The US should pay $22bn a year to developing countries to help them to adapt to the effects of climate change, according to a calculation published on Monday by the charity Oxfam.

Japan should pay about $6.5bn, Germany about $3.5bn a year and the UK at least $2.5bn a year in order to give developing countries the aid they need. Other countries, such as European Union member states and Australia, should pay between $1.5bn and $2.5bn in climate change reparations, or “compensatory finance”, said Kate Raworth, senior researcher at Oxfam and author of the report.