London: Nuclear war, cyber attacks and environmental disasters top the list of man-made threats to global stability in 2018, according to a survey of 1000 international leaders from business, government, education and service groups.

The threat of another global financial meltdown, more likely in past years, has ebbed because of economic expansions underway worldwide, the annual World Economic Forum's Global Risks Report found. It was released on Wednesday in advance of the forum's meeting next week in Davos, Switzerland.

Mother Nature topped the most significant risks facing the world for a second year in a row, the survey showed. That includes natural disasters and extreme weather events that human-caused climate change may be abetting.

The risk of nuclear war climbed up the list of concerns as a result of North Korean leader Kim Jong-un's tests of ballistic missiles and nuclear weapons, and US President Donald Trump's bellicose vows to annihilate North Korea if it launches an attack.