[En proceso]
Lazos de realimentación positiva en el sistema climático
- Daniel A. Lashof and and Benjamin J. DeAngelo; Scott R. Saleska and and John Harte (1997) – Terrestrial Ecosystem Feedbacks To Global Climate Change – Annual Review of Energy and the Environment 22:75-118 doi:10.1146/annurev.energy.22.1.75 – 01/11/1997- Natural Resources Defense Council, Washington; University of California at Berkeley
«Anthropogenic greenhouse gases are expected to induce changes in global climate that can alter ecosystems in ways that, in turn, may further affect climate. Such climate-ecosystem interactions can generate either positive or negative feedbacks to the climate system, thereby either enhancing or diminishing the magnitude of global climate change. Important terrestrial feedback mechanisms include CO2 fertilization (negative feedbacks), carbon storage in vegetation and soils (positive and negative feedbacks), vegetation albedo (positive feedbacks), and peatland methane emissions (positive and negative feedbacks). While the processes involved are complex, not readily quantifiable, and demonstrate both positive and negative feedback potential, we conclude that the combined effect of the feedback mechanisms reviewed here will likely amplify climate change relative to current projections that have not yet adequately incorporated these mechanisms.» - K. Wallmann (2003) – Feedbacks between oceanic redox states and marine productivity: A model perspective focused on benthic phosphorus cycling – Global Biochemical Cycles 17:1084-1101 doi:10.1029/2002GB001968 – 16/08/2003 – GEOMAR Research Center
«A new model for the marine cycles of particulate organic carbon (POC), oxygen, nitrate, and phosphorus has been developed and applied to explore the controls and constraints on marine productivity and nutrient inventories. The coupled benthic-pelagic model uses a new approach for the simulation of the reactive phosphorus turnover (Preac corresponding to the sum of organic P, authigenic P, and adsorbed phosphate) in marine sediments … The model runs revealed that the spread of anoxia in bottom waters may enhance the productivity of the global ocean by one order of magnitude if sufficient nitrate is provided by N2-fixation. Thus anoxic bottom waters promote eutrophic conditions and vice versa. Additional model runs showed that the productivity and nutrient inventory of the glacial ocean were probably enhanced due to the falling sea level. Marine regression induced a narrowing of the depositional areas on the continental shelves and thereby an increase in the fraction of POC exported to the deep ocean. The accelerated POC delivery, in turn, decreased the oxygen contents of the deep water and thus favored the release of phosphate from deep-sea and rise sediments. Enhanced recycling of phosphate at the seafloor promoted further POC export in a positive feedback loop.» - Amanda H. Lynch et al (2000) – Impacts of Fire and Warming on Ecosystem Uptake in the Boreal Forest – Journal of Climate 13:2334-2338 – 01/07/2000 – Cooperative Institute for Research in Environmental Sciences, and Program in Atmosphere and Ocean Sciences, University of Colorado – 3 authors «Observations show that the amplitude of the annual atmospheric carbon dioxide cycle has increased. Lagged correlations between carbon dioxide, temperature, and vegetation suggest a modulation by ecosystem response, but the mechanisms remain unclear. Hypotheses include an early season uptake increase and/or winter respiration increase related to climate warming, and increased cycling in cooler conditions caused by disturbances such as fire. The first hypotheses suggest a positive feedback to regional warming, whereas the last suggests a negative feedback. Here it is shown that fire, as it influences species composition, can serve to enhance the increase in early season uptake but that a crucial determinant for the sign of the feedback is the impact of climate change on soil moisture.»
- Richard A. Betts (2000) – Offset of the potential carbon sink from boreal forestation by decreases in surface albedo – Nature 408:187-190 doi:10.1038/35041545 – 36839 – Hadley Centre for Climate Prediction and Research, The Met Office
«Carbon uptake by forestation is one method proposed (ref) to reduce net carbon dioxide emissions to the atmosphere and so limit the radiative forcing of climate change (ref). But the overall impact of forestation on climate will also depend on other effects associated with the creation of new forests. In particular, the albedo of a forested landscape is generally lower than that of cultivated land, especially when snow is lying (refs) and decreasing albedo exerts a positive radiative forcing on climate. Here I simulate the radiative forcings associated with changes in surface albedo as a result of forestation in temperate and boreal forest areas, and translate these forcings into equivalent changes in local carbon stock for comparison with estimated carbon sequestration potentials (refs). I suggest that in many boreal forest areas, the positive forcing induced by decreases in albedo can offset the negative forcing that is expected from carbon sequestration. Some high-latitude forestation activities may therefore increase climate change, rather than mitigating it as intended.» - J. Alcock (2003) – Positive Feedback and System Resilience from Graphical and Finite-Difference Models: The Amazon Ecosystem—An Example – Earth Interactions 7:1-23 – July 2003 – Department of Environmental Sciences, The Pennsylvania State University
«Positive feedback created by interactions among tropical forest, regional hydrology, and climate in the Amazon basin may produce multiple steady states. As deforestation progresses, one state—the normal forest with a high leaf area index—is stable and promotes system resilience. However, deforestation can cause the system to shift toward and past a second, unstable state at moderate levels of forest cover. The latter separates forest stability in the face of stress from runaway behavior and system collapse into an alternative grassland ecology. To test this inference, a two-dimensional finite-difference model has been constructed that includes parameterizations of the functions controlling feedback. Results of the experiment indicate that human-driven deforestation may shift regions of the Amazonian ecosystem to instability after 25%–30% of the forest has been permanently cleared, within two to four decades if the current practice is maintained.» - K. Wallmann (2003) – Feedbacks between oceanic redox states and marine productivity: A model perspective focused on benthic phosphorus cycling – Global Biochemical Cycles 17:1084-1101 doi:10.1029/2002GB001968 – 16/08/2003 – GEOMAR Research Center
«A new model for the marine cycles of particulate organic carbon (POC), oxygen, nitrate, and phosphorus has been developed and applied to explore the controls and constraints on marine productivity and nutrient inventories. The coupled benthic-pelagic model uses a new approach for the simulation of the reactive phosphorus turnover (Preac corresponding to the sum of organic P, authigenic P, and adsorbed phosphate) in marine sediments. The simulated POC/Preac burial ratio in shelf, slope and rise, and deep-sea sediments increases under strongly reducing conditions in agreement with field observation. The model runs revealed that the spread of anoxia in bottom waters may enhance the productivity of the global ocean by one order of magnitude if sufficient nitrate is provided by N2-fixation. Thus anoxic bottom waters promote eutrophic conditions and vice versa. Additional model runs showed that the productivity and nutrient inventory of the glacial ocean were probably enhanced due to the falling sea level. Marine regression induced a narrowing of the depositional areas on the continental shelves and thereby an increase in the fraction of POC exported to the deep ocean. The accelerated POC delivery, in turn, decreased the oxygen contents of the deep water and thus favored the release of phosphate from deep-sea and rise sediments. Enhanced recycling of phosphate at the seafloor promoted further POC export in a positive feedback loop.» - James Hansen and Larissa Nazarenko (2004) – Soot climate forcing via snow and ice albedos – Proceedings of the National Academy of Sciences PNAS 101:423–428 doi:10.1073/pnas.2237157100 – 13/01/2004 – National Ae – 13/01/2004- NASA Goddard Institute for Space Studies and Columbia University Earth Institute
“If, as we suggest, melting ice and sea level rise define the level of dangerous anthropogenic interference with the climate system, then reducing soot emissions, thus restoring snow albedos to pristine high values, would have the double benefit of reducing global warming and raising the global temperature level at which dangerous anthropogenic interference occurs … The soot effect on snow albedo may be responsible for a quarter of observed global warming. Restoration of snow albedos to something approaching pristine preanthropogenic values would have the double benefit of reducing global warming and raising the global temperature threshold at which dangerous anthropogenic interference with climate occurs.” - R. A. Betts et al (2004) – The role of ecosystem-atmosphere interactions in simulated Amazonian precipitation decrease and forest dieback under global climate warming – Theoretical and Applied Climatology 78:157–175 doi:10.1007/s00704-004-0050-y – 06/05/2004 – Hadley Centre for Climate Prediction & Research, Met Office
«This analysis helps to explain why the Amazonian precipitation reduction simulated by HadCM3LC is more extreme than that simulated in other GCMs; in the fully-coupled, climate-carbon cycle simulation, approximately half of the precipitation reduction in Amazonia is attributable to a combination of physiological forcing and biogeophysical and global carbon cycle feedbacks, which are generally not included in other GCM simulations of future climate change. The analysis also demonstrates the potential contribution of regional-scale climate and ecosystem change to uncertainties in global CO2 and climate change projections. Moreover, the importance of feedbacks suggests that a human-induced increase in forest vulnerability to climate change may have implications for regional and global scale climate sensitivity.» - F.S. Chapin III et al (2005) – Role of Land-Surface Changes in Arctic Summer Warming – Science 310:657-660 doi:10.1126/science.1117368 – 22/09/2005 – Institute of Arctic Biology; University of Alaska Fairbanks – 21 authors
“Reduced snow cover and albedo (reflectivity) in the summertime Arctic landscape, caused by global warming, has added local atmospheric heating “similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric CO2 … Continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating 2-7 times’.” - David M. Lawrence and Andrew G. Slater (2005) – A projection of severe near-surface permafrost degradation during the 21st century – Geophysical Research Letters, 32, L24401, doi:10.1029/2005GL025080 – 17/12/2005 – Climate and Global Dynamics Division, National Center for Atmospheric Research
«The current distribution and future projections of permafrost are examined in a fully coupled global climate model, the Community Climate System Model, version 3 (CCSM3) with explicit treatment of frozen soil processes. The spatial extent of simulated present-day permafrost in CCSM3 agrees well with observational estimates – an area, excluding ice sheets, of 10.5 million km2. By 2100, as little as 1.0 million km2 of near-surface permafrost remains. Freshwater discharge to the Arctic Ocean rises by 28% over the same period, largely due to increases in precipitation that outpace increases in evaporation, with about 15% of the rise directly attributable to melting ground ice. Such large changes in permafrost may provoke feedbacks such as activation of the soil carbon pool and a northward expansion of shrubs and forests.» - Margaret S. Torn and John Harte (2006) – Missing feedbacks, asymmetric uncertainties, and the underestimation of future warming – Geophysical Research Letters 33 L10703 doi:10.1029/2005GL025540 – 26/05/2006 – Earth Sciences Division, Lawrence Berkeley National Laboratory; Energy and Resources Group, University of California, Berkeley
“The warming of 1.5–4.5°C associated with anthropogenic doubling of CO2 is amplified to 1.6–6.0°C … Thus, anthropogenic emissions result in higher final GhG concentrations, and therefore more warming, than would be predicted in the absence of this feedback … A symmetrical uncertainty in any component of feedback, whether positive or negative, produces an asymmetrical distribution of expected temperatures skewed toward higher temperature. For both reasons, the omission of key positive feedbacks and asymmetrical uncertainty from feedbacks, it is likely that the future will be hotter than we think.” - Fred Pearce – Climate change: What the IPCC didn’t tell us – New Scientist 2590 – 39122 – – http://www.newscientist.com/article/mg19325903.800-climate-change-what-the-ipcc-didnt-tell-us.html
“They identified a series of potential positive feedbacks and «tipping points» not included in current models of the Earth’s climate system that could accelerate global warming or sea-level rise. These included the physical collapse of the Greenland ice sheet, rapid melting in Antarctica, a shut-down of the Gulf Stream in the Atlantic, and the release of carbon dioxide and methane from soil, the ocean bed and melting permafrost.” - Scott C. Doney (2007) – Carbon and climate system coupling on timescales from the Precambrian to the Anthropocene – Annual Reviews of the Environment and Resources – 29/05/2007 – Climate and Global Dynamics, National Center for Atmospheric Research
«The global carbon and climate systems are closely intertwined, with biogeochemical processes responding to and driving climate variations. Over a range of geological and historical time-scales, warmer climate conditions are associated with higher atmospheric levels of CO2, an important climate-modulating greenhouse gas. The atmospheric CO2-temperature relationship reflects two dynamics, the planet’s climate sensitivity to a perturbation in atmospheric CO2 and the stability of non-atmospheric carbon reservoirs to evolving climate. Both exhibit non-linear behavior, and coupled carbon-climate interactions have the potential to introduce both stabilizing and destabilizing feedback loops into the Earth System. Here we bring together evidence from a wide range of geological, observational, experimental and modeling studies on the dominant interactions between the carbon cycle and climate. The review is organized by time-scale, spanning interannual to centennial climate variability, Holocene millennial variations and Pleistocene glacial-interglacial cycles, and million year and longer variations over the Precambrian and Phanerozoic. Our focus is on characterizing and, where possible quantifying, the emergent behavior internal to the coupled carbon-climate system as well as the responses of the system to external forcing from tectonics, orbital dynamics, catastrophic events, and anthropogenic fossil fuel emissions. While there are many unresolved uncertainties and complexity in the carbon cycle, one emergent property is clear across time scales: while CO2 can increase in the atmosphere quickly, returning to lower levels through natural processes is much slower, so the consequences of the human perturbation will far outlive the emissions that caused them.» - Gordon B. Bonan (2008) – Forests and Climate Change: Forcings, Feedbacks, and the Climate Benefits of Forests – Science 320:1444-1449 doi:10.1126/science.1155121 – 13/06/2008 – National Center for Atmospheric Research
“The most studied region is Amazonia, where large-scale conversion of forest to pasture creates a warmer, drier climate. Surface warming arising from the low albedo of forests is offset by strong evaporative cooling. Similar results are seen in tropical Africa and Asia, and the climatic influence of tropical forests may extend to the extratropics through atmospheric teleconnections. However, forest-atmosphere interactions are complex, and small-scale, heterogeneous deforestation may produce mesoscale circulations that enhance clouds and precipitation. Flux tower measurements in the Brazilian Amazon confirm that forests have lower albedo compared with pasture, greater net radiation, and greater evapotranspiration, particularly during the dry season (11, 12), producing a shallow, cool, and moist boundary layer. Observations show that forest transpiration is sustained during the dry season (11); this is seen also in CO2 fluxes (12) and satellite monitoring of vegetation (13, 14), to a greater extent than represented in many models.” - A. E. Dessler, Z. Zhang, and P. Yang (2008) – Water-vapor climate feedback inferred from climate fluctuations, 2003-2008 – Geophysical Research Letters 35 L20704 doi:10.1029/2008GL035333 – – 23/10/2008 – Department of Atmospheric Sciences, Texas A&M University
“The existence of a strong and positive water-vapor feedback means that projected business-as-usual greenhouse-gas emissions over the next century are virtually guaranteed to produce warming of several degrees Celsius. The only way that will not happen is if a strong, negative, and currently unknown feedback is discovered somewhere in our climate system.” - Ryouta O’ishiet al (2009) – Vegetation dynamics and plant CO2 responses as positive feedbacks in a greenhouse world – Geophysical Research Letters 36 L11706 doi:10.1029/2009GL038217 – 06/06/2009
“The biospheric response to CO2 and climate change becomes dominated by positive feedbacks that overwhelm the effect of CO2 fertilization on terrestrial carbon stocks … This feedback amplifies global warming by 13%. About half of it is due to climatically induced expansion of boreal forest into tundra, reinforced by reductions in snow and sea ice cover. The other half represents a global climatic effect of increased vegetative cover (an indirect consequence of plant physiological responses to CO2) in the semi-arid subtropics.” - Oliver L. Phillips et al (2009) – Drought Sensitivity of the Amazon Rainforest – Science 323:1344-1347 doi:10.1126/science.1164033 – 06/03/2009 – Ecology and Global Change, School of Geography, University of Leeds – 66 authors
“Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 1015 to 1.6 x 1015 grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.” - Amy C. Clement et al (2009) – Observational and Model Evidence for Positive Low-Level Cloud Feedback – Science 325:460-464 doi:10.1126/science.1171255 – 24/07/2009 – Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Division of Meteorology and Physical Oceanography
“This observational analysis further indicated that clouds act as a positive feedback in this region on decadal time scales … The only model that passed this test simulated a reduction in cloud cover over much of the Pacific when greenhouse gases were increased, providing modeling evidence for a positive low-level cloud feedback.” - Marc Mallet et al (2009) – Impact of sea-surface dust radiative forcing on the oceanic primary production: A 1D modeling approach applied to the West African coastal waters – Geophysical Research Letters 36 L15828 doi:10.1029/2009GL039053 – 15/08/2009 – Laboratoire d’Aérologie, Université de Toulouse
“Simulations reveal that dust are able to induce a significant decrease of PP due to the attenuation of light by about 15–25% for dust optical depth (DOD) larger than 0.6–0.7 (at 550 nm). For DOD lower than ∼0.2–0.3, the influence of dust on PP is weak (∼5%). In addition to DOD, the important role played by dust single scattering albedo (DSSA) is also shown.” - William Ingram (2010) – A very simple model for the water vapour feedback on climate change – Quarterly Journal of the Royal Meteorological Society – 19/01/2010 – Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, University of Oxford
“The partly-Simpsonian approach also provides a physical explanation for the well-established fact that, in water-vapour-dominated regions of the spectrum, the heat radiated by the climate system is a function primarily of relative humidity, not temperature.” - Rui Mei and Guiling Wang (2010) – Rain follows logging in the Amazon? Results from CAM3–CLM3 – Climate Dynamics 34:983-996 doi:10.1007/s00382-009-0592-x – 18/05/2009 – Department of Civil and Environmental Engineering and Center for Environmental Sciences and Engineering, University of Connecticut
«The impact of logging on precipitation in the Amazon region is investigated based on numerical experiments using the community atmosphere model version 3 coupled with the community land surface model version 3 (CAM3–CLM3). Three different representations of logging are examined, ranging from selective logging, to partial deforestation, to clear cut. Precipitation increases in response to modest selective logging, and decreases as the severity of logging progresses to partial deforestation and clear cut. Further experiments indicate that the increase of precipitation is mostly due to the decrease of surface albedo following selective logging, resulting from a low contrast between bare soil albedo and vegetation optical properties (i.e., leaf reflectance) in CLM3. This study demonstrates the complexity of representing land cover changes in climate models, and underlines the importance of accuracy in albedo measurement from satellite remote sensing.» - Abigail L. Swanna et al (2010) – Changes in Arctic vegetation amplify high-latitude warming through the greenhouse effect – Proceedings of the National Academy PNAS Early Edition doi:10.1073/pnas.0913846107 – 01/12/2010 – Department of Earth & Planetary Science, University of California – 5 authors
“Land surface albedo change is considered to be the dominant mechanism by which trees directly modify climate at high-latitudes, but our findings suggest an additional mechanism through transpiration of water vapor and feedbacks from the ocean and sea-ice … The long-wave effects from changes in atmospheric moisture are not generally considered in studies of high-latitude vegetation change, but we find the radiative forcing from water vapor to be the same magnitude as the direct shortwave forcing from albedo, indicating that the energy budget of the entire column should be considered and not just the balance of surface fluxes.”
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Oliver L. Phillips et al (2009) – Drought Sensitivity of the Amazon Rainforest – Science 323:1344-1347 doi:10.1126/science.1164033 – 06/03/2009 – Ecology and Global Change, School of Geography, University of Leeds – 66 authors
“Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 1015 to 1.6 x 1015 grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.”
Me parece muy importante lo que escribes. A mi también me preocupa profundamente lo del cambio climático y he tratado de entenderlo.
Por otra parte, creo que el título » ¿Por qué a un círculo vicioso se le llama retroalimentación positiva?» es incorrecto, porque también un círculo virtuoso es de retroalimentación positiva, sólo que sus efectos son positivos, aplicado por ejemplo al hecho de dar amor, que generalmente se regresa aumentado.
En cambio esta retroalimentación positiva se convierte en circulo vicioso, cuando sus efectos son negativos como por ejemplo el ejercer la violencia. Esta puede crecer hasta los límites de la muerte.
Para el caso del cambio climático, creo que existen factores de ambos tipos, además de los factores de retroalimentación negativa.
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El único lazo de retroalimentación negativa en el sistema climático con la intensidad suficiente es la carbonatación, es decir, la conversión del CO2 en carbonatos. Pero es tan lento que se produce en decenas de miles de años, mucho después de todos los demás lazos rápidos (albedo Ártico, nubosidad, vapor de agua) e incluso lentos (emisiones de la biosfera, fusión de hielos) y es el que que estabiliza el clima a las condiciones del Máximo Térmico del Paleoceno Eoceno. Afortunadamente, porque de otro modo el síndrome de Venus (runaway climate change) sería imparable. Es posible que estés pensando en el ‘efecto de fertilización del CO2’. Éste y muchos más existen en el sistema climático pero, superado cierto umbral, no alcanzan a compensar para estabilizar el clima a los niveles del Holoceno. Estos umbrales han sido superados.
A tener en cuenta además que el hecho de que en cualquier sistema haya retroalimentación negativa (sólo retroalimentación negativa) no es condición suficiente como para que existan estados estables. La única condición necesaria y suficiente (en un sistema lineal, o linealizable dentro de ciertos márgenes que tengan sentido físico) es de tipo matemático: la parte real de todas las raíces del polinomio del denominador de la función de transferencia del sistema debe encontrarse en el semiplano negativo del plano complejo. Esto no ocurre nunca cuando la retroalimentación es positiva, pero no ocurre siempre por el solo hecho de que la retroalimentación sea negativa. De lo que se trata es de que la variable de estado (por ejemplo, la temperatura) evolucione en el tiempo siempre según e-at y nunca según e+at (a>0). Perdón por el tecnicismo, pero a veces (me) resulta inevitable para evitar malos entendidos.
Estoy de acuerdo en que también hay círculos virtuosos. Perdón por la simplificación, pero a veces es conveniente para llamar la atención. En todo caso lo volveré a reflexionar.
Gracias alva por tu participación.
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Hola, creo que no me expliqué bien.
La observación iba en el sentido del título solamente.
En todo lo demás coincido contigo que el problema es bastante grave, sobre todo porque se desconocen al 100% la influencia que tienen cada uno de los elementos que componen a los factores físicos, químicos y biológicos, en el funcionamiento del clima.
Cada vez con mayor frecuencia leo que algún grupo de científicos concluye en sus trabajos que no esperaban que tal factor pudiera ser tan importante en la regulación del clima, sobre todo porque su dinámica es no lineal.
Lo que sí parece cierto es que los factores de retroalimentación positiva con efectos negativos, (para nosotros los humanos y demás especies que nos llevamos de cola) de aumento de temperatura van ganando terreno con respecto a los de retroalimentación negativa (fundamentalmente los de carácter biológico, más o menos en la línea de la teoría Gaia), de tal forma que científicos bastante serios afirman que en el mejor de los casos nos quedan dos décadas para evitar la irreversibilidad en el desbordamiento del clima.
Los círculos virtuosos en el clima (para nosotros los humanos) según algunos científicos ocurrieron hace millones de años, cuando la temperatura del planeta empezó a descender y estabilizarse debido a causas geo-biológicas internas.
Desde mi particular punto de vista, creo que es muchísimo más lo que desconocemos, que lo que conocemos. Me parece que el hombre moderno no ha sabido cultivar la humildad y la sabiduría.
Por otra parte, impartí hace algunos años teoría de control y entiendo de los tecnicismos.
Otra vez, gracias por tus aportaciones. Alva
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James Lovelock, que es de los pocos climatólogos que sabe de teoría de sistemas (es curioso ¿verdad? – estoy preparando una entrada que habla de esta sorprendente carencia), dice que el estado estable del clima de la Tierra en las condiciones actuales es el de las edades de hielo, y que los interglaciares son fallos de la regulación.
Por otra parte, estando de acuerdo en que no se ha cultivado ni humildad ni sabiduría, encuentro resistencia íntima a creer que es cosa del hombre. No es sólo emocional, sino fundamentada en cierto conocimiento del movimiento anti-ilustración que se desencadenó tras el New Deal y que, ayudado por el fundamentalismo cristiano (al que no se le da la importancia que creo que tiene), ha triunfado posiblemente mucho más allá de lo que sus promotores originarios pudieron llegar a imaginar. Tanto, que llegamos a creer que somos así ‘por naturaleza’.
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Hola,
No entiendo muy bien lo que me dices en el segundo párrafo.
Pero en las causas internas de los cambios en al planeta, creo que hay dos protagonistas: el hombre con su diversidad de culturas y todas sus estructuras, y por otro lado la naturaleza, excluyendo al hombre, con su dinámica compleja.
Por lo que no me queda claro a que te refieres cuando dices «cosa del hombre».
Y cuando digo que nos ha faltado cultivar la humildad y la sabiduría, me refiero a todos los humanos, pero con dedicatoria especial a los que ejercen cualquier tipo de poder en los diferentes ámbitos, empezando por los que tienen el ejercicio del saber y que deberían tener un mayor compromiso con los ciudadanos, pero que al no hacerlo, esto finalmente se traduce en el control o manipulación, (temporal o permanente; consciente o inconsciente) de los que se han dejado seducir por las promesas del “progreso”.
saludos. alva
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