By Jess Hunt-Ralston
At the direction of Congress, the National Academies of Sciences, Engineering, and Medicine is establishing a Climate Security Roundtable convening experts from academia, the private sector, and civil society to provide support to the Climate Security Advisory Council (CSAC).
CSAC is a joint partnership between the U.S. Intelligence Community and the Federal Science Community and seeks to better understand and anticipate the ways climate change affects U.S. national security interests.
The new Climate Security Roundtable will support CSAC in anticipating, preparing, and ultimately preventing climate security crises from escalating into national security challenges and threats.
There are millions of tips out there on “The weather of the past will not be the weather of the future,” says a NOAA scientist. “As long as we are emitting greenhouse gases at a historically unprecedented rate, we should expect this change to continue.”
Scores of studies presented this week at the world’s largest climate science conference offered an unequivocal and unsettling message: Climate change is fundamentally altering what kind of weather is possible, and its fingerprint can be found in the rising number of disasters that have claimed lives and upended livelihoods around the world.
Record-shattering heat waves, devastating floods, scorching wildfires and persistent droughts are among the litany of catastrophes scientists say they can definitively link to human activities — primarily the burning of fossil fuels.
By James Temple
On a Saturday morning in December of 2020, the RRS Discovery floated in calm waters just east of the Mid-Atlantic Ridge, the massive undersea mountain range that runs from the Arctic nearly to the Antarctic.
The team onboard the research vessel, mostly from the UK’s National Oceanography Centre, used an acoustic signaling system to trigger the release of a cable more than three miles long from its 4,000-pound anchor on the seabed.
The expedition’s chief scientist, Ben Moat, and others walked up to the bridge to spot the first floats as they popped up. The technicians on deck, clad in hard hats and clipped into harnesses, reeled the cable in. They halted the winch every few minutes to disconnect the floats as well as sensors that measure salinity and temperature at various depths, data used to calculate the pressure, current speed, and volume of water flowing past.
The scientists and technicians are part of an international research collaboration, known as RAPID, that’s collecting readings from hundreds of sensors at more than a dozen moorings dotting the Atlantic roughly along 26.5° North, the line of latitude that runs from the western Sahara to southern Florida.
They are searching for clues about one of the most important forces in the planet’s climate system: a network of ocean currents known as the Atlantic Meridional Overturning Circulation (AMOC). Critically, they want to better understand how global warming is changing it, and how much more it could shift in the coming decades—even whether it could collapse.
Hurricane Ida made landfall last weekend near New Orleans as a Category-4 storm, lashing the region with winds of up to 150mph (240kph), heavy rains and several feet of storm surge on the 16th anniversary of Hurricane Katrina.
Several factors linked to the climate crisis are helping to fuel more powerful, destructive storms like Ida, scientists say.
The latest report from the Intergovernmental Panel on Climate Change, the world’s leading authority on climate science, found that storms with sustained higher wind speeds – in the Category 3-5 range – have likely increased in the past 40 years.
The ocean absorbs over 90 percent of excess heat caused by greenhouse gas emissions from the burning of fossil fuels and that warm water feeds hurricanes.
“There is more energy available, so intensification of these hurricanes is expected,” Dr. Susan Lozier, president of the American Geophysical Union and an expert on the interaction of oceans, hurricanes and climate change, told The Independent. “And intensification brings more winds.”
More than a million people lost power when Ida toppled thousands of transmission lines and knocked 216 substations offline. Utility companies warned that thousands could remain in the dark and without air conditioning or running water for several weeks amid stifling heat and humidity.
By Heather Murphy
The water in the Atlantic is constantly circulating in a complex pattern that influences weather on several continents. And climate scientists have been asking a crucial question: Whether this vast system, which includes the Gulf Stream, is slowing down because of climate change.
Now, scientists have detected the early warning signs that this critical ocean system is at risk, according to a new analysis published Thursday in the scientific journal Nature Climate Change.
“I showed that this gradual slowing down of the circulation system is associated with a loss of stability,” said Niklas Boers, a researcher at the Potsdam Institute for Climate Impact Research in Germany, “and the approaching of a tipping point at which it would abruptly transition to a much slower state.”
[Susan Lozier] called Dr. Boers’ study “interesting,” but said she wasn’t convinced that the findings showed that circulation in that ocean system is slowing. “There are lots of things to worry about with the ocean,” she said, such as the more definitive concerns involving sea-level rise.
Read full article: https://www.nytimes.com/2021/08/05/us/gulf-stream-collapse.html
By Allison Shirreffs
The ocean covers more than 70% of the Earth and operates in a state of equilibrium with the atmosphere to regulate climate and CO2 levels. As a result, dynamics that affect the uptake of CO2 across the ocean surface affect global atmospheric temperatures.
Lozier, who ( in addition to her duties as dean and AGU president ) studies ocean circulation and the impact of ocean physics on marine ecosystems, is currently leading the NSF-funded project OSNAP, the Overturning in the Subpolar North Atlantic Program. OSNAP is an international observing network with a necklace of ocean instruments — strung from Canada to Greenland to Scotland — measuring what’s commonly known as “the ocean conveyor belt,” explains Lozier. “The overturning circulation is a huge current system that drives regional and global climate.
“What happens if the overturning circulation slows down because the waters of the surface warm — or if they get fresher because there’s more glacial melt?” Lozier asks. “If the ocean doesn’t take up as much CO2, that’s a good news, bad news story.” Good news because less CO2 in the water means fewer adverse effects, such as ocean acidification, but bad news because more CO2 stays in the atmosphere.
Read full article: https://news.gatech.edu/features/2021/08/leading-quest-ocean-solutions
By MOISES VELASQUEZ-MANOFF and JEREMY WHITE
The warming atmosphere is causing an arm of the powerful Gulf Stream to weaken, some scientists fear.
It’s one of the mightiest rivers you will never see, carrying some 30 times more water than all the world’s freshwater rivers combined. In the North Atlantic, one arm of the Gulf Stream breaks toward Iceland, transporting vast amounts of warmth far northward, by one estimate supplying Scandinavia with heat equivalent to 78,000 times its current energy use. Without this current — a heat pump on a planetary scale — scientists believe that great swaths of the world might look quite different.
Now, a spate of studies, including one published last week, suggests this northern portion of the Gulf Stream and the deep ocean currents it’s connected to may be slowing. Pushing the bounds of oceanography, scientists have slung necklace-like sensor arrays across the Atlantic to better understand the complex network of currents that the Gulf Stream belongs to, not only at the surface, but hundreds of feet deep.
“We’re all wishing it’s not true,” Peter de Menocal, a paleoceanographer and president and director of the Woods Hole Oceanographic Institution, said of the changing ocean currents. “Because if that happens, it’s just a monstrous change.”
College of Sciences Dean Susan Lozier has been elected a member of the American Academy of Arts and Sciences.
Susan Lozier, dean and the Betsy Middleton and John Clark Sutherland Chair in the College of Sciences, has been elected a member of the American Academy of Arts and Sciences. She is among 276 artists, scholars, scientists, and leaders in the public, non-profit, and private sectors who will be inducted Oct. 9-11.
The Academy was founded in 1780 by John Adams, John Hancock, and others to honor exceptionally accomplished individuals and engage them in advancing the public good. Lozier, an expert in physical oceanography with an interest in large-scale ocean circulation, is being recognized for decades of extraordinary work.
“It’s incredibly humbling to be recognized by members of this arts and sciences community, given its rich history,” Lozier said. “I have always balked at the myth that science is the journey of a lone individual as I have enjoyed working with students, postdocs, and colleagues over the years and have gained immeasurably from those interactions. Since I view science as a community effort, building on the work that others have done and laying the foundation for the future, being recognized by the community is particularly gratifying.”
Why is an ocean current critical to world weather losing steam? Scientists search the Arctic for answers.
BY CHERYL KATZ
A conveyor belt of ocean water that loops the planet and regulates global temperatures could be heading for a tipping point.
THE HIGH ARCTIC, ABOARD THE R.V. KRONPRINS HAAKON
Summer sea ice has been shrinking so dramatically here in the Fram Strait, high in the Arctic between Norway and Greenland, that researchers who make this trip annually point out missing patches like memories of departed friends.
“The first time I was here, in 2008, you could walk on the ice,” says Norwegian Polar Institute (NPI) oceanographer Paul Dodd, gesturing from the deck of this research icebreaker toward the spot, near the Prime Meridian, where his team is about to take samples for temperature, salinity, dissolved carbon, and other chemical measurements of what is now open water. It’s dotted with only a few random, battered-looking ice drifts.
Temperatures are rising and ice is melting all over Earth. But this place is special: The ocean changes that are happening right here could dramatically alter the climate for much of the rest of the planet.
Unscripted and informal — unearthing leadership’s thinking behind the big ideas taking shape across the Institute — this new video series is meant to capture candid conversations between President Ángel Cabrera and other Georgia Tech leaders.
In this first installment, President Cabrera chats with Susan Lozier, the new dean of the College of Sciences. They not only share the same start date at Tech (Sept. 3, 2019), they also point to the same campus event as one of their most treasured highlights since then.
The Atlantic Meridional Overturning Circulation, shown here, serves as a conveyor belt that transports heat and pulls carbon from the atmosphere into the deep ocean.(Credit: R. Curry, Woods Hole Oceanographic Institution/Science/USGCR)
By Roni Dengler
Massive volumes of water circulate throughout the Atlantic Ocean and serve as the central drivers of Earth’s climate. Now researchers have discovered that the heart of this circulation is not where they suspected.
“The general understanding has been [that it’s] in the Labrador Sea, which sits between the Canadian coast and the west side of Greenland,” said Susan Lozier, a physical oceanographer at Duke University in Durham, North Carolina, who led the new research. “What we found instead was that … the bulk [of it] is taking place from the east side of Greenland all the way over to the Scottish shelf.”
The discovery will help improve global climate models.
Observations over 21 months cast doubt on ideas of what drives Atlantic Ocean ‘conveyor belt’
New findings from an international ocean observing network are calling into question the long-standing idea that global warming might slow down a big chunk of the ocean’s “conveyor belt.” The first 21 months of data from sensors moored across much of the North Atlantic are giving new insight into what controls the strength of the Atlantic Meridional Overturning Circulation, a system of currents that redistributes heat around much of the Western Hemisphere.
Researchers had thought the strength of that circulation, known by the acronym AMOC, was largely influenced by the sinking of cold freshwater in the Labrador Sea, between Greenland and Canada. And climate simulations suggest that the sea’s deepwater formation might slow as the world continues to warm — which also could slow down the entire Atlantic current system and possibly make temperatures on land in the northeastern United States and the United Kingdom plunge. That concept inspired the (otherwise unrealistic) 2004 climate apocalypse film The Day After Tomorrow.
By SETH BORENSTEIN
WASHINGTON (AP) — One of the key drivers of the world’s climate is an area in the North Atlantic Ocean where warmer and colder water mix and swirl. When scientists went for their first close look at this critical underwater dynamo, they found they were looking in the wrong place.
By hundreds of miles.
The consequences are not quite yet understood, but eventually it could change forecasts of one of the worst-case global warming scenarios — still considered unlikely this century — in which the mixing stops and climate chaos ensues.
It’s called the Atlantic Meridional Overturning Circulation , and scientists describe it as a giant ocean conveyor belt that moves water from Greenland south to beyond the tip of Africa and into the Indian Ocean.
By Chris Mooney
Some experts say the Atlantic Ocean circulation is already slowing down — but we’re just beginning to learn how it really works.
It may be the biggest wild card in the climate system. Scientists have long feared that the so-called “overturning” circulation in the Atlantic Ocean could slow down or even halt due to climate change — a change that would have enormous planetary consequences.
But at the same time, researchers have a limited understanding of how the circulation actually works, since taking measurements of its vast and remote currents is exceedingly difficult. And now, a major new research endeavor aimed at doing just that has suggested a dramatic revision of our understanding of the circulation itself.
A new 21-month series of observations in the frigid waters off Greenland has led to the discovery that most of the overturning — in which water not only sinks but returns southward again in the ocean depths — occurs to the east, rather than to the west, of the enormous ice island. If that’s correct, then climate models that suggest the circulation will slow as the climate warms may have to be revised to take this into account.
The magnitude of the scientific surprise, on a scale of 1 to 10, is pretty large, said Susan Lozier, an oceanographer at Duke University who was lead author of the research published Thursday in Science.
BY NICOLA JONES
Scientists are closely monitoring a key current in the North Atlantic to see if rising sea temperatures and increased freshwater from melting ice are altering the “ocean conveyor belt” — a vast oceanic stream that plays a major role in the global climate system.
Susan Lozier is having a busy year. From May to September, her oceanographic team is making five research cruises across the North Atlantic, hauling up dozens of moored instruments that track currents far beneath the surface. The data they retrieve will be the first complete set documenting how North Atlantic waters are shifting — and should help solve the mystery of whether there is a long-term slowdown in ocean circulation. “We have a lot of people very interested in the data,” says Lozier, a physical oceanographer at Duke University.
A similar string of moorings across the middle of the Atlantic, delving as deep as 3.7 miles from the Canary Islands to the Bahamas, has already detected a disturbing drop in this ocean’s massive circulation pattern. Since those moorings were installed in 2004, they have seen the Atlantic current wobble and weaken by as much as 30 percent, turning down the dial on a dramatic heat pump that transports warmth toward northern Europe. Turn that dial down too much and Europe will go into a deep chill.
More data are needed to determine whether the slowing is a result of human-induced climate change
The marked slowdown in the past decade of the warm Atlantic Ocean currents that bring mild weather to northwestern Europe may be caused by natural variation and not anthropogenic climate change, as has been previously suggested.
The Atlantic Meridional Overturning Circulation (AMOC) is part of the great ocean ‘conveyor belt’ that ceaselessly circulates sea water, heat and nutrients around the globe. In particular, it transports large amounts of warm water from the tropics to the poles, warming the British Isles and maritime northern Europe along the way (see ‘Current affair’). But since 2004, ocean sensors have detected a significant decline in the strength of the currents and a cooling of the subtropical Atlantic as a result. From mid-2009 to mid-2010, for example, the circulation slowed to two-thirds of its usual strength — and some oceanographers suggested that the drop caused the harsh weather in the United Kingdom and western Europe that winter (see Nature 497, 167–168; 2013).