17/12/2016

Inside The Largest Earth Science Event: 'The Time Has Never Been More Urgent'

The Guardian - 

Scientists hold signs during a rally in conjunction with the American Geophysical Union’s fall meeting. Photograph: Marcio Jose Sanchez/AP
They argued about moon-plasma interactions, joked about polar bears, and waxed nostalgic for sturdy sea ice.
But few of the 20,000 Earth and climate scientists meeting in San Francisco this week had much to say about the president-elect, Donald Trump – though his incoming administration loomed over much of the conference.
For some, the annual meeting of the American Geophysical Union (AGU) – the largest Earth and space science gathering in the world – was a call to action. California’s governor, Jerry Brown, addressed the scientists on Wednesday morning, telling them, “the time has never been more urgent or your work ever more important. The danger is definitely rising.”
Citing financial inequality, the risks of nuclear arms and the mounting effects of climate change, Brown said, “we’re facing far more than one or two or even thousands of politicians.
“We’re facing big oil, we’re facing big financial structures that are at odds with the survivability of our world. It’s up to you as truth tellers, truth seekers, to mobilize all your efforts to fight back.”
Brown compared the struggle to the campaigns waged by the tobacco industry, noting that health science and the law eventually curtailed its power. “Some people need a heart attack to stop smoking,” he said. “Maybe we just got our heart attack.”
Scientists rally during the American Geophysical Union meeting. Photograph: Marcio Jose Sanchez/AP
“This is not a battle of one day or one election,” he added, calling scientists “foot soldiers” for truth. The governor promised to help lead the campaign, daring Trump to shut down climate science satellites and mocking Rick Perry, his pick for secretary of energy.
“If Trump turns off the satellites, California will launch it’s own damn satellites,” Brown said. “Rick, I’ve got some news for you: California’s growing a hell of a lot faster than Texas. And we’ve got more sun than you’ve got oil.”
Not far away, a team of lawyers with the Climate Science Legal Defense Fund met with scientists to discuss the threats ahead. The group helps defend scientists from harassment and suits over climate change research, most prominently a case brought by a climate change-denying organization to obtain emails and research of scientist Michael Mann.
At the AGU table, attorneys handed out guides to “handling political harassment and legal intimidation”.
Some scientists are taking action on their own, including Eric Holthaus, a meteorologist who has started one of several “guerrilla archiving” efforts to preserve public climate data on non-government servers. Holthaus and others fear that a Trump administration could take down the data, as former Canadian prime minister Stephen Harper tried to silence scientists.
Sally Jewell, the outgoing secretary of the interior, tried to reassure scientists that the Trump administration could not quickly gut federal research. Science would be “foundational” to government, she told attendees: “We have a president-elect that likes to win, and we can’t win without science.”
Jewell argued that scientists should stress the benefits of science to industry, saying they should start speaking “in the language of business, perhaps, to translate” for the Trump administration.
Many federal researchers had already begun to speak in those terms. Scott Hagen, presenting on the dangers of rising tides to Louisiana, said the state could face losses of up to $280m in agricultural lands. Jennifer Francis, a Rutgers professor, said the extreme heat in the Arctic would almost certainly contribute to extreme weather around the world next year. Marco Tedesco, presenting on the “Arctic report card 2016” – a year of record lows – noted that changes in snowfall patterns would affect hydropower and freshwater resources.
“Snow melting sooner and faster is leaving a drier soil exposed to a drier summer,” he said. “You might have more drought, might have more forest fires, ramifications for economy, population.”
Thomas Zurbuchen, the head of Nasa’s science mission directorate, stressed that scientists should “behave like scientists” and “focus on the data that we get and not amplify the noise”.
He too drew a link between science and business: “What you’re carrying around in your pocket is a lot of space data that’s doing work for you.”
At the meeting, scientists were feeling the pressure of a looming Trump administration. Photograph: Marcio Jose Sanchez/AP
Jewell urged scientists to “speak up for scientific integrity”, and tried to assure them that pro-science policies “are not going to be easy to undo”. But uncertainty and anxiety reigned, for the future of research and the planet.
“Trump’s leadership will have a chilling effect on environmental and science policy no matter what,” said one climate scientist, who asked for anonymity for fear of work being politicized. “What worries me most is that this administration might launch a fundamental attack on the scientific process.”
The best-case scenario, the scientist said, would resemble the Bush administration, in which “leadership doesn’t care much about what the climate scientists say, but they continue to support funding for research”. A worst-case scenario would be “an effort to undermine the scientific infrastructure of the country”.
A worst case scenario would be 'an effort to undermine the scientific infrastructure of the country'
Agencies could radically restructure their staff, for instance, shuffling scientists to unappealing projects while Republicans in Congress slash budgets and Trump reneges on world climate talks. Charles Kennel, a former Nasa official, said that the US’s withdrawal for several years would be “serious but not fatal”.
Other scientists stressed that the world is already changing in dramatic, unpredictable ways. Donald Perovich, a professor at Dartmouth University, said that the Arctic in 2016 looked “as though part of the United States has melted”, a region comparable to all the states east of the Mississippi plus the midwest and North Dakota.
When the researchers began doing a yearly report card in the mid-2000s, Perovich said, “you kind of had to listen closely, because the Arctic was whispering change.”
“Now it’s not whispering anymore,” he said. “It’s shouting.”

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Climate Change Played A Role In Australia’s Hottest October And Tasmania’s Big Dry In 2015

The Conversation - Pandora Hope | Andrew King | Guomin Wang | Julie Arblaster | Michael Grose

Wildfires in Tasmania in 2016 were in part the result of an extended dry period beginning in 2015. Rob Blakers, CC BY-SA
Climate change made some of Australia’s 2015 extreme weather events more likely, according to research published today in the Bulletin of the American Meteorological Society.
As part of an annual review of global weather extremes, these studies focused on October 2015, which was the hottest on record for that month across Australia. It was also the hottest by the biggest margin for any month.
October 2015 was also the driest for that month on record in Tasmania, which contributed to the state’s dry spring and summer, and its bad fire season.
El Niño events usually drive global temperatures higher, and 2015 had one of the strongest on record. So were these records due to El Niño, or climate change? The research shows that while El Niño had some influence on Australia’s weather, it was not the only culprit.

El Niño packed a punch – or did it?
In 2015, a strong El Niño developed, with record high temperatures in the central equatorial Pacific Ocean contributing to 2015 being the hottest year on record globally (although 2016 will smash it). The Indian Ocean was also very warm.
El Niño is often associated with warm and dry conditions across eastern Australia, particularly in spring and summer. The new studies found that for Australia as a whole, while El Niño did make the continent warmer, its direct contribution to record temperatures was small.
Only in the Murray Darling Basin did El Niño make it more likely that the October 2015 heat would be a record. El Niño also played a small but notable role in the dry October in Tasmania.

Temperatures were at a record high across the south of the country. Bureau of Meteorology
The hottest October
Although record-high spring temperatures might not make you sweat as much as a summer heatwave, ecosystems and agriculture can be susceptible. October 2015 was 2.89℃ warmer than the previous hottest October in 2014, beating the margin set by September 2013, which was 2.75℃ warmer than the previous hottest September.
Even before October 2015 was over, Mitchell Black and David Karoly at the University of Melbourne reported that human-induced climate change played a strong role in the excessive October heat.
The first paper (chapter 23 in the annual review) explains this further. Using the citizen science Weather@home ANZ system, the researchers analysed thousands of simulations of the world’s climate of 2015, generated on home computers (you can donate your computer power here).
To find out whether climate change played a role, some of those simulations included the observed ocean temperatures of 2015, while some included ocean temperatures as if human-caused climate change had never occurred.
According to this method, climate change made breaking the October record four times more likely compared to a world without climate change.
The second paper (chapter 24 in the review) backed this up. This study used the Bureau of Meteorology’s seasonal forecast system to compare the real world to a world with less carbon dioxide in the atmosphere. The researchers came to exactly the same conclusion: rising carbon dioxide levels made a record October four times more likely.
This second study also found that the atmospheric conditions – the series of high and low pressure systems that shift heat from inland Australia towards the south – were more important in driving the extra heat than the extreme global ocean temperatures.
If these weather systems had occurred in a low-CO₂ world, it would still have been an extremely warm month. But for October 2015, climate change increased the temperature by an extra 1 degree.

Driest October for Tasmania
In October 2015, Tasmania received only 21mm of rainfall, just 17% of its normal amount. It was much drier than the previous driest October in 1965 (in the era with reliable record, when the state received 56mm). This was part of the driest spring on record, and a dry and warm run of months through spring and summer.
This run of warm and dry months had major impacts on agriculture and hydroelectricity, and helped to set up a catastrophic fire season.
Rainfall extremes can be complex, and it is generally much harder to figure out what caused them than temperature extremes. So the third Australian study (ch. 25 in the review) used two different methods to compare October 2015 to the previous record.
The results showed that El Niño did affect the October climate, but human-caused climate change also played a small but significant role. Climate change probably increased the chances of Tasmania having its driest October by 25-50%.
The record-dry October appears to be linked to higher atmospheric pressure in a band around the whole southern hemisphere, which is consistent with trends over recent time.

Rainfall across Tasmania was the lowest on record across nearly the whole state. Bureau of Meteorology
Climate change is altering our extremes
More extreme events and more broken climate records are causing many people to ask whether climate variability or climate change is to blame. But of course it is never just one of these; it is always a combination of both.
For the extreme October of 2015, while short-term weather patterns and the El Niño contributed to the extremes, breaking these climate records would have been substantially less likely without human-induced climate change.
Climate change has already altered the extreme weather we experience in Australia and will continue to do so over the coming years.

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This Stunning Antarctic Lake Is Buried In Ice. And That Could Be Bad News

Fairfax - Chris Mooney

Atop the ice sheet covering the Arctic island of Greenland, you now see dramatic melting in the summer. It forms lakes, rivers and even dangerous "moulins" in the ice where rivers suddenly plunge into the thick ice sheet, carrying water deep below.
East Antarctica is supposed to be different. It is extremely remote and cold. It doesn't see such warm temperatures in the summer - yet - and so its ice tends to remain more pristine.

Underwater camera explores Antarctic lake
Video from inside a borehole showing an englacial lake four metres below the surface of East Antarctic ice shelf.

"Many people refer to East Antarctica as being too cold for significant melt," says Jan Lenaerts, a glaciologist with the Utrecht University in the Netherlands. "I mean there's marginal melt in summer, but there's not a lot."
That's the common wisdom, at least, but it is challenged in a new study in Nature Climate Change, by Lenaerts and his colleagues from universities in the Netherlands, Belgium and Germany. They do so based on research they conducted atop the very large Roi Baudouin ice shelf in East Antarctica, which floats atop the ocean, and where they found a very Greenland-like situation in early 2016.
The researchers had travelled to investigate what had been described as a nearly two-mile-wide "crater" in the shelf, glimpsed by satellite, which some sources believed had been caused by a meteorite. To the contrary, they found that it was a large, 10 foot deep, icy lake bed. In its centre, meanwhile, were multiple rivers and three moulins that carried water deep down into the floating ice shelf.
And even this, perhaps, was not the most dramatic finding. The researchers also drilled through the ice and found what they called "englacial" lakes, sandwiched between the surface of the ice shelf and its base, which is in contact with the ocean beneath it. They found 55 lakes in total on or in the ice shelf, and a number of them were in this buried, englacial format. The video of one such discovery, of a crystal blue lake four meters below the ice shelf surface, is shown above, and an image from the video is below:
Underwater picture of englacial lake 4m below the surface of the Roi Baudouin ice shelf, East Antarctica. Photo: Stef Lhermitte
This meant that the ice shelf is anything but solid - it had many large pockets of weakness throughout its structure, suggesting a greater potential vulnerability to collapse through a process called "hydrofracturing," especially if lake formation continues or increases. That's bad news because when ice shelves fall apart, the glacial ice behind them flows more rapidly to the ocean, raising sea levels.
But why was all this happening, and here?
The researchers postulate that a "microclimate" exists on the ice shelf that made it all possible - and that a similar mechanism is operating on other East Antarctic ice shelves. Here's what they believe happens to create so much wetness and melt:
In  East Antarctica, so-called "katabatic" winds blow downhill from higher reaches of the ice sheet toward the sea. These powerful winds scour the surface and lift off all the snow, exposing blue ice beneath. At the same time, they mix with warmer air higher in the atmosphere and pull it downward. (In this part of Antarctica there is a temperature "inversion" with cooler winds near the surface and warmer air aloft.)
This has a double melting effect: The warmth raises temperatures atop the ice, even as the exposure of the blue ice reduces the "albedo," or reflectivity, of the surface, meaning that more sunlight gets absorbed. The result is a pocket of melt in the form of a lake and in some cases the pouring of water into the ice shelf.
As for the submerged lakes, these appear to form from surface lakes that freeze over on top in winter, but stay liquid beneath, Lenaerts said. Then subsequent layers of snow may bury them, even as the steady flow of the glacier into the ice shelf carries them out further over the ocean.
Indeed, it turns out that the further out over the ocean you go, the deeper the lakes tended to occur, presumably due to this flow and burial process. The lake in the video provided is four metres below the ice surface, but "we have found one eight metres below the surface even further, and one 15 metres below the surface, even further," Lenaerts said.
As for the plunging moulins, where that water ends up remains mysterious. But it does not appear to be feeding the buried lakes. "We don't have the tools, the instrumentation, to detect this right now. This is a really big unknown," Lenaerts said. The water could even be travelling all the way through the ice shelf and pouring into the ocean.
Moulin inside the crater on the Roi Baudouin ice shelf showing the drainage of meltwater. Photo: Sanne Bosteels
Importantly, the researchers went to satellite images to show that what's happening on the Roi Baudouin ice shelf isn't unique to East Antarctica. Rather, they say, they have seen similar features atop other nearby East Antarctic ice shelves, at least remotely.
"We see similar things going on on neighbouring ice shelves, and also for instance on the Amery ice shelf, which is also a notorious, very large ice shelf on East Antarctica," Lenaerts said. "We see this link between strong winds and blue ice formation, enhanced absorption of solar radiation, and the melt that is enhanced by this process."
The researchers are not saying, to be sure, that these processes are caused by human-induced climate change - they note in particular that on the Roi Baudouin shelf, it appears that there has been some melting at the surface since the 1980s. However, Lenaerts said it is already clear that there is much more meltwater during warmer summers than in cooler ones. And global warming will gradually produce warmer Antarctic temperatures, which should increase the volume of meltwater atop of these ice shelves, pushing them still further in the Greenland direction.
What this means is that the shelves could be subject to the risk of what researchers call "hydro-fracturing": when a great deal of meltwater forms atop the shelf and pushes inside of it, eventually leading to a crackup. That's what's believed to have happened in the classic case of the shattering of the Larsen B ice shelf in the Antarctic peninsula in 2002. Now the fear is that it could happen in the East Antarctic too, where there is a massive amount of ice to potentially lose.
"If this region can get warmer in the future, the meltwater production will enhance a lot, and we can only expect these features, these processes to be more present than they are now," said Lenaerts said. "With potential implications for hydrofacturing to happen and for ice shelf stability."

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