Harnessing Rain: Does it Impact the Climate?

Summer is the peak season for wildfires, with hot weather and lack of rainfall significantly increasing the risk. In 2023, wildfires devastated regions such as Greece (resulting in 28 deaths and over 20,000 evacuations), the Spanish island of Tenerife (over 26,000 evacuations), Algeria (34 deaths), Russia (29 deaths), and Chile (26 deaths). Often, it's not just the abnormally warm weather to blame, but also human actions like arson and negligence with fire.

One effective method for combating forest fires today is to artificially induce rainfall directly over the burning areas. This approach can halt forest fires advancing towards cities, which release not only the carbon stored in trees but also large amounts of soot and particulate matter into the atmosphere.

The impact of forest fires is significant even in northern regions. Soot can settle on the snowy expanses of the Arctic Ocean, darkening the surface and reducing its albedo (the ability to reflect sunlight), which accelerates melting.

So, how do we make clouds release rain over a raging fire? This process is controlled by a meteorological aircraft equipped with devices that shoot pyrotechnic cartridges filled with silver iodide. An observer pilot, flying about five kilometers above the ground and guided by a map of forest fires, shoots the cartridges into the upper part of a cloud, causing rain to fall within approximately half an hour. Silver iodide forms crystals—snowflakes—that begin to fall to the ground, resulting in tens of thousands of tons of water, which no fleet of planes or helicopters could deliver to the fire. Moreover, in remote areas like the taiga, there are often no suitable water sources for helicopters, and fires rage over large areas.

However, artificial precipitation has one significant limitation—it can only be induced from rain clouds. If the fires are in a zone of a stable anticyclone, the meteorological aircraft stays grounded. In such cases, ground-based firefighting methods must be relied upon.

Reducing the number and area of forest fires is the simplest forest climate project, which quickly and drastically reduces CO2 emissions. Depending on the year, these emissions can account for 10% to 25% of all annual carbon dioxide emissions into the atmosphere.

Artificial rainfall requires careful preparation and includes aerial monitoring of forest fires using small aircrafts, detecting fire hotspots on satellite images with artificial intelligence, and thorough training for pilots and forest firefighters.