but I have seen some things with my own eyes and can understand linear and non-linear concepts(including mathematics). Re Erosion I have seen clear sandy bottomed lakes turned into dirty water sludge pits through housing development. I haven't measured the water or black sediment that covers the floor but I assume it contains some compounds and elements that were introduced(ie not natural run off from development). I would... Roger, I am no expert at climate science(there are so many these days) but I have seen some things with my own eyes and can understand linear and non-linear concepts(including mathematics). Re Erosion I have seen clear sandy bottomed lakes turned into dirty water sludge pits through housing development. I haven't measured the water or black sediment that covers the floor but I assume it contains some compounds and elements that were introduced(ie not natural run off from development). I would assume concentrations of organochlorines etc since they were deployed willy nilly when they were considered safe and properly legal. Now I consider this geo engineering because everyman and his dog knew what would happen. This is microcosm. It is easy, through troubling, to extrapolate. Re mIning Some mines are isolated holes in the ground. Some have tailing dams cf Hungary last year, that can break or leach to top water. Then we have artesian water systems which are already under threat and measurably polluted. Then we have Gladstone Harbour. QLD. Of course these are microcosms, but again it is easy, though