16 November 2023, The Conversation: We’re burning too much fossil fuel to fix by planting trees – making ‘net zero’ emissions impossible with offsets. The idea that we can mitigate current carbon emissions by “offsetting” them with carbon reduction initiatives elsewhere has become central to government and business responses to climate change. But it’s an idea we need to seriously question. Essentially, the offsetting strategy assumes the release of carbon stored by ancient biology a hundred million years ago can be mitigated in the current active carbon cycle. Since the Kyoto protocol was signed, offsetting has become the preferred option globally. The concept of “net zero” carbon emissions is also at the heart of New Zealand’s official climate response and its Emissions Trading Scheme. How this might change under a new government is hard to predict, with the different positions held by the negotiating parties potentially leading to a “coalition of climate chaos”, according to one commentator. At one level, net zero makes sense. Planting trees to mitigate the effects of forest clearance – or to provide shade, stabilise land and enhance biodiversity – means carbon in the atmosphere can be sequestered where it otherwise would not be. But that doesn’t automatically mean the planet can absorb all the fossil carbon human industry continues to release. The idea that harm done in the present can be “offset” somewhere else in the future – something also seen in the field of freshwater ecology – cannot be taken at face value. How the carbon cycle works. To put things in perspective, global carbon emissions from burning fossil fuels are currently around 10 billion tonnes per year. If we continue emitting at this rate, total fossil fuel emissions from now to 2050 will be about 280 billion tonnes – seven times larger than the maximum estimated biological carbon sequestration of 38 billion tonnes from 2015 to 2050. Before humans began extracting fossil fuels, carbon cycled in a dynamic equilibrium: the total amount of carbon entering each carbon pool was balanced by the total amount of carbon leaving, so the amount of carbon stored did not change. Read more here