The gravest threat and change driver affecting human society and the global economy is climate change. There is one "measurable" that all of us must become aware of if we are to face and deal with this reality: the concentration of carbon in the earth's atmosphere. According to Jim Hansen, it should not be allowed to exceed 350 parts for million if we are to prevent global average temperatures to rise to dangerous levels. As you can see from the meter below (which will be updated monthly), human activity is making matters worse, not better at present. Let the data speak for itself.