Section 1.1: The EU's Focus on Stratospheric Aerosol Injection

The geoengineering method that has captured the EU's attention is Stratospheric Aerosol Injection (SAI), which seeks to mimic the cooling effects of volcanic eruptions. For instance, when Mount St. Helens erupted in 1980, it released approximately 490 billion tons of ash, with 0.03% comprising sulfate particles. These particles are small enough to remain airborne for extended periods, reflecting sunlight and thereby reducing the amount of solar energy that reaches the Earth's surface.

The greenhouse effect driven by carbon dioxide relies on sunlight penetrating the atmosphere. Carbon dioxide allows visible light to pass but absorbs infrared radiation. When sunlight reaches the ground, it heats up, subsequently radiating energy back as infrared light. This is absorbed by atmospheric carbon dioxide, which in turn warms the atmosphere, contributing to climate change. However, sulfur particles from volcanic eruptions block sunlight and do not emit infrared radiation, resulting in a temporary cooling effect.

To achieve a significant cooling effect, SAI proposes the injection of sulfate aerosols into the upper atmosphere using aircraft or rockets. To counteract a 2-degree Celsius increase in global temperature, an estimated 40 million tons of sulfate would need to be released annually—equivalent to the weight of 80 Burj Khalifas!

The first video delves into the question: "Can Geoengineering Stop Climate Change?" It explores the potential benefits and pitfalls of this controversial approach.

Section 1.2: Potential Risks of Geoengineering

While the prospect of SAI may sound promising, it raises significant concerns. For starters, the ecological consequences of mining the necessary sulfate, as well as the emissions from the aircraft or rockets employed, must be considered. More alarmingly, SAI could exacerbate existing global tensions and create new risks, including:

1. Ecological Stressors: The introduction of sulfate aerosols could lead to increased acid rain, which can devastate ecosystems and agricultural yields. The reduced sunlight would further hinder photosynthesis, leading to widespread crop failures and potential famines.
2. Nuclear War Escalation: Like volcanic eruptions, nuclear detonations also release particles that block sunlight. This could result in a "nuclear winter" scenario, which, when combined with SAI, would lead to even more severe cooling and catastrophic conditions.
3. Global Interconnectedness: The cooling effects of SAI may have uneven impacts across different regions, leading to geopolitical strife and complicating international relations, especially regarding the financial burden of maintaining SAI operations.
4. Snap-Back Scenario: If SAI is deployed without simultaneous efforts to reduce atmospheric carbon dioxide, we risk a rapid return to even higher temperatures if the SAI program is halted. This could lead to a swift and devastating climate crisis.

The second video, "Can Geoengineering UNDO Climate Change?" featuring @ClimateAdam, discusses the risks and uncertainties surrounding geoengineering efforts.