Is the EU ‘cheating’ on its net-zero emissions plan? Here’s what science says
A subtle form of double accounting
But there is a much more fundamental problem with the Commission’s approach. It is a subtle form of double accounting that sets a precedent for more significant accounting tricks further down the line – or by other countries with larger land carbon sinks.
The problem is that when scientists calculated how much CO₂ we can emit and still keep within the safe limits of the Paris Agreement, nature’s free carbon sucking service was already included. The net-zero goal is strictly in addition to that. By the time we hit net zero, we actually need those natural sinks to continue functioning, taking up over22 billion tonnes of CO₂ per yearand continuing to reduce CO₂ levels in the atmosphere below where they ended up at the net-zero point. Because current levels of atmospheric CO₂ arenot safe. In other words, the needed net zero really is a “big minus”.
How much carbon is stored in EU countries through natural processes is essentially unknown.Estimatesvary between 0.6 and 1.7 gigatonnes of CO₂ per year, with no consensus about how much of it is within EU boundaries. Contrary to the global land sink, which can be inferred fromcombining CO₂ and oxygen measurements, the European sink cannot be measured directly because these gases mix too quickly in the atmosphere.
But what happens if, at some point in future, the EU produces data that shows its carbon sink has increased? The amount of fossil fuels it would be legally-required to cut would be reduced – but the scientifically-determined global carbon budget to meet the Paris Agreement would remain unchanged. Given what we know about the global land carbon sink, it is likely the EU carbon sink will approximately double between 1990 and 2030.
This is clearly a bad start on the road to net zero as it sets a precedent for double accounting. A possible solution might be to only account for sinks that are genuinely additional, such as planting more trees orno-till farming to increase soil carbon. However there is still no consensus about which processes govern the natural carbon sink, and it is likely to be partly human-induced. It is therefore next to impossible to reliably determine how much of a sink is truly additional.
Another solution could be to allow only direct CO₂ uptake by human activities to be counted as “removal”. So-called bioenergy with carbon capture and storage (BECCS) is one option, however it interferes with the biosphere’s capacity to soak up CO₂ as it requiresvast amounts of landto grow biofuel crops (and competes with food production). The other option is to directly capture carbon from the air, but for now this haslimited realistic potential.
By far the most scientific, ethical and sensible approach would be to concentrate on emissions reductions and leave the terrestrial biosphere as intact as possible to carry on removing carbon. This free service, after all, is worth at least US$1.3 trillion per year (at a price of 100 US$/tonne). Natural habitats should be restored for that purpose, but the resulting carbon sink should not enter territorial accounting schemes for two reasons: because it has already been counted, and because we have no way of reliably quantifying how much is down to human policy and how much is just the natural background rate.
This article is republished fromThe ConversationbyWolfgang Knorr, Senior Research Scientist, Physical Geography and Ecosystem Science,Lund Universityunder a Creative Commons license. Read theoriginal article.
Story byThe Conversation
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