I wasn't worried about climate change. Now I am.

Sabine Hossenfelder
27 Jan 202421:36
EducationalLearning
32 Likes 10 Comments

TLDRThe video discusses the controversy surrounding climate sensitivity, a critical factor in climate models that predicts the Earth's temperature response to increased carbon dioxide levels. It highlights the concern that newer models suggesting higher climate sensitivity may be more accurate than previously thought, potentially leading to more severe and rapid climate change impacts. The speaker advocates for urgent action on climate change, emphasizing the importance of pricing carbon emissions, expanding renewable energy, building nuclear power, and supporting carbon removal initiatives.

Takeaways
  • ๐ŸŒ Climate change videos often face dislikes, reflecting the public's fatigue or denial regarding the topic.
  • ๐ŸŒก๏ธ The central debate among climate scientists revolves around the climate sensitivity, a measure of potential temperature change.
  • ๐Ÿ”ฅ 2023 was recorded as the hottest year since the mid-19th century, with record high temperatures, heatwaves, and low Antarctic sea-ice.
  • ๐ŸŒŠ Changes in global climate patterns, such as the transition from La Nina to El Nino, can influence annual temperature trends.
  • ๐ŸŒฟ Air pollution has a cooling effect, and a decrease in ship exhaust pollution may have contributed to the warming observed in 2023.
  • ๐Ÿ”„ Climate sensitivity estimates from models have historically ranged between 2 to 4.5ยฐC, but recent models suggest it could be higher.
  • ๐ŸŒค๏ธ 'Hot models' with higher climate sensitivity have been criticized for not aligning with historical paleoclimate data.
  • โ˜๏ธ The accuracy of climate models, particularly their representation of clouds and supercooled water droplets, is a significant challenge.
  • ๐ŸŒก๏ธ A study using a 'hot model' for short-term weather prediction found it to be more accurate than its 'colder' counterpart.
  • ๐ŸŒ The potential for a high climate sensitivity poses serious implications for regions around the equator, which are densely populated and vulnerable to rapid climate change.
  • ๐ŸŒฑ The discussion on climate change is not just academic; it has profound implications for human survival, economic stability, and global conflict.
Q & A
  • What is the main issue discussed in the video regarding climate change?

    -The main issue discussed is the debate among climate scientists about a single number called the climate sensitivity, which determines how fast temperatures will rise if carbon dioxide levels continue to increase.

  • What is the Equilibrium Climate Sensitivity (ECS) and why is it important?

    -The Equilibrium Climate Sensitivity (ECS) is a property of climate models that refers to the temperature change that occurs when atmospheric carbon dioxide levels double over pre-industrial times and the system reaches equilibrium. It is important because it is the key quantity that determines the predictions for temperature increase in different emission scenarios.

  • What was the range of climate sensitivity in the world's most sophisticated climate models up to 2019?

    -Up to 2019, the climate sensitivity of the world's most sophisticated climate models was roughly between 2 and 4.5 degrees Celsius.

  • Why did some climate scientists reject the models with a higher climate sensitivity?

    -Some climate scientists rejected the models with a higher climate sensitivity because they believed these models were unrealistic and not compatible with historical data from paleoclimate studies.

  • What did the 2020 study analyzing paleoclimate data conclude about climate sensitivity?

    -The 2020 study concluded that the paleoclimate data fits with a climate sensitivity between 2.6 and 3.9 degrees Celsius, implicitly suggesting that the 'hot' models with higher climate sensitivity were not compatible with this historical data.

  • How does the video address the issue of clouds and their role in climate models?

    -The video addresses the issue of clouds by discussing the challenges in understanding the physical processes that occur in clouds, particularly the supercooled phase of water, which complicates the question of the influence of clouds on climate sensitivity.

  • What was the outcome of the test comparing the 'hot' climate model with an older version in a 6-hour weather forecast?

    -The test found that the newer 'hotter' model, which had a climate sensitivity of more than 5 degrees Celsius, provided a better forecast, agreeing more closely with what actually happened.

  • What is the significance of the Hanson et al paper mentioned in the video?

    -The Hanson et al paper is significant because it re-analyzes historical climate data and claims that it is compatible with a climate sensitivity of 4.8 ยฑ 1.2 degrees Celsius, which agrees with the 'hot models' and challenges the reason climate scientists had for dismissing models with higher climate sensitivity.

  • What are the potential consequences of a high climate sensitivity if we continue with current policies?

    -The potential consequences include widespread crop failure, mass migration, political tensions, possible wars, public health disasters, and an enormous economic downturn, leading to a phase of regress and a reduction in world population by a few billion.

  • What recommendations does the speaker make to address climate change?

    -The speaker recommends putting a price on carbon dioxide emissions, continuing to expand renewables, building more nuclear power plants, embracing carbon removal, and stopping direct actions like gluing oneself to things.

  • How does the video end, and what is the speaker's stance on the role of AI in solving climate change?

    -The video ends with the speaker expressing a wish list of actions to combat climate change and highlighting the work of Planet Wild, an environmental protection organization. The speaker believes that AI is not the solution to the problem, as the issue lies in the inability to agree on and implement existing solutions.

Outlines
00:00
๐ŸŒ Climate Change and Dislike on YouTube

The speaker begins by discussing the negative reactions received on YouTube for videos about climate change, regardless of whether the news is positive or negative. They express understanding for the public's fatigue with the topic, but emphasize the importance of discussing climate change due to its significant impact on millions of lives. The speaker introduces the concept of climate sensitivity, a crucial number in climate models that determines the rate of temperature increase in response to carbon dioxide levels. They express concern over recent findings that suggest a higher climate sensitivity than previously thought, which could lead to more rapid and severe consequences.

05:03
๐ŸŒก๏ธ Rising Concerns about Climate Sensitivity

The speaker delves into the specifics of climate sensitivity, explaining that it was traditionally estimated to be between 2 and 4.5 degrees Celsius. However, in the 2019 model assessment, some models indicated a higher sensitivity of over 5 degrees Celsius, suggesting a faster rate of global warming. Despite this, these 'hot models' were deemed unrealistic by some scientists due to their incompatibility with historical data. The speaker then discusses the importance of cloud physics in climate models and the challenges of using historical data to predict future climate behavior. They highlight a study where a 'hot model' outperformed an older model in short-term weather predictions, indicating that higher climate sensitivity might be more accurate.

10:04
๐ŸŒŽ Equatorial Regions at Risk

The speaker focuses on the potential impact of climate change on equatorial regions, which are densely populated and highly vulnerable to temperature increases. They stress the urgency of understanding the correct climate sensitivity to inform appropriate action. The speaker criticizes the lack of attention given to the new findings and the potential consequences of inaction, including economic collapse and a significant reduction in world population. They also discuss the broader implications of climate change, such as mass migration, political tensions, and public health crises, emphasizing the global nature of the problem.

15:07
๐ŸŒฟ Environmental Protection and Planet Wild

The speaker concludes by shifting the focus to positive action, highlighting the work of Planet Wild, an environmental protection organization. They describe the community-based approach of the organization and its efforts in restoring ecosystems and preserving wildlife. The speaker encourages viewers to join the community and contribute to the cause, emphasizing the direct impact of collective efforts. They also mention the possibility of observing the effects of their contributions through video reports, providing a sense of transparency and involvement.

Mindmap
Keywords
๐Ÿ’กClimate Change
Climate change refers to significant changes in global temperatures and weather patterns, often attributed to human activities such as the burning of fossil fuels and deforestation. In the video, the speaker discusses the public's reaction to climate change content and the serious implications of not addressing this issue, including its impact on millions of lives and the potential for rapid environmental and societal changes.
๐Ÿ’กClimate Sensitivity
Climate sensitivity is a measure used in climate models to estimate the change in global temperatures resulting from a doubling of atmospheric carbon dioxide levels from pre-industrial times. It is a crucial factor in predicting the rate of future temperature increases and the severity of climate change impacts. The video highlights a debate among climate scientists about whether the climate sensitivity is higher than previously thought, which could lead to more severe and rapid climate change.
๐Ÿ’กEquilibrium Climate Sensitivity (ECS)
Equilibrium Climate Sensitivity (ECS) is the change in global temperature when atmospheric carbon dioxide concentration is doubled, after the climate system has reached a new state of equilibrium. It is a key parameter in understanding the long-term temperature response to carbon dioxide emissions and is central to the discussion in the video about the potential severity of future climate change.
๐Ÿ’กPaleoclimate Data
Paleoclimate data refers to indirect evidence of past climates derived from sources such as ice cores, tree rings, and sedimentary records. This data helps scientists understand historical climate variations and provides context for current climate changes. In the video, the speaker mentions a study that compiled paleoclimate data, suggesting a climate sensitivity within the range of 2.6 to 3.9 degrees Celsius, which is lower than what some 'hot models' predict.
๐Ÿ’กSupercooled Water
Supercooled water is a state of water that remains liquid even when it is below its normal freezing point. In the context of the video, the speaker highlights the complexity of predicting cloud behavior in climate models due to the reflectivity of clouds being affected by whether the water droplets are supercooled or frozen, which has significant implications for understanding the Earth's climate sensitivity.
๐Ÿ’กWeather Forecasting
Weather forecasting is the process of predicting the state of the atmosphere for a future time and place, typically using computer models that process vast amounts of data. In the video, the speaker discusses an experiment where a 'hot' climate model was used to make a 6-hour weather forecast, and it was found to be more accurate than an older version, suggesting that the model's higher climate sensitivity may be more accurate in predicting future climate changes.
๐Ÿ’กPlanet Wild
Planet Wild is an environmental protection organization mentioned in the video that focuses on community-based conservation efforts. They fund the restoration of ecosystems and document their missions, allowing individuals to see the direct impact of their contributions to environmental preservation.
๐Ÿ’กCarbon Pricing
Carbon pricing is a strategy to reduce greenhouse gas emissions by assigning a cost to the emission of carbon dioxide, incentivizing reductions in pollution. In the video, the speaker suggests carbon pricing as one of the measures that need to be implemented to effectively address climate change.
๐Ÿ’กRenewable Energy
Renewable energy refers to power sources that are replenishable and sustainable, such as solar, wind, and hydroelectric power. In the video, the speaker emphasizes the need to continue expanding the use of renewable energy to combat climate change and reduce reliance on fossil fuels.
๐Ÿ’กNuclear Energy
Nuclear energy is the production of power through nuclear reactions, offering a low-carbon alternative to fossil fuels. The speaker in the video argues for the construction of more nuclear power plants as part of a comprehensive strategy to reduce greenhouse gas emissions and combat climate change.
๐Ÿ’กCarbon Removal
Carbon removal involves the capture and storage of carbon dioxide from the atmosphere, with the goal of reducing the concentration of greenhouse gases that contribute to climate change. The speaker in the video criticizes the reluctance to embrace carbon removal technologies, stating that they are a necessary part of the solution to the climate crisis.
Highlights

YouTube has removed the dislike counter, but the numbers are still available backstage, showing that climate change videos are often disliked.

The speaker's most disliked videos are those on climate change, regardless of whether they contain good or bad news.

The speaker understands why some people might be tired of hearing about climate change, but emphasizes the importance of the topic.

The video discusses the concept of climate sensitivity, a crucial number in climate models that determines the predicted temperature rise.

Climate sensitivity is the temperature change resulting from doubling atmospheric carbon dioxide levels and allowing the system to reach equilibrium.

Until 2019, the accepted climate sensitivity range was between 2 and 4.5 degrees Celsius.

In the 2019 model assessment, some models suggested a climate sensitivity higher than 5 degrees Celsius, which could significantly worsen the situation.

Climate scientists debated the validity of these 'hot models' due to their incompatibility with historical data.

A study using paleoclimate data found that it aligns with a climate sensitivity between 2.6 and 3.9 degrees Celsius, supporting the lower sensitivity models.

The speaker highlights the issue of modeling clouds and their supercooled phase, which complicates determining climate sensitivity.

One 'hot' climate model showed better accuracy in short-term weather forecasting, suggesting a potentially higher climate sensitivity than previously accepted.

A new paper re-analyzing historical climate data suggests a climate sensitivity of 4.8 ยฑ 1.2 degrees Celsius, which aligns with the 'hot models'.

The possibility of a high climate sensitivity above 5 degrees Celsius cannot be dismissed, especially considering the rapid rise in average temperatures.

If climate sensitivity is indeed high, it could lead to catastrophic consequences, including economic collapse and mass migration.

The speaker calls for immediate action, including pricing carbon emissions, expanding renewable energy, building nuclear power, and embracing carbon removal.

Planet Wild, an environmental protection organization, is highlighted for their hands-on approach to preserving nature and ecosystems.

The speaker encourages viewers to join Planet Wild and become part of a community making a real difference in environmental conservation.

Transcripts
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