<P> The pressure melting point is the temperature at which ice melts at a given pressure . The pressure melting point is nearly a constant 0 ° C at pressures above the triple point at 611.7 Pa, where water can exist in only the solid or liquid phases, through atmospheric pressure (100 kPa) until about 10 MPa . With increasing pressure above 10 MPa, the pressure melting point decreases to a minimum of − 21.9 ° C at 209.9 MPa . Thereafter, the pressure melting point rises rapidly with pressure, passing back through 0 ° C at 632.4 MPa . </P> <P> Glaciers are subject to geothermal heat flux from below and atmospheric warming or cooling from above . As the pressure increases with depth in a glacier from the weight of the ice above, the pressure melting point of ice decreases within bounds, as shown in the diagram . The level where ice can start melting is where the pressure melting point equals the actual temperature . In static equilibrium conditions, this would be the highest level where water can exist in a glacier . It would also be the level of the base of an ice shelf, or the ice - water interface of a subglacial lake . </P>

What is the minimum pressure required to release this water in kilobars