  In the study of planetary habitability and terrestrial atmospheric evolution,
the divergence of surface conditions for Venus and Earth remains an area of
active research. Among the intrinsic and external influences on the Venusian
climate history are orbital changes due to giant planet migration that have
both variable incident flux and tidal heating consequences. Here, we present
the results of a study that explores the effect of Jupiter's location on the
orbital parameters of Venus and subsequent potential water loss scenarios. Our
dynamical simulations show that various scenarios of Jovian migration could
have resulted in orbital eccentricities for Venus as high as 0.31. We quantify
the implications of the increased eccentricity, including tidal energy, surface
energy flux, and the variable insolation flux expected from the faint young
Sun. The tidal circularization timescale calculations demonstrate that a
relatively high tidal dissipation factor is required to reduce the eccentricity
of Venus to the present value, which implies a high initial water inventory. We
further estimate the consequences of high orbital eccentricity on water loss,
and estimate that the water loss rate may have increased by at least $\sim$5\%
compared with the circular orbit case as a result of orbital forcing. We argue
that these eccentricity variations for the young Venus may have accelerated the
atmospheric evolution of Venus towards the inevitable collapse of the
atmosphere into a runaway greenhouse state. The presence of giant planets in
exoplanetary systems may likewise increase the expected rate of Venus analogs
in those systems.
