New York (CNN Business) Recession fears are on the rise in the United States. Memories of the last downturn are exacerbating these worries: The last time America faced a recession was in 2008, as the financial crisis was unfolding. Millions of people lost their jobs, GDP growth plummeted and businesses shut down.

But not all recessions are like that. Sometimes the economy can grow all the way through a recession. In fact, some economists believe the world is in a recession now and most people don't even realize it.

"By our metrics, we're in a global growth recession," said Alessio de Longis, senior portfolio manager at Invesco. "As we enter 2020, growth is slowing and it's slowing in a synchronized way."

A growth recession is when the economy grows below trend and decelerates. Trend growth is the average growth rate that sustains unemployment and inflation at a stable level.

The world economy has grown at a trend rate of roughly 3%, de Longis said. In 2018, global GDP grew at a pace of 3.04%, according to the World Bank. The International Monetary Fund predicted earlier this month that the world's economy will grow by 3% this year. But that's just a forecast: The economy could currently be in worse shape, putting the world in a growth recession.

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