Sentences with phrase «occurring over tens of thousands of years»
Glacial cycles (ice ages) are set in motion by (1) periodic wobbles in the tilt of the Earth's rotation, (2) changes in the tilt of its axis, and (3) the shape of its orbit occurring over tens of thousands of years.
http://illconsidered.blogspot.ru/ Not exact matches
«There must have been regional climate and chemical conditions that varied in time and space,» he says, adding that this would occur as the tilt of Mars's spin axis changed over tens of thousands of years, a wobble caused by the lack of a massive moon to stabilise the planet.
Processes that have historically altered the face of the planet, like cycles in the Earth's orbit around the Sun or shifts in continental tectonic plates, occur over tens of thousands to millions of years.
Reality: Whilst there are many areas of interesting research with respect to the glacial - interglacial cycles of the Quaternary, we have a good understanding of the primary drivers i.e. orbital variations occurring over cycles of tens of thousands of years.
Problem being that the huge influx of anthropogenic CO2 has pretty much overwhelmed this negative feedback process as it occurs over thousands and tens of thousands of years, and we'll have doubled CO2 in just a few hundred years.
Only one of the past «Big Five» mass extinctions (the dinosaur extinction event at the end of the Cretaceous) is thought to have occurred as rapidly as would be the case if currently observed extinctions rates were to continue at their present high rate (Alvarez et al., 1980; Barnosky et al., 2011; Robertson et al., 2004; Schulte et al., 2010), but the minimal span of time over which past mass extinctions actually took place is impossible to determine, because geological dating typically has error bars of tens of thousands to hundreds of thousands of years.
Surely what matters are (i) the effects on future generations over tens of thousands of years if runaway warming of several C is allowed to occur (ii) loss of biodiversity forever (iii) effects on developing world in our lifetime as well as beyond.