Whilst in many respects I welcome the headline framing of the Government’s “net-zero” proposal, sift amongst the detail and all is far from rosy
1) although on the one hand the Government’s “net -zero” proposal is for the UK to make its ‘fair’ contribution to delivering on the Paris Agreement, on the other it is recklessly pursuing UK shale gas (an energy source that is 75% carbon by mass!). Moreover, it recently celebrated both BP’s new Clair Ridge oil platform, with its accompanying quarter of a billion tonnes of carbon dioxide, and the new Glengorm gas field, adding a further 100 millions tonnes of CO2. To top it all, they plan to expand Heathrow, facilitating more flights with more fossil fuel consumption and hence more carbon emissions (even with efficiency improvements across the sector).
2) the mitigation proposals of Government and its Committee on Climate Change (the CCC) rely in large measure on future and highly speculative Negative Emission Technologies (NETs). These technologies exist, at best, as small pilot schemes, and often only in the imagination and computers of professors and entrepreneurs. So in reality we are passing the buck on to our children to invent and deploy technologies to suck the CO2 out of the air that we choose to continue to emit today. The unprecedented and planetary scale of NETs assumed by the Government and the CCC needs to be understood. Already the tentative potential of NETs is being used to undermine the requirement for immediate and widespread decarbonisation, passing further unacceptable burdens and risks onto the next generation.
3) against the advice of their own Committee on Climate Change the UK Government intend to rely on ‘international credits’ whereby they can buy so-called offsets from other countries rather than making the reductions themselves. This is typically paying poorer nations to plant trees, change industrial processes, install renewables, etc. Such developments internationally are necessary to meet the Paris Agreement’s climate commitments, but not as a means for permitting the UK’s ongoing emissions. With the UK’s world leading renewable energy potential we should be making the reductions ourselves not paying others to do it for us.
4) the Government and the CCC foresee emissions from the UK’s aviation sector continuing at today’s very high levels (currently around 12% of UK CO2) out to 2050 and on through subsequent decades. So any claim made of the UK being zero carbon by 2050, is simply not true. The scale of anticipated aviation emissions is such that this single sector will consume around one third of the UK’s Paris-compliant carbon budget, putting still further mitigation pressures on schools, hospitals and businesses to compensate for this privileged sector.
5) the share of the global ‘carbon budget’ that the UK Government and its Committee on Climate Change assume appropriate for the UK, is far higher than any defensible quota. So the UK not only has significant responsibility for historical emissions, but it is planning to take a disproportionately large slice of the remaining global carbon pie; colonialism thriving in 2019!
Finally, and based on work with University of Manchester & Uppsala colleagues, to meet its Paris obligations the UK must achieve zero-carbon energy by around 2035; that’s ‘real-zero’ not ‘net-zero’. This requires an immediate programme of deep cuts in energy emissions rising rapidly to over 10% p.a.; such an economy-wide agenda will need to embed equity at its core if it is to succeed mathematically and politically, as well as morally.
 NETs is also variously referred to as Carbon Dioxide Removal (CDR), Greenhouse Gas Removal (GGR), and previously as one form of Geo-engineering. Two other acronyms are commonly used, but are related to particular technology routes. Biomass Energy with Carbon Capture and Storage (BECCS) and Direct Air Carbon Capture and Storage (DACCS). Whilst a fully decarbonised energy system is achievable, there will remain some non-CO2 greenhouse gases from agriculture and food. These can certainly be reduced by changes in diets and agricultural practices, but some emissions of methane and nitrous oxide will inevitably remain. In this regard, a well-funded programme of research, development and potential deployment of NETs is required alongside improvement of ‘natural’ processes of sequestration, including forestry management, reforestation and potentially afforestation.
 The carbon budget refers to the total quantity of carbon dioxide emissions that we can dump in the atmosphere from now and out across the century if we are not to renege on our Paris 1.5-2 degree Celsius commitments.