Scientists have a new idea to save Earth from global warming. Geo-engineers believe that spraying "sun-dimming" chemicals high above the Earth could slow down global warming. They say this would be "remarkably inexpensive," costing about $2.25 billion. The technique is called stratospheric aerosol injection (SAI). It would need huge, high-powered hoses to spray chemicals into the stratosphere. This would be a barrier against sunlight.
The scientists said their idea is still in the planning stages. They said: "We simply show that a hypothetical deployment program, while both highly uncertain and ambitious, would indeed be technically possible." Some scientists think the idea is pie in the sky. They say special planes would need to make 4,000 missions a year across the globe's airspace. Over 100 governments would need to agree to this. It could increase droughts and extreme weather.