Net zero refers to achieving a balance between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere. There are two different routes to achieving net zero, which work in tandem: reducing existing emissions and actively removing greenhouse gases.
A gross-zero target would mean reducing all emissions to zero. This is not realistic, so instead the net-zero target recognises that there will be some emissions but that these need to be fully offset.
When the amount of carbon emissions produced are cancelled out by the amount removed, the UK will be a net-zero emitter. The lower the emissions, the easier this becomes.
The four highest-emitting sectors are transportation, energy supply (generating electricity from burning fuels such as coal, oil and natural gas), business (commercial use of electricity), and residential (heating homes). Together these account for around 78% of current emissions.
From heating our homes to filling up our cars, burning fossil fuels releases the greenhouses gases that increase global temperatures. We are already seeing the effects here in the UK and Wales, with devastating floods in the West Midlands in January 2022, torrential downpours submerging London Underground stations in summer 2022 and locally the ever more frequent breaching of sea defences around the Pembrokeshire Coast at, for example, Newgale and Amroth.
People are rightly concerned, with the latest IPCC report showing that if we fail to limit global warming to 1.5°C above pre-industrial levels, the floods and fires we have seen around the world this year will get more frequent and more fierce, crops will be more likely to fail, and sea levels will rise driving mass migration as millions are forced from their homes. Above 1.5°C we risk reaching climatic tipping points like the melting of arctic permafrost – releasing millennia of stored greenhouse gases – meaning we could lose control of our climate for good.
There is, still, a path to avoid catastrophic climate change. The science could not be clearer: by the middle of this century the world has to reduce emissions to as close to zero as possible, with the small amount of remaining emissions absorbed through natural carbon sinks like forests, and new technologies like carbon capture. If we can achieve this, global emissions of greenhouse gases will be ‘net zero’.
Delivering this requires urgent global action, including ending coal fired power generation, retiring petrol and diesel engines from all cars, and halting deforestation.