Nearly 66% of the ocean and 77% of marine national jurisdictions show increased impact from human stressors, reports a paper in Nature Communications this week. The research, which measured changes from 2008 to 2013, suggests that most of this increase is driven by climate change pressures.
Many human activities, such as pollution, commercial shipping and sea level rise, put pressure on marine ecosystems. In many areas little is known about which stressors are having the biggest impact, how these stressors change over time and what their cumulative effects are.
Benjamin Halpern and colleagues model cumulative impacts in marine ecosystems from fishing, climate change, and ocean- and land-based stressors, globally over five years. They find that five percent of the ocean is heavily impacted, with increasing pressures requiring immediate attention. Certain individual stressors showed regional decreases such as demersal destructive fishing (trawling) in many European countries and pelagic high bycatch (long-line) fishing in parts of the Middle East.
Overall, their results indicated that global increases in climate change stressors (sea-surface temperature anomalies, ocean acidification and ultraviolet radiation) were the main drivers behind the increases in human impact. In addition, while there are signs of decreasing cumulative impact of certain stressors, the results show that impact across the board is generally increasing, especially in coastal areas. The results confirm the importance of addressing climate change to maintain and improve the condition of marine ecosystems and the authors hope that the study might provide guidance about where to prioritize management efforts.