Greenhouse Gas Emissions at 400 PPM:  The New Normal

It seems like every day the normal changes.  Last year was hotter than the previous one, which was the hottest year on record.  Storms have reached greater intensity than the year before.  In some places spring comes sooner with trees budding in January and in others the snow rests until late May, only to see record temperatures in June bypassing spring altogether.  No matter where any of us lives, all of us can claim that the weather is freaky and abnormal.  But why?  Maybe greenhouse gas emissions in the atmosphere are the reason.