My wife and I use soya milk instead of cow's milk. It is fine when added to tea, but when added to coffee it curdles horribly. Why?

I have been learning about Global Warming at school and, assuming Global warming is caused by humans, if we ate less meat (which I would love, being vegetarian) could we reduce the effects of the dreaded Global Warming? If so, why hasn't this been employed by the Government and used as a way to contribute to the end of global warming?