We have revised our previously published estimates of the carbon emissions that would occur as a consequence of implementing the Greater Manchester Combined Authority‘s (nine district) spatial plan, Places for Everyone.

That plan is currently going through an extended series of hearings, the Planning Inspectorate‘s Examination in Public.  We have commented here (and here and here) on  the sessions that have covered the overall strategy, the integrated assessment of the plan and some of the cross cutting policies.

We produced our estimates of the carbon impact of implementing the plan last May.  This we did because it seemed that the Combined Authority (GMCA) had not done this work, something that was confirmed by GMCA and the consultancy, Arup, that did the Integrated Assessment.  You might ask how the GMCA could possibly claim that their plan was consistent with the stated policy of carbon neutrality by 2038, if they hadn’t made any quantitative assessment of the emissions that plan implementation would lead to.  We remain puzzled too, despite the GMCA’s lawyer invoking the “Wednesbury precedent”, that it was reasonable for them to do this because other assessors would have done (or rather failed to do) the assessment in the same way.  Our invoking of the Cambridge plan, which did conduct quantitative modelling of the carbon impact of different spatial options, was dismissed as an outlier.  We contend that it set a standard that other plans should be following.

The hearings also produced some clarifications and changes to policies.  In summary these were,

1.  The policy for buildings to be net zero by 2038 was clarified.  The plan was more ambitious than we had understood from the plan document, particularly on embodied emissions, so we have taken that into account.
2. The GMCA has backtracked on a number of policies, net zero buildings is now something to be worked towards rather than an expectation, and it will be subject to ‘financial viability’ – the ‘get out of jail card’ routinely used by developers to avoid planning policy obligations.  These two reversals will mean that the net zero buildings policy implementation will be partial.  We have made an estimate to take that into account.
3. GMCA also backtracked on some other aspects, namely the targets for affordability and the brownfield first preference.  We have not made adjustments to our modelling for these changes as their impact is uncertain, although the weakening of the brownfields first policy (viability again) will surely increase the take of green space and this will have some additional carbon impact.
4. The Wildlife Trusts provided some evidence about the extent of deep peat in some of the development sites in the plan, and we have uplifted our estimate for the carbon escape from building on peatlands as a result.  The impact is not great in the scale of things (land-related emissions are small compared to the other classes of emission).

A further, and significant change has been made to our estimates of emissions from the increase in passenger numbers that the plan envisages.  Previously we estimated this by taking an average between the unmitigated emissions at current levels and a trajectory based on the UK’s carbon budgets, to net zero in 2050.  Since it is generally understood that aviation emissions can not be mitigated to anything like that extent, on the basis of known and likely technology change, and they would have to be mitigated by further reductions in the other carbon budgets, we have now used the guidance from the government’s independent Committee on Climate Change (CCC) which indicated that aviation emissions are likely to be at no less than 80% of current levels in 2050.  We have made a linear reduction of emission intensity, per passenger, over that period.  Since the CCC notes that most reduction will have to come from demand reduction, we think it likely that we are still being over-generous.  While the policy on the airport in Places for Everyone does not state that passenger numbers will double, other policies make that assumption and the narrative text also makes mentions of this ‘ambition’.  At best, we suggest that the GMCA is taking a laissez faire approach to this area of climate threat.

The changes we have made do not make any difference to our overall message.  Building on the scale envisaged in Places for Everyone will incur significant additional carbon emissions and that will make it difficult for the conurbation to stay within its stated carbon budget, which represents its fair of the Paris agreement, on the basis of a two thirds chance of staying within 2 degrees of average global overheating.

You can read the revised and detailed report, HERE.  Our methodology and assumptions are explained there and the detailed results presented.  We are also clear about the limitations of the work: we will welcome informed contributions to help refine our estimates.

Here are some snapshots of the data but do examine the report for the full story and explanations.

Overall emissions are down from our previous estimate, largely due to assumed mitigation of embodied emissions in buildings.

This is the top level of breakdown by sector.  Here and elsewhere we show the additional emissions that the plan would cause.  Aviation, which is said to involve a doubling of passengers by 2037, would be the biggest contributor.

This is what the emissions would look like year on year.  See how the embodied emissions fall after 2027.  That assumes they are successfully avoided (by using alternative, low carbon or carbon capturing materials, or by using offsets – problematic as we explore in the report).  We allow a generous 75% reduction in these embodied emissions.  Our previous estimates were over-generous regarding operational building emissions (making a double reduction for the government’s gas boiler ban and the local net zero policy) so we have changed our modelling to reflect what the policy should have stated (and will, in the proposed revision).  Although stock built after 2024 and after 2027 will have lower inherent emissions than that from previous years, the higher (operational) emissions levels will be ‘baked in’ – those buildings will be churning our emissions at a higher level than the later stock every year, unless the owners and occupiers took (costly and inconvenient) steps to retrofit them.

This is what that looks like cumulatively.  This is important since it is the total emissions over the time period that matters – greenhouse gases stick around for a long time!

Finally, let’s look at the two types of transport emissions on the same scale, again cumulatively.  You can see what a big problem all those flights are.  In both cases, again, we just show the additional emissions associated with Places for Everyone.

And here, again, is the link to the new version of the report.

Finally, as you will probably have seen, the Secretary of State for Levelling Up, Housing and Communities and Minister for Intergovernmental Relations (to give Michael Gove his full, current, title) made an announcement before Christmas that has major implications for the planning system.  For Places for Everyone, it could reduce the level of housebuilding undertaken (we and other objectors believe this to be both inflated and of little real relevance to the housing crisis) and also encourage the use of brownfield sites.  While Gove has responded to back-bench Tory agitation, not the best recipe for policy change, we do consider his statement to be potentially helpful.  We will continue to monitor and report on developments and, if indicated, will update our estimates in the light of policy changes.