GREENLAND HEADING BACK TO GREEN
Modelling of why Greenland stopped being green and became covered with ice indicates that it was the drop three million years ago in the global concentration of carbon-dioxide in the atmosphere from high to pre-industrial levels, reports ScienceDaily.
The present level is now approaching those ancient levels.
No wonder Arctic ice-coverage is on the verge of another all-time low.
This BBC News report says the Arctic is passing through a tipping-point.