<p class="p1"><span class="s1">Large scale volcanism has played a critical role in the long-term habitability </span><span class="s1">of Earth and possibly Venus.<span class="Apple-converted-space">&#160; </span>We examine the timing of Large Igneous Provinces </span><span class="s1">(LIPs) through Earth&#8217;s history [1] to estimate the likelihood of nearly simultaneous </span><span class="s1">events that could drive a planet into an extreme moist or runaway greenhouse, </span><span class="s1">quenching subductive plate tectonics. Such events would end volatile cycling </span>and may have caused the heat-death of Venus. Using the Earth's LIP record <span class="s1">a conservative estimate of the rate of LIPs in a random history statistically </span>the same as Earth&#8217;s, pairs and triplets of LIPs closer in time <span class="s1">than 0.1-1 Myrs are likely. This simultaneity threshold is significant to the </span><span class="s1">extent that it is less than the time over which environmental effects </span><span class="s1">have been shown to persist, for example in the Siberian Traps record [2,3].</span></p>
<p class="p1"><span class="s1">[1] Ernst, R.E. et al. (2021). Large Igneous Province Record Through Time and </span><span class="s1">Implications for Secular Environmental Changes and Geological Time-Scale </span>Boundaries. In: Ernst, R.E., Dickson, A.J., Bekker, A. (eds.) Large Igneous <span class="s1">Provinces: A Driver of Global Environmental and Biotic Changes. AGU Geophysical </span><span class="s1">Monograph 255 (pp. 3-26).</span></p>
<p class="p1"><span class="s1">[2] Burgess, S.D. et al. (2014). High-precision timeline for Earth&#8217;s most </span><span class="s1">severe extinction. Proceedings of the National Academy of Sciences, 111:</span></p>
<p class="p1"><span class="s1">3316&#8211;3321 [correction 2014, 111: 5050].&#160;</span></p>
<p class="p1"><span class="s1">[3] Burgess, S.D. & Bowring, S.A. (2015). High-precision geochronology confirms </span><span class="s1">voluminous magmatism before, during and after Earth's most severe extinction. </span><span class="s1">Sci. Adv. 1 (7), e1500470. http://dx.doi.org/10.1126/sciadv.1500470. </span></p>