Climate security

Geoengineering: What is it, how does it work and is it good or bad?

Earth's climate fluctuates. It has done since it formed more than 4.6 billion years ago. At present, we are in an interglacial period – that means that while technically we are in an ice age, we are in a warmer part of it. What we commonly consider the "last ice age" ended roughly 11,000 years ago.

Because scientists understand the conditions involved in periods of warming and cooling, it is possible to artificially recreate them. Enter geoengineering.

Since Marchetti's paper, many different methods have been put forward to artificially alter Earth's climate, but they all have the same end goal: to stop the planet heating up at the rate it is at the moment. Largely speaking, all the different geoengineering proposals fall into one of two categories. Here we look more closely at the two plans...