news: democratic national convention

u.s. presidential candidate jill stein cites a study by a leading climate scientist that predicts a 2-meter or greater increase in sea levels as soon as 50 years from now.(p o: daniel o/the news journal)

the media: internet.

who said it: jill stein.

race: u.s. president.

party: green party.

the comment: "jim hansen, the foremost climate scientist is predicting meters-worth ... of sea level rise as soon as 50 years from now."

the forum: news conference.

what we're looking at: whether the study stein cites predicts a 2-meter or greater increase in sea levels as soon as 50 years from now, and how credible that study is.

analysis: stein stated her claim during a news conference in washington, d.c., to discuss her visit to areas of louisiana affected by recent floods. during the news conference she talked about how climate change contributes to such emergencies and discussed her “green new deal” — an agenda to tackle problems of climate change connected to the u.s. economy.

stein referenced a study by james hansen, a renowned climate scientist and professor at columbia university. the study mentions “several meters” of sea level rise during a time frame of 50-150 years.

the study outlines a particularly disastrous situation where ice loss from greenland and antarctica will increase exponentially. and it predicts the ice loss will “yield multi-meter sea level rise in about 50, 100 or 200 years.”

but other climate scientists view the study as an outlier relative to the scientific consensus.

jonathan bamber, a physical geog hy professor at university of bristol who studies sea levels and how they are affected by climate change, told az fact check in an email: “the claim that sea level could rise by multiple meters within 50 years is not supported by numerous other studies and i do not find this a credible prediction.”

bamber wrote that hansen’s scenario is still unlikely, even within 150 years. scientific consensus references the u.n.’s intergovernmental panel on climate change, which predicts sea levels will rise by up to a meter by 2100.

jonathan overpeck, co-director of the institute of the environment at university of arizona, told az fact check: “the big ice sheets of greenland and antarctica take centuries to millennia to fully adjust to warmer temperatures. unfortunately, the time scale of adjustment is not well known, so there are some leading climate scientists who think future sea level rise could be faster and larger.” he puts hansen in this group that predicts this scenario of accelerating rises in sea level.

john englander, president of the international sea level institute, told az fact check that the paper stein referenced is good science, but is a step beyond the scientific mainstream.

“usually scientists are asked ‘what will happen’ and with what statistical probability or certainty. if you ask what ‘could happen,’ rather than will happen, you get a very different answer. it depends on what odds you are willing to take a risk,” he wrote in an email.

englander said the problem is that scientists can’t predict how soon greenland and antarctica will destabilize.

“we simply do not know. we do not have enough data to calculate the odds. so we either ume the worst — as she (stein) suggests — or hope for the best and are not prepared if the worst happens. my personal preference would be to go with her view,” he wrote in an email.

bottom line: stein correctly cites the study by a respected climate scientist, but references the lower end of the time scale for the predicted changes in sea level. the study itself, however, predicts a highly disastrous scenario that doesn’t match general scientific consensus. stein's claim amounts, therefore, to an exaggeration of what most scientists expect will occur.

the finding: two stars: somewhat false/somewhat true.

sources: green party presidential nominee jill stein news conference; power to the people plan; ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 ºc global warming could be dangerous.

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