Could the Galactic disc heating be due to globular cluster impacts?

So far, six mechanisms have been proposed to account for the Galactic disc heating. Of these, the most important appear to be a combination of scattering of stars by molecular clouds and by spiral arms. We study a further mechanism, namely the repeated disc impact of the original Galactic globular cluster population up to the present. We find that globular clusters could have contributed at most a small fraction of the current vertical energy of the disc, as they could heat the whole disc to Sigma(z) = 5.5 km s(-1) (c.f. the observed 18 and 39 km s(-1) for the thick and thin discs, respectively). We find that the rate of rise of disc heat (alpha = 0.22 in Sigma(z) similar to t(alpha) with t being time) is close to that found for scattering by molecular clouds.