This idea came to me when watching two programs about the Maya.
In one program, water levels in cenotes are now much higher than they used to be. We saw a Mayan camp fire about ten metres underwater.
In the other program, lidar had found Mayan defensive fortifications hidden in the jungle, arranged in such as way that they would have been useless for defence if they were built in the jungle.
This jelled with what I already knew about North Africa, Egypt and the fertile crescent.
We all know about two major periods of climate change, the current anthropogenic climate change due to atmospheric CO2 and the massive warming and sea level rise at the end of the ice age circa 10,000 years ago.
The third climate change occurred between the two, after the end of the ice age and before the current anthropogenic CO2 era. Unlike the other two, it was not associated with changes in global temperature. Instead, it was associated with changes in rainfall.
The climate changes of the third climate change include:
- Scandinavia: polar to temperate
- Central America: temperate to jungle
- Southern Peru: temperate to desert
- Northern Africa: temperate to desert
- Egypt: temperate to desert
- Mesopotamia: temperate to desert
- Northern India: no change
- SE Asia: temperate to jungle
OK, do you see a pattern? No? I do.
Consider hurricane/typhoon/cyclone/tropical storm. There are twice as many typhoons over the south China sea as over northern Australia. As many over northern Australia as over the Caribbean. And none at all at the same latitudes of South America. The difference is due to coral reefs. The shallow water over coral reefs gets heated by the Sun, the hot water fuels topical storms. The sizes of the tropical reefs in the four locations: South China sea, northern Australia, Caribbean and South America exactly match the proportions of tropical storms in the four locations.
At the end of the last ice age, it took coral reef growth a long time to catch up to the 40 metre rise in sea level. They caught up about 2,000 years ago, and growth since then has been small. Small, but not insignificant. As the coral reefs grow, the water above them gets shallower, which picks up more heat from the Sun during the day, making more tropical storms.
The increase in number of tropical storms led directly to more rain in Central America and South East Asia (and northern Australia) converting the climate there from temperate to jungle and dooming the Maya and Khmer civilisations. Areas at similar latitudes away from coral reefs: northern Africa, Egypt, Mesopotamia, get drier and change from temperate to desert dooming those civilizations.
It’s an interesting hypothesis n’est-ce pas.