JERUSALEM/BEIJING - What will happen when computers push humans out of the job market and create a massive new class of "useless people"?

Yuval Noah Harari, author of the international bestseller Sapiens: A Brief History of Humankind, who has recently made quite a splash in China with the launch of the Chinese version of his equally compelling new book Homo Deus: A Brief History of Tomorrow, expressed his concerns about the development of Artificial Intelligence (AI).

In the new book, he turns his focus toward humanity's future and the quest to upgrade humans due to the development of science, particularly the rise of AI.

Talking about the potential threats and hazards brought about by AI in a written interview with Xinhua, Harari said he is more worried about non-conscious AI driving billions of humans out of the job market and creating a massive new class of "useless people" as he thought it is unrealistic that AI could develop consciousness and try to manipulate or even exterminate humankind.

While computers have gained impressive intelligence, they still have zero consciousness. So the fear of killer robots trying to exterminate humankind is actually unwarranted, he said.

What is more worrying is that experts estimate that within 20-30 years, about 50 percent of all the jobs in advanced economies might be taken by computers as we are now developing smart machines that outperform humans in more and more tasks.

Humans have basically just two types of skills - physical and cognitive - and if computers outperform us in both, they might outperform us in the new jobs just like in the old ones.

"What will we do with billions of economically useless humans? We don't know. We don't have any economic model for such a situation. This may well be the greatest economic and political question of the 21st century," Harari said.

In addition, as algorithms push humans out of job, wealth might become concentrated in the hands of the tiny elite that owns the all-powerful algorithms, creating unprecedented social and political inequality.

Harari said that the key to the balance of relations between humans and AI is to make technology serve us, instead of us serving it.

According to him, very often in history, humans invented new technologies, but instead of letting the technologies help us live a better life, we became slaves to them.

"The most famous example of such a process is the Agricultural Revolution. The invention of farming gave humankind immense new powers, but that power enriched only a tiny elite, whereas the vast majority of simple peasants found themselves enslaved to the needs of the new agricultural economy, and living a worse life than their hunter-gatherer ancestors," said the historian.

"We should be very careful that the rise of AI won't result in something like the Agricultural Revolution -- enriching a tiny elite while enslaving the majority of humans," he said.

Harari has a PhD in history from the University of Oxford and now lectures at the Department of History, the Hebrew University of Jerusalem, specializing in world history.

Harari's 2014 book Sapiens became an international bestseller which Microsoft founder Bill Gates recommended to his wife, calling it one that would spark great conversations.

Homo Deus was first published in Hebrew in 2015. The English version was published in September 2016 in Britain and will be published next month in the United States. The Chinese version hit the shelves in China in January, 2017.