Q: I have just been watching a programme about James Lovelock, in which he was quiet pessimistic about global warming. It strikes me that if our current ice age was triggered by the erosion of the then newly uplifted Himalayas, then it ought to be possible to cause a similar drop in temperature by increasing the mechanical erosion of some of the worlds undammed mountain rivers. A few tonnes of explosive could move a few water falls back by a thousand years or so. As much again could widen some mountain ravines or gorges by tens of thousands of years.
Of course if the cause of global warming is the end of the current ice age triggered by the northward movement of Australia closing down the supply of warm Pacific water to the Indian monsoon, then maybe increasing erosion elsewhere would fail.
From J P Fellows (June 2010)
Reply by Dr Ted Nield
What you have proposed is correct. The uplift of the Himalayan Plateau is thought to have been instrumental in bringing on the Ice ages because all silicate weathering reduces Co2 in the atmosphere and hence cools the planet. So the uplift created more silicate weathering, which lowered the greenhouse effect and hence - glaciation.
However, to affect current anthropogenic global warming using this method would mean quarrying, crushing and transporting teratonnes of material in order for this extremely weak and slow process to have any effect in anything like the timescale required. The energy required to do that would have to come from fossil fuels, whose combustion would wipe out any positive effects.