Emissions Mean Rising Sea Temps Here to Stay

     (CN) — The 30-year increase in average ocean temperatures will continue for the foreseeable future, as greenhouse gases continue to build up in the atmosphere.
     In a report by the International Union for Conservation of Nature released last week, scientists explain that the Southern Hemisphere has experienced severe warming over the past decade, with a strong heat buildup in the mid-altitude regions of the Pacific and Indian Oceans.
     “Ocean warming may well turn out to be the greatest hidden challenge of our generation,” the report says.
     While natural patterns such as El Nino and La Nina can have short-term effects on temperatures, and individual storms can influence ocean temperatures for a few months or longer, overall temperature trends by decade reveal human-caused factors that lead to unnatural warming.
     In 2015, most observed ocean surface temperatures registered above average due to conditions caused by El Nino combined with human-induced warming. About a quarter of those observations were record highs.
     Since 1955, more than 90 percent of the excess heat trapped by Earth as a result of increased greenhouse gases has been absorbed by the ocean, an important aspect of climate change that is often overlooked.
     Over the past several decades, more energy has been absorbed than emitted at the top of the planet’s atmosphere and, according to National Oceanic and Atmospheric Administration oceanographer Gregory Johnson, the rate of energy gained between 1970 and 2010 was roughly equal to the power required to run 140 billion 1,500-watt hair dryers over the same time frame.
     The rate has only increased in the past decade.
     “The focus of the report is on gathering facts and knowledge and communicating this to show what is now happening in and to the ocean,” the report says. “We hope that this report will help stimulate further debate and action on such issues.”
     Climate change has already produced several negative effects in marine life, including a disruption of sea urchin sperm fertilization and marine ecosystems in general.
     Storing heat causes oceans to expand, which has caused about one-third of the rise in sea levels over the past decade, scientists have shown.
     While the near-surface ocean requires only a few decades to warm in response to increasing concentrations of greenhouse gases, the deep ocean will take centuries or millennia to heat up — and sea levels will continue to rise.
     “This report represents the most comprehensive review to date on ocean warming,” the report says. “It contains many recommendations from the scientists on capability gaps and research issues that need to be resolved if we are to tackle the impacts of ocean warming with greater confidence in the near future.”

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