Climate Change: Impacts and Responses Topic 6: Impacts of Climate Change topic 6 – Impacts of...
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Transcript of Climate Change: Impacts and Responses Topic 6: Impacts of Climate Change topic 6 – Impacts of...
Climate Change: Impacts and Responses
Topic 6:Impacts of Climate Change
Why be concerned about climate change impacts?
What impacts have been observed to date?
What impacts are likely in the future?
Summary
Topic outline
UN image, Logan Abassi
Learning outcomes for this topic
Demonstrate an understanding of the major risks arising from climate change
Discuss observed climate impacts to date
Name projected impacts for a range of environments and sectors
Demonstrate an understanding of why attribution of observed impacts can be problematic
Demonstrate and understanding of why uncertainty exists over impact projections
Discuss possible regional impacts for Africa
Section 1:Why be concerned about climate change impacts?
Risks to unique and threatened systems
Risks from extreme climate events
Unfair distribution of climate impacts
Increasingly negative impacts with higher mean temperatures
Risks from large-scale discontinuities
Outline:Why be concerned about climate impacts?
Risk The potential for consequences where
something of human value (including humans themselves) is at stake and where the outcome is uncertain. Risk is often represented as probability of occurrence of hazardous events or trends multiplied by the consequences if these events occur.
Definition of risk
IPCC AR5 WGII, 2014 - Glossary
Risks to unique and threatened systems
e.g. Reptiles and amphibians are moving upslope in Tsaratanana Massif (Madagascar)
Calumma tsaratananensis,. credit: American Museum of Natural HistoryRaxworthy et al., 2008
Risks from extreme climate events
Woman in the Sahel terracing the soil to control for erosion.UN Photo/John Isaac
e.g. in Africa - reduced crop productivity associated with heat and drought stress
Unfair distribution of impacts
Image: FAO
e.g. productivity losses will occur in areas already at temperature maximum
As temperatures rise further, aggregate impacts become increasingly negative everywhere
Image: NRC
Risks from future large scale discontinuities
Image: NASA
Risks of climate related impacts
IPCC AR5 WGII, 2014, FigTS-1
Section 2:Observed impacts
Observed global impacts
Snow, ice and frozen ground
Hydrological systems
Terrestrial biological systems
Marine and freshwater systems
Human systems
Outline:Observed impacts
1
Observed global impacts
IPCC 2014 SPM2 WGII
Snow, ice and frozen ground
All images: NASAColumbia Glacier, Alaska
Muir Glacier, Alaska
Iceberg separating from Pine Island Glacier, Antarctica
Shrinking mountain glaciers
Declining Arctic sea ice cover
Declining areas of frozen ground in summer
Reduced snow cover in NH winter
Increasing freshwater release to ocean
Trends in rainfall are complicated
Temperature trends are impacting large lakes
Hydrological systems
Image: NASA
Image: IPCC 2007
Lake Tanganyika from space Historical and recent measurements from Lake Tanganyika
Plant and animal species are likely to respond to climate change in various ways.
Responses may include changes to:
• Timing of life cycle events
• Boundaries of inhabited ranges
• Population density
• Morphology
• Local or global extinction.
Terrestrial biological systems
Creative commons
Image: A. Barra
13
Marine and freshwater biological systems
IPCC 2014 WGII Fig 6.8
Human and managed systems
IPCC WGII 2014 (adapted from Fig 7-2)
Section 3:Future climate impacts
Future climate-related risks
Future sectorial risks:
• Freshwater resources
• Marine systems
• Food production systems and food security
• Terrestrial ecosystems
• Coastal and low-lying areas
• Global economic impacts
• Human health
• Human security
Regional impacts: Africa
Outline:Future climate impacts
Risks of climate change
IPCC AR5 WG II 2014; Box TS5, Fig1
Freshwater resources
IPCC WGII 2014,Fig 3.4
Marine systems
IPCC AR5 WGII 2014, Fig6-14
Summary of projected changes in crop yields, due to climate change over the 21st century. The figure includes projections for different emission scenarios, for tropical and temperate regions, and for adaptation and no-adaptation cases combined.
Food production system and food security
2010-2029 2030-2049 2050-2069 2070-2089
20
40
60
80
100
PER
CEN
TAG
E O
FYIE
LD P
RO
JEC
TIO
NS
02090-2109
0 – -5%
-5 – -10%
-10 – -25%
-25 – -50%
-50 – -100%
50 – 100%
25 – 50%
10 – 25%
5 – 10%
0 – 5%
Range of Yield Change
Increasein Yield
Decreasein Yield
IPCC AR5, 2014 WGII, Fig 7.-5
Terrestrial ecosystems
Soil erosion and deforestation – Guatemala; UN Photo/John Olsson
Coastal and low-lying areas
UN Photo/Logan Abassi
Global economic impact
UN Photo/Kibae Park
Human health
UN Photo/John Isaac
Human security
IPCC AR5 2014 WGII, Fig 12-3
Far-reaching impacts in human and natural systems
Predominantly negative impacts, especially if global mean temperature increase exceeds 2°C
Impacts likely to alter ecosystems
Floods and droughts likely to increase, with increasing risks of water pollution and incidence of water-related diseases
Coastal areas likely to suffer erosion, flooding, salt-water intrusion
Negative health impacts could occur, especially heat-related deaths, malnutrition and transmission of some diseases
Summary of projected impacts
Africa: key risks from climate change
IPCC AR5 2014, WGII, Chapter 22
Observed warming trend higher than the global average
Rainfall highly variable across Africa:
• West Africa has seen a decline
• Increase along Guinean coast
• No long term trends in precipitation in the rest of Africa
Increased rainfall inter-annual variability
Africa observed impacts
Mean temperature increase will exceed 2°C by mid to end of this century.
Precipitation projections more uncertain
Shifts in ecosystems
Water stress
Food security
Africa projected impacts
Reasons for concern about impacts include: damage to ecosystems, extreme weather events, unfair impacts distribution, sudden abrupt climate change.
Observed impacts to date include changes to glaciers, crops and ecosystems on land, in freshwater and oceans.
Future impacts are potentially far-reaching. Impacts are likely but projections are inevitably uncertain.
Summary
IPCC (2007). Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment. Report of the Intergovernmental Panel on Climate Change, [M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden, C.E.Hanson, (eds)]. Cambridge University Press, Cambridge, UK, 976pp
IPCC (2014). Climate Change 2014: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fifth Assessment. Report of the Intergovernmental Panel on Climate Change, [Barros, V.R., C.B. Field, D.J. Dokken, M.D. Mastrandrea, K.J. Mach, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA
Raxworthy et al., (2008). Extinction vulnerability of tropical montane endemism from warming and upslope displacement: a preliminary appraisal for the highest massif in Madagascar. Global Change Biology (2008) 14, 1703–1720. OnlineOpen: This article is available free online at www.blackwell-synergy.com
References
End of Topic 6:Impacts of Climate Change
Next Topic: Adaptation