Saturday, April 1, 2017

Sneaky Climate Change in Chesapeake Bay

A pair of apparently unrelated stories about the Chesapeake Bay from yesterday. First, an all too typical, climate change story. The weather is changing and it's all your fault: Research shows significant ways climate already has changed for the Chesapeake
Frost coated the Chesapeake Bay region about 100 times a year in the early 1900s. A century later, there are about 30 fewer chilly mornings.

The number of balmy nights, during which temperatures don't drop below 68 degrees, has grown by a similar margin. Plants spend a month less in winter hibernation than they once did.

Climate change is not an abstract concept about microscopic changes in carbon dioxide levels or subtle rises in sea level, scientists at the University of Maryland Center for Environmental Science say. It's already evident in the Chesapeake.

The center's researchers have gathered more than 100 years of data from continuously monitored sites around the bay to document what has been occurring so gradually that it's mostly unnoticed by area residents.

The scientists analyzed trends in temperature and precipitation, looking at extremes and variability, to show the ways climate has changed, often imperceptibly, over generations. They found that the changes, as subtle as they might seem, have been significant. Rainfall, for example, has increased by more than 4 inches over a century, a gain of 12 percent.

Slightly warmer weather, less frost and more rain? Sounds like North Carolina to me.

What's interesting here is that they start the baseline 100 years ago, around the end of the Little Ice Age, and well before most of the increase in atmospheric CO2, which really picked up a head of steam about 1950. So while the climate may have, indeed almost certainly, warmed, much of that warming occurred before there was much change in ambient CO2. So while there was climate change, we don't really understand what was driving it. Could it be anthropogenic? Maybe, but if so, we don't know what we did.

Climate is generally defined at the 30 year average of a particular weather parameter at a given site. That's long enough to avoid being strongly affected by a few extreme events, but short enough to show change over the course of a human life span. And it's always changing.

In other news Five signs of resilience in Chesapeake Bay health
Since our formation in 1983, the Chesapeake Bay Program has been leading the effort to reduce pollution and restore ecosystem health across the Chesapeake Bay region. Whether through the Chesapeake Bay Watershed Agreement, signed in 2014, or the Bay’s ‘pollution diet’—i.e., the Chesapeake Bay Total Maximum Daily Load (TMDL)—our partners have continued to work collaboratively toward our shared goal of a healthy Bay.

With decades-worth of environmental data, our scientists are able to study how the health of the nation’s largest estuary is changing over time. Below, learn about a few of the ways the Bay and its rivers have been showing signs of resilience:

So is it a crisis or not? I'm slowly coming around to the viewpoint that the Bay has turned a corner.

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