Report says prepare for more floods

Study warns City Dock, Baltimore’s Inner Harbor could face daily problems

A new report from the University of Maryland Center for Environmental Science predicts sea levels around the state could rise by as little as 1 foot or as much as 7 feet by the end of the century — depending on how much carbon the world emits into the atmosphere.

In any case, flooding is likely to become a near-daily occurrence in places like Annapolis’ City Dock and Baltimore’s Inner Harbor by 2100, scientists said.

But the effects of surging seas could be minimized if goals laid out in the 2015 Paris climate accord are upheld, constraining global warming to 2 degrees Celsius.

“If we want to avoid the worst case, we have to reduce emissions and do it quickly,” said Donald Boesch, lead author of the report and former president of the center.

The researchers did not find any significant change to relatively short-term increases in sea levels, expected over the next 30 years. They predict about 7 inches of rise by 2030 and 1.2 feet by 2050, similar to projections from a report they wrote five years ago.

But for the first time, they laid out expectations under a range of emissions scenarios — whether the Paris goals are met and emissions are stabilized, or carbon levels continue to increase in the atmosphere. They also assigned probabilities to the range of estimates.

Under the best-case scenario with full

implementation of the Paris Agreement, they estimate two-in-three chances that the rise could be held to between 1.1 to 2.4 feet by 2080, 1.2 to 3 feet by 2100 and 1.8 to 4.2 feet by 2150.

But if emissions continue to grow, those levels become the low end of projections and they estimate a two-in-three chance that sea level rise could reach 3.1 feet by 2080, 4.2 feet by 2100 and 6.6 feet by 2150.

Under the worst-case scenario, researchers estimate a one-in-100 chance sea level rise could reach 4.7 feet by 2080, 6.9 feet by 2100 and 12.4 feet by 2150.

That risk is expected to include more frequent and damaging flooding, the report says.

It suggests that a Category 2 storm following the same path as Hurricane Isabel did in 2003 would result in water levels at Baltimore rising 10.6 feet above what is known as mean sea level. Waters rose 7.3 feet during Isabel, inundating the Inner Harbor and Fells Point.

And it predicts an unavoidable increase in “nuisance” flooding events, when high tides spill onto streets. Even under the Paris accord goals, flooding that now affects Baltimore about 10 days a year would occur nearly 100 days, on average, by 2050. Under the worst-case scenario, nuisance floods would occur nearly every day in Baltimore by 2080.