Environmental Engineering Reference
In-Depth Information
Professor Dieter Helm of Oxford University ''There is enough oil and gas
(and coal too) to fry the planet several times over''.
13
Shell has responded to Carbon Tracker's work, saying ''There is really
nothing to argue about in terms of the CO
2
math itself. It is certainly the case
that current proven reserves will take us well past 2 1C if completely con-
sumed and the CO
2
emitted''.
14
However, the UK Government's policy is to maximise hydrocarbon re-
covery. In June 2013, Energy Secretary Ed Davey wrote that ''maximising
recovery of the UK's indigenous supplies of oil and gas'' was important
economically and for the UK's energy security.
15
Maximising hydrocarbon recovery is not compatible with the UK playing
its part in meeting the global 2 1C climate change target which the UK
Government has repeatedly endorsed. The UK Government needs to leave
some of its proven or potential fossil fuel resources in the ground and, given
the risk of unavoidable and serious environmental impacts associated with
its extraction and the uncertainty over the scale of resources, the starting
point for this should be unconventional gas, including shale gas.
The background to this is explained below and is drawn from a Friends of
the Earth briefing paper The UK, Shale Gas and Unburnable Carbon: Questions
for the Government.
16
2.1.1 Carbon Budgets and Unconventional Gas. The work of Meinshausen
et al. on carbon budgets has assessed the percentage chance of exceeding
a given temperature target for a given amount of global carbon dioxide
emissions.
17
This shows that if we are prepared to accept a 50 : 50 chance
of the global temperature rise exceeding 2 1C, then the world can emit
1400 Gt CO
2
18
between 2000 and 2049.
w
However, if we want only a 1 in 3
chance of a greater than 2 1C global temperature rise, then the global car-
bon budget for 2000-2049 falls to 1150 Gt CO
2
.
Clearly, some of this carbon budget has already been used up since 2000.
Subtracting global carbon emissions for 2000-2012 gives the remaining
global carbon budget for 2013-2049.
18
For a 50 : 50 chance of going over two
degrees, this is 1050 Gt CO
2
and for keeping to a 1 in 3 chance of going over
2 1C, the budget is 750 Gt CO
2
. The IPCC's 5
th
Assessment Report, released
in September 2013, gives very similar carbon budgets.
The IPCC has definitions of different likelihoods, ranging from 'virtually
certain' (a 99-100% likelihood) to 'exceptionally unlikely' (a 0-1% likeli-
hood). Given the clear stating of the EU's target (see previous), Friends of the
Earth believes that the highest level of risk compatible with this 'do not
exceed' wording would be to keep the likelihood to 'unlikely' or lower. This
translates to a less than 33% chance of exceeding 2 1C. (The UK's binding
climate change target - the first in the world - implies only a 50 : 50 chance of
staying below 2 1C). This implies that the appropriate remaining global
carbon budget would be 750 Gt CO
2
, though even this accepts a relatively
w
All figures are rounded to the nearest 50 - for precise numbers, see Ref. 16.
