This entry looks at modelling the 34% 2020 greenhouse gas (GHG) reduction target set to an adjusted CO2 only 2005 baseline. The target adjustment formula is given below:
The UK Greenhouse Gas Inventory, 1990 to 2005 Annual Report for submission under the Framework Convention on Climate Change, gives a total greenhouse gas reduction from 1990 until 2005 of 15.4%. This includes land use, land use change and forestry (LULUCF). Excluding LULUCF, the reduction figure becomes 14.8%. When applying the above formula to translate the 34% reduction target onto 2005, the target adjusts to 22.0% and 22.5% respectively.
This all seems well and good, but there is the aspect of GHG vs. CO2 to consider. Whilst GHG reduced by 15.4% (inc LULUCF) and 14.8% (exc LULUCF) between 1990 and 2005, CO2 only reduced by 6.4% (inc LULUCF) and 5.6% (exc LULUCF). When applying the formula to translate the 34% reduction target onto 2005, the target adjusts to 29.5% and 30.1% respectively.
So which is correct?
It depends if you are looking forwards or backwards. If you are looking retrospectively at the 1990 baseline, and assuming that it is equally difficult to reduce all GHGs, then one could argue that taking the CO2 only reduction figures is correct.
If you are looking forward and setting 2005 as your baseline, then you could argue that the problem as it stands is to reduce emissions across the board up to the 2020 and 2050 target. It is interesting to note that local authorities were not tasked with reducing emissions until much later than 1990, and for most authorities the first glimpse at their carbon footprint came along with the National Indicator 186 and Full Local CO2 emissions data set which were both post 2005. The Climate Change Act also only came into legislation in 2008, so in consideration of this, it is best to look at the total GHG account in 2005 for the baseline. This means modelling 2020 targets of 22% (inc LULUCF) and 22.5% (exc LULUCF).