1. Climate Change -- the scientific debate

potholer54

AI-assisted summary of 1. Climate Change -- the scientific debate — original source. Check the original for full context.

Source published: 2008-09-22

Key ideas

The scientific debate on climate change relies on peer-reviewed research and the established physics of carbon gases rather than political punditry or ideological framing. (0:02)
A long-standing contradiction between warming surface temperatures and cooling satellite readings in the lower troposphere was resolved in 2005 as an artifact of satellite orbital decay. (3:57)
The observed 800-year lag of carbon dioxide behind temperature in Antarctic ice cores reflects a positive feedback loop, where initial orbital shifts were amplified by greenhouse gas release from oceans and soils. (5:58)
While an overwhelming majority of climate scientists accept anthropogenic global warming, legitimate peer-reviewed research exploring alternative non-carbon mechanisms continues to be evaluated. (10:06)

Detailed notes

## Background Published on YouTube by potholer54 on September 22, 2008, this video provides a foundational examination of how climate scientists determine that man-made carbon gases are altering Earth's climate. The channel description emphasizes that the presentation grounds itself strictly in scientific evidence rather than political punditry, while clarifying minor illustrative simplifications regarding photon absorption models and Earth's theoretical albedo without greenhouse gases.

## TL;DR The video strips away political talking points from commentators on both sides to evaluate the core scientific consensus and debates surrounding climate change. It explains the fundamental physics of the greenhouse effect, showing how carbon dioxide and methane absorb and re-radiate outgoing terrestrial infrared radiation. The narrative traces key historical milestones, resolving past contradictions such as the global dimming debate of the 1970s and the 1990s satellite tropospheric temperature discrepancy caused by orbital drift. Finally, it explains the 800-year ice core carbon dioxide lag as a natural positive feedback mechanism, warning that modern industrial emissions are now functioning as the initial warming trigger.

## Atmosphere & style The presentation carries a calm, measured, and dryly witty tone characteristic of classic investigative journalism and pragmatic scientific exposition. potholer54 speaks with an unflappable, deliberate cadence that cuts through ideological hysteria, methodically dissecting complex atmospheric data with accessible analogies. The resulting viewing experience feels grounded, sober, and clarifying, instilling confidence through an unhurried reliance on peer-reviewed evidence and empirical logic.

## Bulletin - [00:02](https://www.youtube.com/watch?v=52KLGqDSAjo&t=2s) The scientific debate on climate change relies on peer-reviewed research and the established physics of carbon gases rather than political punditry or ideological framing. - [03:57](https://www.youtube.com/watch?v=52KLGqDSAjo&t=237s) A long-standing contradiction between warming surface temperatures and cooling satellite readings in the lower troposphere was resolved in 2005 as an artifact of satellite orbital decay. - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) The observed 800-year lag of carbon dioxide behind temperature in Antarctic ice cores reflects a positive feedback loop, where initial orbital shifts were amplified by greenhouse gas release from oceans and soils. - [10:06](https://www.youtube.com/watch?v=52KLGqDSAjo&t=606s) While an overwhelming majority of climate scientists accept anthropogenic global warming, legitimate peer-reviewed research exploring alternative non-carbon mechanisms continues to be evaluated.

## Key takeaways - [00:02](https://www.youtube.com/watch?v=52KLGqDSAjo&t=2s) Evaluating climate change requires focusing on peer-reviewed science rather than political commentators, politicians like Al Gore, or environmental activists. - [00:02](https://www.youtube.com/watch?v=52KLGqDSAjo&t=2s) Labels like 'believers' and 'deniers' distort scientific discourse, which is grounded in evidence and natural skepticism rather than religious dogma. - [01:01](https://www.youtube.com/watch?v=52KLGqDSAjo&t=61s) The greenhouse effect operates because atmospheric trace gases allow shortwave solar radiation to pass through but absorb and re-emit outgoing longwave infrared radiation. - [01:01](https://www.youtube.com/watch?v=52KLGqDSAjo&t=61s) Both proponent and skeptical climate scientists agree on the basic physics that trace carbon gases prevent the planet from freezing like the Moon. - [02:24](https://www.youtube.com/watch?v=52KLGqDSAjo&t=144s) In the 1970s, climatologists evaluated whether aerosol-driven global dimming or greenhouse-driven global warming would dominate, a dilemma resolved by record warming in the 1980s. - [03:57](https://www.youtube.com/watch?v=52KLGqDSAjo&t=237s) During the 1990s, microwave satellite data suggested tropospheric cooling, contradicting surface station measurements and climate model predictions. - [03:57](https://www.youtube.com/watch?v=52KLGqDSAjo&t=237s) The tropospheric cooling discrepancy was resolved in 2005 after correcting for satellite orbital decay, which had caused afternoon temperature measurements to drift into the cooler late afternoon. - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) Vostok ice core records show that ancient atmospheric carbon dioxide increases lagged behind initial temperature increases by approximately 800 years. - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) The ice age carbon lag is explained by positive feedback, where orbital variations initially nudged temperatures upward, prompting oceans and soils to release carbon gases that amplified the warming. - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) Modern industrial emissions bypass the ancient lag mechanism by introducing carbon gases directly as the primary trigger for warming. - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) Melting Siberian permafrost illustrates an active positive feedback loop by releasing methane, which accelerates atmospheric warming and thaws further wetlands. - [10:06](https://www.youtube.com/watch?v=52KLGqDSAjo&t=606s) An overwhelming consensus of climate scientists accepts the primary role of anthropogenic greenhouse gases in contemporary global warming.

## Detailed walkthrough ### [00:02](https://www.youtube.com/watch?v=52KLGqDSAjo&t=2s) Moving Beyond Punditry to the Scientific Debate

The discussion opens by firmly setting aside political figures and media pundits when evaluating climate science. Rather than leaning on pronouncements from Al Gore, who is neither a scientist nor a geologist or climatologist, or listening to environmental activists who often “don't know a schist from Shinola,” the inquiry must focus on peer-reviewed science. The same disqualification applies to conservative media commentators like Rush Limbaugh and Paul Harvey. Furthermore, politically charged framing is rejected: the terms "believers" and "deniers" distort the conversation, because science is grounded in evidence rather than religious faith, and skepticism is a natural part of scientific inquiry. Instead, the landscape is divided between climate scientists who propose that recent changes are driven by human activity and those who remain skeptical. As potholer54 states: “This video is about science and the debate between climate scientists.”

[01:01](https://www.youtube.com/watch?v=52KLGqDSAjo&t=61s) The Physics of the Greenhouse Effect and the Carbon Gases

Earth's atmosphere is primarily composed of nitrogen and oxygen, alongside minor trace gases including water vapor, carbon dioxide ($\text{CO}_2$), and methane ($\text{CH}_4$). Incoming solar radiation reaches the Earth in short wavelengths, passing directly through these atmospheric gases to warm the surface. The ground absorbs this solar energy and re-emits it as long-wavelength infrared radiation—the identical form of heat felt radiating off a hot electric stove or sun-baked sidewalk pavement. While trace molecules let shortwave rays pass downward, their molecular structure absorbs outgoing longwave infrared rays. This absorption causes the molecules to vibrate and emit thermal energy back into the surrounding atmosphere.

```mermaid flowchart TD accTitle: Greenhouse Mechanism Flowchart accDescr: Diagram illustrating solar shortwave radiation heating Earth and being trapped as longwave infrared by carbon gases.

subgraph Solar_Insolation["Solar Radiation"] Sun["Sun's Energy"] -->|"Shortwave radiation passes through"| Surface["Earth's Ground"] end

The term "greenhouse effect" is technically a misnomer because the underlying physical process differs significantly from how physical glass greenhouses trap warm air. Because two of the primary heat-trapping trace gases—carbon dioxide and methane—are heavily emitted through human activities, it is more precise to refer to them as carbon gases. Basic physics confirms that without these heat-trapping gases, terrestrial longwave heat would escape directly into space, reducing Earth to a frozen planet as cold as the Moon; conversely, superabundant atmospheric carbon gases trap heat until the surface functions like a sauna. As potholer54 emphasizes: “Proponents and skeptics all agree on this because it's well-established basic physics.”

[02:24](https://www.youtube.com/watch?v=52KLGqDSAjo&t=144s) Historical Milestones: Global Dimming vs. Global Warming

The core physics behind radiant absorption by carbon dioxide has been documented for more than a century and a half. A century ago, Swedish scientist Svante Arrhenius proposed that a massive, drastic increase in atmospheric carbon dioxide would heat the planet, though his hypothesis was treated as an academic curiosity during an era dominated by horse-drawn transportation. Serious scientific concern developed by the 1950s, prompting the launch of the first systematic continuous atmospheric $\text{CO}_2$ monitoring programs.

By the 1970s, research sponsored by the United States Department of Energy indicated that accelerated industrial activity could trigger an enhanced greenhouse effect. At that juncture, climatology explored two contrasting hypotheses: - **Global Dimming:** Industrial pollution releases tiny particulate aerosols that scatter and reflect incoming solar shortwave radiation back into space, potentially overriding greenhouse warming and sending the planet into a cooling cycle or a new ice age. - **Global Warming:** Atmospheric accumulations of carbon gases would prove so significant that infrared heat retention would outstrip any reflective cooling from aerosol pollution.

By the 1980s, real-world surface thermometric records resolved the dilemma. The planet was not cooling down; it was steadily heating up, making the 1980s the hottest decade on record up to that point.

[03:57](https://www.youtube.com/watch?v=52KLGqDSAjo&t=237s) The Satellite Troposphere Anomaly and the Kyoto Turnaround

Investigative reporting on the climate issue in 1992 ran into an apparent scientific contradiction. While surface weather stations documented steadily rising global temperatures, microwave satellite sensors monitoring the lower troposphere recorded a cooling trend. Because atmospheric physics models predicted that greenhouse-driven warming must register in the lower troposphere, critics argued the computer simulations were fundamentally flawed. Meanwhile, physical observations across the globe continued to support warming: Greenland's ice sheet was melting rapidly, alpine glaciers were retreating, and Antarctic ice shelves were disintegrating.

When potholer54 traveled to cover the United Nations Framework Convention on Climate Change negotiations in 1997—producing the Kyoto Protocol—a marked shift had taken place among researchers. The accumulating weight of empirical observations had persuaded many former skeptics that climate change was indeed underway and driven by anthropogenic emissions.

The lower troposphere discrepancy was resolved in 2005 when researchers in California discovered a critical calibration error in the satellite record. The satellites had suffered from orbital decay: a satellite designed to collect tropical temperature readings at 2:00 PM had drifted over the decades, recording data at 5:00 PM by the late 1990s. Naturally, measuring temperatures late in the afternoon yielded cooler figures than early afternoon readings. Correcting for orbital drift brought the satellite data into full alignment with climate models and surface thermometers. As potholer54 explains: “At last the models of how the climate should be performing with increased carbon dioxide matched how it was performing.”

[05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) The 800-Year $\text{CO}_2$ Lag and Positive Feedback Loops

Following the resolution of the tropospheric temperature contradiction, skeptics focused on data extracted from the deep Antarctic ice core drilled at Vostok Station, which spans 420,000 years of paleoclimate history. The ice cores allow climatologists to evaluate ancient temperatures alongside air bubbles containing trapped greenhouse gases. While Al Gore featured these ice core charts in *An Inconvenient Truth* to show parallel movements between temperature and $\text{CO}_2$, he omitted a crucial detail: historical carbon dioxide increases lagged behind temperature increases by roughly 800 years. Skeptics pointed out that an effect cannot precede its cause.

The apparent lag is explained by the physics of positive feedback. During historical Ice Age transitions, shifts in temperature and greenhouse gas concentrations operated in an amplifying loop: - **The Balance Analogy:** Imagine a balanced plank holding weights; shifting a round weight just half an inch causes the plank to tilt, making the ball roll further, which tilts the board even more until it collapses. - **Orbital Triggers:** Milankovitch cycles (regular cyclical shifts in the Earth's orbit and axial tilt) subtly altered incoming solar radiation, nudging the global temperature. - **Secondary Gas Release:** This slight initial warming melted a fraction of the ice sheets and warmed ocean waters and soils, releasing dissolved carbon gases into the atmosphere. - **Feedback Loop:** The newly liberated gases trapped extra infrared radiation, driving further warming, which released yet more carbon gas.

```mermaid flowchart LR accTitle: Positive Feedback Loop Diagram accDescr: Flowchart showing how an initial warming trigger initiates a self-reinforcing loop of gas release and increased heat.

Trigger["Orbital Trigger or Industrial CO2"] --> Warm["Initial Warming"] Warm --> Release["Gas Released from Oceans, Soils & Marshes"] Release --> Trap["More Longwave Radiation Trapped"] Trap --> Amplified["Amplified Planetary Heating"] Amplified --> Release ```

Climatologists never claimed carbon dioxide acted as the original historical trigger for terminating ice ages; rather, it served as an amplifier that transformed mild orbital warmings into massive planetary deglaciations. Today, the concern is that humanity's massive industrial emissions are acting as the initial trigger themselves. This dynamic is visible in the Siberian permafrost, where melting ice is thawing vast wetlands that emit massive plumes of methane. Because methane is an even more potent greenhouse gas than $\text{CO}_2$, its release accelerates atmospheric warming, thawing additional marshland and discharging more gas. Reflecting on how the paleoclimate record is weaponized in popular media, potholer54 summarizes: “The 800-year lag time may be a wonderful debating point in the ideological war, but it barely touches the real discussion going on among climate scientists.”

[10:06](https://www.youtube.com/watch?v=52KLGqDSAjo&t=606s) The Scientific Consensus and Dissenting Hypotheses

Addressing the broader state of opinion within the scientific community, the narrator cautions against denying that a prevailing agreement exists. While debate and disagreement naturally accompany nearly every scientific issue, pretending there is no established consensus on anthropogenic climate change misrepresents reality. As the narrator asserts: “There are many ways to measure the views of climate scientists and as we'll see in a later video it's clear that the overwhelming majority accept the role of man-made gases in global warming.”

Even though the balance of evidence and expert opinion is heavily tilted toward the consensus, qualified skeptics still hold differing perspectives. Rather than ignoring these alternative viewpoints, the narrator sets up the subsequent installment in the series to examine the peer-reviewed literature behind them. Specifically, the next video will explore published scientific papers proposing two distinct hypotheses for climate change that do not rely on carbon gases whatsoever.

## Notable quotes > [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) The 800-year lag time may be a wonderful debating point in the ideological war, but it barely touches the real discussion going on among climate scientists. — potholer54

## Mentioned Al Gore, An Inconvenient Truth, Kyoto Protocol, Milankovitch cycles, Paul Harvey, Rush Limbaugh, Svante Arrhenius, United Nations Framework Convention on Climate Change, United States Department of Energy, Vostok Station, potholer54

## Video description A basic look at how climate scientists infer that man-made carbon gases are changing the climate

CORRECTIONS: 1) The animation of a photon striking a carbon atom is not meant to be visually correct, it is simply an illustration of CO2 absorbing energy and re-emitting it at a different wavelength. Given the limitations I have in making animations I could not spend an inordinate amount of time making a visually "correct" image of a photon striking an electron which moves into a different orbital plane, and even if I tried it would never be visually correct because on a quantum scale such an illustration is impossible. But thanks to all those who wrote in.

2) The Earth would in fact be colder than the moon without greenhouse gases, because it would be covered in ice and therefore have a higher albedo (reflect sunlight.)

Neither of these corrections changes the points made or the issues raised in the video.

[Source](https://www.youtube.com/watch?v=52KLGqDSAjo)

中文简报

1. 气候变化——科学辩论该视频摒弃了双方评论员的政治说辞，以评估围绕气候变化的核心科学共识与争议。视频解释了温室效应的基本物理原理，展示了二氧化碳和甲烷如何吸收并重新辐射地球向外发射的红外辐射。叙述回顾了关键的历史里程碑，消解了过去的矛盾，例如20世纪70年代的全球变暗争论以及90年代因轨道漂移导致的卫星对流层温度差异。最后，视频将冰芯中二氧化碳滞后气温800年的现象解释为一种天然的正反馈机制，并警告称现代工业排放如今正扮演着最初变暖触发因素的角色。关于气候变化的科学辩论依赖于同行评审的研究以及碳气体的既定物理学原理，而非政治评论或意识形态定性。 (0:02) 地表升温与低对流层卫星读数降温之间长期存在的矛盾，在2005年被证实是由卫星轨道衰减造成的人为误差，从而得以化解。 (3:57) 在南极冰芯中观察到的二氧化碳滞后气温800年的现象反映了一种正反馈循环，即最初的轨道变化因海洋和土壤释放的温室气体而被放大。 (5:58) 尽管绝大多数气候科学家都认同人为全球变暖，但探索替代性非碳机制的合法同行评审研究仍在继续接受评估。 (10:06)

Reading summary

Potholer54 argues that the debate over anthropogenic global warming must be evaluated through peer-reviewed science rather than political rhetoric, demonstrating that basic physics, historical data reconciliations, and feedback mechanisms substantiate how carbon gases drive climatic shifts. Basic Physics of Carbon Gases and Radiant Heat (1:01) The foundation of climate science rests on well-established physics regarding how the atmosphere interacts with radiation, a concept accepted by both proponents and scientific skeptics. Incoming solar energy passes through trace atmospheric gases in short wavelengths to heat the ground, which then radiates this energy back out as long-wavelength infrared radiation. Molecular structures of trace carbon gases—specifically carbon dioxide and methane, along with water vapor—absorb this outgoing longwave energy, vibrating and radiating thermal energy back into the atmosphere. Without these heat-trapping gases, terrestrial longwave heat would escape entirely into space, leaving the planet frozen like the Moon, whereas excessive accumulation creates extreme heat retention. Because human activities heavily emit carbon dioxide and methane, potholer54 notes it is more precise to refer to them as carbon gases rather than relying on the imprecise analogy of a glass greenhouse. Resolving Historical Contradictions and Satellite Calibration (2:24) Although Svante Arrhenius proposed over a century ago that major carbon dioxide increases would warm the planet, mid-20th-century science debated two outcomes: particulate aerosol pollution reflecting sunlight (global dimming) versus heat retention from carbon gases (global warming). Thermometric records resolved this in the 1980s by confirming steady heating, making it the hottest recorded decade up to that point. However, an apparent contradiction emerged in 1992 when satellite microwave sensors recorded a cooling lower troposphere despite surface warming and melting ice sheets. This discrepancy initially suggested climate models were flawed, but California researchers resolved the anomaly in 2005. They discovered that satellite orbital decay caused observation times to drift from 2:00 PM to 5:00 PM across several decades, recording naturally cooler late-afternoon temperatures. Adjusting for this timing error brought the lower tropospheric satellite data into alignment with surface weather stations and climate model projections. The 800-Year Lag and Amplifying Feedback Loops (5:58) Skeptics frequently highlight that Vostok Antarctic ice cores, spanning 420,000 years, show historical carbon dioxide rises lagging temperature increases by approximately 800 years. Climatologists explain that this lag reflects positive feedback dynamics rather than disproving the greenhouse effect. Orbital shifts known as Milankovitch cycles served as initial triggers by subtly altering incoming solar radiation, which warmed oceans and soils, liberating dissolved carbon gases. These released gases then trapped additional longwave radiation, functioning as an amplifier that drove broad deglaciation rather than initiating it. A modern equivalent of this feedback loop is underway in the Siberian permafrost. Human industrial emissions act as the primary trigger, warming the atmosphere and thawing wetlands, which release massive plumes of methane. Because methane is an even more potent greenhouse gas than carbon dioxide, its atmospheric liberation traps more heat, leading to further melting and continued gas release. While potholer54 emphasizes that an overwhelming consensus of climate scientists accepts the role of man-made gases, qualified skeptics still propose dissenting viewpoints. The analysis establishes that subsequent inquiries must directly examine peer-reviewed hypotheses that attempt to explain climate shifts without relying on carbon gases.

精炼阅读摘要

potholer54指出，关于气候变化的讨论应剔除政治评论员与环保倡导者的非科学言论，聚焦于同行评审的科学证据。其核心论点表明，碳气体截留红外长波辐射的基础物理机制早已确立，且历史上的观测分歧（如卫星对流层数据偏差与冰芯二氧化碳800年滞后）已由后续校准和正反馈机制获得合理解释，主流气候科学家已对人为温室气体的主导作用形成明确共识。基础物理机制与温室气体效应 (1:01) 评估气候科学必须剥离政治人物（如Al Gore）及媒体评论员（如Rush Limbaugh、Paul Harvey）的言论，并摒弃带有宗教意味的“信徒”或“否认者”标签。科学界普遍认同的基础物理学表明，地球大气主要由氮气和氧气构成，水蒸气、二氧化碳（CO2）与甲烷（CH4）等微量气体构成了吸收热量的碳气体。太阳短波辐射可直接穿透大气加热地表，而地表受热后释放出的长波红外辐射（类似于炉具或烈日暴晒下沥青散发的热量）会被碳气体分子吸收并引发振动，进而将热能重新辐射回大气层。 potholer54强调，温室气体是维持地球宜居温度的关键物理要素；若缺乏这些气体，地表长波热量将直接逸散至太空，导致地球如同月球般严寒冻结，而过量的碳气体则会产生如桑拿房般的高温效应。无论持有人为变暖观点还是怀疑论立场的专业科学家，均对这一由基础物理学确立的分子吸热原理无异议。历史分歧的化解与卫星对流层校准 (2:24) 早在19世纪末，瑞典科学家Svante Arrhenius就提出了工业二氧化碳增加将导致全球升温的假说，至20世纪50年代学界展开了连续的系统监测。20世纪70年代，美国能源部资助的研究曾围绕两种假说展开争论：“全球变暗”假说认为工业气溶胶颗粒会散射并反射太阳短波辐射，可能诱发地球降温甚至新冰期；而“全球变暖”假说则认为温室气体的红外热拦截效应将占据上风。20世纪80年代的实际地表气温测算平息了争论，数据证实地球持续升温并创下当时最热年代记录。然而，1992年的观测出现了一项矛盾：地表气温持续上升，但微波卫星监测到的对流层下层却显示出降温趋势，导致批评者质疑气候模拟存在缺陷。随着格陵兰冰盖融化、高山冰川消退及南极冰架崩塌等现实证据积累，1997年《京都议定书》谈判期间许多科学家转向变暖立场。2005年，加州研究人员发现卫星数据存在严重的轨道漂移校准误差：原本设定在下午2点采集热带气温的卫星随时间推移漂移至下午5点采集，傍晚数据偏低造成了降温假象。修正轨道衰减后，卫星监测结果与气候模型及地面测温数据完全吻合。冰芯800年滞后与正反馈循环机制 (5:58) 针对南极沃斯托克站（Vostok Station）跨越42万年的深层冰芯记录，怀疑论者指出历史上二氧化碳浓度的增加滞后于气温升高约800年，并据此主张变暖并非由二氧化碳引发。potholer54解释，气候学界从未断言二氧化碳是古代冰期终结的原始触发点，该滞后现象实际上体现了自然界正反馈放大机制的物理规律。在古代冰期转换期间，米兰科维奇循环（Milankovitch cycles）引发的地球轨道与地轴倾角周期性变化轻微改变了太阳辐射，充当了打破平衡的初始微弱触发力；最初的轻度升温融化了部分冰雪并加热了海洋和土壤，导致溶解的碳气体释放进入大气；新释放的气体随后拦截更多的长波红外辐射，进而加剧变暖并促使更多气体析出。在当代，人类大规模工业排放自身正充当着这种初始触发因素；西伯利亚冻土融化导致湿地释放高致暖潜能的甲烷气体，进一步加速了大气升温的正反馈循环。气候科学界共识与非碳异见假说 (10:06) 针对气候科学界内部的意见分布，potholer54指出，否认主流共识的存在并不符合事实。多项评估气候科学家观点的指标表明，绝大多数专业学者均认可人造气体在全球变暖中起到了核心作用，公众争论中常用的800年滞后等论据并未触及气候科研领域的实质核心。尽管压倒性的证据与专家意见支持人为变暖理论，但严谨的科学探索允许基于证据的怀疑与争论存在。为全面审视同行评审文献中的不同见解，后续研究将探讨气候科学家提出的两种完全独立于碳气体机制之外的替代性变暖假说，以检验其他自然因素对气候系统演变的作用。 potholer54总结认为，人为气候变化的核心论断建立在坚实的基础物理学、经受住检验的观测校准以及古气候正反馈动力学之上，科学界的绝大多数学者已就人造气体的主导作用达成共识。与此同时，科学探索的本质要求保持对替代性解释的审视，后续需要通过同行评审证据进一步考察完全独立于碳气体的其他气候驱动假说。

Detailed notes — zh

## Background 该视频由科学科普创作者 potholer54 于 2008 年 9 月 22 日发布在 YouTube 平台上。视频简介指出，本片旨在以基础视角介绍气候科学家如何推断人为排放的碳气体正在改变全球气候，并在勘误中对碳分子光子动画示意与无温室气体下地球反照率进行了科学修正与说明。 ## TL;DR 视频摒弃了非专业人士与政客的意识形态口水战，专注于气候科学家之间的学术交锋与坚实物理证据。主讲人系统梳理了二氧化碳与甲烷吸收长波辐射的基础温室效应物理学，回顾了从阿伦尼乌斯假说到 1980 年代实测升温终结“全球变暗”争论的历史脉络。随后，视频重点破解了困扰学界的对流层卫星降温假象（实为卫星轨道衰减导致的过境时间漂移），并阐明了南极冰芯中二氧化碳滞后气温 800 年的机制其实是自然正反馈放大效应，而现代人为排放已成为打破平衡的新导火索。最后，主讲人指出绝大多数专业学者已达成共识，并预告后续将深入探讨由专业怀疑派提出的两套非碳替代假说。 ## Atmosphere & style 全片洋溢着冷峻、严谨且极具克制力的科学理性色彩，主讲人语调平静从容、条理分明，毫无政治辩论中的歇斯底里与标签化指责。叙事风格如同一场环环相扣的科学探案，抽丝剥茧般地拆解数据异常与历史谜题，带领观众从最初看似矛盾的反常证据走向底层逻辑的自洽闭环。整部作品给人一种清醒脱俗的踏实感，既有对实证科学严密性的敬畏，也有跳出党派偏见、回归客观事实的沉着底气。 ## Bulletin - [00:02](https://www.youtube.com/watch?v=52KLGqDSAjo&t=2s) 科学界的气候讨论聚焦于硬核物理与同行评议，而非政客与媒体评论员的意识形态标签，基础物理学早已确立碳气体截留地表长波辐射的增温机制。 - [03:57](https://www.youtube.com/watch?v=52KLGqDSAjo&t=237s) 1990年代卫星测得对流层下层变冷的谜团在2005年被破解，证实该异常纯粹是由卫星轨道退化导致测温时间从下午2点漂移至下午5点所致。 - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) 冰芯数据中二氧化碳滞后气温上升约800年的现象是正反馈放大机制的体现；在当代，人类排放的碳气体已取代轨道摄动成为触发增温循环的新起点。 - [10:06](https://www.youtube.com/watch?v=52KLGqDSAjo&t=606s) 虽然压倒性多数的气候科学家认可人为碳排放对全球变暖的主导作用，但后续仍将客观测验合格怀疑论学者提出的两种非碳气体替代假说。 ## Key takeaways - [00:02](https://www.youtube.com/watch?v=52KLGqDSAjo&t=2s) 探讨气候变化应脱离阿尔·戈尔或拉什·林博等非专业人士的政治口水战，聚焦气候科学家阵营内部的学术论证。 - [00:02](https://www.youtube.com/watch?v=52KLGqDSAjo&t=2s) 拒绝使用带有宗教色彩的“信徒”或“否认者”标签，科学界本质上是人为变暖支持派与审慎怀疑派之间的证据交锋。 - [01:01](https://www.youtube.com/watch?v=52KLGqDSAjo&t=61s) 基础物理学早在150多年前就证实，水蒸气、二氧化碳与甲烷等碳气体允许太阳短波辐射穿透，但会吸收并重新辐射地表长波红外线。 - [01:01](https://www.youtube.com/watch?v=52KLGqDSAjo&t=61s) 阿伦尼乌斯在100多年前便预言二氧化碳增加会导致升温；1980年代的创纪录高温彻底终结了“气溶胶导致全球变暗变冷”的科学假说。 - [03:57](https://www.youtube.com/watch?v=52KLGqDSAjo&t=237s) 1990年代初对流层下层卫星测温数据与气候模型矛盾，一度成为怀疑论者的核心论据，但地表冰川消融等宏观证据依然确凿。 - [03:57](https://www.youtube.com/watch?v=52KLGqDSAjo&t=237s) 2005年加州科学家的重新校准揭示卫星轨道衰减造成测温时间推迟数小时，修正该系统误差后，观测数据与计算机模型预测完全吻合。 - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) 南极沃斯托克冰芯记录的二氧化碳上升滞后于气温约800年，这并非推翻因果律，而是揭示了冰期向暖期转换的正反馈循环过程。 - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) 远古冰期的微弱轨道摄动先诱发海洋与土壤释放碳气体，碳气体在大约800年间累积后扮演放大器，将微小变暖演变成融化半个星球的暖期。 - [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) 工业时代人类向大气中排放的海量二氧化碳，直接充当了启动升温正反馈机制的全新触发点，西伯利亚冻土融化释放甲烷即为正在发生的连锁反应。 - [10:06](https://www.youtube.com/watch?v=52KLGqDSAjo&t=606s) 声称科学界在气候变化上“毫无共识”不符合事实，绝大多数气候科学家均已确认人类温室气体排放对变暖的驱动机制。 - [10:06](https://www.youtube.com/watch?v=52KLGqDSAjo&t=606s) 即便主流共识压倒性稳固，严肃科学仍需审视合格怀疑论者提出的脱离碳气体机制的替代假说。 ## Detailed walkthrough ### [00:02](https://www.youtube.com/watch?v=52KLGqDSAjo&t=2s) 抛开政治口水战：聚焦科学界的气候争论视频开门见山地划清界限：这里绝不会去引用阿尔·戈尔（Al Gore）关于气候变化的最新高见。戈尔既不是科学家，更谈不上是地质学家或气候学家；很多环保活动家尽管出发点良好，却连基本的常识都搞不清楚（“don't know a schist from Shinola”）。同样地，像拉什·林博（Rush Limbaugh）或保罗·哈维（Paul Harvey）这类媒体气候预言家也完全不在讨论范畴之内。本视频只聚焦于硬核科学本身，以及气候科学家之间的真实学术交锋。讲述者明确拒绝陷入党派政治的标签化话术中。他既不愿将支持者称为“气候变化信徒（believers）”——仿佛这全凭信仰支撑，而非建立在坚实的证据基础之上；也不愿把反对者斥为“气候变化否认者（deniers）”——好像真有一条绝对不容置疑的真理被他们故意视而不见。在真正的科学界，阵营的划分十分纯粹：一方是认为气候变化由人为因素主导的气候科学家（支持者），另一方则是持有怀疑态度的气候科学家（怀疑派）。探讨必须从厘清我们如何走到当前这场科学辩论的起点开始。 > “This video is about science and the debate between climate scientists.” —— potholer54 --- ### [01:01](https://www.youtube.com/watch?v=52KLGqDSAjo&t=61s) 基础物理与历史渊源：从阿伦尼乌斯到“变暖与变暗”之争地球大气主要由氮气和大量氧气组成，此外还包含微量的水蒸气、二氧化碳（$\text{CO}_2$）和甲烷（$\text{CH}_4$）。来自太阳的大部分辐射属于短波辐射，能够径直穿透这些气体并加热地表；随后地表将能量以长波辐射的形式重新发射出去，也就是如同发热电炉或烈日曝晒后的水泥地面所散发的那种红外线热量。水蒸气、二氧化碳和甲烷分子允许短波长驱直入，却会强烈吸收长波辐射，导致分子剧烈振动，而微观振动即是宏观的热量，这些热量再被辐射回大气中。虽然这种机制常被称为“温室效应”，但由于其物理过程与真正的温室截然不同，讲述者更倾向于将人为增加的二氧化碳与甲烷统称为“碳气体（carbon gases）”。如果没有这三种气体拦截长波辐射，地表热量将直接散逸至外太空，地球将变成一个像月球一样寒冷死寂的冰球（实际上因全球覆盖冰雪具有极高反射率，地表会比月球更冷）；反之，如果这些气体在大气中过度富集，长波辐射就会被大量截留，地球就会像桑拿房一样不断升温。这套基础物理学早已有定论，二氧化碳吸收长波辐射的现象在150多年前就已被发现： * **100多年前**：瑞典科学家万特·阿伦尼乌斯（Svante Arrhenius）在理论上提出，若大气中二氧化碳急剧增加，全球将会升温；但在马车代步的时代，这仅仅是个科学假想。 * **1950年代**：工业排放引发足够关切，人类开启了全球首次二氧化碳浓度连续监测。 * **1970年代**：美国能源部（US Department of Energy）的研究表明，日益扩大的工业化进程很快可能引发温室效应。 * **两种假说的交锋**：当时学界存在两种可能：其一是工业污染排放的气溶胶（aerosols）微滴会将阳光反射回太空，抵消温室效应甚至引发地球降温乃至新冰期（即“全球变暗”，global dimming）；其二是二氧化碳的急剧累积将压倒气溶胶的冷却效应（即“全球变暖”）。 * **1980年代胜负揭晓**：地面实测气温彻底终结了这场争论，1980年代成为有记录以来最炎热的十年，证实地球并未变冷而是在持续变热。 > “Proponents and skeptics all agree on this because it's well-established basic physics.” —— potholer54 --- ### [03:57](https://www.youtube.com/watch?v=52KLGqDSAjo&t=237s) 卫星数据乌龙与对流层冷却谜题的破除 1992年讲述者开始报道气候变化议题时，一项新数据带来了巨大困扰：地表温度虽然在上升，但卫星对对流层下层（lower troposphere）的测量结果却显示出明显的冷却趋势。当时所有气候计算机模型均预测对流层下层应当同步变暖；既然卫星测得变冷，模型似乎必然存在严重缺陷。然而现实中全球变暖的宏观证据却极其直观且无可辩驳——格陵兰岛冰川急剧消融、陆地冰川大步后退、南极冰架不断坍塌崩解。随着证据日益确凿，国际社会寻求一致行动。1997年讲述者前往日本报道《联合国气候变化框架公约》会议（即催生《京都议定书》的峰会）。相比90年代初，科学界与舆论的态度发生了巨大转变，绝大多数怀疑派被压倒性的事实证据说服，主流科学界已达成共识：气候变化客观存在，且人类排放的碳气体起到了关键推动作用。转折发生在2005年：加利福尼亚州的科学家对1992年的对流层下层测温数据进行了重新校准，终于揪出了导致反常的根本原因。原来，执行测温任务的卫星运行轨道随时间发生了衰减退化：卫星投入使用初期是在每天下午2:00掠过赤道上空测温，但到了90年代末，其过境测温时间已漂移推迟到了下午5:00。下午5点比下午2点温度更低是自然规律，卫星由此记录下的逐年降温纯粹是轨道漂移造成的假象。修正这一系统误差后，全球变暖拼图上最后一块看似矛盾的数据被彻底剔除，计算机模拟预测与现实气候演变完全吻合。 > “The discovery knocked out the final piece of evidence that contradicted global warming. The computer models had been right all along.” —— potholer54 --- ### [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) 800年滞后之谜：正反馈放大机制与工业触发点对流层异常刚解决，反对阵营又抛出了一项新论据：南极沃斯托克站（Vostok station）通过长达42万年的深层冰芯钻探，恢复了远古时期的气温与大气二氧化碳含量。在纪录片《难以忽视的真相》（*An Inconvenient Truth*）中，戈尔使用曲线展示两者高度吻合，却遮蔽了一个关键时间差——冰芯数据显示，二氧化碳浓度上升往往滞后于温度上升约800年。怀疑派借此质疑：如果是二氧化碳导致了变暖，因果律怎么可能颠倒？科学界对这一滞后现象不仅完全承认，而且其原委本身就是全球变暖模型的核心环节。在地球气候系统中，微小的变化会启动“正反馈（positive feedback）”机制，正如讲述者用平衡木模型打的比方： ```mermaid flowchart TD accTitle: 气候系统正反馈机制演变示意图 accDescr: 展示从初始轨道扰动到海洋土壤释放碳气体，再到现代人为碳排放直接充当触发机制的正反馈循环 subgraph Natural["远古自然冰期转换循环"] A["轨道摄动（米兰科维奇循环）"] -->|"日照轻微增加"| B["浅层冰雪微量融化"] B --> C["土壤与增温海洋释放碳气体"] C -->|"滞后约800年累积"| D["碳气体吸收长波辐射增温"] D -->|"恶性循环/正反馈放大"| C end subgraph Modern["现代人为温室机制"] E["工业活动直接排放二氧化碳"] -->|"充当全新触发点"| F["全球地表与大气升温"] F --> G["西伯利亚冻土大面积融化出沼泽"] G --> H["释放海量强效温室气体：甲烷"] H -->|"加剧正反馈变暖循环"| F end ``` 在冰期循环中，初始触发器通常是地球轨道或位置的周期性摄动（日照量改变），这融化了极少部分冰雪，继而导致变暖的海洋与土壤缓慢释放碳气体。这些在大约800年间累积释放的碳气体随后捕获更多长波辐射，推动温度进一步攀升并析出更多气体，将微弱的初始扰动放大为融化半个星球的温暖期。气候变化学者从未主张远古升温的“初始导火索”是二氧化碳，而是指出碳气体充当了放大变暖的恶性循环加速器。问题的关键在于：任何能引起微小升温的因素都能启动这套正反馈机制。虽然地球的轨道参数在未来16,000年内都将保持稳定、不会自然触发暖期，但人类在过去100年间向大气中倾泻的海量工业二氧化碳，本身已经成为了强力的新触发点。这一反馈在现实中已然启动：西伯利亚冰冻层消融正暴露出数百万平方英里的泥泞沼泽，释放出大量比二氧化碳潜能更强（虽然丰度较低）的甲烷气体，甲烷升温又制造出更多沼泽并释放更多甲烷。因此，拿800年滞后当作驳斥武器，只是政治意识形态论战中的空洞噱头，早已脱离了严肃气候科学家之间真正探讨的核心前沿。 > “The 800-year lag time may be a wonderful debating point in the ideological war, but it barely touches the real discussion going on among climate scientists.” —— potholer54 ### [10:06](https://www.youtube.com/watch?v=52KLGqDSAjo&t=606s) 气候共识的现实与怀疑论假说的预告针对科学界内部不同观点的讨论，主讲人 potholer54 指出，虽然每一个科学议题都可能存在分歧，但若据此声称科学界“毫无共识”，这种说法同样是完全错误的。评估气候科学家的主流观点有多种方式，后续视频也将进一步展示具体数据，事实清楚表明绝大多数科学家都认可人造温室气体在引发全球变暖中所起的作用。然而，即便这场学术争论的力量对比极其悬殊，学术界依然存在由具备专业资质的怀疑论者提出的反对意见。在视频结尾处，主讲人预告了下一期的核心内容：他将跳过非专业的舆论喧嚣，专门深入探讨几篇由合格怀疑论者撰写的学术论文。这些论文提出了两种截然不同的气候变化替代假说，而这两种机制都完全与碳排放气体无关。正如主讲人 potholer54 所总结的那样：“在接下来的视频中，我想探讨一些提出两种气候变化替代假说的科学论文，而这两种假说都与碳气体毫无关系。”（“In the next video I want to look at some scientific papers that suggest two alternative hypotheses on climate change neither of which has anything to do with carbon gases.”） - **科学界共识的实质**：声称缺乏共识是站不住脚的，压倒性多数的气候科学家均已承认人为温室气体对全球变暖的主导影响。 - **后续探讨方向**：即使主流观点占据绝对优势，依然需要审视合格怀疑论者提出的替代假说，下一期将聚焦两套脱离碳气体机制的科学研究方案。 ## Notable quotes > [05:58](https://www.youtube.com/watch?v=52KLGqDSAjo&t=358s) The 800-year lag time may be a wonderful debating point in the ideological war, but it barely touches the real discussion going on among climate scientists. — potholer54 ## Mentioned potholer54, 阿尔·戈尔 (Al Gore), 拉什·林博 (Rush Limbaugh), 保罗·哈维 (Paul Harvey), 万特·阿伦尼乌斯 (Svante Arrhenius), 美国能源部 (US Department of Energy), 联合国气候变化框架公约, 京都议定书 (Kyoto Protocol), 沃斯托克站 (Vostok station), 难以忽视的真相 (An Inconvenient Truth), 米兰科维奇循环 (Milankovitch cycles) ## Video description A basic look at how climate scientists infer that man-made carbon gases are changing the climate CORRECTIONS: 1) The animation of a photon striking a carbon atom is not meant to be visually correct, it is simply an illustration of CO2 absorbing energy and re-emitting it at a different wavelength. Given the limitations I have in making animations I could not spend an inordinate amount of time making a visually "correct" image of a photon striking an electron which moves into a different orbital plane, and even if I tried it would never be visually correct because on a quantum scale such an illustration is impossible. But thanks to all those who wrote in. 2) The Earth would in fact be colder than the moon without greenhouse gases, because it would be covered in ice and therefore have a higher albedo (reflect sunlight.) Neither of these corrections changes the points made or the issues raised in the video. [Source](https://www.youtube.com/watch?v=52KLGqDSAjo)

Source quotes

[5:58] potholer54: The 800-year lag time may be a wonderful debating point in the ideological war, but it barely touches the real discussion going on among climate scientists.

Source quotes

[5:58] potholer54: The 800-year lag time may be a wonderful debating point in the ideological war, but it barely touches the real discussion going on among climate scientists.

Original transcript

[0:02] no I'm not going to give you the latest [0:04] pronouncements from Al Gore on the [0:05] subject of climate change Al's not a [0:08] scientist let alone a geologist or a [0:11] climatologist and neither of these guys [0:13] however well-meaning they may be most [0:16] environmental activists don't know a [0:17] shist from Shinola and the same goes for [0:20] climate prognosticators like rash limbo [0:22] and Paul Harvey this video is about [0:25] science and the debate between climate [0:28] scientists I'm not going to descend into [0:31] Political jargon by talking about [0:33] climate change Believers as if the issue [0:35] depends on faith rather than a strong [0:37] body of evidence and I'm not going to [0:39] talk about climate change deniers as if [0:42] there's an absolute and unassailable [0:44] truth that they're deliberately refusing [0:46] to see no there are climate scientists [0:48] who are proponents of the idea that [0:50] climate change is being driven by [0:52] man-made causes and there are climate [0:54] scientists who are Skeptics so let's [0:57] start by looking at how we got to the [0:58] current state of debate [1:01] our atmosphere is composed mainly of [1:03] nitrogen gas a lot of oxygen and then [1:05] smaller amounts of other gases like [1:07] water vapor carbon dioxide and methane [1:10] most radiation from the Sun Passes right [1:12] through these gases because it has a [1:14] short wavelength the radiation heats up [1:17] the ground and is reemitted as long [1:19] wavelength radiation the kind of [1:21] infrared heat you feel from a hot [1:23] electric stove or a warm sidewalk but [1:26] although water vapor carbon dioxide and [1:28] methane molecules allow most of this [1:30] shortwave radiation to pass right [1:32] through them they absorb the longwave [1:34] radiation this causes them to vibrate [1:37] and of course vibration is heat they [1:40] radiate this heat through the [1:42] atmosphere this is the so-called [1:44] greenhouse effect but in fact the [1:46] physics is quite different to a [1:47] greenhouse so I dislike the term of the [1:50] three so-called greenhouse gases two of [1:52] them are being produced by human [1:54] activity so it would be more accurate to [1:56] describe these as carbon gases if none [1:59] of these these three gases was there the [2:01] longwave radiation from the ground would [2:03] simply radiate into space the Earth [2:05] would be a frigid Planet as cold as the [2:08] moon so of course the opposite is true [2:11] that if these gases were abundant in the [2:13] atmosphere most of the long wave [2:15] radiation would be trapped and the Earth [2:17] would heat up like a sauner proponents [2:19] and Skeptics all agree on this because [2:21] it's wellestablished basic physics [2:24] longwave radiation absorption by carbon [2:26] dioxide was first discovered over 150 [2:28] years ago a hundred years ago the [2:31] Swedish scientist Vante arenus suggested [2:34] that theoretically if carbon dioxide [2:36] levels were to increase drastically in [2:38] the atmosphere the world would heat up [2:41] in an age of horsedrawn carriages the [2:43] idea was interesting but not something [2:45] to worry about but by the 1950s there [2:48] was enough concern to begin the world's [2:50] first monitoring of carbon dioxide [2:52] levels and in the 1970s studies [2:55] conducted by the US Department of energy [2:57] showed that increasing industrialization [3:00] could very soon produce what's become [3:02] known as the greenhouse effect the [3:04] emphasis is on the word could because [3:06] there were two schools of thought one [3:09] possibility was that tiny droplets of [3:11] pollution in the atmosphere so-called [3:13] aerosols would reflect the sun's [3:15] radiation back into space and that would [3:17] tend to overcome any warming effect from [3:19] increased carbon dioxide it could even [3:22] cause the Earth to cool down sparking [3:24] another Ice Age this became known as [3:27] global dimming the other possibility was [3:30] that the buildup of carbon dioxide would [3:32] be so great that global warming would [3:34] overcome any cooling caused by [3:36] reflective Aerosoles by the 1980s the [3:39] contest between global warming and [3:41] global dimming was pretty much settled [3:43] by temperature readings on the ground [3:46] the Earth wasn't getting cooler it was [3:48] getting hotter and the 1980s turned out [3:50] to be the hottest decade on record by [3:53] the way we'll look at some of the flaws [3:54] in temperature reading in a later video [3:57] I began reporting on this issue in 1992 [4:00] when new data threw a curve ball [4:03] crucially although temperatures on the [4:05] Earth's surface were Rising satellite [4:07] measurements of temperatures in the [4:08] lower troposphere showed a distinct [4:10] cooling all the computer models showed [4:13] that the Earth should be warming in the [4:14] lower troposphere and since it was [4:17] cooling the models had to be wrong but [4:20] all the other evidence for a warming [4:21] Earth was clear and compelling ice was [4:24] rapidly melting in Greenland glaciers [4:26] were retreating and Antarctic Ice Sheets [4:29] were breaking Away by 1997 there was [4:32] more than enough evidence for the world [4:33] to take concerted action or at least try [4:36] to that year I was sent to Kyoto to [4:39] cover the framework convention on [4:40] climate change which resulted in what [4:42] became known as the Kyoto Protocol [4:45] compared to the early 1990s I was struck [4:48] by how a lot of attitudes had changed [4:50] most of the Skeptics had become [4:52] convinced by the increasing weight of [4:54] evidence and the majority opinion was [4:56] that climate change was real and that [4:58] man-made carbon gases played a crucial [5:01] role then in 2005 scientists in [5:04] California reanalyzed the 1992 data that [5:08] showed Cooling in the lower troposphere [5:10] and they found a crucial error the orbit [5:13] of the satellite taking the temperature [5:15] readings had degraded it had started [5:17] life taking temperatures over the [5:19] equator at 2:00 in the afternoon but by [5:21] the late 1990s it was taking the [5:23] readings at 5:00 hardly surprising then [5:27] that the satellite had been recording a [5:28] decrease in temperature over the years [5:31] the discovery knocked out the final [5:33] piece of evidence that contradicted [5:35] global warming the computer models had [5:37] been right all along at last the models [5:40] of how the climate should be performing [5:41] with increased carbon dioxide matched [5:44] how it was performing even most Skeptics [5:47] now accepted that the Earth was warming [5:49] but that didn't necessarily mean that [5:51] the warming was caused by man-made [5:53] carbon gases and just as the lower [5:56] troposphere anomaly was resolved another [5:58] argument Rose the 800-year carbon [6:01] dioxide lag time at the VTO station in [6:05] Antarctica an ice core was drilled [6:07] looking back 420,000 years in time you [6:10] can see an explanation of how this works [6:12] in my video The Ice Age climatologists [6:15] were able to measure both the [6:16] temperature and the carbon dioxide [6:18] content of the atmosphere in his film An [6:21] Inconvenient Truth Al Gore used a graph [6:24] like this to show a correlation between [6:26] carbon dioxide levels and increased [6:28] temperatures but he obscured the fact [6:30] that the carbon dioxide increases lag [6:33] the temperature increases by 800 years [6:36] if carbon dioxide is supposed to cause [6:38] global warming as Gore claims the lag [6:41] time would suggest it's the other way [6:43] round well yes and yes let's look at the [6:47] science not the hype in my video The Ice [6:50] Age I said there was a trigger that set [6:52] off a vicious circle of events each [6:54] tipping the earth into a cooling or a [6:56] warming phase in scientific terms the [6:58] vicious circle is is called positive [7:00] feedback and it's best explained by [7:02] looking at some weights on a balanced [7:04] plank if the weights are equidistant [7:06] from the Pivot Point the plank is in [7:08] balance a slight offset will tilt the [7:10] plank but it won't upset the balance but [7:13] let's say one of the weights is round [7:15] and is moved half an inch this causes [7:18] the plank to tilt slightly but the Tilt [7:20] causes the weight to roll a bit and the [7:23] shift in position causes the plank to [7:25] tilt a bit more until soon there's a [7:27] runaway event and the plank comes crack [7:29] ing to the ground we know that similar [7:32] positive feedback happened during the [7:33] ice ages each Cooling and warming phase [7:36] is Amplified so that a tiny bit of [7:38] cooling ends up freezing half the planet [7:41] and a tiny bit of warming ends up [7:43] thrwing it out again but each time [7:46] something had to act as that initial [7:48] trigger something had to nudge the round [7:50] weight just a fraction a strong [7:53] Contender has always been regular [7:54] cyclical deviation in the Earth's [7:56] position or orbit changing the amount of [7:58] sunlight the Earth received whatever it [8:01] was in the depths of the Ice Age this [8:03] change melted a tiny part of the ice [8:05] sheet and released carbon gases from the [8:07] soil and from the warmer oceans the [8:10] carbon gases that were released trapped [8:12] more longwave radiation and warmed the [8:14] planet a bit more and that released more [8:17] carbon gases and so on climate change [8:20] proponents have never suggested that a [8:22] carbon dioxide increase was the trigger [8:24] for past warming only that the trigger [8:26] released carbon gases which set off this [8:28] vicious circle of heating so the lag [8:31] time shown in the VTO ice core isn't [8:33] disputed and the reasons for it are part [8:35] of the global warming model but without [8:38] a trigger this positive feedback [8:40] wouldn't even begin so if the trigger [8:43] was a cyclical variation in the Earth's [8:45] position then we don't have anything to [8:47] worry about right because as we saw in [8:49] the video the Ice Age the Earth's orbit [8:51] will remain steady for another 16,000 [8:54] years the problem is anything that [8:56] causes a tiny increase in temperature [8:58] can trigger this vicious circle and the [9:01] premise of the climate change proponents [9:03] is that our industrial output of carbon [9:05] dioxide itself is now the trigger they [9:08] calculate that the dramatic rise we've [9:10] seen in carbon dioxide levels over the [9:12] last 100 years will increase [9:14] temperatures just enough to trigger a [9:16] positive feedback loop that will result [9:18] in more greenhouse gases causing more [9:21] warming causing the release of more [9:23] greenhouse gases and so on this is [9:26] already being seen for example in [9:28] Siberia melting ice is throwing out [9:30] millions of square miles of marsh [9:32] producing tons of methane gas methane is [9:35] a more potent greenhouse gas than carbon [9:38] dioxide but it's much less abundant in [9:40] the atmosphere even so the methane which [9:43] goes into the atmosphere adds to global [9:45] warming creating more marsh land which [9:48] releases more [9:49] methane the 800-year lag time may be a [9:52] wonderful debating point in the [9:53] ideological war but it barely touches [9:56] the real discussion going on among [9:58] climate scientists [9:59] so what is the debate going on in that [10:02] field to say that there's no debate is [10:04] nonsense there's always a debate about [10:06] every scientific issue but to claim [10:09] there's no consensus is equally false [10:12] there are many ways to measure the views [10:13] of climate scientists and as we'll see [10:15] in a later video it's clear that the [10:17] overwhelming majority accept the role of [10:20] man-made gases in global warming but [10:23] however unequal the debate might be [10:25] there are still dissenting views of [10:27] qualified Skeptics in the next video I [10:30] want to look at some scientific papers [10:31] that suggest who alternative hypotheses [10:34] on climate change neither of which has [10:36] anything to do with carbon [10:40] gases