Climate Change

I am not a climate change denier just a skeptic. I question why Global Warming has now changed to Climate Change. I question why if the planet is warming why has most parts of Australia had the coldest March since recordings first began. This info from the BOM. I question why CO2 readings in the atmosphere do not take into account the amount contributed by natural events such as the recent volcano in Iceland. Apparently it spewed into the atmosphere many times what we humans contribute??