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Circulation in meltdown
THIS WEEK
Circulation in meltdown Shutdown threat
Polar ice melt may shut down the Atlantic current that warms Europe This is how the North Atlantic current brings warm water to Europe. Fresh water from melting ice is putting this delivery process at risk
Colin Barras GREENLAND
GREENLAND SEA
LABRADOR SEA
NORWEGIAN SEA
N
CU RR
NEWFOUNDLAND
EN T
LABRADOR
Shutdown threat 13
OR TH
10
E
N
N
A
T
I EG RW O N
ATLA RR N TIC C U
7
Temperature (°C)
4
This is how the North Atlantic current brings warm water to Europe. Fresh water from melting ice is putting this delivery process at risk
N
13
OR TH
10
to convection because, being less
GREENLAND GREENLANDit has to be dense than seawater, SEA
N
CU RR
EN T
cooled to a greater degree before it will sink. To make matters worse, Oltmanns’sNORWEGIAN team also found SEAsummers evidence that the featuring the largest bodies of fresh water are followed by IA EG mild to winters that are W too R NO
T
2014. In some summers, the LABRADOR seawater at the surface had an unusually high temperature LABRADOR and SEA in 2010. low salinity – particularly This is a sign that more fresh NEWFOUNDLAND water was flooding into the region, perhaps from melting ice in Greenland or the Arctic Ocean. The fresh water poses a threat
E Climate threatens iconic wildlife
N
THE ocean current that gives western and northern Europe a relatively mild climate might be at greater risk of shutdown than we thought. If the North Atlantic current – the northern segment of the Gulf Stream – does grind to a halt, the effects could be severe, from greater sea level rise on Atlantic coasts to more intense droughts in Africa. During the winter months, seawater in the Arctic cools and sinks, causing warm water to flow into the region from the tropics. But this convection of water to the depths is threatened by the rapid warming in polar regions. To investigate, Marilena Oltmanns and her colleagues at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, studied seawater salinity and temperature data collected in the Irminger Sea to the south of Greenland between 2002 and
ATLA RR N TIC C U
4 Temperature (°C) 7 IF WE don’t stop climate change, half the animals and plants in the world’s wildlife havens will be gone by 2100. That’s according to a study gauging what will happen to 80,000 species in 35 of the most wildlife-rich areas, including the Amazon rainforest and the Galapagos Islands. If no action is taken, the ensuing 4.5°C rise in global temperatures means the Amazon would lose 69 per cent, and Madagascar 60 per cent, of its plant species (Climatic Change, DOI: 10.1007/s10584-128-2158-6). Snow leopards may lose 20 per cent of their habitat, and rising seas could swamp 96 per cent of Sundarbans tigers’ Bangladeshi breeding grounds.
provide adequate chilling. Measurements taken during the northern hemisphere winter of 2010-11 confirmed the significance of the problem. Conditions were mild, and so much fresh water had accumulated during the previous summer that 40 per cent of it still remained in the upper 200 metres of the water column when spring arrived. “We were very surprised that so much remained after winter,” says Oltmanns. “It shows that the fresh water clearly impeded convection.” It was a similar story in other years. For seven of the 12 winters examined, more than 25 per cent of the fresh water that pooled in the summer remained in place at the end of winter (Nature Climate Change, doi.org/cmbw). Oltmanns says that if several unusually warm years occur in succession, so much fresh water could build up that it would become impossible for
But if we limit global warming over the next century to 2°C – the target of the 2015 Paris Agreement – only 25 per cent of the species will be lost. “We can greatly reduce the impacts,” says Rachel Warren of the University of East Anglia, UK. She says COPY SUB we can cut losses to 20 per cent by also helping species move by creating PAGE SUB wildlife corridors.
PACIFIC PRESS/ALAMY
Atlantic current 170318
OK for press
Fertility clinic malfunctions THOUSANDS of frozen eggs and embryos may have been damaged following the malfunctioning of a fertility clinic storage tank. When the tank at the Pacific Fertility Center in San Francisco
6 | NewScientist | 17 March 2018
COPY SUB
For new stories every day, visit newscientist.com/news
convection to begin at all in winter. In effect, part of the North Atlantic current might shut down (see map, left). No one knows for sure what would happen in the event of such a shutdown. Oltmanns says some people think it might spell the end of the North Atlantic’s relatively mild climate. Eirik Galaasen at the University of Bergen, Norway, says we could expect other impacts too. Some models suggest that a breakdown in ocean circulation would trigger
Oltmanns, representing a tipping point that leaves the climate fundamentally and irreversibly changed. Galaasen, however, points to evidence that convection has stopped a number of times in the past. “The Atlantic recovered every time,” he says. For instance, about 8400 years ago a vast glacial lake in North America burst, dumping at
least 150,000 cubic kilometres of fresh water into the North Atlantic. Circulation halted, but Galaasen says it restarted within roughly a century – barely anything in geological terms but quite a long period of time in human terms.
What are Novichok nerve agents?
and 7. Both are binary agents, made from two precursor chemicals mixed together just before use. The use of a Novichok makes it highly likely that Russia was involved, because no one else knows how to make them, says John Lamb at Birmingham City University, UK. “It could have been a demonstration of capability,” says Lamb.
Meltwater from Greenland is interfering with ocean currents–
a sea level rise of 40 centimetres or more around Europe and eastern North America. Others conclude that a shutdown would worsen the severity of droughts in West Africa. And some climate scientists argue that effects could be seen even further afield: South America might experience greater droughts, which could be bad news for the region’s rainforests. Some argue that a shutdown could be permanent, says
stopped working properly on 4 March, temperatures inside rose. A spokesperson told the Washington Post that “several thousand” eggs and embryos were affected – around 15 per cent of the total stored there. Reportedly, 400 people had all their stored eggs and embryos in the malfunctioning tank, while a further 100 had at least some tissue affected. Over the same weekend, a similar incident occurred at University Hospitals Fertility Center in Cleveland, Ohio, where around 2000 eggs and embryos are thought to be affected. It is currently unclear to what extent the tissue involved in these incidents may have been damaged or if it is still fit for use in treatments. A couple with embryos stored at the Cleveland clinic filed a class action lawsuit on 11 March.
JOHN ELK III/GETTY
“A breakdown in ocean circulation could trigger a sea level rise of 40 centimetres”
THE poison used to target ex-Russian spy Sergei Skripal and his daughter in Salisbury, UK, was a Novichok nerve agent, it has been revealed. Novichok agents – also known as the “N-series” – were secretly developed by the former Soviet Union from the 1970s. They work in the same way as other nerve agents, which disrupt signals to the muscles by inhibiting an enzyme called acetylcholinesterase. The gaps between nerve cells become flooded with acetylcholine, causing continuous muscle contractions. Symptoms include convulsions and difficulty breathing. The most potent members of the N-series are reportedly Novichok-5
Inhabit a robot from a distance A $10 MILLION competition aims to get people to control a robot and carry out tasks from 100 kilometres away. Not just that, but the controllers should be able to feel, hear and touch the robot’s surroundings too.
Not everyone is convinced the new research suggests that a shutdown – even a temporary one – is imminent. “The implications are physically conceivable,” says Carl Wunsch at Harvard University – but he says we can only speculate about how the entire ocean convection system would respond. “If North Atlantic convection slows down or stops because of local freshening, will there be an increased – or decreased – import of much saltier water from the south?” Michael Alexander at the NOAA Earth System Research Laboratory in Colorado says making broad conclusions on the basis of limited data is speculative at best. But he thinks that the connections Oltmanns’s team makes are interesting and important. Oltmanns agrees that it is wise not to infer too much about ocean currents from this. But she says the study still gives us valuable information about ocean convection. “Until now, models have predicted that fresh water will threaten convection in the future,” she says. “It is already affecting convection to a greater extent than we thought.” ■
The XPrize non-profit organisation launched the ANA XPrize Avatar Challenge on Monday at the SXSW festival in Austin, Texas. Teams must submit their plans to a panel of expert judges by the end of January 2019. In April 2020 and April 2021, teams will then have to show what their avatars can do, and a $1 million purse will be available for the best performer each year. Then, in October 2021, a bumper $8 million will be up for grabs, with teams tested over a five-day finale. Eventually, XPrize hopes that the technology will enable people to deploy immediate emergency response in natural disaster scenarios. “The idea is that if there was another nuclear disaster like in Fukushima, we could send avatars instead of people,” says Jyotika Virmani of XPrize. 17 March 2018 | NewScientist | 7
Circulation in meltdown Shutdown threat
Polar ice melt may shut down the Atlantic current that warms Europe This is how the North Atlantic current brings warm water to Europe. Fresh water from melting ice is putting this delivery process at risk
Colin Barras GREENLAND
GREENLAND SEA
LABRADOR SEA
NORWEGIAN SEA
N
CU RR
NEWFOUNDLAND
EN T
LABRADOR
Shutdown threat 13
OR TH
10
E
N
N
A
T
I EG RW O N
ATLA RR N TIC C U
7
Temperature (°C)
4
This is how the North Atlantic current brings warm water to Europe. Fresh water from melting ice is putting this delivery process at risk
N
13
OR TH
10
to convection because, being less
GREENLAND GREENLANDit has to be dense than seawater, SEA
N
CU RR
EN T
cooled to a greater degree before it will sink. To make matters worse, Oltmanns’sNORWEGIAN team also found SEAsummers evidence that the featuring the largest bodies of fresh water are followed by IA EG mild to winters that are W too R NO
T
2014. In some summers, the LABRADOR seawater at the surface had an unusually high temperature LABRADOR and SEA in 2010. low salinity – particularly This is a sign that more fresh NEWFOUNDLAND water was flooding into the region, perhaps from melting ice in Greenland or the Arctic Ocean. The fresh water poses a threat
E Climate threatens iconic wildlife
N
THE ocean current that gives western and northern Europe a relatively mild climate might be at greater risk of shutdown than we thought. If the North Atlantic current – the northern segment of the Gulf Stream – does grind to a halt, the effects could be severe, from greater sea level rise on Atlantic coasts to more intense droughts in Africa. During the winter months, seawater in the Arctic cools and sinks, causing warm water to flow into the region from the tropics. But this convection of water to the depths is threatened by the rapid warming in polar regions. To investigate, Marilena Oltmanns and her colleagues at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, studied seawater salinity and temperature data collected in the Irminger Sea to the south of Greenland between 2002 and
ATLA RR N TIC C U
4 Temperature (°C) 7 IF WE don’t stop climate change, half the animals and plants in the world’s wildlife havens will be gone by 2100. That’s according to a study gauging what will happen to 80,000 species in 35 of the most wildlife-rich areas, including the Amazon rainforest and the Galapagos Islands. If no action is taken, the ensuing 4.5°C rise in global temperatures means the Amazon would lose 69 per cent, and Madagascar 60 per cent, of its plant species (Climatic Change, DOI: 10.1007/s10584-128-2158-6). Snow leopards may lose 20 per cent of their habitat, and rising seas could swamp 96 per cent of Sundarbans tigers’ Bangladeshi breeding grounds.
provide adequate chilling. Measurements taken during the northern hemisphere winter of 2010-11 confirmed the significance of the problem. Conditions were mild, and so much fresh water had accumulated during the previous summer that 40 per cent of it still remained in the upper 200 metres of the water column when spring arrived. “We were very surprised that so much remained after winter,” says Oltmanns. “It shows that the fresh water clearly impeded convection.” It was a similar story in other years. For seven of the 12 winters examined, more than 25 per cent of the fresh water that pooled in the summer remained in place at the end of winter (Nature Climate Change, doi.org/cmbw). Oltmanns says that if several unusually warm years occur in succession, so much fresh water could build up that it would become impossible for
But if we limit global warming over the next century to 2°C – the target of the 2015 Paris Agreement – only 25 per cent of the species will be lost. “We can greatly reduce the impacts,” says Rachel Warren of the University of East Anglia, UK. She says COPY SUB we can cut losses to 20 per cent by also helping species move by creating PAGE SUB wildlife corridors.
PACIFIC PRESS/ALAMY
Atlantic current 170318
OK for press
Fertility clinic malfunctions THOUSANDS of frozen eggs and embryos may have been damaged following the malfunctioning of a fertility clinic storage tank. When the tank at the Pacific Fertility Center in San Francisco
6 | NewScientist | 17 March 2018
COPY SUB
For new stories every day, visit newscientist.com/news
convection to begin at all in winter. In effect, part of the North Atlantic current might shut down (see map, left). No one knows for sure what would happen in the event of such a shutdown. Oltmanns says some people think it might spell the end of the North Atlantic’s relatively mild climate. Eirik Galaasen at the University of Bergen, Norway, says we could expect other impacts too. Some models suggest that a breakdown in ocean circulation would trigger
Oltmanns, representing a tipping point that leaves the climate fundamentally and irreversibly changed. Galaasen, however, points to evidence that convection has stopped a number of times in the past. “The Atlantic recovered every time,” he says. For instance, about 8400 years ago a vast glacial lake in North America burst, dumping at
least 150,000 cubic kilometres of fresh water into the North Atlantic. Circulation halted, but Galaasen says it restarted within roughly a century – barely anything in geological terms but quite a long period of time in human terms.
What are Novichok nerve agents?
and 7. Both are binary agents, made from two precursor chemicals mixed together just before use. The use of a Novichok makes it highly likely that Russia was involved, because no one else knows how to make them, says John Lamb at Birmingham City University, UK. “It could have been a demonstration of capability,” says Lamb.
Meltwater from Greenland is interfering with ocean currents–
a sea level rise of 40 centimetres or more around Europe and eastern North America. Others conclude that a shutdown would worsen the severity of droughts in West Africa. And some climate scientists argue that effects could be seen even further afield: South America might experience greater droughts, which could be bad news for the region’s rainforests. Some argue that a shutdown could be permanent, says
stopped working properly on 4 March, temperatures inside rose. A spokesperson told the Washington Post that “several thousand” eggs and embryos were affected – around 15 per cent of the total stored there. Reportedly, 400 people had all their stored eggs and embryos in the malfunctioning tank, while a further 100 had at least some tissue affected. Over the same weekend, a similar incident occurred at University Hospitals Fertility Center in Cleveland, Ohio, where around 2000 eggs and embryos are thought to be affected. It is currently unclear to what extent the tissue involved in these incidents may have been damaged or if it is still fit for use in treatments. A couple with embryos stored at the Cleveland clinic filed a class action lawsuit on 11 March.
JOHN ELK III/GETTY
“A breakdown in ocean circulation could trigger a sea level rise of 40 centimetres”
THE poison used to target ex-Russian spy Sergei Skripal and his daughter in Salisbury, UK, was a Novichok nerve agent, it has been revealed. Novichok agents – also known as the “N-series” – were secretly developed by the former Soviet Union from the 1970s. They work in the same way as other nerve agents, which disrupt signals to the muscles by inhibiting an enzyme called acetylcholinesterase. The gaps between nerve cells become flooded with acetylcholine, causing continuous muscle contractions. Symptoms include convulsions and difficulty breathing. The most potent members of the N-series are reportedly Novichok-5
Inhabit a robot from a distance A $10 MILLION competition aims to get people to control a robot and carry out tasks from 100 kilometres away. Not just that, but the controllers should be able to feel, hear and touch the robot’s surroundings too.
Not everyone is convinced the new research suggests that a shutdown – even a temporary one – is imminent. “The implications are physically conceivable,” says Carl Wunsch at Harvard University – but he says we can only speculate about how the entire ocean convection system would respond. “If North Atlantic convection slows down or stops because of local freshening, will there be an increased – or decreased – import of much saltier water from the south?” Michael Alexander at the NOAA Earth System Research Laboratory in Colorado says making broad conclusions on the basis of limited data is speculative at best. But he thinks that the connections Oltmanns’s team makes are interesting and important. Oltmanns agrees that it is wise not to infer too much about ocean currents from this. But she says the study still gives us valuable information about ocean convection. “Until now, models have predicted that fresh water will threaten convection in the future,” she says. “It is already affecting convection to a greater extent than we thought.” ■
The XPrize non-profit organisation launched the ANA XPrize Avatar Challenge on Monday at the SXSW festival in Austin, Texas. Teams must submit their plans to a panel of expert judges by the end of January 2019. In April 2020 and April 2021, teams will then have to show what their avatars can do, and a $1 million purse will be available for the best performer each year. Then, in October 2021, a bumper $8 million will be up for grabs, with teams tested over a five-day finale. Eventually, XPrize hopes that the technology will enable people to deploy immediate emergency response in natural disaster scenarios. “The idea is that if there was another nuclear disaster like in Fukushima, we could send avatars instead of people,” says Jyotika Virmani of XPrize. 17 March 2018 | NewScientist | 7