Davos, Switzerland (CNN Business) A year ago, the mood in Davos was upbeat. The global economy was humming, President Donald Trump's tax cuts were kicking in and a trade war between the United States and China was still just a threat.

Fast forward to this week's World Economic Forum and the atmosphere could hardly have been more different.

"There's not much optimism," said Nelson Cunningham, lawyer and a former adviser to the Clinton administration who has been coming to Davos for 21 years. "But are we too pessimistic? I don't know, I think the pessimism this year is warranted."

The week started with the International Monetary Fund cutting its outlook for global economic growth in 2019, the second downgrade to this year's forecast. The IMF warned of worse to come if the trade war remains unresolved and Britain crashes out of the European Union without a deal that protects business.

"After two years of solid expansion, the world economy is growing more slowly than expected, and risks are rising," IMF Managing Director Christine Lagarde said at a press conference in Davos on Monday.

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