Human induced climate change is claimed to be the greatest challenge of the 21st century. But man-made carbon emissions continue to rise - the 400ppm carbon milestone causes barely a ripple. I am intrigued as to why, in society at large, there is little grass roots support, no loud and clear call for action to address this issue.
400 parts per million. Why is the figure in the news? Can we help people make 400 ppm meaningful for themselves by showing what it looks like?