Last week a Lords Select Committee report backed “all out” development of a UK shale gas industry, pointing to compatibility with UK climate change commitments. But this conclusion flies in the face of a wealth of evidence to the contrary, writes Dr John Broderick.

The message from last week’s House of Lords Economic Affairs Committee report was clear; the Government should do more to speed development of the UK’s shale gas and oil resource.

The Committee’s report emphasises shale gas’s comparative emissions intensity per unit of energy and the “positive contribution that shale gas development would make to achievement of the UK’s commitments on climate change”. But this perspective omits three important considerations raised in their evidence gathering.

Firstly, that the climate responds to cumulative emissions – that is, the total quantity released through time, not the emissions in a given year or by a specific nation or technology. The IPCC reiterated this in its latest working group 1 report (Summary For Policy Makers Section E8). Emissions must be assessed in terms of pathways to fully appreciate a particular development’s contribution to climate change.

Secondly, the impact of new sources of energy, be they fossil fuels or otherwise, must be judged from a systemic perspective because of the global nature of the climate change problem. This includes the indirect impact of, for instance, the trade in fossil fuels. Citing gas’s lower emissions intensity as beneficial assumes that an alternative, more-carbon-intensive fuel remains underground.

It also assumes the growth in energy demand due to cheaper supply does not outpace carbon intensity savings, and that it does not jeopardise the development of low- and zero-carbon energy systems. It is not clear that these criteria are currently being met in the absence of a global carbon cap.

Drawing together these two matters Prof David MacKay, DECC’s Chief Scientific adviser, has concluded (see page 33): “If a country brings any additional fossil fuel reserve into production, then in the absence of strong climate policies, we believe it is likely that this production would increase cumulative emissions in the long run. This increase would work against global efforts on climate change.”

He raised this in his oral evidence to the committee (see page 353) – and whilst the committee cites his 2013 report repeatedly to justify its other conclusions, it does not address these points.

Thirdly, there is the substantial discrepancy between UK domestic carbon budgets and our international commitments. From the Copenhagen Accord (2009) and subsequent UN climate negotiations through to the G8 Camp David Declaration (May 2012)  the UK has repeatedly committed to making its fair contribution to “hold the increase in global temperature below 2°C, and take action to meet this objective consistent with science and on the basis of equity”.

However, the Government’s choice of a global budget, from which our national budget is derived – equivalent to a 63% chance of exceeding 2°C – is clearly inconsistent with the language of “hold below” and “must not exceed”.

This variation in probability makes a substantial difference to the size of the emissions budget and the consideration of appropriate energy technologies and policies. The UK’s current, legally-binding budgets essentially reject 2°C in favour of maintaining some emission space out to 2050, and hence a relatively slow transition to a lower-carbon society.

Tyndall Manchester has raised these matters in relation to nuclear power as well as shale gas, and indeed we made these points in our own submission to the committee (p498). These points are neither dismissed nor refuted within the House of Lords report, but they are simply not considered.

Discussions of natural gas, whatever the sources, as a “transition fuel” frequently fail to specify a number of important parameters.

Without transparent consideration of the acceptable extent and probability of climate change, the proportion of a global budget to be consumed by the UK, the time period over which the transition is to occur and the final level of decarbonisation, little can be meaningfully said of the contribution of any new energy source.

Ultimately, if the UK wants to develop a consistent and evidence-based framing of its climate change commitments, it needs to match its legally binding domestic budgets with its international rhetoric on 2°C.

If it does so, then the window of opportunity for domestic shale gas production to contribute to a low carbon transition will be very limited.

• Dr Broderick will be speaking at the Shale Gas World conference in Birmingham on Tuesday 13 May.