Climate change is a rapidly increasing problem in our society. Its effects have significantly impacted oceans and aquatic organisms globally, as animal populations and their habitats deteriorate as a result of rising water temperatures.

In response to the ocean’s increasing water temperatures, fish migrate to  cooler water. Hundreds of species of shellfish and fish rely on a specific water temperature range for survival, and thus will migrate to a different location where the temperature better suits their needs. Scientists have even predicted that, should the current trend of climate change continue to 2050, a substantial amount of fish species will have evacuated the tropics. Already, fishermen in the United Kingdom have reported changes in the types and quantities of fish they are capturing.

In a recent study led by researchers at Rutgers University, scientists predicted that climate change will cause hundreds of species of ocean fish to move northward where the climate is habitable for their population. Using sixteen different climate models, each with a high and low level of greenhouse gas emissions, researchers were able to develop projections for future ocean temperatures around North America. While they discovered that both high and low emission scenarios projected some northward shift, the migration of marine species will be two or three times greater under a high emissions future. Researchers also predicted that some species along the United States and Canadian Pacific coasts will migrate as far as 900 miles away from their original habitat. As a result, commercial fishers must undergo longer commutes. Moreover, the migration of fish affects North American fisheries that depend on Pacific rockfish, Atlantic cod, and black sea bass for commercial purposes.

In addition to the migration of many marine species, climate change also leads to excessive ocean acidification. Currently, oceans absorb one-third of carbon dioxide that humans emit into the atmosphere, approximately 22 million tons each day. The absorption of carbon dioxide into the oceans has benefited humans as it slows down climate change these emissions would have led to if they remained in the air. This service, though significantly slowing down global warming, has been accomplished at a great cost; new research is finding that the excessive amounts of CO2 that enter the oceans is altering water chemistry and overall affecting the life cycles of marine organisms. The average surface ocean pH, the standard measure of acidity, has dropped by 0.1 units. That’s a whole 25 percent increase in acidity, which significantly impacts marine organisms and their ecosystems.

Rising ocean temperatures and acidity have also increased the difficulty for marine organisms, such as shrimp, oysters, and coral to undergo calcification, the process by which they form shells. Many microorganisms that form the base of the marine food chain, such as zooplankton, also have calcium shells. As a result of climate change altering the entire marine food web, the distribution, productivity, and species composition of global fish production are changing. This creates complex impacts on oceans, estuaries and seagrass beds that provide habitats for numerous fish and other marine organisms.