Horn Point sci­en­tist talks cli­mate change in Ch­e­sa­peake Bay

Kent County News - - NEWS - By KAYLA RI­VAS kri­[email protected]­dem.com

ST. MICHAELS — Univer­sity of Mary­land’s Horn Point Lab­o­ra­tory of­fered a pro­gram called “Chang­ing Ch­e­sa­peake: What’s in store for the Eastern Shore” on Dec. 3 at the St. Michaels branch of the Tal­bot County Free Library.

The pur­pose of the lec­ture se­ries is to have an ed­u­cated cit­i­zenry on the Eastern Shore, ac­cord­ing to Horn Point Direc­tor Mike Ro­man.

Cli­mate sci­en­tist Dr. Vic­to­ria Coles led an in­ter­ac­tive pre­sen­ta­tion to about 35 peo­ple, ex­am­in­ing global cli­mate change on a lo­cal ba­sis.

Coles drew on re­search from her find­ings dat­ing back two years. The study ex­am­ined weather sta­tions po­si­tioned close to the Ch­e­sa­peake Bay. Data trends over the past cen­tury ul­ti­mately re­vealed fewer frost days, more heat events and more rain in big events.

While the sci­en­tist ac­knowl­edged that the au­di­ence may al­ready be aware of such facts, the data con­firmed ev­i­dence of global cli­mate change on a lo­cal ba­sis.

In the early 1900s, the per­cent­age of days with daily highs be­low the 10th per­centile — or top 10 per­cent of cold­est days — num­bered about 17, whereas now the statis­tic has dropped to just eight, ac­cord­ing to Coles’ re­search.

Night­time tem­per­a­tures are warm­ing faster than day­time tem­per­a­tures, Coles said. At the start of the 20th cen­tury, the per­cent­age of days with daily lows above the 90th per­centile num­bered nine, as op­posed to about 13 days as of re­cent.

The sci­en­tist said the rain­fall from heavy events is in­creas­ing; how­ever, an­nual rain­fall has re­mained the same. There­fore, lo­cal ar­eas are ex­pe­ri­enc­ing a small in­crease of con­sec­u­tive dry days.

One au­di­ence mem­ber ques­tioned ac­cu­racy in the data, given its lengthy time­frame.

Coles said the num­bers are sup­ported by a to­tal of 146 weather sta­tions, 27 of which had data from 1900 to 1920.

“For pre­cip­i­ta­tion, I’m not so sure that they’re ex­cel­lent, but for tem­per­a­ture they’re not so bad,” she said.

Like­wise, Coles said there is con­fi­dence in long-term pro­jec­tions, but not so much in the next decade.

The sci­en­tist also pointed out some as­pects have not changed sig­nif­i­cantly.

“We don’t seem to be get­ting max­i­mum changes in the ab­so­lute min­i­mum tem­per­a­ture we ob­serve over time,” she said. “We still are go­ing to hit freez­ing con­di­tions, and we will get snow all the way pro­jected into the fu­ture.”

A ma­jor topic of dis­cus­sion was grow­ing sea­son length, which is de­fined as the num­ber of days that crops can grow and Coles said is specif­i­cally de­fined by wheat.

Since 1910, the length of the grow­ing sea­son has in­creased by more than 30 days, ac­cord­ing to www. chesa­peake­data.com/chang­ingch­esa­peake.

With spring be­gin­ning ear­lier and win­ter start­ing later, Coles said farm­ers could po­ten­tially do dou­ble crop­ping, or two crops in every year.

Risks, how­ever, can in­clude crop losses in wet or freez­ing springs and ex­cess nu­tri­ents from agri­cul­ture seep­ing into wa­ter bod­ies.

“Tem­per­a­ture in­creases ac­tu­ally hurt crop yield in some cases,” Coles said. “When there is an in­crease in tem­per­a­ture by one de­gree, farm­ers might be able to dou­ble crop but crop yields will lower as a re­sult of the in­creas­ing tem­per­a­tures.”

Coles said sub­merged aquatic veg­e­ta­tion like sea grasses ex­pe­ri­ence heat stress when wa­ter tem­per­a­tures are above 30 de­grees Cel­sius for an ex­tended pe­riod of time.

She asked the crowd to think about restor­ing grasses that are less heat sen­si­tive, and there­fore sug­gested against re­plant­ing Zostera.

In shal­low ar­eas of the Bay, there is a tight cou­pling be­tween at­mo­spheric tem­per­a­tures and wa­ter tem­per­a­tures, which breaks down at the freez­ing point, with a oneto- one cor­re­la­tion be­tween the two, Coles said.

“Marshes are gain­ing sed­i­ment — some are los­ing el­e­va­tion and sink­ing faster,” she said. “Sea level rise is over­whelm­ing their abil­ity to ab­sorb sed­i­ment.”

The marsh ecosys­tem is cen­tral to re­mov­ing nu­tri­ents be­fore they en­ter the Bay, she said.

“We should make sure we don’t over­build be­hind the marshes so they aren’t able to re­treat up the land­scape,” Coles said.

Ac­cord­ing to Coles, global sea rise is at about 3 mil­lime­ters per year.

“Science is sug­gest­ing that we need peo­ple in the com­mu­nity to be hon­est, trusted sources,” Coles said. “It takes peo­ple talk­ing amongst them­selves in the com­mu­nity to sort of open that dis­cus­sion and get ... peo­ple think­ing more about cli­mate change. We have to go out and in­tro­duce those top­ics to them. And start re­spond­ing.”


Horn Point Lab cli­mate sci­en­tist Vic­to­ria Coles says the com­mu­nity needs to open dis­cus­sion about cli­mate change, and start re­spond­ing to it.

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