GILLIAN Martin, the Cabinet Secretary for Climate Action and
Energy, recently stated that “we are over halfway on our journey to net zero”.
Net zero is achieved by a combination of reducing emissions and then balancing the remaining emissions by the removal of an equivalent amount of greenhouse gases from the atmosphere by using “carbon sinks”, like forests for example.
Net zero is accounted for on an annual basis. At the end of a year you calculate your emissions and removals and if your removals are the same or more than your emissions then you have achieved net zero for that year. In following years you may not achieve net zero because of an increase in emissions or a reduction in removals, obviously.
By how much you have reduced your emissions from 1990 is not included in the formula to calculate net zero. The year was proposed by the UN so countries could compare how well they were doing in reducing emissions.
Scotland’s greenhouse gas emissions in 2023 were gross 54.4 million tonnes, though this figure is not stated in the published statistics as far as I could see. The figure used is net 39.6 million tonnes which is after deducting the removals of 14.8 million tonnes of emissions estimated to have been sequestered by Scottish forests. So in 2023 Scotland removed 14.8 million tonnes of the 54.4 million tonnes of greenhouse gases it produced, which is 27.2%. To claim “halfway to net zero” we would have to have removed 50%, ie 27.2 million tonnes.
So based on the latest figures we have – for 2023 – Scotland has net 39.6 million tonnes of emissions to remove by 2045 by a combination of reductions and removals to “carbon sinks”. Because of the length of time it takes to compile the emissions statistics we do not know even what has happened in the past two and a half years, let alone trying to predict emissions for the next 20 years which many people are forecasting will increase. Also trying to increase the amount of carbon sinks will be extremely difficult: we cannot double Scotland’s forests.
When net zero was first proposed it was envisioned that countries would employ direct air capture, which is using very large fans to suck in air from which CO2, the main greenhouse gas, could be extracted and this would count towards their removals to help achieve net zero. CO2 is very dilute in the atmosphere, only 429 parts per million which is a ratio of 2,331 to 1. So if you want to find one tonne of CO2 you need to suck in 2,331 tonnes of air, which uses a lot of electricity, the production of which would, they say, create more than a tonne of CO2, so that is not going to work.
Hugh Mcadams, Bearsden
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