April 15, 2021

For years, misinformation about the climate has circulated online. Now, some social media users are claiming that billionaire Bill Gates is planning to spray dust into the atmosphere to “block the sun” as a way to combat global warming.

These claims have circulated widely across social media, including YouTube, with some questioning how blocking the sun would affect solar panels. Others are convinced this is a move from a mad scientist.

However, these claims are missing one major thing: context. Here’s how we fact-checked it.

Read past the headline

Whenever you read news online, you want to make sure you read past the clickbaity headlines or trending Twitter phrases to make sure you’re getting the full story. Seeing that Gates is going to “block the sun” with zero context or additional information could sound really scary to people.

Bonus tip: Question how a post makes you feel. Claims that spark an intense emotional reaction, like anger, shock or fear are usually missing a lot of context.

Try doing a keyword search

Searching with words like “Bill Gates spray dust and block the sun,” brought up several fact checks on this subject, including an article from Snopes.

According to the article, Gates has funded research and provided grants for solar radiation management experiments for about 14 years. One of the projects supported by Gates is a Harvard experiment named SCoPex. But here’s why context matters. According to their reporting, the objective of SCoPEx isn’t to block the sun. As a matter of fact, the most this experiment will do is release about 4.4 pounds of calcium carbonate, a nontoxic dust, 12 miles in the sky through the use of a weather balloon above the Arctic. The purpose is to collect data to investigate the impacts and potential risks of solar geoengineering.

If you’re not familiar with what geoengineering is, it’s sometimes called climate intervention. It’s basically a deliberate intervention in the Earth’s climate system to counteract climate change. According to Snopes, some fear that it could come with unintended and dangerous consequences. Others fear that if geoengineering became a solution, it would only encourage further fossil fuel use.

However, the experiment will be very small scale. According to the article, there is no way that the amount of nontoxic dust used is capable of altering our climate, and it would not actually block the sun. The first flight with the weather balloon is still waiting on approval from Harvard and would only test the balloon, not to release the calcium carbonate dust.

See what multiple sources are reporting

As a general media literacy tip, it’s always a good idea to read multiple sources. After doing another keyword search, I found this video from PBS of the scientists talking about the experiment. It turns out, the amount of material the experiment is putting out is less than that of a normal airplane flight.

Head straight to the source

According to the SCoPEx website, the test will pose no significant hazard to people or the environment. Instead, the experiment is to help inform computer models that look into the potential risks of actual geoengineering.


Mostly not legit. While Gates is one of SCoPex’s funders, the experiment is overseen by advisers run by Harvard. Additionally, the SCoPEx experiment will not actually block or dim the sun. Instead, the experiment will only release nontoxic dust to study the potential risks of geoengineering — not actually test it out.

Support high-integrity, independent journalism that serves democracy. Make a gift to Poynter today. The Poynter Institute is a nonpartisan, nonprofit organization, and your gift helps us make good journalism better.

More News

Back to News