Photo: Cody Gallo

Taking the Heat

Scripps researcher contributes to major international report showing dangerous consequences of a warming ocean

Climate change is not a problem of the future: it’s happening right now, and action needs to be taken to prevent it from getting worse, said authors of a comprehensive report on the oceans and cryosphere in September.

An Intergovernmental Panel on Climate Change (IPCC) report found that carbon emissions affecting the ocean and cryosphere will ultimately disrupt marine ecosystems that are vital to the survival of human communities and their economies.

Lisa Levin, a Scripps Institution of Oceanography biological oceanographer, represented Scripps in co-authoring the fifth chapter, “Changing Ocean, Marine Ecosystems, and Dependent Communities,” of the IPCC’s Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC). The chapter authors write that the ocean is exhibiting physical and biochemical changes due to carbon emissions from human activity. These emissions have led to the ocean’s warming, acidification, and oxygen loss.

“The ocean is a huge mitigator, combating climate change because it has been taking up a large amount of heat and carbon dioxide from the atmosphere. However, it will become a less effective regulator once it becomes warmer and more acidic,” said Levin. “The ocean alone is not going to solve human problems: humans themselves must be willing to evaluate their choices and reduce carbon footprints.”

Ocean temperatures and sea levels have been rising at a greater pace since the mid-1990s. Going forward, people can expect more extreme repercussions that affect their everyday lives and the ocean services they depend on. Changes in nutrient cycling, species distribution, and primary production will impinge on fisheries and food security.

“I think this is the first time the IPCC has really had a hard and serious focus on the climate and its impacts in the ocean. The report is very integrative across the IPCC working groups. Normally, the physical and chemical changes in the oceans, or the biological responses and social consequences would be treated separately in IPCC reports,” said Levin. “We have all of that together in our chapter.”

IPCC reports are syntheses of published work. This SROCC report focused on knowledge acquired since the last major assessment report, AR5 Climate Change 2014: Impacts, Adaptation, and Vulnerability, which came out in March 2015. Information cannot be included unless it has been peer-reviewed and previously published in academic literature. The IPCC had three major special reports come out this year.

For the SROCC, Levin and other authors had  four in-person meetings with coordinating and lead authors approving research to be included in the report, and addressing thousands of comments from both the government and qualified individuals from all over the world. Levin enlisted the help of other authors involved in the report to help her address sections on the deep sea, where she believes there is still a lot of research to be done.

“We have to make a choice now, about whether we want to tackle climate change and reduce the severity of the upcoming impacts. With inaction, in 50 or more years we will face catastrophic consequences,” said Levin. “We are already committed to some climate change with a much warmer climate and more natural disasters, like marine heat waves and hurricanes.”

Although seafloor habitats are suffering degradation, ecosystems can show improved resilience through conservation efforts and possibly restoration activities. In particular, fostering mangrove forest growth and maintaining salt marshes and sea grass beds to capture blue carbon–which is carbon specifically captured by ocean and coastal ecosystems–can help. But only about 0.5 percent of emissions can be addressed with blue-carbon solutions alone, said the authors.

Further action that can be taken to combat global warming starting today can range from making small to big changes in lifestyle such as walking more, driving electric cars, and reducing carbon footprints by eating less meat, Levin said.

“Most of all, however, we must exercise political will in order to encourage leaders to engage in active changes,” she said. “Change is possible because we have all the tools in hand. We need to leave this planet habitable for the next generation and their children—not just ourselves. We have to reduce the focus on our own convenience and think about how our decisions now will affect the lives of those living in the future.”

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