• In the meantime, the administration will set up a Unified Combatant Command for space, to be known as U.S. Space Command. This command will absorb the space-related responsibilities previously assigned to U.S. Strategic Command, according to a senior administration official.

What they're saying: Administration officials said the White House and Defense Department will submit the proposal to Capitol Hill to form a 6th branch of the military, on par with the Marine Corps that sits within the Navy, that would be dedicated to space.

• Congress must approve the funds for the Space Force and will play a major role in determining how it is structured.
• The idea of housing the force within the Air Force is seen as a move to satisfy critics on Capitol Hill who raised concerns about the cost of providing the infrastructure for an entirely new department.

In the meantime, the administration is moving to set up a unified combatant command for space that will be separate from the existing Air Force Space Command. The White House said it would not release a cost estimate for these changes until its Fiscal Year 2020 budget release next month.

Why it matters: The Trump administration says it's moving to create the Space Force in response to adversaries' increased space capabilities, particularly China.

• The U.S. has long been dominant in space exploration and the military use of space, such as through spy satellites and a constellation of GPS satellites for navigation and weapons guidance.
• Now, however, China and other countries are launching ambitious space programs, including military capabilities that could threaten American space assets.

Go deeper: Axios' deep dive on space

The big picture: Scientists are racing to better understand and anticipate the pace, extent and impacts of melting glaciers, both in Greenland and Antarctica. Since the last report from the UN Intergovernmental Panel on Climate Change in 2014, sea level rise estimates have increased, but uncertainties remain high.

• The new study, by a group of researchers from New Zealand, Canada, Germany and the U.K., is one of the first to pair a climate model with an ice sheet model — fed with the latest observational data on ice loss — to see how ice melt might alter the planet's climate.
• It finds that the influences may be profound.

The threat: If the Greenland or Antarctic ice sheets melt quickly and significantly enough, they could pour enough cold, relatively light freshwater into adjacent areas of the ocean to disrupt global ocean circulation, the study finds.

• In particular, the study adds to the growing concern in the scientific community about a slowdown in a current known as the Atlantic-Meridional Overturning Circulation, or AMOC.
• This current is also referred to as a global conveyor belt or global thermohaline circulation, carrying heat and oxygen from the bottom of the world to the far north, and back again.
• There are clear signs that part of this current is already slowing down, due to freshwater inputs from Greenland.

The new study says this could lessen the heat transported to Europe and may make weather more variable in the northeastern U.S., among many other areas. Worse yet, in the Antarctic, adding freshwater to the surface ocean would serve to reduce the amount of mixing between ocean layers, the study says.

• This would trap salty and warm water well below a film of cool, freshwater on the surface.
• Such warm, salty waters are melting marine-terminating glaciers in West Antarctica by eating away at their floating ice shelves and infiltrating the ice bed in areas where the bedrock is below sea level.

What they're not saying: The study assumes that the ocean is not playing a large role in melting Greenland's glaciers, which is at odds with observations, according to Eric Rignot, a professor of Earth system science at UC Irvine, who was not involved in the new study.

• Rignot says Greenland will melt faster and more extensively than the study's models show.

What they're saying: Luke Trusel, a study coauthor and geology professor at Rowan University, told Axios that melting ice sheets will have effects far beyond sea level rise.

"Ice sheets aren't passive bodies of ice, they're dynamic, interactive components of the Earth system. They change in response to climate, and climate then responds to their change."

"'Melting ice sheets don't just cause sea level rise. They also disrupt the climate system, by dumping a lot of cold freshwater into the ocean," says study coauthor Kaitlin Naughten of the British Antarctic Survey, in an email to Axios. "This affects deep ocean circulation, surface ocean currents, and weather patterns across the globe."

Go deeper:

• Greenland Ice Sheet melting at unprecedented rate in past 350 years or more
• Scientists find new evidence of life beneath Antarctic ice
• Antarctica is losing ice 6 times faster than in 1980s

• If there were a "Most Wanted List" for glaciers, Thwaites would be No. 1. Scientists are desperately trying to determine its fate.
• Thwaites acts as a gateway to vast quantities of inland ice that rest on bedrock well below sea level.
• If ocean waters were to access that inland ice, it could all melt, raising sea levels by at least 10 feet.

Geologist Richard Alley of Penn State University, who was not involved in the new study, called Thwaites a "geometric accident" that could lead to "large and rapid" ice loss if ice cliff instability that has happened elsewhere occurs there.

"Cliff retreat is not some strange and unexpected physical process; it is happening now in some places, has happened in the past, and is expected wherever sufficiently high temperatures occur in [the] ocean or air around ice flowing into the ocean."

Details: The study reports the ebb and flow of salty, dense and relatively warm ocean waters had taken a gigantic bite out of the base of Thwaites, leaving a gap between the glacial floor and the bedrock below. Its dimensions are staggering.

• The gap is 2.5 miles wide and 6 miles long, about 1,100 feet high and once contained about 14 billion tons of ice that have melted in the past few years.

What they're saying: "What we are seeing with high resolution data is the ocean eating away large portions of the ice, taking big bites at a time instead of eroding slowly," UC Irvine's Rignot, a co-author of the new study, told Axios.

A second study on West Antarctic glaciers including Thwaites was published on Wednesday in Nature, scrutinizing the alarming findings of another study published in 2016. That study showed that marine-terminating glaciers become inherently unstable when their calving front forms tall cliffs, upwards of 330 feet tall.

• This marine ice-cliff instability causes such glaciers to rapidly break apart.
• Observations of this physical process in Greenland's outlet glaciers have lent credence to this hypothesis.

The catch: The new research uses statistical techniques to find that past episodes of rapid sea level rise could've happened without this ice cliff instability.

• The study suggests sea level rise will be lower than the numbers the 2016 study put forward, projecting only a 5% chance that the Antarctic contribution to sea-level rise will top 15 inches by 2100.
• "Our study demonstrates that the jury’s still out on marine ice-cliff instability," study lead author Tamsin Edwards, a geographer at Kings College in London, told Axios via email.

Rob DeConto of U-Mass Amherst, who co-authored the 2016 study, said the new study is useful but does not rule out the more alarming possibilities. "I don't really see ice fracture as an optional process that can be excluded from ice sheet models," DeConto told Axios. "Ice that flows into the ocean essentially always ends in a cliff regardless of the setting or spatial scale."

Richard Alley, a geoscientist at Penn State University who was not involved in either of the new studies, told Axios that marine ice-cliff instability poses a grave danger.

The bottom line: More work is needed for scientists to confidently winnow down the forecast range of sea-level rise. A new, multiyear U.S.-British research campaign focused on Thwaites should help.

Go deeper: Antarctica is losing ice 6 times faster than in the 1980s