The rising threat to businesses in 2022? Water.

COVID-19 has emptied office building and shuttered stores, crippling America's downtowns. But if climate scientists are right, a slower moving foe — flooding — could pose an even greater risk, threatening to drown the nation's commercial real estate.

The rising waters are already endangering hundreds of thousands of commercial structures, according to a first-of-its-kind report released this month. More than 700,000 apartment buildings, malls and office complexes face flooding risks in 2022 severe enough to impede business access, according to the analysis from the nonprofit First Street Foundation and engineering firm Arup. For businesses, the total downtime could reach 3 million days, while the economic impact of closures would approach $50 trillion. For perspective, that's nearly half of global GDP.

"American businesses and local economies face much more uncertainty and unpredictability when it comes to the potential impact of flooding on their bottom line than they may realize," said Matthew Eby, executive director of the First Street Foundation.