‘Net zero’ has become a catch-all phrase for almost everything to do with climate and nature. It can sometimes feel like it has been picked on randomly as a target. But the term ‘net zero’ actually has a specific scientific definition and ‘net zero by 2050’ became the UK’s target, not on a whim but because of careful scientific considerations and political consultations.
What is net zero?
The UK hitting net zero does not mean that the UK’s greenhouse gas emissions will be zero, but that any emissions will be offset by negative emissions, giving a ‘net average’ of zero.
Absolute zero greenhouse gas emissions is impossible to achieve because almost everything, up to and including breathing, emits some greenhouse gas (mostly carbon dioxide). But net zero means that these unavoidable emissions are offset by negative emissions.
This is done in nature by planting trees or restoring peatlands, both of which are carbon sinks. Or it can be done technologically through things like direct air capture and industrial carbon capture that takes carbon dioxide out of the air or at source which are then stored.
Why do we want net zero by 2050?
The last Conservative government set a legally binding target for the UK to achieve net zero by 2050 in 2019. This was set based on scientific advice from the UN’s Intergovernmental Panel on Climate Change (IPCC). Every few years the IPCC produces a meta report on all of the scientific evidence on climate change, its likely effects, and how to mitigate them.
These reports are assessed by large panels of scientific experts and every line has to be individually agreed by every country before being published.
The IPCC report that came out in late 2018 made it clear that the best way to limit global warming to 1.5 degrees, a level that limited the damaging effects of extreme weather events, was to reach global net zero emissions by ‘around 2050’.
Limiting global warming to 1.5 degrees is our best chance of avoiding the worst extreme weather effects, including several ‘tipping points’ that the planet cannot reverse. Examples of these include the melting of glaciers and the mass bleaching of coral reefs.
These extreme weather events have already caused fatalities and cost trillions to the global economy.
Even in the UK it is estimated that the cost of not achieving net zero will far outweigh the cost of getting to the target when we factor in the billions we pay towards flood defences, adaptation to heat waves every year. The cost of hot days during the heatwave of 2022 were estimated to be around £28 billion in lost productivity alone.
Adapting to the effects of climate change without mitigating the problem as much as we can is not a sustainable solution. There are many effects, like sea level rise or coral die off where we cannot adapt entirely and so the only way to deal with them will be to avoid them happening in the first place.
Is net zero by 2050 achievable for the UK?
Yes.
Before adopting the 2050 net zero target, the UK Climate Change Committee, which is an independent committee that assesses scientific evidence and progress on decarbonisation, was tasked with assessing whether the UK reaching net zero by 2050 was achievable. They found that it was, partially because of technological advancements and partly because the government had made more progress than expected on cutting carbon emissions in the past few years. Since 1990 emissions in the UK have been cut by over 50%. This net zero target was then debated in parliament before being passed without a vote.
How have we done since 2019?
Since the net zero target was adopted, there has been more progress on policies designed to reduce carbon emissions, including;
The ZEV mandate will ensure that 80% of new car sales are zero-emission vehicles by 2030.
Marine protected areas around our British Overseas territories that help to absorb carbon.
Annual contracts for difference auctions that encourage investment in new renewable energy generators.
The next five years will determine whether we can reach this target and will require the government to keep raising its ambition. The Conservative governments over the last 14 years have had a strong environmental record and in opposition should continue to hold the Labour government to this high environmental ambition to make sure we hit net zero and avoid the worst effects of climate change. We can do this in a way that minimises disruption and doesn’t impact the poorest unfairly.
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