Comment on ‘Impact of Current Climate Proposals’
| Date | 01 February 2016 |
| Author | Robert E.T. Ward |
| DOI | http://doi.org/10.1111/1758-5899.12316 |
| Published date | 01 February 2016 |
Comment on ‘Impact of Current Climate
Proposals’
Robert E.T. Ward
London School of Economics and Political Science
Lomborg suffers from a fundamental methodological flaw
which means that it could not fulfil its aim, stated in the
‘Abstract’, to investigate ‘the temperature reduction impact
of major climate policy proposals implemented by 2030’.
Projections of global mean surface temperature for the
period up to 2100 are based on cumulative annual global
emissions of greenhouse gases. While Lomborg purports to
analyze the temperature changes associated with policies
affecting emissions up to 2030, the author fails to acknowl-
edge that the temperature projections to 2100 are deter-
mined primarily by assumptions that are made about
cumulative annual global emissions over the 70-year period
after 2030, rather than cumulative annual emissions during
the period up to 2030.
The results cited by Lomborg are almost entirely due to
the assumptions he makes about the post-2030 annual
emissions from the US, EU and China. In each of these
cases, annual emissions are assumed not to reduce any fur-
ther, and in most of his ‘scenarios’, to rise. In most of his
‘scenarios’, emissions are assumed to rise by the end of the
century to levels that reverse completely the effects of emis-
sions reductions by 2030, and in some cases they also
reverse the effects of emissions reductions that have
occurred in the period up to 2015. As such, most of the
‘scenarios’used by Lomborg assume that climate policies
are abandoned or reversed after 2030, and it is this assump-
tion that primarily determines the projected global mean
surface temperature in 2100. Hence, Lomborg does not
investigate ‘the temperature reduction impact of major cli-
mate policy proposals implemented by 2030’.
In the case of the US, Figure 3 of Lomborg illustrates the
assumptions made about annual emissions in relation to the
pledge contained in the ‘intended nationally determined
contribution’(INDC) that was submitted to the secretariat of
the United Nations Framework Convention on Climate
Change (UNFCCC) on 31 March 2015.
1
The INDC indicates
that ‘the US intends to achieve an economy-wide target of
reducing its greenhouse gas emissions by 26–28 per cent
below its 2005 level in 2025 and to make best efforts to
reduce its emissions by 28 per cent’. Figure 3 shows this
reduction in emissions. However, the INDC also notes: ‘This
target is consistent with a straight line emission reduction
pathway from 2020 to deep, economy-wide emission reduc-
tions of 80 per cent or more by 2050’. Lomborg disregards
this statement, without justification. Instead, he assumes for
his ‘Optimistic USINDC’scenario that annual emissions by
the US remain at about the same level of around 4.6 giga-
tonnes of carbon-dioxide-equivalent (Gt CO
2
e) for the period
between 2025 and 2100. For his ‘Pessimistic USINDC’, Lom-
borg assumes that annual emissions by the US rise asymp-
totically to just under 6 Gt CO
2
e, exceeding current annual
emissions levels during the 2070s. Hence this scenario com-
pletely reverses emissions reductions to be achieved by
2030 as well as emissions reductions achieved over about
the past five years. Neither of these scenarios corresponds
to expected policies beyond 2030.
In the case of the 28 member states of the EU, Figure 7
of Lomborg shows the assumptions made about annual
emissions in relation to the pledge contained in the INDC
that was submitted to the secretariat of the UNFCCC on 6
March 2015.
2
The INDC indicates that ‘the EU and its Mem-
ber States are committed to a binding target of an at least
40 per cent domestic reduction in greenhouse gas emis-
sions by 2030 compared to 1990’. Figure 7 shows this
reduction. However, the INDC also states that the 2030 tar-
get is ‘in line with the EU objective, in the context of nec-
essary reductions according to the IPCC by developed
countries as a group, to reduce its emissions by 80–95 per
cent by 2050 compared to 1990’. Lomborg ignores this
statement, without justification. Instead, he assumes for his
‘Optimistic EUINDC’scenario that annual emissions by the
EU rise gradually after 2030, exceeding current levels dur-
ing the 2070s and reaching about 4.6 Gt CO
2
e by 2100.
Hence this scenario assumes the reversal of emissions cuts
achieved by 2030 as well as the reversal of reductions
since about 2010. For his ‘Pessimistic EUINDC’, Lomborg
assumes that annual emissions by the EU climb even more
A response to ‘Impact of Current Climate Proposals’
Bjorn Lomborg
*
*Lomborg, B. (2015) ‘Impact of Current Climate Proposals’,Global
Policy, 7 (1), pp. 109–118. DOI: 10.1111/1758-5899.12295.
Global Policy (2016) 7:1 doi: 10.1111/1758-5899.12316 ©2016 The Authors. Global Policy published by Durham University and John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use,
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Global Policy Volume 7 . Issue 1 . February 2016 125
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