The Chesapeake Bay is already experiencing the effects of climate change. Key among these is sea level rise: water levels in the bay have already risen one foot, with a predicted increase of 1.3 to 5.2 feet in the next 100 years. This has related environmental effects, causing changes in marine ecosystems, destruction of coastal marshes and wetlands, and intrusion of saltwater into otherwise brackish parts of the bay. Sea level rise also compounds the effects of extreme weather on the bay, making coastal flooding as part of the events more extreme and increasing runoff from upstream in the watershed.
With increases in flooding events and sea level rise, the 11,600 miles of coastline, which include significant historic buildings and modern infrastructure, will be at risk of erosion. Islands such as Holland Island have disappeared due to the rising sea levels.
Beyond sea level rise, other changes in the marine ecosystem due to climate change, such as ocean acidification and temperature increases, will put increasing pressure on marine life. Projected effects include decreasing dissolved oxygen, more acidic waters making it harder for shellfish to maintain shells and changing the seasonal cycles important for breeding and other lifecycle activities. Seasonal shifts and warmer temperatures also mean that there is a greater likelihood of pathogens to stay active in the ecosystem. 
Climate change may worsen hypoxia. However, compared to the current effects of nutrient pollution and algal blooms, climate change’s effect to increase hypoxia is relatively small. Warmer waters can hold less dissolved oxygen. Therefore, as the Bay warms, there may be a longer duration of hypoxia each summer season in the deep central channel of the Bay. However, comparing the effects of climate change and nutrient pollution, reduced nutrient pollution would increase oxygen concentrations more dramatically than if climate change were to level out. 
Climate change adaptation and mitigation programs in Maryland and Virginia often include significant programs to address the communities in the Chesapeake Bay. Key infrastructure in Virginia, such as the port of Norfolk, and major agriculture and fishing industries of the Eastern Shore of Maryland will be directly impacted by the changes in the Bay.