We May Have Already Committed Ourselves to 6-Meter Sea-Level Rise
Even if humanity were to stop throwing carbon dioxide and methane into the atmosphere today, a catastrophic rise in sea levels of six meters may be inevitable. Two previous prehistoric interglacial periods, in which the carbon dioxide content of the atmosphere was believed to be about what it is today, resulted in dramatic rising of the oceans.
High-latitude ice sheets are melting, and given that global warming is most pronounced in the Arctic, it may already be too late stop a rise in sea levels that would flood out hundreds of millions around the world. Two new papers, the latest in a series of scientific studies, paint a picture considerably less rosy than conventional ideas that major damage can still be avoided.
One of these papers, a nine-scientist report led by geologist Andrea Dutton at the University of Florida published in the journal Science, found that modest rises in global temperatures in the past led to sea levels rising at least six meters. She summarized the findings this way to Climate Central:
“Even if we meet that 2°C target, in the past with those types of temperatures, we may be committing ourselves to this level of sea level rise in the long term. The decisions we make now about where we want to be in 2100 commit us on a pathway where we can’t go back. Once these ice sheets start to melt, the changes become irreversible.”
Professor Dutton was referencing the widely held belief that catastrophic damage can be avoided if global warming is held to no more than 2 degrees C. from pre-industrial levels. The “permissible” level may be less than that, however. More sophisticated “sea-level reconstructions” through interdisciplinary studies of geological evidence and better understanding of the behavior of ice sheets enabled the paper’s authors to infer that temperatures only slightly higher than what we are experiencing today upset the climatic balance. A summary of the paper concludes:
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