INSIGHTS | PERSPECTIVES
34 4 JULY 2014 • VOL 345 ISSUE 6192 sciencemag.org SCIENCE
In April in Berlin, governments approved the third of three reports comprising the fifth assessment report (AR5) of the Intergovern- mental Panel on Climate Change (IPCC). The report from Working Group 1 (WGI) made clear that human impact on climate change
is almost certain. WGII showed that impacts of
climate change are evident and poised to worsen.
WGIII focused on how to mitigate the emissions
that cause global warming (1).
Although the underlying technical report from
WGIII was accepted by the IPCC, final, heated
negotiations among scientific authors and dip-
lomats led to substantial deletion of figures and
text from the influential “Summary for Policy-
makers” (SPM). The deleted content focused
largely on historic emissions trends analyzed by
country income groups and interna-
tional cooperation. IPCC authors are
instructed to be policy-relevant, without being
policy-prescriptive, and the SPM is intended to
balance governmental and scientific input. But
some fear that this redaction of content marks
an overstepping of political interests, raising
questions about division of labor between sci-
entists and policy-makers and the need for new
strategies in assessing complex science. Others
argue that SPM should explicitly be coproduced
To promote discussion of whether and how to
reform IPCC in advance of the 15th Meeting of
the Conference of the Parties to the UN Frame-
work Convention on Climate Change (UNFCCC)
in November 2015, Science invited several WGIII
members to share their perspectives on what
happened in Berlin and what it means for the
IPCC and climate policy.
Getting serious about categorizing countries
By David G. Victor,1, 9 Reyer Gerlagh,2, 9 Giovanni Baiocchi3, 10
A central finding of WGIII is that growth of income has been the largest single driver of emissions. Governments accepted that finding at the global level, where it is safe to discuss gen- eralities because no country is in the spotlight. But WGIII also showed how different categories of countries contribute to global emissions (charts 1 to 3). We explain what was lost
when these figures were cut from the SPM.
Since the industrial revolution, today’s highly industrialized countries have been the main contributors to greenhouse gas (GHG) emissions (chart 1). But over the past decade, their emissions have been
roughly flat, whereas emissions from upper-middle-income countries
(UMCs) have risen rapidly (chart 2A). The central implication is that
inter-national climate policy needs to update how it categorizes countries. In the early 1990s when the UNFCCC was created, countries
were divided into two categories—industrialized nations (Annex I),
and the rest (non–Annex I). As non–Annex I countries’ emissions have
soared, their participation in future climate agreements is essential.
Getting serious about categorizing countries will reopen old, but
unavoidable, political fissures. Industrialized countries—which, on
average, still have the highest per capita emissions—must do more to
By Brad Wible
Did the “Summary for Policymakers”
become a summary by policy-makers?
1University of California, San Diego, La Jolla, CA 92093, USA. 2Tilburg University, 5037AB Tilburg,
Netherlands. 3University of Maryland, College Park, MD 20742, USA. 4Centre for Policy Research,
New Delhi, DL 110021, India. 5Princeton University, Princeton, NJ 08544, USA. 6Stockholm
Environment Institute, Stockholm 10451, Sweden. 7Potsdam Institute for Climate Impact
Research, 14473 Potsdam, Germany. 8Mercator Research Institute on Global Commons and
Climate Change, 10829 Berlin, Germany. 9IPCC WGIII Coordinating Lead Author. 10IPCC WGIII
Lead Author. 11IPCC WGIII Cochair. 12IPCC WGIII Head of Technical Support Unit.