Post on 30-May-2020
Climate and climate change sciences:
30 years of IPCC assessment reports
Valérie Masson-Delmotte
@valmasdel
Global emissions from fossil fuel and industry: 36.2 ± 2 GtCO2 in 2016, 62% over 1990
Projection for 2017: 36.8 ± 2 GtCO2, 2.0% higher than 2016
Estimates for 2015 and 2016 are preliminary. Growth rate is adjusted for the leap year in 2016.Source: CDIAC; Le Quéré et al 2017; Global Carbon Budget 2017
Emissions from fossil fuel use and industry
Uncertainty is ±5% for one standard deviation
(IPCC “likely” range)
Haustein et al, Scientific Report, 2017
Warming due to human influence
O’Neil et al, NCC, 2017
More warming = more risks
Global warming
(°C) above 1850-
1900
Unique and
threatened
systems
Extreme
eventsDistribution
of impactsGlobal
aggregated
impacts
Large scale
singular
events
2017
Paris Agreement mechanism
Rogelj et al, Nature, 2016
Long term target
Talanoa Dialogue 2018
Global stocktake 2023adaptation, mitigation, finance
Emission decrease
towards carbon
neutrality
Antiquity Middle
Age
17th C
Weather
instruments
19th C
Networks
Ice ages
Greenhouse
effect
Fluid physics
Thermodynamics
Radiative transfers
20th C
Past climate
Climate modelling
Chronology, proxies
Super computors
Satellites
A major scientific endeavour
From knowledge production …
0
5000
10000
15000
20000
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
Number of peer-review papers with
the keyword « climate change »
…to the assessment of the state of knowledge
The IPCC assesses the scientific, technical and socio-economic
information relevant to understanding the scientific basis of risk of
human-induced climate change, its potential impacts and options for
adaptation and mitigation.
The IPCC is organized in Working Groups and one Task Force :
- WGI : the physical science basis
- WGII : impacts, adaptation and vulnerability
- WGIII : mitigation of climate change
- Task Force on national greenhouse gas inventories
IPCC reports must be policy-relevant but not policy-prescriptive
COMPREHENSIVE, OBJECTIVE, OPEN AND TRANSPARENT BASIS
Science/Policy Interface
Plenary
Bureaux
Working Group (WG) I
The Physical
Science Basis
WGIII
Mitigation of
Climate Change
WGII
Impacts,
Adaptation &
Vulnerability
Task Force on
National
Greenhouse
Gas Inventories
Authors
Expert
Reviewers
Review
Editors
Intergovernmental Panel: 195 member States
appointing National Focal Points
IPCC – jointly established by WMO and UNEP, action endorsed by the UN General Assembly
Hundreds of scientists and experts from around the world are involved in the preparation of IPCC
reports
From published literature to Summaries for Policy-Makers
• Assessments are based on published literature, preferably peer-reviewed; updates of figures/tables using published methodology are OK, but new research is not.
• Assessment statements must be traceable and the lines of evidence made clear.
• Executive Summaries distill key results/messages from each chapter, and Summary for Policy Makers (SPM) distills even further.
– SPM must be approved line-by-line by governments.
– Underlying chapter text provides foundation for SPM.
How does an assessment differ from a review?
• It is intended to objectively summarize the state of (scientific) knowledge in
a balanced way, including an assessment of confidence/uncertainty.
• It is to be policy relevant (and not policy prescriptive); therefore it need not
comprehensively cover all of the literature in the field.
Indicative bullet points provide guidance
• It is a consensus document produced by the author team, not a collection of
individual contributions. Assessment statements should be agreed as a
group, based on expert judgment.
• Calibrated language is an essential element.
Using a calibrated language
to report confidence in findings
Concrete example : Chapter section and summary statement
{this section is 14 pages long}
Concrete example … Chapter Executive Summary …
Concrete example : … Summary for Policy Makers …
1988
IPCC – jointly
established by
WMO and UNEP
1990
FAR
1995
SAR
2001
TAR
2007
AR4 AR5 AR6
2013-2014
UNFCCC
Global
Stocktake
2023
1970s-1980s
Kyoto
Protocol
UNFCCC Adaptation 2 °C limit Paris Agreement
Nobel Peace Prize
2018
1990
broad overview of climate
change science, discussion
of uncertainties and
evidence of warming
1995
“The balance of evidence
suggests a discernible
human influence on global
climate”
2001
“new and stronger
evidence that most of the
warming observed over the
last 50 years is attributable
to human activities”
2007
"Warming of the
climate system is
unequivocal…"
2013
“Human influence
on the climate
system is clear.”
Improvements:
Methods of attribution : global scale
IPCC AR5
New developments for single extreme events
Magnusson et al 2013 WMR
Example : role of high sea
surface temperature on wind
speeds of Hurricane Sandy
1950s 1960s 1970s 1980s 1990s
Emergence of sea level science
2000s 2010s
-
Extreme sea levelAstronomical theory
and ice ages
Vulnerability of West
Antarctic ice sheet
Observed sea
level rise
Sea level projections
Fast glacier flow
Irreversibility
Interior rivers
Regional
aspectsGlacier
mass
balance
Ice sheet - ocean
Coastal habitats
Sea level in the FAR (1990) and AR5 (2013)
Over the last century, global sea level has increased by 10-20 cm
Over the period 1901 to 2010, global mean sea level rose by 0.19 [0.17 to 0.21]
m.
1.7 [1.5 to 1.9] mm yr–1 between 1901 and 2010
2.0 [1.7 to 2.3] mm yr–1 between 1971 and 2010,
3.2 [2.8 to 3.6] mm yr–1 between 1993 and 2010.
Over the period 1993 to 2010, global mean sea level rise is, with high confidence,
consistent with the sum of the observed contributions from ocean thermal
expansion due to warming, from changes in glaciers, Greenland ice sheet, Antarctic
ice sheet and land water storage.
It is very likely that there is a substantial anthropogenic contribution to the
global mean sea level rise since the 1970s.
Sea level in the FAR (1990) and AR5 (2013)
Under the business as usual scenario, the predicted rise is about 65cm by the end
of the next century. There will be significant regional variations.
For RCP8.5, the rise by the year 2100 will likely be
in the range of 0.52 to 0.98 (relative to 1986-2005)
There is currently insufficient evidence
to evaluate the probability of specific levels
above the assessed likely range.
Sea level rise will not be uniform. By the end of the 21st century, it is very likely that
sea level will rise in more than about 95% of the ocean area. About 70% of the
coastlines worldwide are projected to experience sea level change within 20% of the
global mean sea level change.
Although, over the next 100 years, the effect of the Antarctic and Greenland ice
sheets is expected to be small they make a major contribution to the
uncertainty in predictions
Changes in outflow from both ice sheets combined will likely make a
contribution in the range of 0.03 to 0.20 m by 2081−2100
Only the collapse of marine-based sectors of the Antarctic ice sheet, if initiated,
could cause global mean sea level to rise substantially above the likely range
during the 21st century. However, there is medium confidence that this
additional contribution would not exceed several tenths of a meter of sea level
rise during the 21st century.
Sea level in the FAR (1990) and AR5 (2013)
Sea level in the FAR (1990) and AR5 (2013)
Even if greenhouse forcing increased no further, there would still be a
commitment to a continuing sea level rise for many decades and even centuries
due to delays in climate ocean and ice mass responses
It is virtually certain that global mean sea level rise will continue beyond 2100,
with sea level rise due to thermal expansion to continue for many centuries.
RCP 2.6 : <1 m by 2300
RCP8.5 : 1 m to more than 3 m
Sustained mass loss by ice sheets would cause larger sea level rise, and some
part of the mass loss might be irreversible. There is high confidence that sustained
warming greater than some threshold
would lead to the near-complete loss of the
Greenland ice sheet over a millennium or more,
causing a global mean sea level rise of up to 7 m.
m
The most severe effects of sea level rise are likely to result from extreme events
(for example, storm surges) the incidence of which may be affected by climatic
change
It is very likely that there will be a significant increase in the occurrence of future
sea level extremes by 2050 and 2100. This increase will primarily be the result of an
increase in mean sea level (high confidence), with the frequency of a particular sea level
extreme increasing by an order of magnitude or more in some regions by the end of the
21st century. There is low confidence in region-specific projections of storminess
and associated storm surges.
Sea level in the FAR (1990) and AR5 (2013)
64%
36%
Developed Countries
Developing Countries & Economies in
Transition
79%
21%
Male writing team members
Female writing team members
63%
37%
New to the IPCC process
Previously involved
The Fifth Assessment Report (AR5)
830 Coordinating Lead Authors, Lead Authors and Review Editors
from 85 countries
2030 international agenda
Paris Agreement
Knowledge: risk management & solutions
Specificities of the IPCC AR6
• More experts from developing countries
• More integration across Working Groups
• High level scenarios and concrete steps
• Connections with sustainable development goals
• Focus on solutions linked to domestic challenges
Poverty alleviation, job creation, health, innovation, energy access…
• Strengthen relevance for a variety of stakeholders
Three Conventions (climate, biodiversity, desertification)
Subnational policy makers (cities…)
Business, industry, finance…
Aspirations for the AR6
Improve communication (graphics, SPM, FAQ…)
IPCC report preparation steps
Cut-off dates for
cited references
The Physical Science Basis
The Synthesis Report
Climate ChangeImpacts,
Adaptation and Vulnerability
Mitigationof
Climate Change
April 2021 April 2022October 2021
July 2021
Global stocktake2023
UNFCCC
Global warming of
1.5 oC
Oct. 2018 Oct. 2019
Aug. 2019
FacilitativedialogueUNFCCC
Land
Oceans and cryosphere
Schedule
Cities and Climate Change Science Conference
Emissioninventories
May 2019
March2018
May 2018 Expert Meeting on Short Lived Climate Forcers
May 2018 Expert Meeting on Assessing Climate Information for Regions
Chapter 1: Framing and context
Chapter 2: Mitigation pathways compatible with 1.5°C
in the context of sustainable development
Chapter 3: Impacts of 1.5°C global warming on natural
and human systems
Chapter 4: Strengthening and implementing the global
response to the threat of climate change
Chapter 5: Sustainable development, poverty
eradication and reducing inequalities
Global warming of 1.5°C (SR1.5)
15
40
60
50
20
Chapter 1: Framing and context
Chapter 2: Land-climate interactions
Chapter 3: Desertification
Chapter 4: Land degradation
Chapter 5: Food security
Chapter 6 : Interlinkages between desertification, land
degradation, food security, and greenhouse gas fluxes
: synergies, trade-offs and integrated response options
Chapter 7 : Risk management and decision making
In relation to sustainable development
IPCC Special Report on Climate
Change and Land (SRCCL)
15
50
35-40
40
50
40
40
Chapter 1: Framing and context
Chapter 2: High mountain areas
Chapter 3: Polar regions
Chapter 4: Sea level rise and implications for low lying
islands, coasts and communities
Chapter 5: Changing ocean, marine ecosystems, and
dependent communities
Chapter 6 : Extremes, abrupt changes and managing
risks
Box : Low lying islands and coasts
IPCC Special Report on the Ocean and
Cryosphere in a Changing Climate (SROCC)
15
30
50
50
65
20
<5
WGI OutlineSummary for Policy Makers
Technical Summary
Chapter 1: Framing, context, methods
Chapter 2: Changing state of the climate system
Chapter 3: Human influence on the climate system
Chapter 4: Future global climate: scenario-based projections and near-term information
Chapter 5: Global carbon and other biogeochemical cycles and feedbacks
Chapter 6: Short-lived climate forcers
Chapter 7: The Earth’s energy budget, climate feedbacks, and climate sensitivity
Chapter 8: Water cycle changes
Chapter 9: Ocean, cryosphere, and sea level change
Chapter 10: Linking global to regional climate change
Chapter 11: Weather and climate extreme events in a changing climate
Chapter 12: Climate change information for regional impact and for risk assessment
Annexes incl. options for a Regional Atlas and Technical Annexes
Glossary
Index
Large-scale climate change
WGI OutlineSummary for Policy Makers
Technical Summary
Chapter 1: Framing, context, methods
Chapter 2: Changing state of the climate system
Chapter 3: Human influence on the climate system
Chapter 4: Future global climate: scenario-based projections and near-term information
Chapter 5: Global carbon and other biogeochemical cycles and feedbacks
Chapter 6: Short-lived climate forcers
Chapter 7: The Earth’s energy budget, climate feedbacks, and climate sensitivity
Chapter 8: Water cycle changes
Chapter 9: Ocean, cryosphere, and sea level change
Chapter 10: Linking global to regional climate change
Chapter 11: Weather and climate extreme events in a changing climate
Chapter 12: Climate change information for regional impact and for risk assessment
Annexes incl. options for a Regional Atlas and Technical Annexes
Glossary
Index
Climate processes
Regional climate
information
WGI OutlineSummary for Policy Makers
Technical Summary
Chapter 1: Framing, context, methods
Chapter 2: Changing state of the climate system
Chapter 3: Human influence on the climate system
Chapter 4: Future global climate: scenario-based projections and near-term information
Chapter 5: Global carbon and other biogeochemical cycles and feedbacks
Chapter 6: Short-lived climate forcers
Chapter 7: The Earth’s energy budget, climate feedbacks, and climate sensitivity
Chapter 8: Water cycle changes
Chapter 9: Ocean, cryosphere, and sea level change
Chapter 10: Linking global to regional climate change
Chapter 11: Weather and climate extreme events in a changing climate
Chapter 12: Climate change information for regional impact and for risk assessment
Annexes incl. options for a Regional Atlas and Technical Annexes
Glossary
Index
WGI OutlineSummary for Policy Makers
Technical Summary
Chapter 1: Framing, context, methods
Chapter 2: Changing state of the climate system
Chapter 3: Human influence on the climate system
Chapter 4: Future global climate: scenario-based projections and near-term information
Chapter 5: Global carbon and other biogeochemical cycles and feedbacks
Chapter 6: Short-lived climate forcers
Chapter 7: The Earth’s energy budget, climate feedbacks, and climate sensitivity
Chapter 8: Water cycle changes
Chapter 9: Ocean, cryosphere, and sea level change
Chapter 10: Linking global to regional climate change
Chapter 11: Weather and climate extreme events in a changing climate
Chapter 12: Climate change information for regional impact and risk for assessment
Annexes incl. options for a Regional Atlas and Technical Annexes
Glossary
Index
Link to WGII
Link to WGIII
WGII ChaptersChapter 1: Point of departure and key concepts
SECTION 1: Risks, adaptation and sustainability for systems impacted by climate change Chapter 2: Terrestrial and freshwater ecosystems and their services
Chapter 3: Ocean and coastal ecosystems and their services
Chapter 4: Water
Chapter 5: Food, fibre, and other ecosystem products
Chapter 6: Cities, settlements and key infrastructure
Chapter 7: Health, wellbeing and the changing structure of communities
Chapter 8: Poverty, livelihoods and sustainable development
SECTION 2: Regions Chapter 9: Africa
Chapter 10: Asia
Chapter 11: Australasia
Chapter 12: Central and South America
Chapter 13: Europe
Chapter 14: North America
Chapter 15: Small Islands
SECTION 3: Sustainable development pathways: integrating adaptation and mitigation Chapter 16: Key risks across sectors and regions
Chapter 17: Decision-making options for managing risk
Chapter 18: Climate resilient development pathways* *connection to WG III
ANNEX I: Regional Atlas
CROSS-CHAPTER PAPERS
• Biodiversity hotspots (land, coasts and oceans)
• Cities and settlements by the sea
• Deserts, semi-arid areas, and desertification
• Mediterranean region
• Mountains
• Polar regions
• Tropical forests
15. Investment and finance16. Innovation, technology development and transfer
5: Demand, services and social aspects of mitigation6: Energy systems 9. Buildings7. Agriculture, Forestry, and Other Land Uses 10. Transport8. Urban systems and other settlements 11. Industry12. Cross sectoral perspectives
Outline of WG III AR6 on mitigationFraming (1 chapter)
High-level assessment of emission trends, drivers and pathways (3 chapters)
Sectoral chapters (8 chapters)
Institutional drivers (2 chapters)
Synthesis (1 chapter)
17. Accelerating the transition in the context of sustainable development
13. National and sub-national policies and institutions 14. International cooperation
1. Introduction and framing
2. Emissions trends and drivers3. Mitigation pathways compatible with long-term goals4. Mitigation and development pathways in the near- to mid-term
Set up sustainable development as key framing concept
Balancing sources and sinks/warming levels
NDCs, emissions peaking, mid-century long-term low greenhouse
gas emission development strategies
Orients sectors to human needs
The sectoral core: maps on to inventories
Financial flows + technological innovation
Synthesis sustainable development in different geographical scales
Financial and technological drivers (2 chapters)
Responses not captured by sectoral framing
Institutions, policies and cooperation
The Physical Science Basis
The Synthesis Report
Climate ChangeImpacts,
Adaptation and Vulnerability
Mitigationof
Climate Change
April 2021 April 2022October 2021
July 2021
Global stocktake2023
UNFCCC
Global warming of
1.5 oC
Oct. 2018 Oct. 2019
Aug. 2019
FacilitativedialogueUNFCCC
Land
Oceans and cryosphere
Schedule
Cities and Climate Change Science Conference
Emissioninventories
May 2019
March 2018
May 2018 Expert Meeting on Short Lived Climate Forcers
May 2018 Expert Meeting on Assessing Climate Information for Regions
Cut-off dates for reports
Report Cut-off dates for
submitted papers to
be cited in Second
Order Drafts
Cut-off dates for
papers accepted for
publication to be cited
in report
SR1.5 01 November 2017 15 May 2018
SROCC October 2018 May 2019
SRCCL September 2018 April 2019
AR6, WG1 31 January 2020 15 October 2020
Author teams
Coordinating Lead Authors (CLAs)
Lead Authors (LAs)
Review Editors (REs)
Contributing Authors (CA)
Chapter Scientists (CS)
2017 2018 2019
SR15 FOD – JulySOD – JanApproval – Oct
SRCCL FOD – MaySOD – Oct
Approval – Aug
SROCC FOD – AprSOD – Nov
Approval – Sept
Next review processes
Outreach Activities
Closing remarks
• Multiple roles of IPCC reports :
- assessment of the state of knowledge for governments
- synthesis of available research, regional results into global context
- identification of knowledge gaps and uncertainties
- maturation of science and stimulation of research
- teaching
• New knowledge is vital for IPCC assessments
• The review process is crucial for the quality of the assessment
• AR6 : a new IPCC approach with 3 special reports
• Which approach for the AR7 and beyond?
@IPCCNews
IPCC_Climate_Change
http://www.slideshare.net/ipcc-media/presentations
https://www.youtube.com/c/ipccgeneva
Find us on:
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https://www.flickr.com/photos/ipccphoto/sets/
https://vimeo.com/ipcc
THANK YOU FOR YOUR ATTENTION!
For more information:
Chapter 1:
Framing, context, methods
Executive Summary
• Synthesis of key findings from AR5 and earlier assessment reports, and
connections to AR6 Special Reports
• Framing of the physical science information relevant for mitigation,
adaptation, and risk assessment in the context of the Global Stocktake
• Assessment approach
• Observational and reanalysis developments since the AR5
• Model and experimental design developments since the AR5
• Emissions and forcing scenarios
• Treatment and evaluation of uncertainty throughout the report
Frequently Asked Questions
Chapter 2:
Changing state of the climate system
Executive Summary
• Multi-millennial context, pre-industrial to present day
• Natural and anthropogenic forcings
• Radiative forcing
• Large-scale indicators of observed change in the atmosphere, ocean,
cryosphere, land, and biosphere
• Modes of variability
Frequently Asked Questions
Chapter 3:
Human influence on the climate system
Executive Summary
• Overview of model performance and development since the AR5
• Simulated large-scale indicators of change in the atmosphere, ocean,
cryosphere, land, and biosphere
• Simulated modes of variability
• Natural variability versus anthropogenically-forced change
• Attribution of large-scale observed changes
Frequently Asked Questions
Chapter 4:
Future global climate: scenario-based projections
and near-term information
Executive Summary
• Projections of global mean surface temperature and other key global
indicators
• Evaluation of multi-model ensemble methods
• Large scale patterns of climate change
• Committed climate response, climate targets, overshoot, irreversibility,
abrupt change
• Climate response to greenhouse gas removal scenarios
• Climate response to solar radiation management scenarios
• Interplay between internal variability and response to forcings, including
short-lived forcers
• Variability and unexpected changes of global mean surface temperature
• Near-term predictability, sources and capabilities
• Synthesis of climate information in the near-term
Frequently Asked Questions
Chapter 5:
Global carbon and other biogeochemical cycles and
feedbacks
Executive Summary
• Feedbacks between climate and biogeochemical cycles, including
paleoclimate information
• Ocean acidification
• Historical trends and variability of CO2, CH4 and N2O; sources and sinks
• Projections of global biogeochemical cycles from near-term to long-term
• Abrupt change, irreversibility
• Model evaluation, emergent constraints
• Transient climate response to cumulative emissions and remaining carbon
budgets for climate targets
• Biogeochemical implications of land and coastal management mitigation
options including greenhouse gas removal
• Biogeochemical implications of solar radiation management scenarios
Frequently Asked Questions
Chapter 6:
Short-lived climate forcers
Executive Summary
• Key global emissions: global overview, natural, anthropogenic, historical
and scenarios
• Observed and reconstructed concentrations and radiative forcing
• Direct and indirect-aerosol forcing
• Implications for greenhouse gas lifetimes
• Implications of different socio-economic and emission pathways, including
urbanisation, for radiative forcing
• Connections to air quality and atmospheric composition
Frequently Asked Questions
Chapter 7:
The Earth’s energy budget, climate feedbacks,
and climate sensitivity
Executive Summary
• Energy budget and its changes through time
• Radiative forcing: definitions, estimates, and its representation in models
• Climate feedbacks
• Sensitivity of the climate system: methods and uncertainty
• Empirical constraints on the sensitivity of the climate system, including
paleoclimate
• Global warming potential, global temperature change potential, and other
metrics
Frequently Asked Questions
Chapter 8:
Water cycle changes
Executive Summary
• Observations, models, methods and their reliability
• Past, present and projected changes, trends, variability and feedbacks in
the physical components of the water cycle
• Circulation, processes and phenomena (e.g. monsoon systems) affecting
moisture and precipitation patterns, including extremes
• Cloud-aerosol processes affecting the water cycle
• Changes in seasonality of natural storage and water availability
• Abrupt change
• Confidence in projections
Frequently Asked Questions
Chapter 9:
Ocean, cryosphere, and sea level change
Executive Summary
• Past and future changes in ocean circulation and properties (trends,
variability and extremes)
• Past and future changes in marine and terrestrial cryosphere
• Evaluation of models and projection methods
• Detection and attribution
• Past global and regional sea level changes
• Projections of global and regional sea level change
• Abrupt change and long-term commitment
• Extreme water levels (tides, surge and ocean waves)
Frequently Asked Questions
Chapter 10:
Linking global to regional climate change
Executive Summary
• Regional phenomena, drivers, feedbacks and teleconnections
• Regional scale observations and reanalyses
• Interplay between internal variability and forced change at the regional
scale, including attribution
• Evaluation of model improvements, methods, including downscaling and
bias adjustment and regional specificities
• Confidence in regional climate information, including quantification of
uncertainties
• Scale specific methodologies e.g. urban, mountains, coastal, catchments,
small islands
• Approaches to synthesizing information from multiple lines of evidence
Frequently Asked Questions
Chapter 11:
Weather and climate extreme events in a changing climate
Executive Summary
• Extreme types encompassing weather and climate timescales and
compound events (including droughts, tropical cyclones)
• Observations for extremes and their limitations, including paleo
• Mechanisms, drivers and feedbacks leading to extremes
• Ability of models to simulate extremes and related processes
• Attribution of changes in extremes and extreme events
• Assessment of projected changes of extremes and potential surprises
• Case studies across timescales
Frequently Asked Questions
Chapter 12:
Climate change information for regional impact and for risk
assessment
Executive Summary
• Framing: physical climate system and hazards
• Region-specific integration of information, including confidence
• Information (quantitative and qualitative) on changing hazards: present
day, near term and long term
• Region-specific methodologies
• Relationship between changing hazards, global mean temperature
change, scenarios and emissions
Frequently Asked Questions
“Ultimately what we do about climate issues depends upon the state of our
scientific knowledge. Only to the extent that we have understanding can we
help our governments.
Governments wish to know where to focus effort and resources. The
international resources that can be made available to deal with climatic
problems are limited. This is so not merely because finances are limited, but
because the number of scientists capable of working effectively on these
problems is limited.
Because of this, efforts must be focused on those climatic problems where
there is an urgent need for answers, and where the state of our scientific
knowledge leads us to believe that it may be possible for science to make a
useful contribution.”
Robert White, Keynote address, World Climate Conference, 1979