All day long a flood of thousands scientists and students ebbs and flows across San Francisco’s 4th Street and Howard Avenue, coursing between the cavernous Moscone West and Moscone South convention buildings. The AGU is like a supercomputer of earth science, with human currents of data swapping information, heading from one talk to another, processing what they’ve heard, who they’ve met, what’s coming next.
What’s coming next in New York City, sooner or later, is a long dry spell, according to research by Lamont-Doherty’s Neil Pederson. The city has seen repeated shortages of water over the past 20 years — even though the climate has been relatively wet over the past few decades, and despite a decline in overall water use. Pederson says the water system emergencies of recent years suggest that “maybe the system is not in tune with the climate.”
Ultimately, he said in a talk today at AGU, New York City “is not prepared for the next significant drought.”
Pederson and his colleagues looked at 12 species of trees along the Hudson River Valley and, combined with research by Ed Cook, director of Lamont’s Lamont’s Tree Ring Lab, and others, constructed a record of rain and drought going back into the 1500s. There are still a few trees around who’ve seen four or more centuries pass, Pederson said, including on in the Hudson Valley dating to the early 1500s. Additional records researched by Cook come from the beams cut for now-historic homes built in the 18th century, Pederson added.
The use of 12 species has expanded the accuracy of the chronology, Pederson believes, though it’s hard to gauge by how much just yet. He found that the region has suffered severe droughts in every century through the 1800s. But except for a short period in the 1960s, the dry periods over the past 120 years have been relatively minor. Is the New York City region due for another paleo-scale drought?