Roxana Bojariu

1. Working Group I of IPCC
Overview
Dr. Roxana Bojariu
Lead Author in WG I of AR5
National Meteorological Administration (Bucharest, Romania)

2.  Motivation - the role of WG I of IPCC
 The Structure of WG I Report of IPCC AR5
 Key findings in WG I Report
 New topics in the WG I Report of IPCC
 Next steps

3. Motivation - the role of WG I of IPCC
 In a changing world we need to speed up the
knowledge generation and transfer to serve
society in its mitigations and adaptation
efforts.
 Decisions in society should be knowledge
based.
 Science of climate change provides this type
of knowledge.

4. The Structure of WG I Report of IPCC
AR5
14 Chapters covering:
 climate change observation
(Ch 2, 3, 4, 5);
 climate change understanding
(Ch 6, 7, 8, 9, 10 );
 future-projected climate (Ch
11, 12, 13, 14);
 the Atlas of Regional Change.

5. Key findings of WG I Report
 Warming of the climate system is unequivocal -
each of the last three decades has been
successively warmer at the Earth’s surface than any
preceding decade since 1850
From SPM

6. Key findings of WG I Report
 Warming of the climate system is unequivocal - it is
virtually certain that the upper ocean (0-700 m)
warmed from 1971 to 2010
From SPM

7. Key findings of WG I Report
 Warming of the climate
system is unequivocal –
there are coherent
changes in all climate
system components
From SPM

8. Key findings of WG I Report
 The atmospheric concentrations of greenhouse gases (GHGs) have
increased since 1750 due to human activity and their radiative
forcing dominates aerosol, solar, volcanic and internal variability
(with CO2 providing largest radiative forcing).

9. Key findings of WG I Report
 It is extremely likely that human influence has been
the dominant cause of the observed warming since
the mid-20th century.

10. Key findings of WG I Report
 Global surface temperature change for the end of the 21st
century will continue to increase and is likely to exceed
1.5°C relative to 1850−1900 for all scenarios except RCP2.6.

11. Key findings of WG I Report
 Global mean sea level will continue to rise during
the 21st century and virtually certain beyond 2100.
From SPM

12. Key findings of WG I Report
 Continued emissions of greenhouse gases will cause further
warming and changes in all components of the climate
system. Limiting climate change will require substantial and
sustained reductions of greenhouse gas emissions.
From SPM

13. New topics in the WG I Report of IPCC
 Analyses of Coupled Model Intercomparison Project Phase 5 (CMIP
5) experiments under concentration scenarios (RCPs)
From:
http://www.easterbrook.ca/steve/2011/09/the-cmip5-climate-experiments/

14. New topics in the WG I Report of IPCC
 Ch 11. Near term predictions
and projections based on
CMIP 5 – requested by the
decision makers and
adaptation communities;
 There are some encouraging
evidence from numerical
experiments for certain
seasonal to decadal
predictability (regionally
dependent).
From:
http://www.easterbrook.ca/steve/2011/09/the-cmip5-climate-experiments/

15. New topics in the WG I Report of IPCC
 The Atlas of Regional Change (temperature and
precipitation changes for 35 regions, using 42 global
models under 4 RCPs)

16. New topics in the WG I Report of IPCC
Examples from the Atlas of Regional Change – you can play around to get
projected regional changes at http://climexp.knmi.nl/atlas but please be
aware that these results are climate model outputs, not an assessment of
the likelihood of changes.

17. Next steps
 Assessment Report 6 (AR6) based on Coupled Model
Intercomparison Project Phase 6 (CMIP6) will continue
to reduce as much as possible and better quantify
uncertainties related to physical science basis of climate
change.
 AR6 has to respond to increase requests for regional
and near term information on climate change signal vs.
climate variability.
 AR6 has to find improved approaches to couple climate
with impact and adaptation information.

18. Thank you!