British physicist Stephen Hawking believes pollution isn’t the only threat to our Earth. Human greed and stupidity is also a major factor to the world’s problems and the biggest threat to humankind.

Speaking to Larry King on his show Larry King Now, Hawking expressed his concerns about the increasing threat to the environment and commented that his concerns haven’t ceased in the six years since he first began thinking about the issue and bringing it up. Population growth and increase in air pollution has got dramatically worse just in the past five years, Hawking commented.

“We certainly have not become less greedy or less stupid,” Hawking said. “The population has grown by half a billion since our last meeting, with no end in sight. At this rate, it will be eleven billion by 2100.”

“Air pollution has increased over the past five years,” he said. “More than 80% of inhabitants of urban areas are exposed to unsafe levels of air pollution.”

During his interview he also brought up concerns that climate change is an issue that needs to be resolved as soon as possible and worries that humanity may have already reached the point of no return.

Hawking also discussed the potential for artificial intelligence and although he believes it could be used in positive ways such as detecting early signs of cancer or making accurate stock market predictions, he warns that it could easily get out of hand.

“Governments seem to be engaged in an AI arms race, designing planes and weapons with intelligent technologies,” Hawking says in the interview. “The funding for projects directly beneficial to the human race, such as improved medical screening, seems a somewhat lower priority. I don’t think that advances in artificial technology will necessarily be benign. Once machines reach the critical stage of being able to evolve themselves, we cannot predict whether their goals will be the same as ours.”

You can watch the full Larry King interview with Stephen Hawking here.