Tim Radford / Nation of Change & Marlee Kokotovic / Nation of Change – 2017-04-24 00:27:49
Giant Waterfall in Antarctica Worries Scientists
The big question is: has the level of
surface melting increased in the last seven decades?
Tim Radford / Nation of Change
(April 23, 2017) — Scientists poring over military and satellite imagery have mapped the unimaginable: a network of rivers, streams, ponds, lakes and even a waterfall, flowing over the ice shelf of a continent with an annual mean temperature of more than -50C.
In 1909 Ernest Shackleton and his fellow explorers on their way to the magnetic South Pole found that they had to cross and recross flowing streams and lakes on the Nansen Ice Shelf.
Now, US scientists report in the journal Nature that they studied photographs taken by military aircraft from 1947 and satellite images from 1973 to identify almost 700 seasonal networks of ponds, channels and braided streams flowing from all sides of the continent, as close as 600km to the South Pole and at altitudes of 1,300 meters.
And they found that such systems carried water for 120km. A second research team reporting a companion study in the same issue of Nature identified one meltwater system with an ocean outflow that ended in a 130-meter wide waterfall, big enough to drain the entire surface melt in a matter of days.
In a world rapidly warming as humans burn ever more fossil fuels, to add ever more greenhouse gasses into the atmosphere, researchers expect to observe an increase in the volume of meltwater on the south polar surface. Researchers have predicted the melt rates could double by 2050. What isn’t clear is whether this will make the shelf ice around the continent — and shelf ice slows the flow of glaciers from the polar hinterland — any less stable.
“This is not in the future — this is widespread now, and has been for decades,” said Jonathan Kingslake, a glaciologist at Columbia University’s Lamont-Doherty Earth Observatory, who led the research.
“I think most polar scientists have considered water moving across the surface of Antarctica to be extremely rare. But we found a lot of it, over very large areas.”
The big question is: has the level of surface melting increased in the last seven decades? The researchers don’t yet have enough information to make a judgment.
“We have no reason to think they have,” Dr. Kingslake said. “But without further work, we can’t tell. Now, looking forward, it will be really important to work out how these systems will change in response to warming, and how this will affect the ice sheets.”
Many of the flow systems seem to start in the Antarctic mountains, near outcrops of exposed rock, or in places where fierce winds have scoured snow off the ice beneath. Rocks are dark, the exposed ice is a blue color, and during the long days of the Antarctic summer, both would absorb more solar energy than white snow or ice. This would be enough to start the melting process.
The Antarctic is already losing ice, as giant floating shelves suddenly fracture and drift north. There is a theory that meltwater could be part of the fissure mechanism, as it seeps deep into the shelves.
But the companion study, led by the polar scientist Robin Bell of the Lamont-Doherty Observatory suggests that drainage on the Nansen Ice Shelf might help to keep the ice intact, perhaps by draining away the meltwater in the dramatic waterfall, the scientists had identified.
“It could develop this way in other places, or things could just devolve into giant slush puddles,” she said. “Ice is dynamic, and complex, and we don’t have the data yet.”
ACTION ALERT: Tell Trump Not to Abandon Climate Progress
Bullhorn / Nation of Change
For every 1,000 signatures, NationofChange will send letters to President Trump and Scott Pruitt demanding that they reinstate the Clean Power Plan and continue providing funding for climate science.
Since being sworn into office, President Trump has issued numerous Executive Orders that have rolled back progress on climate change.
Among these are orders directly to the EPA and other government agencies to abandon climate research and roll back policies put into place to combat climate change.
Agencies are being ordered to ignore the impacts of carbon pollution and begin leasing coalmining rights on federal land. The EPA is being ordered to dismantle its landmark climate protections, the Clean Power Plan.
Trump is also pulling funding from projects that would help us learn more about climate change and our effects on it, such as NASA’s climate science department.
We can’t let the Trump administration get away with this. It has been shown that an outpouring of public outrage can have a profound effect on policy. Public response and activism has helped combat the Muslim ban and prevented Republicans from passing a disastrous health care plan.
Now we need this same outrage to keep Trump from obliterating all climate action and protections.
Science Celebrities Speak Out on Earth Day
“We are at a critical juncture. Science is under attack.”
Marlee Kokotovic / Nation of Change
(April 23, 2017) — Thousands of scientists and science supporters gathered yesterday, on Earth Day, to March for Science. This comes at a time when many are in fear over the policies threatened by President Trump. Several prominent figures in the science community and science celebrities spoke up for science, including American astrophysicist, Neil deGrasse Tyson:
Show me a Nation with a science-hostile government, and I’ll show you a society with failing health, wealth, & security.
TV host and scientist Bill Nye, one of the event’s speakers, told the rain-soaked crowd, “Today we have a great many lawmakers — not just here but around the world — deliberately ignoring and actively suppressing science.”
The march was a celebration of science and the many ways it serves our communities and the world.
“We are at a critical juncture. Science is under attack,” said Cara Santa Maria, a science communicator who was one of several emcees of the four-hour rally that kicked off at 10 a.m. “The very idea of evidence and logic and reason is being threatened by individuals and interests with the power to do real harm.”
After the Women’s March in January, the idea of a science march was discussed online on Reddit. After numerous science organizations showed their support, it became an event that would come to include more than 600 cities around the world.
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