United Nations calculates that poor countries, excluding China, will need $2.4trn annually by 2030 to tackle global warming. Around half can be raised domestically, leaving an annual shortfall of more than $1trn. From tonnes of carbon to degrees of global temperature rise, it is not unusual for un climate summits to revolve around numbers. At the Copenhagen summit in 2009 rich countries promised to supply annual climate financing of $100bn to poor countries by 2020, to help them slow climate change and resist its effects. How do you think the poor countries should be helped ?

