Climate change: Scientists explore ‘injecting ice’ to reduce water vapor and cool Earth

livemint.com:

National Oceanic and Atmospheric Administration (NOAA) and NASA plan to inject ice high up in the air so that water vapour in the upper atmosphere would get a bit drier and that could counteract a small amount of the human-caused warmth. Notably, Water Vapour is a potent player in the Earth's greenhouse effect that eventually leads to the increase in the planet's surface temperature. According to NASA, Earth's surface temperature would be about 59 degrees Fahrenheit (33 degrees Celsius) colder without the greenhouse gases.

The greenhouse effect is a natural process that helps maintain Earth's temperature within a habitable range. But in recent years, the surface temperature has been rising because of human activities like burning of fossil fuels and deforestation, leading to global warming. Now, scientists have found a new way to cool an overheating earth - by reducing the amount of water vapour in the atmosphere.

NASA has explained that water vapour amplifies the warming of Earth's surface caused by other greenhouse gases like carbon dioxide (CO2) and methane. Water vapour is generated when the amount of methane and CO2 go up in the atmosphere, which leads to increased evaporation. Since warmer air holds more moisture, its concentration of water vapour increases.

Specifically, this happens because water vapour does not condense and precipitate out of the atmosphere as easily at higher temperatures, said NASA. The water vapour then absorbs heat radiated from Earth and prevents it from escaping out to space. This further warms the atmosphere, resulting in even more water vapour in the atmosphere - something the agency dubbed as a "positive feedback loop".