this post was submitted on 25 Nov 2025
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I will repost my comment from the other day where this can of worms was opened, because it's actually very fucking important:
Increasing the albedo of Earth (i.e. the total reflectivity) is a very different concept to "blocking out the sun". If it was a gas or particles reflecting energy in regions outside the visible spectrum, say thr infrared, for the most part people, solar panels and plants wouldn't notice. There are obvious concerns about secondary effects, but aren't we seeing already the primary effects from the opposite, that being greenhouse gas emissions? We are already doing geoengineering, whether we like it or not, and scientifically looking for solutions isn't a bad idea.
Now, should this be in the hands of a startup called Stardust or whatever shit? Absolutely fucking not, this should be a collective worldwide scientific discussion and effort, on the order of magnitude of the LIGO experiment, the LHC or similar projects. But as always, this is a matter of execution within capitalism and not of the theory, which needs a lot of scientific development and, yes, experimentation.
Useful experiments that we have already unintentionally carried out with "inverse greenhouse gases" are for example the emissions from transoceanic merchant ships. In 2020, regulations about sulphur dioxide emissions in merchant ships entered internationally, and abruptly cut 80% of SO2 emissions from said ships. As a result, given SO2's inverse greenhouse effect, there has been a significant undesired increase in global radiation absorption.
We NEED to push for the study of these phenomena internationally by public entities and actual scientists in research institutions, and not let journalists and companies muddy up the topic as has happened with climate change overall.
We already know the cooling effect of aerosols, including SO2. Noone is blocking academic research on impacts of adding/removing aerosol to change Earth's albedo. In fact we already know the impact, what is the lifetime of individual aerosol in the atmosphere, their negative (cooling) global warming potential, and their deleterious effect on human health as pollutant.
You can already show on a piece of paper why this experiment is not worth doing. The maximum lifetime of aerosol in the stratosphere is 2 years, you have to keep injecting and replacing the aerosol to maintain the cooling effect. Production of these reflective aerosol uses energy (i.e. produce GHG) so as the greenhouse gases accumulate in the atmosphere, you need more and more aerosol injection to offset the warming effect. On paper this is already a terrible idea, not even accounting for the additional particulate matter pollution from the fallout of this reflective aerosol injection, tldr, it's going to end up in someone's lung and other unintended consequences of injecting tons of dirt into Earth's stratosphere.
Why should we waste resources to conduct planetary scale geoengineering experiment for an idea that is already bad on paper? Remember there is no control experiment for planetary scale geoengineering, there is no Earth 2. Thousands of serious climate scientists waste their time writing IPCC reports every 5 years and arguing over countless hours and the solutions have been the same since 1990, reduce oil and gas consumption, plant trees, make solar panels and wind turbines.