Is the threat of Global Warming (now cled as Climate Change) a true threat or is it one big scam ?

Years ago the threat was of a big FREEZE, and we were told the earth was cooling down. Then came ACID rain threat that was going to defoliate the planet. Yet along came another inevitable the OZONE LAYER, we were ALL going to get skin cancer. Now it's GLOBAL WARMING/CLIMATE CHANGE. How many of these HAVE happened ?. The MAXIMUM co2 level that can be constant is 0.032% no more, and can be less. This SCARE is just to extract money by big businesses, or grants, eg, you will be refused a grant if you ask for a grant to study animals...BUT if you ask for a grant to study the effects on animals by climate change, a grant will be given. If they care so much about the so called climate change due to co2.....Why are the big electrical manafacter's being allowed to produce so much plastic based items, T.V's, mobile phones, Ipods, digital cameras, compiters, coffee machines, electric kettles. The list is ENDLESS. THINK ABOUT it. The scam, con, whatever, How can you buy co2 and sell it again ???