there is a considerable difference between natural selection or selective breeding (slow gradual changes within a species) and direct manipulation of genetic material in a lab. in the early 90's a company called Genetech released a bacterium into the atmosphere which was designed to
Significantly increase the temperature at which water turns to ice or snow! over the past 20 years this genetically modified bacterium has been fond in samples from the stratosphere to the ocean's benthic deeps. climatologists are still trying to figure out how badly we are fucked.
this could be the only
real source of man made climate change. and the best part is why they did it... to reduce the damage that early frosts do to strawberries.
http://en.wikipedia.org/wiki/Ice-minus_bacteria
some wacky experiments could conceivably result in a strain of a plant or animal thta could displace it's natural competitors resulting in destabilization of the biosphere.
heres a nightmare scenario for you:
in an attempt to create a microbe based heavy metal contamination cleanup program, a little of the stuff escapes to the sea. the critter spreads and reproduces feeding on the naturally occuring heavy metal content of the oceans. they collect and concentrate the metals in their cell membranes, and out-compete their normal competitors by being deadly to their predators. including whales, fish crabs coral tube worms etc.
in a matter of a few hundred years the sea is a gelatinous toxic mass of a single microbe. all life on earth ends.
this is not only terrifying, it is possible.
careless genetic modification could result in global death, but nudging a food crop to increase production is not gonna end the world. its all about balance. science has dangers, but insane pathological terror leads only to bullshit.
edit: the above scenario is astronomically unlikely. the fools who froth at the mouth and convince starving africans that GM crops are poison are pure evil, irredeemable and wicked beyond belief. they should be stoned to death in the village square for their hateful agenda driven lies that serve no purpose but to enhance their personal feelings of power. GM crops are powerful tools, and not any different than the normal crops when you eat them. if the lies told by the econauts were true, they would all have devolved into organic small batch artisinal kale by now. Eating food does NOT transfer genetic material to the eater from the food. that is retarded.