Quantum energy inequalities (QEIs) were established by Flanagan for the
massless scalar field on two-dimensional Lorentzian spacetimes globally
conformal to Minkowski space. We extend his result to all two-dimensional
globally hyperbolic Lorentzian spacetimes and use it to show that flat
spacetime QEIs give a good approximation to the curved spacetime results on
sampling timescales short in comparison with natural geometric scales. This is
relevant to the application of QEIs to constrain exotic spacetime metrics.Comment: 4 pages, REVTeX. This is an expanded version of a portion of
gr-qc/0409043. To appear in Phys Rev