Toll of climate change on the oceans – will take thousands of years to recover
the abrupt fluctuations offer a glimpse at the duration of the effects of climate change driven by human activity pumping more planet-warming gases into Earth’s atmosphere, Moffitt said.
“What this shows us is that there are major biomes on this planet that are on the table, that are on the chopping block for a future of abrupt climate warming and unchecked greenhouse gas emissions,” Moffitt said. “We as a society and civilization have to come to terms with the things that we are going to sacrifice if we do not reduce our greenhouse gas footprint.
Oceans might take thousands of years to recover from climate change, study suggests, SMH, April 2, 2015 Geoffrey Mohan Naturally occurring climate change lowered oxygen levels in the deep ocean, decimating a broad spectrum of seafloor life that took some 1,000 years to recover, according to a study that offers a potential window into the effects of modern warming.
Earth’s recovery from the last glacial period, in fact, was slower and more brutal than previously thought, according to the study, published online Monday in the journal Proceedings of the National Academy of Sciences.
Researchers deciphered that plotline from a 30-foot core of sea sediments drilled from the Santa Barbara Basin off the coast of California containing more than 5,000 fossils spanning nearly 13,000 years.
“The recovery does not happen on a century scale; it’s a commitment to a millennial-scale recovery,” said Sarah Moffitt, a marine ecologist at the University of California, Davis’ Bodega Marine Laboratory and lead author of the study. “If we see dramatic oxygen loss in the deep sea in my lifetime, we will not see a recovery of that for many hundreds of years, if not thousands or more.”………
beginning around 13,500 years ago, the seafloor community began a slow recovery with the rise of grazers that fed on bacterial mats. Recovery eventually was driven by a fluctuation back toward glaciation during the Younger Dryas period, a cooling sometimes called the Big Freeze.
“The biological community takes 1,000 years to truly recover to the same ecological level of functioning,” Moffitt said. “And the community progresses through really interesting and bizarre states before it recovers the kind of biodiversity that was seen prior to the warming.”……..
The climate changes chronicled in the study arose from natural cycles involving Earth’s orbit of the sun, and the oxygen declines that ensued were more extreme than those that have occurred in modern times, the study noted.
Still, the abrupt fluctuations offer a glimpse at the duration of the effects of climate change driven by human activity pumping more planet-warming gases into Earth’s atmosphere, Moffitt said.
“What this shows us is that there are major biomes on this planet that are on the table, that are on the chopping block for a future of abrupt climate warming and unchecked greenhouse gas emissions,” Moffitt said. “We as a society and civilization have to come to terms with the things that we are going to sacrifice if we do not reduce our greenhouse gas footprint.” http://www.smh.com.au/environment/climate-change/oceans-might-take-thousands-of-years-to-recover-from-climate-change-study-suggests-20150401-1md7qk.html
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