GreenLaurel: Four Ways Climate Change Is Affecting Baltimore Today

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A smart bunch of oceanographers from the University of Maryland Center for Environmental Science and others combed through 114 years of Maryland weather data. They discovered something you may already suspect: Baltimore’s weather and climate have changed significantly. Yet, how it’s changing — and will continue to change — our daily life may surprise you. Here’s what to expect and how you can be part of the climate solution. 

Funded by the National Oceanic and Atmospheric Administration — the same agency for which Trump’s budget would slay funding — the UMCES scientists analyzed pretty much every aspect of the Chesapeake Bay region’s weather since 1903. They found that climate change is affecting every weather factor from rain to season length, from day and night temperatures to rainfall.

The team has also created a user-friendly Chesapeake Bay Changing Climate data portal with easy-to-read graphs and details so the public and educational groups can easily access the data.

Here are the study’s highlights:

#1: Baltimore weather vs. our region’s climate?

It’s a bit confusing to distinguish the two concepts because they’re linked together.

“Think of our climate as your outerwear closet that holds all types of jackets based on the climate that you live in. The day-by-day weather can be thought of as which jacket you choose to wear each day,” said Dr. Kari St. Laurent, a post-doctoral researcher on the project. Basically, a coat closet in Hawaii will be vastly different than a coat closet in Iceland because both places have very different climates. 

Because Baltimore’s climate is getting hotter (see below), we won’t be needing to wear our down parkas as often because our daily weather is changing.

It’s getting hotter with wider temp swings over time. Credit: NOAA state temps

“That’s why it’s important to show how our weather and climate extremes are changing right here in our communities. We want people to understand that their own lives are impacted by our changing climate,” said Victoria Coles, a research associate professor at UMCES at Horn Point Laboratory.

#2: Twice as Many Summer Tropical Nights

Baltimore now experiences 30 more nights of tropics-like heat. According to the U.S. Census, about 20 percent of Baltimore-area homes either have no central AC or use window AC units. Credit:

“Since 1903, the number of nights where the temperature doesn’t fall below 68℉ has more than doubled,” said Coles. “Those muggy and super-hot summer nights are tough on kids and the elderly in households without air conditioning.  Add to that, the heat island effect is magnified if our nighttime temperatures don’t cool down.”

#3: Longer Farming Growing Seasons are Disastrous for Farmers

“This data supports what we’re finding out in the fields: Climate change is an existential threat to farming, especially high-value perennial crops.” according to Paul Roberts, owner of Maryland’s own Deep Creek Cellars.

A month longer agriculture season is throwing off nature’s clock and calendar. Credit:

One could argue high-value perennial crops make life worth living: Wine, coffee, chocolate, fruits, stone fruits and honey top this list. These crops flower once a year, and if frost zaps the baby flower buds, a year’s harvest can be wiped out.

Longer growing seasons sound better in theory, but the longer Chesapeake Bay growing season — by 30 days, longer — adds weather unpredictability into the farming mix.

“Before 2010, the growing season was like clockwork,” said Roberts. “On May 1, plus or minus a few days, our vines would bud. In 2010, that all changed. The timing has changed from one to six weeks before May 1. This year, the vines just bloomed and we will now stress for weeks waiting for a potential pre-May 1 frost, which could wipe out our year’s crop.”

“Climate change is messing with the farming timing,” he added. “The chances for success aren’t in our favor.”

#4: More Intense Rainstorms, and 12 Percent More of Them

Has your basement flooded lately in places it didn’t before? The 2016 Ellicott City and Meadow Mill floods were the consequence of Baltimore’s more intense rain storms.

According to Coles, Baltimore’s maximum rain intensity has increased by nearly two inches this past century. When it rains now, it really pours. 

Baltimore’s storm drain systems and our natural and cement creeks were not designed to handle six inches of rain in five hours. Increased urban rain runoff also wreaks havoc on the Chesapeake Bay.

More rain equals more city road grime, toxins and trash polluting our bay. More pollution means fewer grasses, less oxygen, less fish and more algae. For humans, it also means more nasty bacteria that make people really sick.

4 inches more rain over 100 years. Warmer temperatures mean clouds absorb more water leading to intense rain storms. Credit:

I’m Bummed Out Now. What Can I do?

“Let’s face it, addressing climate change ultimately has to happen at the individual level,” said Raleigh Hood, co-lead researcher on UMCES’s report. “We all are going to have to reduce our emissions. We all need to understand that we have to go to alternative energy sources.” 

Your individual climate actions can make a difference:

Update 4/7/17: I thought readers may find my email conversation with Paul Roberts yesterday interesting. “Laurel- I read yesterday that Georgia, which is the #2 producer of blueberries now (who knew?), lost 98% of this year’s crop due to the early warm-up/late-frost dynamic that we discussed. Closer to home, it’s supposed to be 25 degrees here in Garrett County tonight, and my pear tree buds were just starting to open, so they will be fried. Several inches of snow, to boot.”

Laurel Peltier
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