Increasing temperatures, ocean acidification, and deoxygenation are the outcomes from climate change that will cause the most damage the world’s marine economy, according to National Climate Assessment report released by the U.S. Global Change Research Program on Friday, 23 November.

The federal program that released the report was mandated by Congress to coordinate federal research and investments in understanding the forces shaping the global environment and their impacts on society. Compiled by top scientists at 13 U.S. agencies, it paints a grim picture of the future of both U.S. and global fisheries as the effects of climate change continue to advance.

The report stated with “very high confidence” that the world stands to suffer “the loss of iconic and highly valued” habitats, and said intensifying ecosystem disruption as a result of ocean warming, acidification, deoxygenation, and other aspects of climate change will result in major changes in species composition and food web structure. In fact, these changes are already underway and have caused significant shifts in how the marine environment is functioning, especially in the warmest and coldest environments, and the report stated – also with very high confidence – these transformative impacts on ocean ecosystems cannot be avoided In the absence of significant reductions in carbon emissions.

“Warming, acidification, and reduced oxygen conditions will interact with other non-climate-related stressors such as pollution or overfishing,” the report said. “Conservation measures such as efforts to protect older individuals within species, maintain healthy fish stocks, and establish marine protected areas can increase resilience to climate impacts. However, these approaches are inherently limited, as they do not address the root cause of warming, acidification, or deoxygenation. There is growing evidence that many ecosystem changes can be avoided only with substantial reductions in the global average atmospheric CO2 concentration.”

When it comes to fisheries, the impacts of climate change are hard to predict with precision, as the effects of each aspect of climate change are likely to compound the others, causing cascading effects across ecosystems. The report notes that differences in how species respond to changing physical conditions could lead to drastic shifts in both the abundance of certain species, and the locations where they may be found in the future, as they abandon areas where conditions are no longer favorable to them, or as they seek to colonize new locations that may be more amenable to their existence. And this is likely to happen around the world – the report found that 86 percent of global marine ecosystems will experience combinations of temperature and acidification that have never before been experienced by modern species.  Read the article.

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