Formation of Panama isthmus and its influence on climate.
The Isthmus of Panama is believed to be responsible for the decrease in global temperature around 3 mln years ago. The official explanation is that it altered the flow of heat in the oceans. Here is an alternative hypothesis for this event which needs to be verified.
According to the Gaia theory (accepted theory): “living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps to maintain and perpetuate the conditions for life on the planet.” There is a hypothesis that life-forms (fungi, geobacter and ungulates among others) actively try to influence the local weather within three-weeks from the onset of large-scale movement of ungulates.
What if there are unidentified natural selection rules which help life forms to evolve to be best in terms of influencing the local weather to make the place livable?
234 mln years ago it rained for two mln years (Carnian Pluvial Period). Inner land was transformed from dry hot red unlivable areas to green jungles. From that period on, the evolution of organisms exploded with diversity.
Among other things, Nature seems to have been selecting the best animals to spread microbiomes. Ungulates are like bees which are necessary to spread precious microbiome over land surface. While some ungulates developed instincts of natural migration, other ungulates needed predators to be moved around (humans have been removing predators destabilising the biosystem, so we have to do jobs of the predators, we have to chase ungulates).
Before 3 mln ago, continents of the South Hemisphere (South America, Australia, Antarctica) had ungulates of “previous generation” in comparison to the continents of North Hemisphere and Africa, where ungulates may be more efficient in spreading microbiome. When the Panama isthmus formed, The Great American Biotic Interchange happened and the ungulates from North America replaced the ones in South America. Thus it could be the reason for the decrease in global temperature around 3 mln ago.
What about Australian ungulates? Camels and horses were brought to Australia in the end of the 1800s. They don’t have natural predators there. If they are moved regularly by humans like during culling campaigns it would decrease the average temperature. There was a big feral horse culling campaign that started in 1996 and culminated in 2000. Another big culling was in 2010–2011 but at that time it was culling of feral camels. Both culling campaigns resulted in the decrease of annual mean temperature in Australia, as you can see in the chart below.
Thus, we could exploit this mechanism which might have evolved to deal with the climate change in the past. A regular ecological service would be needed to cool down the planet. This service would consist of cavalries which would simulate natural migration of ungulates.