Left: Current edition of NOAA chart 13279 / Right: 1912 edition of chart 243.
From NOAA by Nick Perrugini
Most NOAA Office of Coast Survey customers have a practical mariner’s
bent—they are interested in up-to-date and accurate navigational
products and services.
However, an increasing number of customers are
using Coast Survey online resources for historical research.
In May 2017, Coast Survey received an inquiry via the Inquiry and Discrepancy Management System (IDMS) that illustrates this point. Original message: My dad is from Manchester-By-Sea, MA. There is a
ledge on the NAUTICAL charts, “Kitfield Ledge”. Is there a place where
we can get some history, when it was named, and how it came about. We
have not been able to find any information on that. My dad was born in
1926, and he and his dad, used to lobster off of Black Beach in the
1930’s. We were back there 2 years ago and did some research at the Cape
Ann Museum, but were not able to locate any information. Appreciate any
help you may be able to provide. Thank you.
Kitfield Ledge with the GeoGarage platform & Google Maps search
Kitfield Ledge with the GeoGarage ENC platform and Bing satellite imagery (ENC with depths in meters)
The first step in solving this mystery was to locate Kitfield Ledge on
the current chart.
Using the “Place Names” search in the Chart Catalog, Kitfield Ledge was located on the current edition of chart 13279.
Using the Historical Map & Chart Collection,
I was able to trace the name back to Coast and Geodetic Survey Chart
243 published in 1912.
An historic nautical chart of Ipswich Bay to Gloucester Harbor,
Massachusetts published in 1912 by the U.S. Coast & Geodetic Survey
showing topography, water depths in fathoms, and nautical features.
Interesting….but where to go from here?
I then
accessed the hydrographic surveys archive maintained by NOAA’s National Center for Environmental Information (NCEI, formerly NGDC).
Using the interactive map interface for bathymetric data,
I was able to view and download an 1896 hydrographic survey that showed
Kitfield Ledge.
Geographic name references are not always included in
hydrographic survey descriptive reports, however to my surprise,the
following note was discovered in the hand written descriptive report.
(Transcription)
“Kitfield’s Ledge. This ledge lies SW of Crow Island with a
least depth of 2 ½ fathoms. It is covered with kelp and Crow Island
Rock is situated on it. Its name was derived from the fact that at old
woman, Granny Kitfield by name, used to fish for cod on it with much
success.“
Granny Kitfield must have been quite an angler to have a rocky ledge named after her!
The Granny Kitfield inquiry, and its resolution, illustrates that
Coast Survey (and other organizations within the National Ocean Service)
offer impressive online resources to assist in historical research.
Many customers are interested in what shoreline or coastal features
looked like a century ago.
Others are interested in where a currently
charted feature (like a wreck) originated.
Resources that may help
customers interested in historical research include:
Historical information about charted features: Coast Survey’s Marine
Chart Division’s Nautical Data Branch does a stellar job of tracking
down the origin of currently charted features.
So go ahead, check these resources out.
Mysteries of the deep are
waiting to be discovered—or maybe you’ll find another one of Granny
Kitfield’s favorite fishing spots.
Neither company sets targets to reduce emissions and BP’s total
investment in renewable and clean technologies has actually shrunk since
2005, the report said
Companies are trying to 'have their oil and drink it' by committing to 2°C in public while planning for much higher temperature rises, says shareholder campaign group, ShareAction
Oil giants Shell and BP are planning for global temperatures to rise as much as 5°C by the middle of the century.
The level is more than double the upper limit committed to by most countries in the world under the Paris Climate Agreement, which both companies publicly support.
The discrepancy demonstrates that the companies are keeping shareholders in the dark about the risks posed to their businesses by climate change, according to two new reports published by investment campaign group Share Action.
Many climate scientists say that a temperature rise of 5°C would be catastrophic for the planet.
ShareAction claims that the companies’ actions put the value of millions of people's pensions at risk.
Two years after BP and Shell shareholders voted resoundingly in favour of forcing the companies to make detailed disclosures about climate risks, the companies have made unconvincing steps forward, according to the reports.
ShareAction said that Shell and BP are meeting their legal requirements, but are putting shareholders’ capital at risk because of numerous failings in their plans for the future.
Neither company sets targets to reduce emissions and BP’s total investment in renewable and clean technologies has actually shrunk since 2005, the reports said.
That’s despite the company’s public-facing image of being “beyond petroleum”.
BP invests just 1.3 per cent of its total capital expenditure in low-carbon projects while Shell has pledged to invest 3 per cent of its annual spend on low-carbon by 2020.
Both companies assess the resilience of their businesses against climate models in which temperatures warm by between 3°C and 5°C.
A maximum warming of 2°C beyond pre-industrial levels is the central aim of the landmark Paris climate agreement, which both firms say they support.
It is widely believed that any warming beyond 2°C could cause serious and potentially irreversible changes to the climate.
Shell reaffirmed its commitment to the Paris Agreement in a statement publicising its most recent AGM.
“Shell has a clear strategy, resilient in a 2°C world,” the company said, but its change modelling document states that “the emissions pathways until the middle of the century overshoots the trajectory of a 2°C goal”.
ShareAction’s report also found that top executives at both Shell and BP are still given incentives to pursue strategies centred on oil and gas and are paid bonuses over three to six years for fossil fuel projects that could have damaging effects for shareholders decades later.
Michael Chaitow, senior campaigns officer at ShareAction, said the report revealed an “uncomfortable discrepancy” between Shell and BP’s public support for a low-carbon economy and their actual business planning.
“Shell and BP want to have their oil and drink it too, by advocating for the landmark Paris Agreement to limit global temperature rises to below 2°C degrees, while planning for scenarios that would violate it,” he said.
The group called on Shell and BP shareholders, which include powerful institutional investors, to demand that the two oil companies do more to tackle climate change.
In 2015, more than 98 per cent of shareholders in both Shell and BP voted for resolutions that require the companies to regularly report on their emissions, resilience to climate change, investment in low-carbon technology and executive incentives.
The resolutions helped pave the way for subsequent shareholder resolutions on climate-related disclosure at oil and gas companies including Exxon and Occidental Petroleum.
Following the Shell and BP resolutions, billionaire businessman and former New York Mayor, Michael Bloomberg, founded a task force to press companies to properly disclose to the world the risks that climate change presents.
Catherine Howarth, chief executive of ShareAction, said the chief executives of both Shell and BP are running companies that look “poorly prepared for the speed of technological and economic change now underway in the global energy market”.
She added: “Millions of pension savers are exposed to Shell and BP’s shares. These reports challenge the professional investors looking after our pension savings to manage the growing financial risks facing BP and Shell more actively in the coming year.”
Neither BP nor Shell would comment on the report directly.
BP said it “anticipates a range of scenarios to give us flexibility in our approach".
Shot just off the coast of Ilulissat , the best western Greenland has to offer, covering vast glaciers, icebergs and Icefjords melting away.
Rising air and sea temperatures is causing the massive Greenland ice sheet to shed 300 gigatons of ice a year into the ocean, the single largest source of sea level rise from melting ice!
Climate change could lead to sea level rises that are larger, and happen more rapidly, than previously thought, according to a trio of new studies that reflect mounting concerns about the stability of polar ice.
In one case, the research suggests that previous high end projections for sea level rise by the year 2100 — a little over three feet — could be too low, substituting numbers as high as six feet at the extreme if the world continues to burn large volumes of fossil fuels throughout the century.
“We have the potential to have much more sea level rise under high emissions scenarios,” said Alexander Nauels, a researcher at the University of Melbourne in Australia who led one of the three studies.
His work, co-authored with researchers at institutions in Austria, Switzerland, and Germany, was published Thursday in Environmental Research Letters.
The results comprise both novel scientific observations — based on high resolution seafloor imaging techniques that give a new window on past sea level events — and new modeling techniques based on a better understanding of Antarctic ice.
The observational results, from Texas and Antarctica, examine a similar time period — the close of the last Ice Age a little over 10,000 years ago, when seas are believed to have risen very rapidly at times, as northern hemisphere ice sheets collapsed.
Off the Texas coast, this would have inundated ancient coral reefs. Usually, these reefs can grow upward to keep pace with sea level rise, but there’s a limit — one observed by a team of scientists aboard a vessel called the Falcor in 200 foot deep waters off the coast of Corpus Christi.
These so-called drowned reefs showed features that the researchers called “terraces,” an indicator of how the corals would have tried to respond to fast rising sea levels.
Because the organisms must maintain access to a certain amount of sunlight, they would have tried to grow higher to keep up with fast rising seas — but they wouldn’t have been able to do so over a very large area.
And so their growth became concentrated in progressively smaller, stepped regions:
A 3-D representation of Dream Bank, a long-dead reef offshore South
Texas.
The vertical scale of the image has been increased to clearly
illustrate the terrace structures that form due to rising sea levels via
a process known as backstepping.
(Image courtesy of P. Khanna/Rice
University)
“The reef under stress often has a tendency to kind of shrink to this higher elevated area,” said André Droxler, one of the authors of the study in Nature Communications and a researcher at Rice University.
“It creates this pyramid-like system.” (Droxler completed the research with colleagues from Rice and Texas A&M University, Corpus Christi.)
The youngest drowned corals date to the end of the last ice age, around 11,500 years ago — corresponding to what scientists believe were large warming events in the northern hemisphere and so-called meltwater pulses from now melted ice sheets.
And multiple drowned reefs off Texas show a similar pattern — and terminate in similar water depths.
“Over 120 kilometers, the reefs behaved the same way. It’s difficult to find any other reason why they would do this,” Droxler said.
Droxler thinks the reef structures suggest eras when sea level was rising by tens of millimeters annually, far beyond the current, roughly 3 millimeters per year.
(A 50 millimeter annual sea level rise would produce a meter, or over 3 feet, of rise every 20 years.)
The new study therefore concludes that during the last ice age, there were multiple bursts of fast sea level rise — and implies that our future could hold something similar.
“The steady and gradual sea-level rise, observed over the past two centuries [may] not be a complete characterization of how sea level would rise in the future,” the study concludes.
Meanwhile, far away in the Southern hemisphere, a team of scientists used a very similar seafloor mapping technology to detect ancient iceberg “plough marks” etched deep into the seafloor of Pine Island Bay, an ocean body that currently sits in front of one of West Antarctica’s most worrying glaciers, Pine Island.
The results were published in the journal Nature on Wednesday by researchers at the University of Cambridge, the British Antarctic Survey, and the Bolin Center for Climate Research in Stockholm.
The seafloor grooves, the researchers believe, were made during a similar era to the Texas coral steppes (the close of the last ice age), and signal a very rapid retreat of Pine Island over roughly a thousand years.
Here’s what they looked like in the seafloor imagery the study produced:
Linear-curvilinear iceberg-keel ploughmarks on the surface of a
large grounding-zone wedge located in the mid-shelf Pine Island Trough,
West Antarctica. (Martin Jakobsson)
What’s critical about the markings, explains lead study author Matthew Wise of the University of Cambridge, is their maximum depth — 848 meters, or around 2,800 feet.
Because ice floats with 10 percent of its mass above the surface and the remaining 90 percent below it, this suggests that when the ice broke from the glacier, close to 100 meters (over 3oo feet) of it was extending above the water surface.
That’s a key number, because scientists are converging on the belief that ice cliffs of about this height above the water level are no longer sustainable and collapse under their own weight — meaning that when you get a glacier this tall up against the ocean, it tends to crumble and crumble, leading to fast retreat and potentially fast sea level rise.
“If we think about how thick these icebergs would have needed to be considering these float with 90 percent of their mass and thickness beneath the sea,” Wise said, “we think of an ice cliff that was at the maximum thickness implied by the physics of the ice.”
The problem is that if it happened then, well, it could happen again.
Both Pine Island glacier and its next door neighbor, Thwaites, are known to get thicker as one travels inland away from the sea, which means they are capable of once again generating ice cliffs taller than the critical size detected by the current study.
“If a cliff even higher than the ~100 m subaerial/900 m submarine cliffs were to form, as might occur with retreat of Thwaites Glacier in West Antarctica, it might break repeatedly with much shorter pauses than now observed, causing very fast grounding line retreat and sea level rise,” explained Richard Alley, a glaciologist at Penn State University, by email after reviewing the current study for the Post.
The final study, released Thursday morning in Environmental Research Letters, takes a different approach but provides perhaps the most sweeping verdict.
The study used five “shared socioeconomic pathways” that analyze possible futures for global society and its energy system, and resulting climate change, over the course of this century.
These scenarios will feed into the next report of the United Nations Intergovernmental Panel on Climate Change, the most influential scientific body that assesses climate change, according to the University of Melbourne’s Alexander Nauels, the lead author of the current study
The research combined these scenarios with tools to project future sea level rise in light of recent science suggesting that Antarctic ice in key regions could collapse relatively rapidly.
That includes possible fast retreat at Pine Island and Thwaites glaciers due, in part, to the problem of ice cliff instability.
The result was that in one scenario assuming high fossil fuel use and strong economic growth during the century, the study predicted that seas could rise by as much as 4.33 feet on average — with a high end possibility of as much as 6.2 feet — by 2100.
That includes possibly rapid sea level rise as high as 19 millimeters per year by the end of the century.
These numbers are considerably higher than high end projections released in 2013 by the Intergovernmental Panel on Climate Change.
(It is important to emphasize that the highest sea level numbers presented in the new study would result from human choices to pursue large fossil fuel exploitation and economic growth with little attempt to slow climate change. It is far from clear that this is the path the world will actually take.)
On the other hand, if the world limits global warming to the Paris climate agreement emissions target, the study finds that sea level rise might be held as low as 1.7 feet by 2100, on average.
Here’s an image illustrating the results:
21st century global mean sea level rise projections with median and
shaded 66 percent model ranges under a baseline high warming scenario
and low warming scenario.
The dashed lines represent scenarios
consistent with the United Nations’ Intergovernmental Panel on Climate
Change’s (IPCC) findings in 2013, while the solid lines present revised
sea level rise modeling results based on Antarctic ice sheet
contributions suggested by DeConto and Pollard (2016).
The IPCC
consistent sea level rise likely ranges are based on Nauels et al.
(2017).
Global mean sea level rise is provided in centimeters relative
to the 1986-2005 mean.
(Nauels et al.)
When the IPCC undertakes a similar analysis, Nauels said, it could produce results like these.
“I think the numbers will go up,” he said of the body’s report, which is expected in 2021.
So in sum — new research is affirming that seas have risen quite rapidly in the planet’s past, and that major glaciers have retreated quickly because their enormous size makes them potentially unstable.
Meanwhile, additional modeling projects these kinds of observations forward and suggests that the century in which we are now living could — could — see similar changes, at least in more severe global warming scenarios in which the world continues to burn high volumes of fossil fuels.
But unlike those submerged corals off the coast of Texas, the difference is that we know this could be coming — which gives us a chance to stop it.
Home from Frost Films A Cinematic Short Film celebrating the life of a man called Bob. Throughout his entire life he's always put the ocean first, which has
lead to him being homeless and living in a van. But he loves the ocean
and his life as much as ever, and of course, still surfs every day. "Your happiness comes within yourself"
