Actually, from what I've seen, our natural Milankovitch pattern this time will be a slow cooling over the next 10,000 years into the depths of the next Ice Age. When exactly along that time frame you can say we are "in an ice age" is subjective.kurt9 wrote:This is quite believable based on the Milankovich Cycles. However, I have read in places that our agriculture and animal husbandry (creates lots of Methane) is actually keeping us out the next ice age, which would have begun about 3,000 years ago were it not for humans.MSimon wrote:The limit to energy production all depends on whether we are in an intergalcial or a glacial period.
Since the current interglacial is predicted (based on the last million years of Earth history) to end any time now I believe that allowable energy production for the next 100,000 years will be rather higher than the numbers provided.
In fact it may be necessary to just "waste" the energy to keep the ice sheets from covering a significant proportion of the currently ice free land mass.
In any case, a new ice age would be far worse for humanity than any amount of global warming, which would actually benefit everyone except for the limousine liberals with their beachfront houses. Perhaps this is the real reason why they oppose global warming.
That said, Milankovitch isn't the be-all/end-all wrt climate. The configuration of the continents and seas/oceans also plays a major role. For instance, when Antarctica separated from South America and Australia 14-22 mya, the circumpolar current set in and created a thermal bottle effect around Antarctica which is the cause of its stable long term ice caps. Prior to this Antarctica was more temperate.
Similarly, when the straits of panama closed 3 mya, it shut off a major ocean current pattern and made our present 100ky ice age pattern pretty solid.
However since the end of the last ice age, we have seen the Mediterranean be flooded by the breach of Gibraltar, the Black Sea be flooded by the breach of the Bosporus, and the water level of the Caspian rise and fall frequently. These increases in sea area changed climate.
Similarly, the draining of Lake Agaziz down the St Lawrence set up the Younger Dryas.
The ENSO/PDO patterns have over time become increasingly amplified by the rising of Tibet in altitude due to the impact of India with Asia.