The U.S. Central Intelligence Agency (CIA) contacted an environmental expert to ask if other countries are manipulating the world's climate and if there is a way to detect these activities.

Professor Alan Robock from Rutgers University in New Jersey shared that the agents consulted him three years ago to know if hostile countries are triggering droughts and flooding in the United States, The Telegraph reported.

"Consultants working for the CIA rang and said we'd like to know if someone is controlling the world's climate would we know about it?" Prof Robock said while speaking before the American Association for the Advancement of Science in San Jose.

He told them that climate manipulation activities can be detected especially if it involves huge equipment. But then he gathered that it could be the other way around; the spies might be planning of manipulating the climate and they would like to know if they can get caught by other nations.

"Of course they were also asking - if we control someone else's climate would they then know about it."

"I was scared. I'd learned of lots of other things the CIA had done that didn't follow the rules...that wasn't how I wanted my tax money to be spent," he added.

The issue of climate manipulation reignites after the National Academy of Sciences published a two-volume report related to climate change. One suggests removing carbon dioxide in the atmosphere while the other plans to alter the clouds or the Earth's surface to bounce the sunlight back into space to cool the planet.

The research was mainly funded by the CIA and other U.S. government agencies including NASA, Department of Energy and NOAA, according to The Guardian.

"The CIA was a major funder of the National Academies report so that makes me really worried who is going to be in control," Prof Robock said.

The CIA has not released any comment yet about the news.