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    TUHOKlimaticka zmena / If the fracturing of our once stable climate doesn’t terrify you, then you don’t fully understand it


    "Given the sheer enormity of climate change, it’s okay to be depressed, to grieve. But please, don’t stay there too long. Join me in pure, unadulterated, righteous anger."


    "I don’t want your hope. I don’t want you to be hopeful. I want you to panic. I want you to feel the fear I feel every day. And then I want you to act. Once you start to act, the hope is everywhere."

    "Our best scientists tell us insistently that a calamity is unfolding, that the life-support systems of the Earth are being damaged in ways that threaten our survival. Yet in the face of these facts we carry on as usual."

    “We’ve got to stop burning fossil fuels. So many aspects of life depend on fossil fuels, except for music and love and education and happiness. These things, which hardly use fossil fuels, are what we must focus on.”

    A nejde o to, že na to nemáme dostatečné technologie, ty by na řešení použít šly, ale chybí nám vůle a představivost je využít. Zůstáváme při zemi, přemýšlíme až moc rezervovaně. Technologický pokrok to sám o sobě nevyřeší. Problém jsme my, ne technologické nástroje.

    Rostouci hladiny oceanu, zmena atmosferickeho proudeni, zmeny v distribuci srazek a sucha. Zmeny karbonoveho, fosforoveho a dusikoveho cyklu, okyselovani oceanu. Jake jsou bezpecnostni rizika a jake potencialni klady dramatickych zmen fungovani zemskeho systemu?
    Ale take jak funguji masove dezinformacni kampane ropneho prumyslu a boj o verejne mineni na prahu noveho klimatickeho rezimu post-holocenu.
    rozbalit záhlaví
    YMLADRIS
    YMLADRIS --- ---
    Hybrid AI supercharges climate models

    A machine-learning tool slashes the computing power needed to predict future climate and could help us be better prepared for extreme weather events. The tool, co-developed by Google, combines AI machine learning with conventional weather forecasting. It opens the door for faster forecasting that is less energy-intensive than existing tools, and better at predicting long-term forecasts than purely AI-based approaches. “The issue with pure machine-learning approaches is that you’re only ever training it on data it’s already seen,” says AI researcher Scott Hosking. “The climate is continuously changing, we’re going into the unknown, so our machine-learning models have to extrapolate into that unknown future.”

    Google AI predicts long-term climate trends and weather — in minutes
    https://www.nature.com/articles/d41586-024-02391-9
    CHOSIE
    CHOSIE --- ---
    MINER: Uvidíme kam se to vědecky vyvine, jak píšeš je to momentálně celkem probírané téma, takže čekám, že následující měsíce a roky nám dají více odpovědí.
    Jak konec článku zmiňuje - na jednu stranu je jedno zda 3C nebo 5C (7C v případě sdílené publikace), obojí je špatný. I když případě těch horních hranic mluvíme o podmínkách, které si těžko dokážeme představit.

    Jinak ještě z článku, který jsem sdílel:
    It should be noted that our ECS is not the same as the ECS used by the IPCC, given that it represents specific climate sensitivity S[CO2,LI]
    (i.e., ESS corrected for potential slow land ice feedback) and does not consider changes in other greenhouse gases (e.g., methane), paleogeography
    , nor solar luminosity; we are currently unable to conduct these additional considerations65. The impact of additional methane and
    water would bring down ECS, which likely explains why paleo ECS is generally higher than modern models.
    CHOSIE
    CHOSIE --- ---
    https://www.nature.com/articles/s41467-024-47676-9
    Using our new range of pCO2 values, we calculate average Earth system sensitivity and equilibrium climate sensitivity,
    resulting in 13.9 °C and 7.2 °C per doubling of pCO2, respectively. These values are significantly higher than
    IPCC global warming estimations, consistent or higher than some recent state-of-the-art climate models, and
    consistent with other proxy-based estimates.

    Pre-industrial CO2 level = 280ppm, doubling tedy je 560ppm
    Momentální hladina CO2 ~425ppm (CO2eq ~520ppm)


    RCP8.5 scénář odhaduje 560ppm v roce ~2052
    RCP6 scénář v roce ~2070
    RCP4.5 stabilizaci těsně pod 560ppm

    Nutno dodat, že tyto scénáře nepočítají s:
    - vyčerpáním zdrojů = lepší scénář (jsem názoru, že nemáme dostatek finančně/technologicky/energeticky dostupných fosilních paliv, abychom se do konce století drželi RCP8.5)
    - pozitivními zpětnými vazbamy a body zvratu/zlomu = horší scénář (IPCC podceňuje, nebo vůbec nepočítá s mnoha zpětnými vazbami a body zvratu/zlomu, které by mimo naši kontrolu začali CO2 (CO2eq) emitovat)
    YMLADRIS
    YMLADRIS --- ---
    VOYTEX: museli by mit uplne jinou, tajnou architekturu nez jsou ty aktualne popularni transformery, protoze na trenovani tech modelu potrebujes tolik GW ze to nejde jen tak utajit, takova spotreba. coz jako ... nevim no. vedelo by se, ze nejlepsi AI mozky zahadne mizi nekam na projekt manhattan. coz se nutne stane, ale jeste se to nedeje

    nezda se mi ze by US do 2030 stihlo projekty ve smyslu nize, Cina v pohode, maji jiny styl prace. Z hlediska emisi se to asi bude hodne zhorsovat. Myslet si, ze AI je k nicemu a neprosadi se, to se bojim ze jako Vaclav Klaus rikaval ze internet je jen nahrazka Zlutych stranek a on by se tim nevzrusoval (to ma byt na Shefika ze to prece nic moc neumi)

    According to Aschenbrenner, by 2028 the most advanced models will run on 10 gigawatts of power at a cost of several hundred billion dollars. By 2030, they’ll run at 100 gigawatts at a cost of a trillion dollars.

    For context, a typical power plant delivers something in the range of 1 gigawatt or so. So that means building 10 power plants in addition to the supercomputer cluster by 2028. What would all those power stations run on? According to Aschenbrenner, on natural gas. “Even the 100 [gigawatt] cluster is surprisingly doable,” he writes, because that would take only about 1,200 or so new natural gas wells. And if that doesn’t work, I guess they can just go the Sam Altman-way and switch to nuclear fusion power.
    SHEFIK
    SHEFIK --- ---
    YMLADRIS: tohle se vyresi do par let trhem

    Napr nize.

    Performance and energy efficiency: a new AI chip for edge computing - Hello Future Orange
    https://hellofuture.orange.com/en/iot-new-energy-efficient-chips-could-expand-the-scope-of-artificial-intelligence-in-edge-computing/

    - An innovative chip architecture that can run on 44 times less energy than the graphics processors used for AI.

    Nebo skrze breakdown LLM modelu na spefializovane modely

    AI energy consumption: Can we produce efficient models?
    https://www.innovationnewsnetwork.com/ai-energy-consumption-can-we-produce-efficient-models/45920/

    - The study shows that by opting for other types of models or by adjusting models, AI energy consumption can be reduced by 70-80% during the training and deployment phase, with only a 1% or less decrease in performance.

    Spis me zajma jak dopadne btc. Nekde uz tezbu regulujou, nekde se nevyplaci, ale trzni greed porad umoznuje preziti, za vzrustajici energy...
    CHOSIE
    CHOSIE --- ---
    TADEAS: To mi připomělo Deep Adaptation od Jema Bendella, hádám že to z jeho práce vychází.
    --
    The models are wrong, climate change is accelerating faster than predicted
    “It’s not like we’re breaking records by a little bit now and then. It’s like the whole climate just fast-forwarded by fifty or a hundred years,” says Brian McNoldy, senior research associate at the University of Miami Rosenstiel School, told the New Yorker…

    “The effects of global warming are progressively more severe, and possibilities such as a worldwide societal breakdown are feasible and dangerously underexplored…”
    TADEAS
    TADEAS --- ---
    Extreme Sahel heatwave that hit highly vulnerable population at the end of Ramadan would not have occurred without climate change – World Weather Attribution
    https://www.worldweatherattribution.org/extreme-sahel-heatwave-that-hit-highly-vulnerable-population-at-the-end-of-ramadan-would-not-have-occurred-without-climate-change/

    Extreme temperatures were reported across the Sahel, including in Senegal, Guinea, Mali, Burkina Faso, Niger, Nigeria and Chad. In many of these countries power cuts occurred during the heat episode, making it especially difficult for the population to cope with the extreme temperatures.

    Heatwaves are arguably the deadliest type of extreme weather event and while the death toll is often underreported and not known until months after the event, a surge in hospital admissions and deaths were reported from the Gabriel Touré hospital in Bamako, Mali between 1-4 April (Bahati, 2024).

    The hospital recorded 102 deaths over the four-day period, which is significantly more than expected – in April 2023, the hospital recorded 130 deaths over the entire month (JolibaFM, 2024). While statistics for the cause of death have not been reported, around half were over the age of 60, and the hospital reports that heat likely played a role in many of the deaths. Furthermore, up to 44 bodies were buried in one cemetery in Bamako on Friday 5 April after the weekly service (DW 2024).

    ...

    To estimate the influence that human-caused climate change has had on the extreme heat since the climate was 1.2°C cooler, we combine climate models with observations. Observations and models both show that heatwaves with the magnitude observed in March and April 2024 in the region would have been impossible to occur without the global warming of 1.2°C to date.
    SHEFIK
    SHEFIK --- ---
    Tak schvalne

    Google builds an AI model that can predict future weather catastrophes | Live Science
    https://www.livescience.com/technology/artificial-intelligence/google-builds-ai-model-seeds-that-can-predict-future-weather-catastrophes

    SEEDS produces prediction models from physical measurements collected by weather agencies. In particular, it looks at the relationships between the potential energy unit per mass of Earth's gravity field in the mid-troposphere and sea level pressure — two common measures used in forecasting.
    SHEFIK
    SHEFIK --- ---
    NREL Unveils Groundbreaking Generative Machine Learning Model To Simulate Future Energy-Climate Impacts - CleanTechnica
    https://cleantechnica.com/2024/04/10/nrel-unveils-groundbreaking-generative-machine-learning-model-to-simulate-future-energy-climate-impacts/

    Sup3rCC is an open-source model that uses generative machine learning to produce state-of-the-art downscaled future climate data sets that are available to the public at no cost. Downscaled climate data is necessary to understand the impacts of climate change on local wind and solar resources and energy demand. There are a multitude of existing downscaling methods, but they all have trade-offs in resolution, computational costs, and physical constraints in space and time. Sup3rCC represents a new field of generative machine learning methods that can produce physically realistic high-resolution data 40 times faster than traditional dynamical downscaling methods.

    Sup3rCC will change the way we study and plan future energy systems,” said Dan Bilello, director of the Strategic Energy Analysis Center at NREL. “The tool produces foundational climate data that can be plugged into energy system models and provide much-needed insights for decision makers who are responsible for keeping the lights on.”
    ...
    Sup3rCC learns physical characteristics of nature and the atmosphere by studying NREL’s historical high-resolution data sets, including the National Solar Radiation Database and the Wind Integration National Dataset Toolkit. The model then injects physically realistic small-scale information that it has learned from the data sets into the coarse future outputs from global climate models. As a result, Sup3rCC generates highly detailed temperature, humidity, wind speed, and solar irradiance data based on the latest state-of-the-art future climate projections. Sup3rCC outputs can then be used to study future renewable energy power generation, changes in energy demand, and impacts to power system operations. The initial Sup3rCC data set includes data from 2015 to 2059 for the contiguous United States, and additional data sets will be released in the coming years.
    TUHO
    TUHO --- ---
    TUHO: In this video I summarize the main pieces of evidence that we have which show that climate change is caused by humans. This is most important that we know in which frequency range carbon dioxide absorbs light, we know that the carbon dioxide ratio in the atmosphere has been increasing, we know that the Ph-value of the oceans has been decreasing, the ratio of carbon isotopes in the atmosphere has been changing, and the stratosphere has been cooling, which was one of the key predictions of climate models from the 1960s.
    TADEAS
    TADEAS --- ---
    Tenth consecutive monthly heat record alarms and confounds climate scientists | Climate crisis | The Guardian
    https://www.theguardian.com/global/2024/apr/09/tenth-consecutive-monthly-heat-record-alarms-confounds-climate-scientists

    Global surface temperatures in March were 0.1C higher than the previous record for the month, set in 2016, and 1.68C higher than the pre-industrial average, according to data released on Tuesday by the Copernicus Climate Change Service.

    This is the 10th consecutive monthly record in a warming phase that has shattered all previous records. Over the past 12 months, average global temperatures have been 1.58C above pre-industrial levels.

    This, at least temporarily, exceeds the 1.5C benchmark set as a target in the Paris climate agreement but that landmark deal will not be considered breached unless this trend continues on a decadal scale.

    The UK Met Office previously predicted the 1.5C goal could be surpassed over the period of a year and other leading climate monitoring organisations said the current levels of heating remain within the bounds anticipated by computer models.
    TADEAS
    TADEAS --- ---
    Global Warming Acceleration: Hope vs Hopium
    https://mailchi.mp/caa/global-warming-acceleration-hope-vs-hopium

    Accumulating evidence supports the interpretation in our Pipeline paper: decreasing human-made aerosols increased Earth’s energy imbalance and accelerated global warming in the past decade. Climate sensitivity and aerosol forcing, physically independent quantities, were tied together by United Nations IPCC climate assessments that rely excessively on global climate models (GCMs) and fail to measure climate forcing by aerosols. IPCC’s best estimates for climate sensitivity and aerosol forcing both understate reality. Preservation of global shorelines and global climate patterns – the world humanity is adapted to – likely will require at least partly reversing global warming. Required actions and time scale are undefined. A bright future for today’s young people is still possible, but its attainment is hampered by precatory (wishful thinking) policies that do not realistically account for global energy needs and aspirations of nations with emerging economies. An alternative is needed to the GCM-dominated perspective on climate science. We will bear a heavy burden if we stand silent or meek as the world continues on its present course.
    MATT
    MATT --- ---
    TADEAS: a vliv honga tonga myslej zanedbatelna ohledne vodni pary nebo prachovech a sirnejch castic?

    Trochu strasidelny mi prijde o kus niz

    “Good News:” Climate models show a fast response to forcing changes, so steps to lower the Earth energy Imbalance (EEI) [such as Sunlight Reflection Methods (SRM)] should result in a quick lowering of temperature.
    18/20

    zvlast, kdyz predtim pisou, ze ten vliv moc studovanej neni (tweet 10/20)..
    TUHO
    TUHO --- ---
    The question resurfaced in the 1970s, when scientists reached consensus that fossil-fuel emissions were putting Earth at risk of dangerous warming. At that time, historians answered that any climatic influence would be undetectable. They gathered at conferences, published three collections of papers in 1980 alone, and studiously avoided any tinge of determinism. Their most senior member, French historian Emmanuel Le Roy Ladurie, was famous for his studies of everyday life among early modern peasants. In the 1960s, Ladurie showed scientists how to use historical documents such as harvest records to track climatic variations. Yet Ladurie saw no point in trying to follow the causal chain any further; it seemed to him improbable if not impossible that historians would ever detect long-term societal consequences of climatic variations. Most other historians followed Ladurie’s lead, assuming that the modernization of agriculture and the globalization of trade had insulated humans from the vagaries of climate.

    Then, about 20 years ago, several historians noticed that the spatial resolution of climate models had increased approximately fourfold, which meant that it was now possible to detect correlations between specific historical events and dips and rises in regional temperatures and precipitation. Carefully comparing historical documents to model output, a couple of them ventured to make bold claims, with the boldest one coming in a weighty book by military historian Geoffrey Parker. He argued that unusually cold weather and poor harvests exacerbated—but did “not cause,” he was careful to add—the spate of wars and revolutions in Europe and other parts of the world in the 17th century. States were able to cope, he argued, according to their ability to manage their populations and centralize governance. Parker’s message was clear: climate change could lead to the total breakdown of social order.

    What’s Next for Histories of Climate Change | Los Angeles Review of Books
    https://lareviewofbooks.org/article/whats-next-for-histories-of-climate-change/
    TUHO
    TUHO --- ---
    A Genealogy of Doomers: World Models in the 1970s by Chiara Di Leone
    Hosted by Suhail Malik

    This talk explores the emergence of climate modelling in the early 1970s, bringing to light a neglected chapter—the Latin American World Model (LAWM). The narrative unfolds against the backdrop of the much more popular Club of Rome’s World3 model, revealing a nuanced tale of scientific divergence imbued with political and ethical dimensions.

    The talk aims to address enduring characteristics and pivotal historical moments where alternate mathematical and political models of the planet could have emerged. It also seeks to uncover why certain dystopian visions embedded in specific world models gained traction, while the scarcity of guiding beacons in global simulations persists. Furthermore, the talk delves into the role of forecasting world models and the mathematical gestures that reside within them as an alternative to traditional narrative forms.

    By dissecting the narratives that surrounded the Club of Rome's Limits to Growth report, and contrasting them with the LAWM, this talk sheds light on the sticky nature of doomsday scenarios in public discourse.

    16 Oct 23- PG Talk 1.2: A Genealogy of Doomers: World Models in the 1970s by Chiara Di Leone
    https://www.youtube.com/watch?v=AmP4aOwJGcw
    TADEAS
    TADEAS --- ---
    Scientists divided over whether record heat is acceleration of climate crisis | Climate science | The Guardian
    https://www.theguardian.com/science/2024/mar/16/scientists-divided-record-heat-acceleration-climate-crisis


    Heat above the oceans remains persistently, freakishly high, despite a weakening of El Niño, which has been one of the major drivers of record global temperatures over the past year.

    Scientists are divided about the extraordinary temperatures of marine air. Some stress that current trends are within climate model projections of how the world will warm as a result of human burning of fossil fuels and forests. Others are perplexed and worried by the speed of change because the seas are the Earth’s great heat moderator and absorb more than 90% of anthropogenic warming.

    Earlier this month, the World Meteorological Organization announced that El Niño, a naturally occurring climate pattern associated with the warming of the Pacific Ocean, had peaked and there was an 80% chance of it fading completely between April and June, although its knock-on effects would continue.

    The WMO secretary general, Celeste Saulo, said El Niño contributed to making 2023 easily the warmest year on record, although the main culprit was emissions from fossil fuels.

    When it came to oceans, she said, the picture was murkier and more disturbing: “The January 2024 sea surface temperature was by far the highest on record for January. This is worrying and can not be explained by El Niño alone.”

    Sea surface temperatures in February were also hotter than any month in history, breaking the record set last August, according to Europe’s Copernicus satellite monitoring programme.

    Worldwide, the heat above the land and sea was remarkable. Between 8 and 11 February, global temperatures were more than 2C above the 1850-1900 average. Over the month as a whole, Europe experienced heat that was 3.3C above that benchmark.

    ...

    Zeke Hausfather, a scientist at Berkeley Earth in the US, said global sea and surface temperatures were “quite high” but he said they were still well within the projections of climate models: “We don’t have any strong evidence yet from observations that suggests the world is warming faster than anticipated given human emissions.”
    TADEAS
    TADEAS --- ---
    climate minsky moment

    důchody v ohrožení .)


    Minsky moment: are pension assets at risk due to flawed climate analysis? | Netzeroinvestor
    https://www.netzeroinvestor.net/news-and-views/are-millions-of-pensions-at-risk-due-to-flawed-climate-analysis

    Widespread reliance on flawed research generates a disconnect between current investment decision making, which assumes relatively trivial impacts from climate change, and the likely real-world effects of global warming, Keen warned.

    "To ensure that the world moves into a new climate secure energy system, it’s crucial pension schemes send the market the right investment signals,” said Mark Campanale, the founder of Carbon Tracker.

    “The signal has to be that a swift, orderly transition is in everyone’s financial interests, particularly for scheme beneficiaries.”

    However, the relationship between economics, climate science and assessing financial risk is not a “comfortable one,” he continued, adding that “the advice pension schemes are receiving risks trivialising the potentially huge damage climate change will have to asset values."

    Campanale stressed that “these flawed climate risk models” are used throughout the financial system, lulling economic decision makers, from pension funds to central banks, into a false sense of security.

    “The result is cavalier positions such as US Federal Reserve Board Governor Christopher Waller who announced: ‘Climate change is real, but I do not believe it poses a serious risk to the safety and soundness of large banks or the financial stability of the United States’,” he said.

    The report issues a direct warning to asset owners for the serious prospect of an “unpleasant, abrupt and wealth destroying” so-called “Climate Minsky moment” with a sudden collapse in asset values as financial markets wake up to the gap between mainstream economist forecasts and the reality of climate impacts.

    Keen, who is also the former head of the School of Economics, History and Politics at Kingston University, London, contrasts scientists’ empirical research with predictions by climate economists that are “a ‘hunch’ based on rather spurious assumptions for global warming, which have been used to generate equally spurious estimates of damages to future GDP.”

    He underscored that global warming, at less than 1.5°C, is already affecting people and companies across the planet, pointing at record heatwaves, floods, and intensifying storms as they halt commerce, damage crops, create uninsurable areas, and impair infrastructure.

    Keen singled out scientific research which finds that exceeding the 1.5°C Paris target would be “dangerous”, passing 3°C would be “catastrophic”, and reaching 5°C will be “beyond catastrophic, raising existential threats”.

    Yet, despite scientific predictions, a survey of 738 climate economics papers in a number of top academic journals found the median prediction of economists was that 3°C of warming would reduce global GDP by just 5%, and warming of 5°C would see a 10% reduction.

    ...

    The researchers singled out investment managers and consultants such as Aon Hewitt, Hymans Robertson and Mercer as they "continue to rely on flawed research" when they advise pension funds on the impacts of global warming on members’ portfolios.

    For example, Mercer, in advice to Australian fund HESTA predicts only a -17% portfolio impact by 2100 in a 4°C scenario. It states that its model primarily reflects coastal flood damage and does not take account of climate tipping points.

    Mercer also advises LGPS Central, which manages £28.5 billion of retirement savings for a million members of Local Government Pension Schemes in the UK.

    One of these schemes, Shropshire County Pension Fund, told members that a trajectory leading to 4°C by 2100 would only reduce annual returns by 0.06% in 2030 and 0.1% by 2050, saying that it relied on LGPS Central for information.

    Moreover, in a 2022 report, Australian superannuation firm Unisuper concluded that even in a “worst case scenario” involving a 4.3°C increase in global temperatures by 2100, “the overall risk to our portfolio is acceptable.”

    “Each layer in the process of assessing the risks of climate change has assumed that the previous layer has done its job adequately, and has relied on the previous layers reputation, rather than scrutiny of the work undertaken," explained Professor Keen.

    “Pension funds rely upon consultants because of their reputation in the field; consultants rely upon academic economists, because their papers had passed academic refereeing,” he added.

    “The final impact is a series of flawed economic assumptions informing pensions’ decision making.”
    SHEFIK
    SHEFIK --- ---
    Povedomi ekonomu nabira uvedomely trend

    ‘Something is not working’: Economists urge EU Commission to overhaul its models – Euractiv
    https://www.euractiv.com/section/economy-jobs/news/something-is-not-working-economists-urge-eu-commission-to-overhaul-its-models/

    More than 200 economists called on the European Commission to overhaul the way it calculates its core economic forecasts and better integrate critical environmental factors into its baseline models in an open letter obtained exclusively by Euractiv on Thursday (15 February).
    ...
    At present, the Commission – and therefore the EU at large, the group of high-profile economists argued – still relies on models that are strictly informed by general-equilibrium principles that may fail to capture the impact of growing climate-related variables on countries’ economic performance, including increased headwinds of financial and economic instability.
    ...
    “I think there’s a growing realisation in the world of macroeconomics that something is not working,” he said.
    ...
    “We are in the middle of a climate crisis and need to act rather fast,” she said.

    Other independent experts contacted by Euractiv — none of whom were formerly aware of the letter — all supported the call for contemporary forecasting to include the lessons and principles of ecological economics.

    Doing this, they added, would improve models’ ability to accurately predict ‘standard’ economic metrics such as inflation and enhance their capacity to measure the environmental impact of government policies.

    “They don’t have the right input data [so they] will not get the right output data,” said Kristian Skånberg, an affiliated researcher at the Stockholm Environment Institute (SEI).

    “And as [environmental issues] are becoming increasingly important and there are repercussions from the climate and there are repercussions from shortages, [they] will affect inflation and … GDP,” he added.
    ...
    Heather Grabbe, a senior fellow at Bruegel think tank, noted that economic models “have long treated environmental impacts as externalities” and that the way they are constructed tends to create a bias against large-scale green investments.

    “Recent research on the macroeconomic impact of climate change and environmental degradation needs to be included in the models used by policymakers,” she said. “They need to include not only the costs of climate action but also the costs of inaction.”

    Stefan Sipka, head of the Sustainable Prosperity for Europe programme at the European Policy Centre (EPC) agreed that, when designing economic policies, leaders need to take into account the impact of climate change and other sustainability challenges.

    “I would say that our current approach to economics and related modelling is still based on old premises that don’t really take into consideration that we live in a world with limited resources,” he said.
    SHEFIK
    SHEFIK --- ---
    TADEAS: realclimate se k tomu taky rozepsali:

    RealClimate: New study suggests the Atlantic overturning circulation AMOC “is on tipping course”
    https://www.realclimate.org/index.php/archives/2024/02/new-study-suggests-the-atlantic-overturning-circulation-amoc-is-on-tipping-course/

    The new study by van Westen et al. is a major advance in AMOC stability science, coming from what I consider the world’s leading research hub for AMOC stability studies, in Utrecht/Holland.
    ...
    The paper results from a major computational effort, based on running a state-of-the-art climate model (the CESM model with horizontal resolution 1° for the ocean/sea ice and 2° for the atmosphere/land component) for 4,400 model years. This took 6 months to run on 1,024 cores at the Dutch national supercomputing facility, the largest system in the Netherlands in terms of high-performance computing.
    ...
    Now this tipping point has been demonstrated for the first time in a state-of-the-art global coupled climate model, crushing the hope that with more model detail and resolution some feedback might prevent an AMOC collapse.
    ...
    “their estimate of the tipping point (2025 to 2095, 95% confidence level) could be accurate.”
    ...
    Most models even have the wrong sign of this important diagnostic, which determines whether the feedback on Atlantic salinity is stabilising or destabilising, and this model bias is a key reason why in my view the IPCC has so far underestimated the risk of an AMOC collapse by relying on these biased climate models.
    ...
    They show how particularly northern Europe from Britain to Scandinavia would suffer devastating impacts, such as a cooling of winter temperatures by between 10 °C and 30 °C occurring within a century, leading to a completely different climate within a decade or two, in line with paleoclimatic evidence about abrupt ocean circulation changes.
    ...
    Given the impacts, the risk of an AMOC collapse is something to be avoided at all cost. As I’ve said before: the issue is not whether we’re sure this is going to happen. The issue is that we need to rule this out at 99.9 % probability. Once we have a definite warning signal it will be too late to do anything about it, given the inertia in the system.
    ...
    ...
    In the reactions to the paper, I see some misunderstand this as an unrealistic model scenario for the future. It is not. This type of experiment is not a future projection at all, but rather done to trace the equilibrium stability curve (that’s the quasi-equlibrium approach mentioned above). In order to trace the equlibrium response, the freshwater input must be ramped up extremely slowly, which is why this experiment uses so much computer time. After the model’s tipping point was found in this way, it was used to identify precursors that could warn us before reaching the tipping point, so-called “early warning signals”. Then, the scientists turned to reanalysis data (observations-based products, shown in Fig. 6 of the paper) to check for an early warning signal. The headline conclusion that the AMOC is „on tipping course“ is based on these data.

    In other words: it’s observational data from the South Atlantic which suggest the AMOC is on tipping course. Not the model simulation, which is just there to get a better understanding of which early warning signals work, and why.
    TADEAS
    TADEAS --- ---
    "kind of scary"

    Atlantic Ocean circulation nearing ‘devastating’ tipping point, study finds | Oceans | The Guardian
    https://www.theguardian.com/environment/2024/feb/09/atlantic-ocean-circulation-nearing-devastating-tipping-point-study-finds

    new paper, published in Science Advances, has broken new ground by looking for warning signs in the salinity levels at the southern extent of the Atlantic Ocean between Cape Town and Buenos Aires. Simulating changes over a period of 2,000 years on computer models of the global climate, it found a slow decline can lead to a sudden collapse over less than 100 years, with calamitous consequences.

    The paper said the results provided a “clear answer” about whether such an abrupt shift was possible: “This is bad news for the climate system and humanity as up till now one could think that Amoc tipping was only a theoretical concept and tipping would disappear as soon as the full climate system, with all its additional feedbacks, was considered.”

    It also mapped some of the consequences of Amoc collapse. Sea levels in the Atlantic would rise by a metre in some regions, inundating many coastal cities. The wet and dry seasons in the Amazon would flip, potentially pushing the already weakened rainforest past its own tipping point. Temperatures around the world would fluctuate far more erratically. The southern hemisphere would become warmer. Europe would cool dramatically and have less rainfall. While this might sound appealing compared with the current heating trend, the changes would hit 10 times faster than now, making adaptation almost impossible.

    ...

    “What surprised us was the rate at which tipping occurs,” said the paper’s lead author, René van Westen, of Utrecht University. “It will be devastating.”

    He said there was not yet enough data to say whether this would occur in the next year or in the coming century, but when it happens, the changes are irreversible on human timescales.

    In the meantime, the direction of travel is undoubtedly in an alarming direction.

    “We are moving towards it. That is kind of scary,” van Westen said
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