Transcript Climate Change Impacts and Responses

Climate Change:
Impacts and Responses
Topic 6:
Impacts of Climate Change
Topic outline
UN image, Logan Abassi

Why be concerned about
climate change impacts?

What impacts have been
observed to date?

What impacts are likely in
the future?

Summary
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?
Outline:
Why be concerned about climate 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
Definition of risk
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.
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 History
Raxworthy et al., 2008
Risks from extreme climate events
e.g. in Africa - reduced crop productivity
associated with heat and drought stress
Woman in the Sahel terracing the soil to control for erosion.
UN Photo/John Isaac
Unfair distribution of impacts
e.g. productivity losses will occur in areas already at
temperature maximum
Image: FAO
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
Outline:
Observed impacts
 Observed global impacts
 Snow, ice and frozen ground
 Hydrological systems
 Terrestrial biological systems
 Marine and freshwater systems
 Human systems
Observed global impacts
1
IPCC 2014 SPM2 WGII
Snow, ice and frozen ground
Iceberg separating from Pine
Island Glacier, Antarctica
Muir Glacier, Alaska
 Shrinking mountain glaciers
 Declining Arctic sea ice cover
 Declining areas of frozen
ground in summer
 Reduced snow cover in NH
winter
Columbia Glacier, Alaska
All images: NASA
 Increasing freshwater release
to ocean
Hydrological systems
Lake Tanganyika from space
Historical and recent measurements
from Lake Tanganyika
Image: NASA

Trends in rainfall are complicated

Temperature trends are impacting
large lakes
Image: IPCC 2007
Terrestrial biological systems
Plant and animal species are
likely to respond to climate
change in various ways.
Responses may include changes
to:
Creative commons
• Timing of life cycle events
• Boundaries of inhabited
ranges
• Population density
• Morphology
• Local or global extinction.
Image: A. Barra
Marine and freshwater biological systems
13
IPCC 2014 WGII Fig 6.8
Human and managed systems
IPCC WGII 2014 (adapted from Fig 7-2)
Section 3:
Future climate impacts
Outline:
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
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
Food production system and food security
Range of Yield Change
100
50 – 100%
25 – 50%
80
Increase
in Yield
10 – 25%
5 – 10%
60
PERCENTAGE OF
YIELD PROJECTIONS
0 – 5%
0 – -5%
40
-5 – -10%
Decrease
in Yield
20
-10 – -25%
-25 – -50%
-50 – -100%
0
2010-2029
2030-2049
2050-2069
2070-2089
2090-2109
IPCC AR5, 2014 WGII, Fig 7.-5
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.
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
Summary of projected impacts

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
Africa: key risks from climate change
IPCC AR5 2014, WGII, Chapter 22
Africa observed impacts

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 projected 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
Summary

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.
References
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.blackwellsynergy.com
End of Topic 6:
Impacts of Climate Change
Next Topic:
Adaptation