Wilfran Moufouma-Okia, IPCC Working Group 1 Technical Support

Unit (TSU), Head of sciencesThanks to Kristie Ebi, Elmar Kriegler, Wolfgang Cramer, Jan Fuglestvedt

First lead authors meeting, SR1.5, San José dos Campos,

Brazil, 6-10 March 2017

Guidance on the degree of certainty in

findings and use of literature

Some considerations to bear in minds

Recommendation from the Oslo 2016 Expert meeting:

Report to be written clearly and elegantly, e.g. Summary for

Policymakers (SPM), Frequently Asked Questions (FAQs),

Executive Summaries and Headline Statements.

Issue of uncertainty:

Communicate degree of certainty

using a calibrated language

Key principles: scientific rigour, policy neutrality, transparency,

accuracy

Impacts from recent climate-related extremes reveal

significant vulnerability and exposure of some

ecosystems and many human systems to current climate

variability (very high confidence)

Global surface temperature change for the end of the

21st century is likely to exceed 1.5°C relative to 1850 to

1900 for all RCP scenarios except RCP2.6

IPCC headline statements

Total anthropogenic GHG emissions have continued to

increase over 1970 to 2010 with larger absolute decadal

increases toward the end of this period (high confidence).

Confidence in scientific findings

Estimated likelihood of scientific findings

Hierarchy in the degree of certainty

Confidence levels for estimates of Radiative Forcing, AR5 WGI chapter 8

Example from Working Group 2

Based on many studies covering a wide range of regions and crops, negative impacts of climate change on crop yields have been more common than positive impacts (high confidence). {SPM2C, 7.2, 18.4, 22.3, 26.5,

Figures 7-2, 7-3, and 7-7}

Cramer et al. 2014 (IPCC AR5 WG2)

IPCC AR5 WG2 Ch 18 Findings

Evidence has grown since … AR4 that impacts of recent changes in climate on natural and human systems occur on all continents and across the oceans.

Reported impacts are caused by changes in climate that deviate from historical conditions, irrespective of the driver of climate change.

Cramer et al. 2014 (IPCC AR5 WG2)

Example from Working Group 3

Guidance on the treatment of literature

Key principles:

• Statements are substantiate by adequate literature• Cited literature is accessible by reviewers• Priority is given to peer reviewed literature

• Critically assess the quality, robustness and validity of the

information they wish to include

• Critically assess the added value of the literature

• Send copy of each unpublished source to be used in the

IPCC Report to Working Group/Task Force Bureau Co-

Chairs

• Literature needs to be accessibility by reviewers at the

time of the review

Guidance on non-peer reviewed literature

a) Who (e.g., what organization) is the source of the grey literature citation?

b) What information does the citation add to the assessment?c) ls the information cited available from a peer-reviewed journal

source? If yes, is the citation needed?d) Are there lines of evidence from other (peer-reviewed or non-peer-

reviewed) sources that support the citation or reach different conclusions? If yes, is the citation needed?

e) What are the qualifications of the author(s) of the document?f) Was there any review of the material presented? If so, how wide or

extensive was that review? How credible are the reviewers?g) Why was the document written? How was the research funded?

Could the researcher and/or publisher of the document be perceived as having a particular bias or agenda? If yes, what caveats are needed?

h) Why wasn't the information published in a peer-reviewed journal?

Questions to help determine the appropriateness

Not acceptable: Blogs, personal communications, social

media sites (e.g. Facebook, Twitter), broadcast media

May provide limited information: newspapers and

magazines

Sources in language other than English: An executive

summary or abstract in English is required

Acceptability of literature sources

First order draft: submitted for peer-review prior to the FOD

deadline and copy provided to the TSU

Second order draft: submitted for peer-review prior to SOD

deadline and copy provided to the TSU

Final draft: accepted for publication and a copy provided to

the TSU prior to the FD deadline

Guidance on peer-reviewed literature

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For more information:

Example from Working Group 1

Global surface temperature change for the end of the 21st century is likely to exceed

1.5°C relative to 1850 to 1900 for all RCP scenarios except RCP2.6. It is likely to exceed 2°C

for RCP6.0 and RCP8.5, and more likely than not to exceed 2°C for RCP4.5. Warming will

continue beyond 2100 under all RCP scenarios except RCP2.6. Warming will continue to

exhibit interannual-to-decadal variability and will not be regionally uniform (see Figures

SPM.7 and SPM.8). {11.3, 12.3, 12.4, 14.8}