Coastal ecosystems are highly interconnected. Because of this network effect, the resilience of coastal ecosystems (like coral reefs) from climate change impacts depends in part on the degree of connectivity and support from the neighboring coastal ecosystems. Coral is a large part of many tropical coastal habitats, and the loss of this important ecosystem infrastructure contributes to fragmentation of coastal waters and the loss of critical habitat for many endemic species.
One major climate change threat to coral populations is ocean acidification, which is tied to increased carbon dioxide in the atmosphere. As atmospheric carbon dioxide levels increase, an increasing amount will be dissolved into the ocean water. Over time this increase in carbon dioxide leads ocean pH to become more acidic. Food webs in the ocean can be negatively impacted by this change, and even the smallest change in water acidity can disrupt ecosystem processes.
This past May, the National Oceanic and Atmospheric Administration reported the highest levels of carbon dioxide ever measured at the Mauna Loa Atmospheric Baseline Observatory at almost 420 parts per million. This announcement was made in collaboration with scientists from both NOAA and the University of California San Diego’s Scripps Institute of Oceanography. Charles David Keeling, a Scripps’s scientist, began recording atmospheric measures of carbon dioxide at the Mauna Loa in 1958. This makes it the oldest continuous carbon dioxide measurement station in the world and is considered to be the primary global benchmark.
Although some people predicted that atmospheric levels of carbon dioxide would decline as a result of the COVID-19 pandemic and its impact on the global economy, this is unlikely. There is large annual natural variability in carbon dioxide released by natural processes, and this variability swamps out the only modest decrease in overall emissions. As a result, the small decline as a result of the pandemic will not lead to overall decreased levels of carbon dioxide in the atmosphere because of its relatively short time frame.
Resources
McManus, L.C., Forrest, D.L., Tekwa, E.W., Schindler, D.E., Colton, M.A., Webster, M.M., Essington, T.E., Palumbi, S.R., Mumby, P.J. and Pinsky, M.L., 2021. Evolution and connectivity influence the persistence and recovery of coral reefs under climate change in the Caribbean, Southwest Pacific, and Coral Triangle. Global Change Biology. DOI: 10.1111/gcb.15725.
