated in a consistent manner, clouds are found to have little impact, and the tropical climate can he quite sensitive to radiative …
 @rollinswitch  Climate intervention: Reflecting sunlight to cool earth Authors Ocean Studies Board, National Research Council Publication date 2015/6/23 Publisher National Academies Press Description The growing problem of changing environmental conditions caused by climate destabilization is well recognized as one of the defining issues of our time. The root problem is greenhouse gas emissions, and the fundamental solution is curbing those emissions. Climate geoengineering has often been considered to be a" last-ditch" response to climate change, to be used only if climate change damage should produce extreme hardship. Although the likelihood of eventually needing to resort to these efforts grows with every year of inaction on emissions control, there is a lack of information on these ways of potentially intervening in the climate system. As one of a two-book report, this volume of Climate Intervention discusses albedo modification-changing the fraction of incoming solar radiation that reaches the surface. This approach would deliberately modify the energy budget of Earth to produce a cooling designed to compensate for some of the effects of warming associated with greenhouse gas increases. The prospect of large-scale albedo modification raises political and governance issues at national and global levels, as well as ethical concerns. Climate Intervention: Reflecting Sunlight to Cool Earth discusses some of the social, political, and legal issues surrounding these proposed techniques. It is far easier to modify Earth's albedo than to determine whether it should be done or what the consequences might be of such an action. One serious concern is that such an action could be unilaterally undertaken by a small nation or smaller entity for its own benefit without international sanction and regardless of international consequences …
 @rollinswitch  Consequences of twenty-first-century policy for multi-millennial climate and sea-level change Authors Peter U Clark, Jeremy D Shakun, Shaun A Marcott, Alan C Mix, Michael Eby, Scott Kulp, Anders Levermann, Glenn A Milne, Patrik L Pfister, Benjamin D Santer, Daniel P Schrag, Susan Solomon, Thomas F Stocker, Benjamin H Strauss, Andrew J Weaver, Ricarda Winkelmann, David Archer, Edouard Bard, Aaron Goldner, Kurt Lambeck, Raymond T Pierrehumbert, Gian-Kasper Plattner Publication date 2016/4 Journal Nature climate change Volume 6 Issue 4 Pages 360-369 Publisher Nature Publishing Group Description Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most profound problems associated with climate change. Here, we argue that the twentieth and twenty-first centuries, a period during which the overwhelming majority of human-caused carbon emissions are likely to occur, need to be placed into a long-term context that includes the past 20 millennia, when the last Ice Age ended and human civilization developed, and the next ten millennia, over which time the projected impacts of anthropogenic climate change will grow and persist. This long-term perspective illustrates that policy decisions made in the next few years to decades will have profound impacts on …
 @rollinswitch  Abrupt climate change: inevitable surprises Authors National Research Council Publication date 2001/1/1 Description The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide expert advice on some of the most pressing challenges facing the nation and world. Our work helps shape sound policies, inform public opinion, and advance the pursuit of science, engineering, and medicine.
 @rollinswitch  Hydrogen greenhouse planets beyond the habitable zone Authors Raymond Pierrehumbert, Eric Gaidos Publication date 2011/5/19 Journal The Astrophysical Journal Letters Volume 734 Issue 1 Pages L13 Publisher IOP Publishing Description We show that collision-induced absorption allows molecular hydrogen to act as an incondensible greenhouse gas and that bars or tens of bars of primordial H 2–He mixtures can maintain surface temperatures above the freezing point of water well beyond the" classical" habitable zone defined for CO 2 greenhouse atmospheres. Using a one-dimensional radiative–convective model, we find that 40 bars of pure H 2 on a three Earth-mass planet can maintain a surface temperature of 280 K out to 1.5 AU from an early-type M dwarf star and 10 AU from a G-type star. Neglecting the effects of clouds and of gaseous absorbers besides H 2, the flux at the surface would be sufficient for photosynthesis by cyanobacteria (in the G star case) or anoxygenic phototrophs (in the M star case). We argue that primordial atmospheres of one to several hundred bars of H 2–He are possible and use a model of hydrogen escape to show …
 @rollinswitch  The hydrologic cycle in deep-time climate problems Authors Raymond T Pierrehumbert Publication date 2002/9 Source Nature Volume 419 Issue 6903 Pages 191-198 Publisher Nature Publishing Group Description Hydrology refers to the whole panoply of effects the water molecule has on climate and on the land surface during its journey there and back again between ocean and atmosphere. On its way, it is cycled through vapour, cloud water, snow, sea ice and glacier ice, as well as acting as a catalyst for silicate–carbonate weathering reactions governing atmospheric carbon dioxide. Because carbon dioxide affects the hydrologic cycle through temperature, climate is a pas des deux between carbon dioxide and water, with important guest appearances by surface ice cover.
 @rollinswitch  Climate stabilization targets: emissions, concentrations, and impacts over decades to millennia Authors National Research Council Publication date 2011/2/11 Publisher National Academies Press Description Emissions of carbon dioxide from the burning of fossil fuels have ushered in a new epoch where human activities will largely determine the evolution of Earth's climate. Because carbon dioxide in the atmosphere is long lived, it can effectively lock the Earth and future generations into a range of impacts, some of which could become very severe. Emissions reductions decisions made today matter in determining impacts experienced not just over the next few decades, but in the coming centuries and millennia. According to Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia, important policy decisions can be informed by recent advances in climate science that quantify the relationships between increases in carbon dioxide and global warming, related climate changes, and resulting impacts, such as changes in streamflow, wildfires, crop productivity, extreme hot summers, and sea level rise. One way to inform these choices is to consider the projected climate changes and impacts that would occur if greenhouse gases in the atmosphere were stabilized at a particular concentration level. The book quantifies the outcomes of different stabilization targets for greenhouse gas concentrations using analyses and information drawn from the scientific literature. Although it does not recommend or justify any particular stabilization target, it does provide important scientific insights about the relationships among emissions, greenhouse gas concentrations, temperatures, and impacts. Climate Stabilization Targets emphasizes the importance of 21st century choices regarding long-term climate stabilization. It is a useful …
 @rollinswitch  Physical climate processes and feedbacks Authors Thomas F Stocker, Gary KC Clarke, Hervé Le Treut, Richard S Lindzen, Valentin P Meleshko, Richard K Mugara, Timothy N Palmer, Raymond T Pierrehumbert, Piers J Sellers, Kevin E Trenberth, AAM Holtslag Publication date 2001 Book IPCC, 2001: Climate change 2001: The scientific basis. Contribution of working group I to the third assessment report of the intergovernmental panel on climate change Pages 417-470 Publisher Cambridge University Press Description Physical Climate Processes and Feedbacks — Research@WUR Skip to main navigation Skip to search Skip to main content Research@WUR Logo Help & FAQ Home Researchers Research Units Research output Datasets Press / Media Activities Projects Prizes Impacts Search by expertise, name or affiliation Physical Climate Processes and Feedbacks TF Stocker, GKC Clarke, H. Le Treut, RS Lindzen, VP Meleshko, RK Mugara, TN Palmer, RT Pierrehumbert, PJ Sellers, KE Trenberth, AAM Holtslag Meteorology and Air Quality Research output: Chapter in Book/Report/Conference proceeding › Chapter › Academic Overview Original language English Title of host publication IPCC, 2001: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change Editors JT Houghton, Y. Ding, DJ Griggs, M. Noguer, PJ van der Linden…
 @rollinswitch  Hydrogen-nitrogen greenhouse warming in Earth's early atmosphere Authors Robin Wordsworth, Raymond Pierrehumbert Publication date 2013/1/4 Journal science Volume 339 Issue 6115 Pages 64-67 Publisher American Association for the Advancement of Science Description Understanding how Earth has sustained surface liquid water throughout its history remains a key challenge, given that the Sun’s luminosity was much lower in the past. Here we show that with an atmospheric composition consistent with the most recent constraints, the early Earth would have been significantly warmed by H2-N2 collision–induced absorption. With two to three times the present-day atmospheric mass of N2 and a H2 mixing ratio of 0.1, H2-N2 warming would be sufficient to raise global mean surface temperatures above 0°C under 75% of present-day solar flux, with CO2 levels only 2 to 25 times the present-day values. Depending on their time of emergence and diversification, early methanogens may have caused global cooling via the conversion of H2 and CO2 to CH4, with potentially observable consequences in the geological record.

 

 

 

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