Global Warming, CO2, Oxygen, Trees, things like that

I was wondering today, looking at the trees still wearing their leaves, about global warming. People around me are starting to get worried. Women are telling me they are seriously thinking about not having kids.
But, it now being November the 25th, it was 16 degrees Celsius today. So, we are hardly warming our houses, so we use little gas, so we produce less CO2. The trees still have leaves, so a part of the trees probably still make a little bit of oxygen during daytime.
I don't know if it has any influence, we will see. It just crossed my mind. Only time will tell...