[Tupelo]

re: They cultivated plants, cleared forests with extensive burning to boost the population of desired animals,

Here in the Sonoran Desert, we survive & prosper via the canals dug & enlarged in the first half of the 20th Century. Canals that follow the paths of the smaller canals dug by the Pima and others.
I am sure every Enviro-Wacko would agree that digging canals changes the eco-structure.

[HangnJudge]

Kudzu
The vine that ate the South

[Apple Pan Dowdy]

There are no honeybees native to America. They have all been imported. Imagine trying to grow many of our fruits and vegetables without pollination by the honeybee.

[B4Ranch]

I’ve often wondered how many civilizations that inhabited the world before us failed due to inbreeding. They didn’t have trains, cars or planes to mix with other civilizations, so I’m guessing that inbreeding led to their downfall.

If these civilizations were so intellectually high why didn’t they forecast what would cause them to fail?

[Theophilus]

Deer and turkey love corn and soybeans.

[DuncanWaring]

Geoengineering proponents hope that such techniques might one day be used to sequester large amounts of carbon from the atmosphere ...

Or we can just wait a few more years (probably less than 10) and the Sun's declining magnetic field will, to make a long story short, result in a cooling earth, with cooling oceans, which will absorb massive amounts of CO2 from the atmosphere.