Download Coastal systems and low- lying areas

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5
IPCC
Assessment Report :
Coastal systems and lowlying areas
University of Adelaide, Australia
20 November 2014
Poh Poh Wong
Coordinating Lead Author
[email protected]
IPCC
Intergovernmental Panel on
Climate Change (IPCC)
• Created in 1988 by WMO and UNEP. Has 195 governments
that commission assessments performed by the
international community on the state of human knowledge
of climate & climate change.
• Role : to assess on a comprehensive, objective, open &
transparent basis the scientific, technical & socio-economic
information relevant to understanding scientific basis of risk
of human-induced climate change, its potential impacts &
options for adaptation & mitigation.
• IPCC assessments : scientific basis for governments at all
levels to develop climate related policies, & they underlie
negotiations at the UN Climate Conference (UNFCCC, United
Nations Framework Convention on Climate Change).
Three Working Groups (WGs) and
Task Force
• WGI : assesses physical scientific aspects of climate system &
climate change.
• WGII : assesses vulnerability of socio-economic & natural
systems to climate change & options for adapting to it.
• WGIII : assesses options for mitigation climate change
through limiting or preventing GHG emissions & enhancing
activities to remove them.
• Task Force : to develop & refine internationally-agreed
methodology & software for calculation & reporting GHG
emissions.
AR5 – WGII
• Scoping meeting in July 2009 to outline 30 chapters : involving
climate change experts from relevant disciplines, users, govt.
reps.
• 1217 author nominations from 92 countries.
• 242 Lead Authors (about 60 are CLAs) & 66 Review Editors from
70 countries : selection criteria include expertise, differing
viewpoints & perspectives, geographic balance, gender balance,
& ensuring involvement of new experts in accordance to
agreed-upon IPCC guidelines. Supplemented by 436
Contributing Authors from 54 countries.
• Undergone two extensive reviews : totaling over 50,000
comments from 1729 expert reviewers from 84 countries & 49
governments.
• Over 12,000 scientific references.
AR5 - Risk assessment
• Focus on risks to support decision making.
• Risks = interactions of CC hazards (incl. hazardous events) with
vulnerability & exposure of human & natural systems.
(IPCC 2014, SPM)
WGII - Larger knowledge base
• Substantial larger knowledge base : from 20 to 30 chapters; 4 on
adaptation; 4 on livelihoods & poverty, human security, urban &
rural areas; 2 on oceans.
• Two parts; part 1 on global & sectorial aspects; part 2 on regions.
Coasts
Post-AR4 – key/new issues
• Higher GMSLR; serious implications for coastal
systems, both physical & human.
• Ocean acidification of increasing concern; serious
implications for shellfish & commercial aquaculture.
• Advances in both vulnerability assessments &
identification of potential actions, costs, benefits &
trade-offs.
• More coastal adaptation with wider range of
approaches & frameworks.
Coastal systems
(IPCC 2014, chapter 5)
Three key drivers related to
Climate Change
• Sea level, ocean temperature & ocean acidity.
• Long term commitment to experience sea level
impacts because of delay in its response to
temperature.
• Coral bleaching & species ranges can be attributed
to temperature change & ocean acidity.
Mean Sea Level Rise MSLR (WG1)
(IPCC 2014, chapter 5)
MSLR (Synthesis)
(IPCC 2014, Synthesis)
Regional Sea Level Rise RSLR
• RSLR can be much larger than projected GMSLR.
• Non-climate change local processes include
subsidence, glacial isostatic adjustment, sediment
transport, coastal development.
• Changes in storms & associated storm surges may
further contribute to sea level extremes.
• Under present levels of global warming, already
committed to higher future SLR above current
levels.
Adverse impacts
• Coastal systems & low-lying areas will be
increasingly subject to submergence, coastal
flooding & erosion.
• Beaches, sand dunes, cliffs continued to be
eroded under increasing sea level.
Acidification and warming
• Acidification continues with large & uncertain
regional & local variations.
• Warming & acidification will lead to coral bleaching,
mortality & decreased constructional ability.
• Coral reefs will be most vulnerable marine
ecosystem with little scope for adaptation.
Summary: major drivers and impacts
(IPCC 2014, chapter 5)
Detection & attribution
(IPCC 2014, chapter 5)
Human pressures on coastal systems
• Increase significantly in future due to population
growth, economic development, & urbanization.
• Humans have been primary drivers of change in
coastal aquifers, lagoons, estuaries, deltas &
wetlands.
• Further exacerbation on coastal ecosystems from
excess input, changes in runoff & reduced sediment
delivery.
Benefits of protection
• Benefits of protection against coastal flooding and
land loss at global scale are larger than social &
economic costs of inaction.
• Without adaptation, hundreds of million will be
affected by coastal flooding & displaced due to land
loss by 2100; majority from East, Southeast & South
Asia.
• Protection against flooding & erosion is
economically rational for most developed coastlines
in many countries for all socioeconomic & SLR
scenarios.
Relative costs of coastal adaptation
• Costs of coastal adaptation expected to vary
strongly among & within regions & countries.
• Some low-lying countries (Bangladesh, Vietnam) &
small islands expected to face high impacts.
Associated damage & adaptation costs could be
several % of GDP.
Coastal adaptation
• Increasingly, coastal adaptation options include those
based on ICZM, local community participation, EBA &
DRR mainstreamed into relevant & management
plans.
• More proactive responses made & based on
technology, policy, financial & institutional support.
• Flexible & reversible options are favoured.
• Should note that protection further attracts
population & development which in turn increases
risk of potential catastrophic consequence in case of
defence failure.
Adaptation among countries
• Coastal adaptation progressed more significantly in
developed countries than in developing countries.
• Innovative approaches, e.g. Dutch approach in
“working with nature”, “room for river” rather than
dikes and structures.
Adaptation options
(IPCC 2014, Synthesis)
Conclusion
Risk and adaptation over timeframe
(IPCC 2014, chapter 30)
Risks impacted by Sea Level Rise
(IPCC 2014, Synthesis)
Thank you