GHGs have risen from around 280ppm two centuries ago to around 370ppm today, thanks chiefly to mankind's use of fossil fuels and, to a lesser degree, to deforestation and other land-use changes.

ECONOMIST: Blowing hot and cold

So far such systems appeal chiefly to disabled people who cannot use a conventional mouse.

ECONOMIST: Computer interfaces

Chiefly, communication: Some people actually use their mobile devices to talk to other folks.

FORBES: Gadgets Entrepreneurs Love

Similarly, with the Kindle Fire, Mr Bezos recognised that a tablet computer designed chiefly for consuming entertainment content is no use unless there is plenty of such content available.

ECONOMIST: Brain scan