I think that tree stumps covered by ice for 7000 years and now they are thawed and uncovered points to something..... In my life the most noticeable sign is that most people I know have worse allergies than they had 5-10 years ago. I remember a talk show I was listening to on the radio when we were driving out west. People from all over the country were asking why their allergies were worse. This was before they figured out that the higher CO2 made it so plants put out more pollen. I noticed a few years back that the poison ivy is thriving in our woods. Worse than it's ever been in the 20 years we have lived here. I read the other day that this was also a sign of global warming. This might not be such a bad thing for the Earth. Maybe just bad/difficult for a few species that will have to adapt.