The biggest-ever US demonstration against climate change
brought 35,000 activists from 30 states to Washington DC
in February. Photo: 350.org / project survival media
The world’s most important CO2 monitoring station recorded short-term CO2 concentrations in the atmosphere above 400 parts per million (ppm), a level not seen for three million years.
Measurements at the Mauna Loa observatory in Hawaii (and elsewhere) show CO2 concentrations…