LOS ANGELES, Nov. 23 (Xinhua) -- Scientists have proposed a new way to tackle climate change by spraying sun-dimming chemicals into the Earth's atmosphere, according to a study published Friday.

Scientists at Harvard and Yale universities have proposed using a technique known as Stratospheric Aerosol Injection (SAI), which they believe could cut the rate of global warming by half, according to a paper published in the journal Environmental Research Letters.

The technique would involve spraying large amounts of sulfate particles into the Earth's lower stratosphere at altitudes as high as 12 miles (19.3 km).

However, no existing aircraft design -- even with extensive modifications -- can reasonably fulfill this mission, said the paper.

The scientists propose developing a new purpose-built high-altitude tanker with substantial payload capabilities to deliver the sulfates.

The estimated cost of deploying material is about 2.25 billion U.S. dollars a year over 15 years, according to the paper. Scientists calculate the number of flights at 4,000 for the first year, linearly increasing by 4,000 a year.

The report also acknowledges that the technique is purely hypothetical.

"We make no judgment about the desirability of SAI. We simply show that a hypothetical deployment program commencing 15 years hence, while both highly uncertain and ambitious, would indeed be technically possible from an engineering perspective. It would also be remarkably inexpensive," the paper said.