The 2008 Climate Change Act, one of the most important acts passed during the 13 yrs of Labour Gov't committed the UK to reducing carbon emissions by at least 80% compared with 1990 levels. This is a very big ask, which needs a complete rethink about how we live. In order to ensure current Gov't's accept responsibility for this today, the 2008 Act requires Gov't to set 'carbon budgets' in law with specific emissions reduction targets (stepping stones sort of) for each 5 yr period leading up to 2050. These 'carbon budgets' are progressively more restrictive caps on emissions. Gov't is currently working on setting the 5th Carbon Budget to cover the period from 2028-2032. The Act requires Gov't to set 'carbon budgets' by 30th June in the 12th year before the beginning of the period in question. The means setting the 5th 'carbon budget' by 30th June this year.
There are two parties involved in negotiating the precise carbon emissions targets - the Government on the day and the Committee for Climate Change. There is a formal timetable in the process of setting the binding target. The carbon emissions reduction anticipated during the 5th Carbon Budget is likely to be about 58% below 1990 levels.
Hope those who didn't know much about this issue now know what we are talking about when reference to carbon budgets crop up in conversation.!