After the most powerful volcanic eruptions, like Tambora in 1815 and Pinatubo in 1991, the Earth’s temperature dropped for a couple of years. This temporary cooling effect is due to the millions of tons of sulfur added to the stratosphere, a stable atmosphere layer situated just above the highest clouds. The particles of sulfur produce a hazy layer that reflects light and cools the planet.

Stratospheric sulfur geoengineering is a proposal to mimic this cooling effect using high-altitude jets to deliver millions of tons of sulfur to the stratosphere. While this would cost many billions of dollars to implement, it's cheap enough that a single nation could do it. 

Climate model simulations suggest it could offset the warming effects of CO2 and reduce many climate risks, though it may lead to significant change in rainfall in some places. It would also do little to address ocean acidification and would have other side-effects, delaying the recovery of the ozone hole and exacerbating the acid rain problem. At this stage scientists don’t know enough to recommend this strategy, and it remains controversial.

Roll the Geoengineering die and add 1 to the result for each Geoengineering tag in this card's stack.

• If the sum is 2–4, remove 1 Temperature Band and draw 2 additional unknown Crisis cards.

• If the sum is 5–6, remove 1 Temperature Bands and draw 1 additional unknown Crisis card.

• If the sum is 7 or more, remove 2 Temperature Bands.

Important! This is a temporary effect. Return the Temperature Bands to the Thermometer at the end of the round (after increasing Energy Demand).

You may take this action once per round.

• Stratospheric aerosol injection (Wikipedia)

• 📄 An overview of the Earth system science of solar geoengineering by Peter Irvine

• Study atmospheric or climate science and you might be able to contribute to our understanding of this idea.

• Contact your political representatives to urge international rules and scrutiny about the test or use of risky technologies such as these.