Air-capture schemes revolve round a process of reversible absorption.

ECONOMIST: Combating climate change

Among the innovations: a cooling system that recycles heat from generators to power an absorption chiller which, in turn, sucks in fresh air through landscaped terraces.

CNN: SPECIAL REPORT CITIES

But the strength of the greenhouse effect depends on the chemical composition of the atmosphere, because the phenomenon is due to the absorption of infra-red radiation by various gases in the air.

ECONOMIST: Climate change: Getting real | The