Tag Archives: sea level

Rising seas alert! Watch how science becomes a sensational news story.

Summary: Another day, another interesting study about our changing climate misreported by journalists to ignite fear in their readers. The subject is rising seas from the melting of Antarctica. First we look at the science, then at journalists’ hype. You decide how this news should influence the public policy debate about the best response to climate change.

Greenpeace artwork about sea levels

Example of Greenpeace at work.

Contribution of Antarctica to past and future sea-level rise

Robert M. DeConto & David Pollard in Nature, 31 March 2016

Abstract

“Polar temperatures over the last several million years have, at times, been slightly warmer than today, yet global mean sea level has been 6–9 metres higher as recently as the Last Interglacial (LIG, 130,000 to 115,000 years ago) and possibly higher during the Pliocene epoch (about three million years ago). In both cases the Antarctic ice sheet has been implicated as the primary contributor, hinting at its future vulnerability.

“Here we use a model coupling ice sheet and climate dynamics — including previously underappreciated processes linking atmospheric warming with hydrofracturing of buttressing ice shelves and structural collapse of marine-terminating ice cliffs — that is calibrated against Pliocene and Last Interglacial sea-level estimates and applied to future greenhouse gas emission scenarios. Antarctica has the potential to contribute more than a metre of sea-level rise by 2100 and more than 15 metres by 2500, if emissions continue unabated. In this case atmospheric warming will soon become the dominant driver of ice loss, but prolonged ocean warming will delay its recovery for thousands of years.”

About the study

Their predictions of rising sea levels

Here is the core of the study’s forecast. Red highlight added to their key finding.

Continue reading

The New Yorker’s “The Siege of Miami” reveals a serious problem

Summary: Today’s post examines a recent example of climate fear-mongering. Not only is this misleading (at best), but it shows how this propaganda makes it more difficult for us to clearly see the world and respond to its many dangers.

AR5: projections of rising sea level

Today’s fear-mongering: “The Siege of Miami

By Elizabeth Kolbert in The New Yorker
“As temperatures climb, so, too, will sea levels.”

The city of Miami Beach floods on such a predictable basis that if, out of curiosity or sheer perversity, a person wants to she can plan a visit to coincide with an inundation. Knowing the tides would be high around the time of the “super blood moon,” in late September, I arranged to meet up with Hal Wanless, the chairman of the University of Miami’s geological-sciences department. Wanless, who is seventy-three, has spent nearly half a century studying how South Florida came into being. From this, he’s concluded that much of the region may have less than half a century more to go.

… According to the Intergovernmental Panel on Climate Change, sea levels could rise by more than three feet by the end of this century. The United States Army Corps of Engineers projects that they could rise by as much as five feet; the National Oceanic and Atmospheric Administration predicts up to six and a half feet. According to Wanless, all these projections are probably low. In his office, Wanless keeps a jar of meltwater he collected from the Greenland ice sheet. He likes to point out that there is plenty more where that came from.

“Many geologists, we’re looking at the possibility of a ten-to-thirty-foot range by the end of the century,” he told me.

Fear-mongering like this is the path to fame for journalists and scientists in today’s America. Let’s look at Kolbert’s well-written propaganda.

“According to the Intergovernmental Panel on Climate Change, sea levels could rise by more than three feet by the end of this century.”

That is the high-end of the range to the worst of the four scenarios considered by the IPCC’s AR5 (RCP8.5; see the graph above).  Professor Wanless forgets to mention that the low-end for that scenario is only 21 inches, that RCP8.5 makes unlikely assumptions about population and technology (e.g., the late 21stC is a coal-burning world like the late-19th), and that the IPCC gives only “medium confidence” to their sea-level projections. See AR5’s conclusions here.

Continue reading

Assigning blame for the flooding of Pacific atolls

Summary: Polar bears and pacific atolls (flooded by rising seas) are the poster children for climate change. Oddly, both are weak examples. Previous posts discussed polar bears. Here Judith Curry (Prof Atmospheric Science, GA Inst Tech) discusses the effect of rising sea levels on coral atolls.

Fanning Island, Kiribati

Fanning Island, Kiribati

Kiribati crisis: the blame game

Small atoll islands may grow, not sink, as sea level rises.
Judith Curry, posted at Climate Etc, 1 November 2015
Reposted under her Creative Commons License

Recent headlines highlight the plight of Kiribati:

Can we blame climate change, or more specifically sea level rise, for the problems of the atoll islands?  From a June 2 article in the New Scientist Small atoll islands may grow, not sink, as sea level rises, we find:

Rising seas are eating away at small islands and will eventually turn their inhabitants into climate refugees, right? Not so for some of the world’s most threatened islands, which have grown despite experiencing dramatic sea level rise.

After poring over more than a century’s worth of data, including old maps and aerial and satellite imagery, they conclude that 18 out of 29 islands have actually grown. As a whole, the group grew by more than 18 hectares, while many islands changed shape or shifted sideways. “There is still considerable speculation that islands will disappear as sea level rises,” says Kench. “Our data indicates that the future of islands is significantly different.”

Storms and other disturbances that churn up the sea seem to be more important than sea level in influencing stability, says Kench. Storms break up coral, which then gets deposited on the atolls. He says other coral reef islands are likely to evolve in the same way, and that the Maldives seem to be showing a similar effect.

“There will be less emphasis on external migration of ‘environmental refugees’ from atoll nations that has gained such prominence in the last few years,” he says. But he notes that the atoll-building sediment comes from productive coral reefs, which face a range of threats such as warming oceans and pollution.

Continue reading