Hungarian-born US investor and philanthropist George Soros.Fabrice Coffrini | AFP | Getty ImagesLiberal billionaire George Soros on Tuesday warned of a global depression, and said Russia’s invasion of Ukraine could be looked back on as the starting point of World War III.At his annual dinner amid the World Economic Forum, Soros said the course of history had changed dramatically since the last Davos, Switzerland, event.”Russia invaded Ukraine. This has shaken Europe to its core,” he told the audience.”The European Union was established to prevent such a thing from happening. Even when the fighting stops, as it eventually must, the situation will never revert to the status quo ante. Indeed, the Russian invasion may turn out to be the beginning of World War III, and our civilization may not survive it.”Soros said that other issues that concern humanity, such as pandemics, climate change and avoiding nuclear war, have had to take a back seat. “That’s why I say our civilization may not survive,” he later added.Soros, born in Hungary to a Jewish family that survived the Nazi occupation, emigrated to Britain and later the United States. The financier funds liberal charities and nongovernmental organizations worldwide through his Open Society Foundations, and famously bet against the British pound back in 1992.Speaking Tuesday, Soros said the fight against climate change has had to take second place amid the Ukraine war.”Yet the experts tell us that we have already fallen far behind, and climate change is on the verge of becoming irreversible. That could be the end of our civilization,” he said.Russia’s invasion of Ukraine is widely seen as putting a planned energy transition at a crossroads. Gas and oil prices have surged and world energy markets have been severely destabilized. Coal use has increased as Western nations desperately seek alternatives to Russian hydrocarbons.U.N. Secretary-General Antonio Guterres has said the Kremlin’s assault on Ukraine will likely have major implications for global heating targets. Guterres described this short-sighted rush to fossil fuels as “madness,” before warning that humanity’s “addiction to fossil fuels is mutually assured destruction.”Soros said he found the prospect of irreversible climate change “particularly frightening.” “Most of us accept the idea that we must eventually die, but we take it for granted that our civilization will survive,” he said.”Therefore, we must mobilize all our resources to bring the war to an early end. The best and perhaps only way to preserve our civilization is to defeat [Russian President Vladimir] Putin. That’s the bottom line,” he added.China Covid policySoros also took aim at Beijing, which is experiencing its worst Covid-19 outbreak since early 2020. Earlier in May, Chinese President Xi Jinping headed a meeting of top leaders that emphasized the country should stick to its “dynamic zero-Covid” policy, and warned that economic consequences would follow if it doesn’t.The officials called on the country to unify behind the decisions of the Chinese Communist Party’s central committee, and “resolutely fight” against all questioning of virus control policies, state media said.”The continuing lockdowns have had disastrous consequences, pushing the Chinese economy into a free fall since March,” Soros said in his speech Tuesday.Citing a Caixin composite purchasing managers’ index, Soros said that China’s “steeply declining economic activity” is bound to have global consequences.”These negative results will continue to gather momentum until Xi reverses course. … Coming on top of the real estate crisis, the damage will be so great that it will affect the global economy. With the disruption of supply chains, global inflation is liable to turn into global depression,” he said.Last week, Goldman Sachs became the latest bank to cut its forecast for China’s GDP, to 4% from 4.5%, after data for April showed a slump in growth as the Covid-19 controls restricted business activity.— CNBC’s Sam Meredith and Evelyn Cheng contributed to this article. Follow CNBC International on Twitter and Facebook.