Keeping nuclear weapons or tackling climate change?

Presentation by Dr Stuart Parkinson, SGR, at a seminar organised by the Campaign for Nuclear Disarmament, at the Houses of Parliament in December, 2006

The presentation uses government and industry data to carry out a new analysis of the degree to which Trident replacement could undermine action on climate change. It concludes there is significant threat - due to competition for both funding and skills.

Many strong arguments have been made for not replacing the Trident nuclear weapons system (or indeed maintaining it) [1], e.g.:

  • UK is safer from large-scale military attack than at any time in its history
  • It is no defence against current security threats, especially terrorists
  • It undermines our efforts to encourage other countries to not develop/ reduce nuclear weapons
  • It could be counter to our obligations under international arms treaties, undermining global arms control

However, the focus of this presentation is on how keeping nuclear weapons could divert resources away from efforts to tackle climate change.


Costs of Trident & Trident replacement

Current cost of Trident system [2, 3]

  • £1.8 bn a year until ~2024 (5.5% of current Ministry of Defence budget)

The White Paper on UK nuclear weapons [4] has provided an outline of the estimated costs of the two preferred options for Trident replacement:

  1. 4 submarine replacement option with 160 warheads (see also [2, 3, 5])

  • Investment cost: ~£20 billion (major military projects often cost at or above the upper end of Government estimates)
  • Annual costs: ~£1.8 bn for 30 years (unlikely to be significantly less than current situation)
  • Total costs over lifetime (undiscounted): ~£75 bn
  1. 3 submarine replacement option with 160 warheads

  • Unlikely to be less than 85% of costs of 4 submarine option (i.e. investment cost: ~£17 bn; annual costs: ~£1.6 bn)
  • Total costs over lifetime (undiscounted): ~£65 bn


Climate change mitigation costs for the UK


  • Wide agreement that climate change poses major threat to UK and the World, to our society, economy and environment - in short, it is major security threat
  • Hence urgent action is needed to reduce greenhouse gas (GHG) emissions (most recently, the case is made in the Stern Review on the economics of climate change [6])
  • UK has a voluntary target to reduce carbon dioxide emissions by 20% by 2010 and 60% by 2050.
  • Although UK has many policies and measures in place to reduce greenhouse gas emissions, it is falling short of its targets (see below).

Three examples are presented which look at the costs of reducing greenhouse gas emissions in different ways - energy efficiency, renewable energy, and broadly across the economy - for comparison with the costs of UK nuclear weapons.

Example 1: Home insulation [7]

  • Energy efficiency measures are generally the cheapest way of reducing greenhouse gas emissions - most are actually cost saving so you get back the money you invest after a few years
  • In UK, 9 million homes need to be fitted with cavity wall insulation (cheap) and 7 million with solid wall insulation (more expensive)
  • Doing this would save 6.6MtC/y (4% current UK carbon emissions)
  • Total cost: ~£16 bn
  • So investment costs of "reduced" (3 submarine) option for Trident replacement could insulate the walls of all 16 million homes (with cash to spare)
  • Added benefit - would help eliminate fuel poverty in the UK (2.25 million households currently living in fuel poverty)
  • Obviously this comparison is illustrative:

-- Energy efficiency measures such as these are already being implemented (although not nearly on a large enough scale)

-- Insulation costs need only be subsidised rather than paid in full, as many house-holders can afford to contribute - hence costs to Government are much smaller (more discussion on the "additional costs" to Government below)


Example 2: Installing wind turbines [8]

  • Wind turbines are currently one of the cheapest low carbon energy technologies
  • Using standard industry figures, SGR has estimated how much energy could be supplied by that source for the same total costs as the "reduced" option for Trident replacement:
  • Either ~25,000 onshore wind turbines
  • Or ~8,000 offshore wind turbines
  • Either of which would generate over 1/3 of current electricity production (significantly greater than the production of the soon to be decommissioned nuclear and coal power stations)
  • Again, the comparison is illustrative:

-- In practice, investment would (and should) be in a diverse set of low carbon technologies, including solar, biomass, wave, tidal etc

-- Investment costs such as these would be borne by the private sector rather than the Government (again, see discussion below on "additional costs")

Example 3: Additional costs required to meet 60% carbon reduction target [9]

  • Government has set a target to reduce carbon emissions to 60% below their 1990 level by 2050
  • Dept of Trade and Industry used energy-economic model to estimate the total "abatement costs" needed over the whole time period to hit this target, ie those additional costs beyond what would have been spent if there were no carbon reduction target
  • Model included all energy use in economy - over 20 different scenarios
  • Most models results (excluding unlikely scenarios) estimated total additional (abatement) cost of hitting target was in range £30bn to £60bn
  • Accounting for differences in economic assumptions (mainly the discount rate) - this range is comparable to the costs of maintaining UK nuclear weapons over the period

But the Government is already committed to hit the 60% target, regardless of the decision on Trident replacement, so they will be obliged to take the necessary action anyway - won't they?


Reasons for doubt

  • Many climate scientists and policy analysts have argued that major action is needed in the next 10y or so (e.g. Stern Review) - which coincides with the time of maximum Government spend on Trident replacement
  • UK carbon emissions are currently rising, something which had not been anticipated by Government.
  • The most recent emissions projections show the UK will miss its 2010 target of a 20% reduction by about 5.6 MtC - currently on course only for ~16.5% reduction [10]. Extra investment, especially in energy efficiency, would help bring us back on course.
  • The target does not currently include UK share of emissions due to international aviation and shipping, estimated to be 10% of the rest of our current carbon emissions (and rising) [11]. Current aviation policy contradicts climate change policy and we are told it is too expensive to impose major restrictions on air travel.
  • The Tyndall Centre for Climate Change Research [11] and others argues that the 60% target is inadequate for tackling climate change - the target for 2050 should be a 90% cut. This will entail significantly more action (including funding) than the Government plans.
  • Investment in energy research and development (R&D) is currently at very low levels, not least in the UK [12]. Indeed, in 2005 the Government only spent £37 million on renewable energy research, development and deployment [13] - little more than 1% of the Ministry of Defence's R&D spending that year [14]. A rapid expansion in that funding would help speed up development of new energy technologies, e.g. wave power, hydrogen-fuelled cars.


Skills shortages?

An additional argument, related to the costs, is the skills issue.

  • Numbers of UK students taking physical sciences and engineering are falling [15].
  • Yet we urgently need to increase the numbers of scientists and engineers to help us tackle climate change - from climate scientists to renewable energy engineers.
  • Large military projects like Trident replacement will compete for scientists and engineers (especially as the military often pays more) and hence are likely to reduce the numbers available to other areas.



Replacing Trident will require huge resources (both funding and skills) that are urgently needed elsewhere, not least in tackling climate change. In fact, reducing the threat of climate change will improve the security of the UK. These arguments reinforce the case, made on the grounds of national and international security, that replacing Trident would be a very costly mistake.



[1] For example, see: Acronym Institute (2006). Worse than Irrelevant? British Nuclear Weapons in the 21st Century.

[2] Hansard (2006). Written answer, Des Browne to Mr Weir. 20 July 2006: Column 597W.

[3] Ministry of Defence (2006). UK Defence Statistics 2006.

[4] Ministry of Defence (2006). The Future of the United Kingdom's Nuclear Deterrent. Defence White Paper. Paper No Cm 6994.

[5] Norton-Taylor R. (2006). New Trident system may cost £76bn, figures show. The Guardian, 21 September.,,1877260,00.html

[6] Stern M. (2006). Stern Review Report on the economics of climate change.

[7] Using figures from: Sustainable Development Commission (2006). "Stock Take": Delivering improvements in existing housing. Chapter 5.

[8] Using figures from the British Wind Energy Association and others, e.g. average turbine sizes: 2.5MW (onshore); 5MW (offshore). For more details of calculations and references, contact SGR <>

[9] DTI (2003). Options for a Low Carbon Future. DTI Economic paper No. 4. p73-74.

[10] Department for Environment, Food and Rural Affairs (2006). Climate Change: The UK Programme 2006.

[11] Bows et al (2006). Living within a carbon budget. Tyndall Centre for Climate Change Research.

[12] UK Energy Research Centre (2006). Research Atlas: Overview.

[13] International Energy Agency (2006). IEA Energy Statistics.

[14] Office of Science and Innovation (2006). Science, Engineering and Technology (SET) statistics.

[15] See eg: HEFCE (2006). Undergraduate students in STEM subjects.