This past Saturday, I joined the Women’s March in Washington, D.C. While I marched for a number of social justice issues, one of my primary concerns in today’s world is climate change, and the preservation of the scientific community. Since this is a blog dedicated to the Chesapeake Bay, I would like to remind readers of the threats climate change pose to the Bay and the greater watershed.
Sea Level Rise:
Sea level rise is one of the most well known impacts associated with climate change. The most recent projection from climate scientists (March 2016), foresee global waters rising by two meters, or over six feet, by 2100. Sea level rise is already having severe impacts in the region, particularly on Smith and Tangier Islands in the Chesapeake. I visited both islands in 2011, and saw – more noticeably on Smith Island- major portions of the island inundated with water. Although sea barriers can delay impacts, waters are rising on the islands by about 2 feet each year. It is estimated that Smith Island will be completely underwater by the end of the century.
Sea level rise is especially potent in this region due to the natural sinking of land at the southernmost part of the Chesapeake Bay watershed. We’re seeing the biggest impact on our islands, but coastal towns and cities are facing sea level rise as well. Because of climate change and land subsidence, the Hampton Roads area for instance, is “experiencing the highest rates of sea level rise along the entire U.S. East Coast,” (WRI, 2014).
Coastal Flooding & Shoreline Erosion:
Related to sea level rise are the issues of coastal flooding and shoreline erosion. Sea level rise contributes to shoreline erosion and leads to an increase in flooding incidents. Cities in Southeast Virginia will be especially vulnerable to increased coastal flooding events (VIMS, 2012). Cities further north in the watershed are seeing a rise in coastal flooding events too. Annapolis reports that floods occur ten times as often as they did in the 1950s (CBP, 2016).
Miles of coastline along the southern Chesapeake region have been eroded; sea level rise may be playing a part (see former post here on Dameron Marsh and Hughlett Point).
Ocean acidification is the acidifying of marine waters as the ocean absorbs carbon dioxide (CO2) from the atmosphere. It is unclear how much of the Bay watershed will be impacted by acidification, however acidification could impact several species in the Bay. Shellfish make their shells out of calcium carbonate. As waters absorb CO2, and water chemistries change, certain shellfish face difficulties building their shell. This is true for the Eastern oyster found in the Chesapeake Bay, whose shells would become more brittle in acidified waters, and leave them more vulnerable to other threats.
Oysters are making a major comeback in Virginia, but the oyster farms and the restaurants that have emerged around this industry in recent years would face the biggest economic losses if and when Bay waters become more acidic.
Scientists are still studying how ocean acidification will impact the blue crab population in the bay (studies are being undertaken at institutions like UMCES). Crabs form their shells differently than oysters, and acidification may actually strengthen the shells of blue crabs. However, a researcher at UMCES has found that juvenile crabs grow more slowly in acidic waters. Given that juvenile crabs are threatened by other environmental issues in the Bay- such as the loss of seagrass habitat- ocean acidification could play a part in reducing blue crab population numbers.
Temperatures of regional bodies of water have been rising in correlation with rising air temperatures. Over the past 50 years, stream temperatures in all six Bay states (NY, WV, DE, MD, PA and VA) and in Washington, D.C. have risen by an average of 1.2 degrees F and up to 2.2 degrees F (CBP, 2016; EPA, 2016). This may not seem like a major increase to us, but it can be to marine species. Warming waters – even seemingly small increases in temperature- can contribute to dead zones and algal blooms. Cold-water fish species are more likely to be displaced by fish that thrive in warmer waters. Warmer waters can also impact fish and plant growth and reproduction.
Scientific studies – including data collection and modeling- play a crucial role in understanding how our climate is changing, and how our environment and wildlife will respond to these changes, both in the Chesapeake Bay watershed and beyond. We must continue to support the collection of data and dissemination of scientific reports on our environment.