  The increased particle flux at the high luminosity phase of the Large Hadron
Collider (HL-LHC), with instantaneous luminosities of up to 7.5 times the
original design value, will have an impact on many sub-systems of the ATLAS
detector. This contribution highlights the particular impacts on the ATLAS
liquid argon calorimeter system, together with an overview of the various
upgrade plans leading up to the HL-LHC. The higher luminosities are of
particular importance for the forward calorimeters (FCal), where the expected
increase in the ionization load poses a number of problems that can degrade the
FCal performance such as beam heating and space-charge effects in the liquid
argon gaps and high-voltage drop due to increased current drawn over the
current-limiting resistors. A proposed FCal replacement as a way to counter
some of these problems is weighed against the risks associated with the
replacement. To further mitigate the effects of increased pile-up, the
installation of a high-granularity timing detector at the front face of each
end-cap cryostat is also currently under consideration. Several different
sensor technologies and layouts are being investigated.
