Geoengineering, or large-scale engineering of the environment, is a controversial method of delaying climate change, especially with reports now claiming that it could actually make climate change worse. But while scientists haven’t yet attempted a large scale geoengineering effort, smaller efforts have been underway around the world for the last 50 years. Below, a map from ETC Group that shows some of the most significant geoengineering projects around the world.
As you can see, the U.S., Canada, the European Union, and Australia are the biggest geoengineering hotspots. Almost all the countries in Asia, South America, and the Middle East have played host to some projects. African countries have done the least—appropriate since they generally contribute the least to climate change (though they will be hit particularly hard when it worsens).
The map uses a pretty broad view of geoengineering. Many of the projects have involved weather modification—either increasing precipitation by seeding clouds with chemicals, or reducing precipitation through a number of techniques (one example: using fleets of vessels to cut down on hurricanes by mixing warm water from the ocean’s surface with cold water found deeper in the ocean). Carbon sequestration using biochar (agricultural waste burned to make charcoal) that is buried in the soil is another popular technique. But others—like cultivating algae to consume CO2, whitening the Earth’s surface with "space mirrors" to redirect sunlight, and fertilizing the ocean with iron or nitrogen to sequester CO2—haven’t seen nearly as much testing.
The most recent plan we’ve seen (it’s not on the map) comes from a pair of Harvard engineers who are aiming to launch a balloon that sprays sun-reflecting chemicals—a technique that could cool down the planet if used on a global scale. This would be the first test of the technique.
Scientists have to do a lot more field testing before geoengineering can be deployed in any significant fashion. Sure, it could backfire, and some would argue that even testing these techniques is admitting defeat in our battle against climate change. But it’s always good to have a backup plan.