VoteClimate: Party Manifestos vs Net Zero

Party Manifestos vs Net Zero

26 June 2024

All the main parties are committed to the UK's Net Zero goal. But which of them are committed to policies that will achieve that?

Please note: reaching Net Zero is insufficient to "keep 1.5 alive". Rather, the target is to achieve Net Zero while limiting CO2e emissions to within a "carbon budget" that would give us a 50% chance of planetary warming not exceeding 1.5C in the long run.

Building on our analysis Party Manifestos - Climate Comparison, here we show how the manifesto commitments measure up against the UK's carbon budget. Spoiler alert: all three main parties' policies send us rapidly over the cliff-edge, with even the Greens having more work to do.


  • We used as a baseline the UK's emissions trajectory, based on current policies and plans, as described in Table 2.1 in Energy and emissions projections 2022 to 2040, choosing to include IAS (international aviation and shipping) as for the world to reach Net Zero those contributions must also reach Net Zero.
  • We subtracted from the baseline the emissions savings that would follow from the full implementation of the climate commitments in each party's manifesto, as described in Party Manifestos - Climate Comparison.
  • The latest IPCC Assessment Report (AR6), estimated the global carbon budget for 1.5C as 500GtCO2e from 1st Jan 2024.
  • If we generously (in the view of developing nations) apportion that pro-rata the UK's current rate of emissions, that gives the UK a carbon budget of 5,000MtCO2e starting on 1st Jan 2020.
  • UK emissions (including IAS) have been running at over 400MtCO2e per year. So the remaining budget from 1st Jan 2024 is, at most, 3,400MtCO2e.


Based on the climate policies promised in their manifestos, we could expect the UK to exceed its share of the world carbon budget, required to limit global warming to below 1.5C, in the following years:

  • Conservative - 2033
  • Labour - 2034
  • Liberal Democrat - 2034
  • Green - 2038

For clarity of presentation, we have not included the 30% error bars that appear on Party Manifestos - Climate Comparison. Variation within the range of estimated uncertainty would make a difference of only one or two years to the date at which the carbon budget is breached.


The proposed climate policies of the main three parties are quite inadequate to enable the UK to live within its share of the global 1.5C carbon budget . And despite the large differences in the scale of their respective ambitions, the ambitions are each so low that the UK will exceed its carbon budget within a 2030-35 parliament, leaving insufficient time for a subsequent government to fix the situation.

Although the Greens' current policies also take the UK beyond its carbon budget, their trajectory is sufficiently shallow that, were their policies to be implemented, there would be enough time in subsequent parliaments to take the necessary steps to achieve Net Zero.

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