How can water freeze at room temperature under high pressure?

Water can be produced in its solid state (ice) at room temperature by subjecting it to extremely high pressure, specifically reaching levels roughly 10,000 times greater than atmospheric pressure.1

While temperature and pressure are both thermochemical variables that influence the state of matter, they affect internal energy in fundamentally different ways. Temperature changes relate to the kinetic energy of vibrating atoms, whereas high pressure forces atoms closer together, altering the energy of atomic bonds and reducing the material's volume.1

In the case of water, the transition to ice at room temperature occurs because the applied pressure overcomes the thermal agitation that otherwise keeps the molecules in a liquid state. By compressing the water, the molecules are forced into a more compact, ordered crystalline structure. Although ordinary ice is less dense than liquid water, at very high pressures, water undergoes structural transformations into denser, more closely packed forms of ice.123