Environment

Miami streets could flood every single day by 2070 under many climate models, NOAA says

A pedestrian walks along a flooded sidewalk along Alton Road near Michigan Avenue on Tuesday, Aug. 1, 2017, in Miami Beach. New research from NOAA suggests this kind of flooding could happen every day by 2070 under most climate models.
A pedestrian walks along a flooded sidewalk along Alton Road near Michigan Avenue on Tuesday, Aug. 1, 2017, in Miami Beach. New research from NOAA suggests this kind of flooding could happen every day by 2070 under most climate models. emichot@miamiherald.com

Years ago, before 2010, the tidal gauge at Virginia Key showed high tide floods maybe twice a year.

By 2070, most climate models show it could flood every single day, according to a new report from the National Oceanic and Atmospheric Administration. The remaining models show flooding ever other day.

In the report released this week, NOAA said the data reflects a prediction made by the late Margaret Davidson, founder of NOAA’s coastal services center — “Today’s flood will become tomorrow’s high tide.”

At this point, Miamians are familiar with the kind of floods that swamp their streets and leave them dashing across sidewalks with shoes in hand. But flooding at the frequency NOAA predicts would double, triple and eventually exponentially increase the amount of puddles residents must ford per year. Massive changes within a lifetime.

That’s not even counting King Tides, the highest tides of the year. William Sweet, lead author on the NOAA study, said King Tide level floods could occur between 10 and 50 days a year by 2050 and every other day to every single day by 2100.

But Ben Kirtman, director of the Cooperative Institute for Marine & Atmospheric Studies at the University of Miami, said that 365-a-year flood number is based on a model that assumes nothing is done to deal with it: no pumps, no sea walls and no change to the amount of greenhouse gas we emit.

“We need to recognize that this is going to really challenge Miami, but at the same time we need to start imagining what our city could be like if we design around it,” he said.

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NOAA data show high tide floods are predicted to increase in the next 50 years, and could be as frequent as every single day by 2070. NOAA

NOAA said the high tide floods are increasing fastest along the Southeast Atlantic Coast; between 2000 and 2015 they increased from a little more than once a year to three times a year. By 2050, the “intermediate” model projection foresees 85 flood days per year and 365 days by 2070.

That’s based on a model that calls for three feet of sea level rise by 2100, which is about the same as the 2015 unified projection from the Southeast Florida Climate Compact.

That’s the same projection Miami Beach and Miami are designing around, with a half billion dollars and around $200 million committed, respectively. Scaling up to meet the floods of the future is going to be pricey, and it’ll rely on having correct predictions.

Reports like NOAA’s latest are crucial in making sure city planners have the right information before they invest hundreds of millions of dollars in taxpayer money. These federal reports help establish “a common language,” Kirtman said.

“That’s going to be useful for Broward planners talking to Miami-Dade planners talking to planners in Norfolk, Virginia, or anywhere in the country,” he said.

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Data from NOAA show how often high tide floods occurred at Florida tidal gauges before 2010. NOAA
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