GENERAL Climate Change Handbook for NE South Africa (Gauteng

Transcription

Compiled by:
Claire Davis, Climate Change Research Group, Council
for Scientific and Industrial Research (Editor)
Cont ributio n s made by:
Dr Emma Archer, Climate Change Research Group,
Council for Scientific and Industrial Research
Dr Francois Engelbrecht, Atmospheric Modelling
Group , Council for Scientific and Industrial Research
Dr Willem Landman, Atmospheric Modelling Group,
Nicola Stevens, Climate Change Research Group,
Lee-Ann Sinden, Ecosystem Processes and Dynamics
Research Group, Council for Scientific and Industrial
Research
Caesar Nkambule, Climate Change Research Group,
Dr. Rebecca Maserumule, Energy Modelling and
Business Process Management Subdirectorate,
Department of Energy
Marna van der Merwe, Ecosystems Processes and
Dynamics Research Group, Council for Scientific and
Industrial Research
Edit orial se r vice s:
Malachite Marketing and Media
D es ign a n d pr in t in g:
CPD Print: +27 12 423 9460
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© CSIR 2010. All rights to the intellectual property and/or contents
of this document remain vested in the CSIR. This document is
issued for the sole purpose for which it is supplied. No part of
this publication may be reproduced, stored in a retrieval system
or transmitted, in any form or by means electronic, mechanical,
photocopying, recording or otherwise without the express written
permission of the CSIR. It may also not be lent, resold, hired out
or otherwise disposed of by way of trade in any form of binding or
cover than that in which it is published.
Scope and purpose of this
ha n d b o o k
In many countries, decision-makers are seeking
information from a wide range of disciplines on the
potential impacts of climate change on environmental
and socio-economic systems.
This handbook is designed to present future climate
change scenarios and possible impacts of these
changes in an understandable and accessible manner.
The handbook is designed to provide a background on
the processes of global change and climate change.
The handbook will also serve as a basic reference guide
to those currently engaged in impacts and adaptation
research.
The future climate change projections (estimates of
future climate possibilities) presented in this handbook
are for the north-eastern region of South Africa only;
namely the Mpumalanga, Limpopo and Gauteng
provinces. These projections are based on newest
information obtained from the latest regionally
downscaled climate change models; provided by the
Climate System Analysis Group at the University of
Cape Town.
It is hoped that readers of this handbook will gain a
better understanding of climate change processes,
impacts and the possible measures that could be taken
to reduce these impacts.
For further information, as well as updated information
since the publication of this handbook, please visit
www.sarva.org.za/k2c.
TA BLE OF C ON TEN TS
Part I: Background information on the global and local state of climate change
Climate change and global change – what is it all about?
2
What causes climate change?
The greenhouse effect
3
Observed changes in climate and their effects
4
Future global changes in climate
4
Impacts of climate change on the African continent
5
A brief description of South Africa’s present-day climate
6
Part II: Future scenarios of climate change for north-eastern South Africa
The future climate of South Africa
7
Regional scenarios of climate change over the north-eastern
region of South Africa
8
Changes in temperature
Maximum day temperature
8
Mean day temperature
9
Minimum day temperature
10
Changes in rainfall
11
Changes in evaporation
15
Changes in duration of dry spells
16
Changes in the frequency of rain events
19
Part III: Sector specific impacts of climate change
Impacts of climate change on key sectors
Forestry
22
Agriculture
23
Conservation and tourism
24
Urban and rural development
26
Human health
27
Water resources
28
Part IV: Responding to climate change
How can we respond to changes in climate?
29
Useful resources on climate change
32
1
Climate change and global change:
WHAT IS IT ALL ABOUT?
The rate of human-induced change is unprecedented.
There is now unequivocal evidence that human
activities are affecting the Earth’s system at the global
scale. Increasingly strong evidence suggests that the
functioning of this system is changing in response.
Global change is more than climate change. Global
change refers to any changes in the Earth system. The
Earth system encompasses the climate system, and
many changes in Earth system functioning directly
involve changes in climate. The Earth system includes,
however other components and processes, bio-physical
and human, which are important for its functioning.
Some Earth system changes (see Table below), natural
or human-driven, can have significant consequences
without involving any changes in climate. Global change
does not operate in isolation but rather interacts with an
array of natural processes and human-driven effects in
Climate refers to the aggregation
of all components of weather –
precipitation, temperature, and
cloudiness.
complex and multidimensional ways; at local, regional
and global scales.
Climate change is “a change of climate which is
attributed directly or indirectly to human activity that
alters the composition of the global atmosphere
and which is in addition to natural climate variability
observed over comparable time periods” (United
Nations Framework Convention on Climate Change).
Global warming refers only to the overall warming of
the planet, based on average increases in temperature
over the entire land and ocean surface. It is important
to note that climate change is more than simply an
increase in global temperatures; it encompasses
changes in regional climate characteristics, including
temperature, humidity, rainfall, wind, and severe weather
events, which have economic and social dimensions.
Changes in the Earth system: Examples of global environmental change (adapted from Steffen et al., 2001)
Component
Proximate driver
Underlying driver
Land cover
Clearing of land (cutting and/
or burning), agricultural practices
(tillage, fertilisation, irrigation, pest
control, high-yielding crops, and
erosion), and abandonment.
Demand for food (bio-fuels),
recreation, migration (refugees),
property rights, incentives, market
growth.
Atmosphere
Fossil fuel burning, land-use change
(rural area to large-scale agricultural
practices), biomass burning, industrial technology.
Demand for mobility, consumer
products, subsidies, technological
changes in transport.
Biodiversity
Clearing of forest/natural
ecosystems, introduction of alien
species.
Demand for food, urbanisation,
changes in policy.
Water
Dams, impoundments, reticulation
systems, waste disposal techniques, management practices.
Demand for water (direct human
use), food (irrigation), consumer
products (water usage in industrial
processes).
Coastal/marine
Land-cover conversion,
groundwater removal, fishing
intensity and technique, coastal
building patterns, sewage
treatment technology, urbanisation.
Demand for recreation, lifestyle,
food, employment.
Social triggers
Rapid economic or political
shifts, War
2
HOW TO ADAPT EFFECTIVELY TO CLIMATE CHANGE
Predisposing environmental conditions
Climatic variability, Soil characteristics,
Fire frequency, Natural disasters
W h a t causes cl i mate c ha ng e ?
T HE GR EEN H O U S E EFFECT
The Earth’s climate system is driven by the energy that is
continuously received from the sun. The bulk of this energy
is in the short-wavelength part of the electromagnetic
spectrum.
form of global warming. These increased atmospheric
temperatures have knock-on effects for atmospheric
moisture availability (rainfall), sea surface temperatures,
ice sheets and glaciers.
About 30% of the incoming solar energy is reflected back
to space by clouds and the Earth’s surface before it can
warm the planet. About 70% of the incoming energy is
absorbed by the oceans, continents and the atmosphere.
The absorbed heat is later re-emitted in the form of
infrared radiation, or transferred by sensible and latent
heat fluxes.
Global GHG (water vapour (H20), carbon dioxide (C02),
nitrous oxide (N20) and methane (CH2) emissions due to
human activities have grown since pre-industrial times,
with an increase of 70% between 1970 and 2004 (IPCC,
Fourth Assessment Report, 2007). This increase has
come from energy supply, transport and industry as well
as emissions from residential and commercial buildings,
deforestation, and agricultural sectors.
Certain gases in the troposphere and stratosphere absorb
most of the outgoing infrared radiation, however before
it can escape to space, thereby warming the atmosphere
before the heat is once again re-emitted. These are referred
to as greenhouse gases (GHG). Without the presence of
these gases in the atmosphere, the average temperature
at the surface of present-day Earth would be about -18°C.
The warming effect of the greenhouse gases, called
the ‘greenhouse effect’ or ‘natural greenhouse effect’,
results , however in the average surface temperature
being about +14°C. Without the greenhouse effect, life
on Earth would be markedly different to that with which
we are familiar. The two gases, carbon dioxide and water
vapour, are primarily responsible for a large portion of the
greenhouse effect.
Anthropogenic (or human-driven) emissions of greenhouse gases, resulting from the burning of fossil fuels
and deforestation, have increased the atmosphere’s
ability to absorb the Earth’s outgoing infrared radiation.
This is referred to as the ‘enhanced greenhouse effect’.
The consequences of this effect can be clearly seen in
the worldwide trend of rising temperatures, that is, in the
Since the industrial revolution in the 18th century human
society has been producing greenhouse gases in everincreasing amounts. As a result, the concentrations of
greenhouse gases in the atmosphere are now higher than
at any time in the past 650 000 years. Source: IPCC, Third
Assessment Report, 2001.
And he huffed
and he puffed but
this problem would
not go away.
3
Obs e rv e d c h a n g e s in clim a t e
…and th e i r e ffe ct s
Anthropogenic (human-induced) climate change is
already occurring and many natural systems are being
affected.
increases during summer of 7.4% per decade. Mountain
glaciers and snow cover have decreased in the northern
and southern hemispheres.
Warming of the climate system is evident from
observations of increases in global average air and
ocean temperatures, widespread melting of snow ice
and rising average sea level (IPCC, 2007 Synthesis
Report, Fourth Assessment Report).
Trends from 1900 to 2005 show that rainfall has increased
in the eastern parts of North and South America,
Northern Europe and northern and central Asia and
has decreased in the Sahel, the Mediterranean, southwestern Africa and parts of southern Asia. This has
affected runoff and earlier spring peak discharge in many
glacier and snow fed rivers. An increased frequency of
high rainfall events has also been observed.
Since 1906 temperatures have increased by 0.74°C.
Eleven of the last twelve years (1995-2006) rank among
the twelve warmest years on record since 1850. Some
of the observed effects of warming can be described
as follows:
•
•
•
•
Heat waves have become more frequent
Cold days, cold nights and frosts have become less
frequent
Earlier timing of spring events, such as flowering,
bird migration, and egg-laying as well as poleward
shifts in animal and plant ranges
Changes in algal, plankton and fish population sizes
and distributions
Future global changes in climate
Despite international concern about climate change,
greenhouse-gas concentrations in the Earth’s atmosphere are set to increase at an accelerated rate if current
trends in emission rates persist.
Temperatures are expected to increase by between
1.8°C and 4.0°C (see figure below).
The global average sea level has risen at an average
rate of about 1.8 mm per year over 1961 to 2003 and
at an average rate of about 3.1 mm per year from
1993 to 2003. This has caused the loss of wetlands and
mangroves in many areas (for more information on sealevel rise experienced in South Africa, see South Africa’s
Second National Communication on Climate Change).
Satellite data show that the average extent of the Arctic
sea ice has shrunk by 2.77% per decade with larger
The global average sea level
has risen at an average rate of
about 1.8 mm per year over
1961 to 2003...
4
Source: United Nations Environmental Programme
Imp acts on Africa
Africa is one of the most vulnerable
continents to climate variability
and change because of multiple
stresses and low adaptive capacity.
The livelihoods of people in Africa,
including South Africa, are often
directly linked to the climate of
the area.
E a s t A f ri c a
Nort h A frica
•
•
•
•
By 2020:
• A large proportion of Africa’s population is
projected to be exposed to increased water
stress due to climate change induced shifts in
water availability coupled with increased water
demand.
• Yields from rain-fed agriculture could be
substantially reduced in certain areas, which
would further adversely affect food security and
exacerbate malnutrition.
Shifts in desert dunes
Climate change could negatively
impact mixed rain-fed and semi-arid
agricultural systems, particulary the
length of the growing season, for
example on the margins of the Sahel
Possible decreases in runoff in parts
of North Africa by 2050
The Nile river is sensitive to rises in
sea-level, as salination could occur
•
•
•
•
•
Changes in the storage of the East African Great Lakes
and reservoirs due to changes in rainfall, which could
adversely impact agricultural production
Previously malaria-free areas in Ethiopia, Kenya, Rwanda
and Burundi could experience modest changes to
stable malaria by the 2050s, with conditions for transmission becoming suitable by the 2080s
Ecosystem impacts, including impacts on mountain
biodiversity
Declines in fisheries in some of the major East African
lakes could occur due to increases in temperature
coupled with overfishing
Drought
Wes t and C e n t r al A f r ica
•
•
•
•
Negative impact on crop production and possible
agricultural GDP.
Populations of West Africa, including the large cities
of Lagos and Banjul, living in coastal settlements
could be affected by the projected rise in sea level
Changes in the coastal environment, such as the
removal of mangroves and coastal degradation,
could have negative impacts on fisheries and tourism
as well as on the resilience of those settlements to
heavy storms
Changes in ecosystem ranges and species locations
as well as possible increased risk of species extinction.
The rate and magnitude of deforestation in Central
Africa could exacerbate these losses in biodiversity
W e s t e rn In di an
O c e a n Is l a nds
Greatest risk of flooding due
to changes in rainfall, intense
storms and sea level rise. Coral
reefs are projected to be further
degraded
S o u t h e rn A fri c a
•
•
•
•
•
Heightened water stress
Possible southward expansion of the transmission zone of malaria
Climate changes may in certain areas favour horticulture over
plantation forestry
Fynbos and Succulent Karoo are likely to be the most vulnerable
ecosystems whilst the savanna is argued to be more resilient
Coastal marine fisheries are likely to be negatively affected by
changes in the Benguela current
5
A brief description of S o uth
Africa’ s present- day cl i m a te
South Africa has a warm climate, and much
of the country experiences average annual
temperatures of above 17°C. The southern and
eastern escarpments are the regions with the
lowest temperatures, due to the decrease in
temperature with altitude. The warmest areas
are the coastal areas of KwaZulu-Natal, the
Lowveld of KwaZulu-Natal and Mpumalanga,
the Limpopo valley and the interior of the
Northern Cape.
The oceans surrounding South Africa have a moderating
influence on the temperatures experienced along the
coastal areas. The warm Agulhas current causes the
east coast to be significantly warmer than the west
coast, where the cold Benguela current and upwelling
induce lower temperatures.
Regional topography and proximity to the oceans
also influence the climate. The western, southern and
eastern escarpments lead to a high plateau of about
1 250m above sea-level. The plateau experiences hot
summers and cold winters, but the oceans moderate the
climate of the coastal plains, providing milder winters.
The warm Agulhas current causes the eastern coastal
areas to have a warm and humid climate, whilst the cold
Benguela current along the west coast contributes to
the arid climate of this region.
South
Africa is a country
that experiences
an astounding variety
of different weather
conditions. Climate
refers to the long-term
average of weather
conditions.
Rainfall over South Africa is highly variable in space, and
a west-east gradient in rainfall totals is evident. The west
coast and western interior are arid to semi-arid areas.
The air above the cold Benguela current and upwelling
region along the west coast is relatively dry and cold,
contributing to the dry climate of the west coast and
adjacent interior. Rainfall totals are high over and to
the east of the eastern escarpment of South Africa due
to orographic precipitation. Rainfall patterns over the
country display well-pronounced intra-annual and interannual variability mainly due to the El Niño Southern
Oscillation (ENSO)1.
The different types of weather experienced over South
Africa in combination cause the country to consist
of vastly different climatological regions, with most
regions also displaying large inter-annual variability in
their climate. The variability of weather and climate over
South Africa poses challenges for weather prediction,
seasonal forecasting and the projection of climate
change over the country.
SEASONAL CLIMATE CHARACTERISTICS
Summer
(December-JanuaryFebruary)
This is the most important
rainfall season for the central
and northern interior of South
Africa.
Heat-induced thunderstorms
frequent the South African
interior, being most abundant
over the eastern escarpment
and Highveld areas.
Autumn
(March-April-May)
Winter
(June-July-August)
Rainfall decreases rapidly
over the eastern interior of
South Africa during this time.
Weather is characterised by
sunny days, clear skies and
cold nights.
This is, however, an important
rainfall season for the western
interior of South Africa (especially the Northern Cape and
Eastern Cape interiors).
Frost is common especially
over the higher altitude parts
of South Africa.
The Cape interior regions
receive significant amounts
of rainfall during autumn
from cloud bands that occur to the west of the most
well-pronounced regions of
subsidence.
Cold front systems bring
rain to the south-western
Cape and the Cape south
coast. On occasion this cold
front intrudes northwards
and brings “cold snaps”,
and in extreme cases causes
snowfall to occur over the
Free State and the Highveld
regions of Gauteng and
Mpumalanga.
Spring
(September-OctoberNovember)
Spring is characterised
by the onset of rainfall
over the interior regions
of South Africa, with the
first of the significant falls
of rain typically occurring
over KwaZulu-Natal before
spreading deeper into the
interior.
A weather system that may
bring snow and heavy falls
of rain to the South African
interior during spring, is the
cut-off low. These weather
systems may occur at any
time of the year, but are most
common during spring and
autumn.
El Niño refers to the large-scale phenomenon associated with a strong warming in sea-surface temperatures across the central and east-central equatorial
Pacific Ocean. An El Niño event occurs every three to seven years. La Niña, on the other hand, refers to the periodic cooling of sea-surface temperatures in the
central and east-central equatorial Pacific Ocean.
1
6
The future climate of South Africa
South Africa’s Second National Communication describes the likelihood of increased temperature as being
greater towards the interior, and less in coastal areas. Assuming a moderate to high growth in greenhouse gas
concentrations by mid century, the coast is likely to warm around 1°C and the interior around 3°C. By 2100,
under the same set of assumptions around greenhouse gas emissions, the temperature increase is likely to
approach 3°C on the coast, and 5°C in the northern interior. By mid century, projected increased temperatures
appear similar for all assumptions around South Africa’s future greenhouse gas emissions.
There are significant geographical differences to future projected rainfall changes. Drier conditions are
predicted for the south west of the country in both seasons. Rainfall intensity is likely to increase, but to not
necessarily imply an increase in total rainfall, with important implications for impacts (see sections to follow).
Greater evaporation rates are likely to increase drought incidence and intensity (as defined by the response of
available soil moisture and available free water), possibly even in regions where total rainfall increases.
Regional scenarios of climate change over
the north-eastern region of South Africa
Global circulation models (GCMs) have become the
primary tools for the projection of climate change.
These mathematical models, based on the laws of
physics, are used to estimate the three-dimensional
changes in the structure of the atmosphere that may
take place in response to enhanced anthropogenic
forcing. Projections of future climate change by GCMs
may provide insight into potential broad-scale changes
in the atmosphere and ocean, such as shifts in the major
circulation zones and the magnitude of sea-level rise.
The term projection refers to estimates of
future climate possibilities.
However, because these models are
computationally expensive, they
can only be integrated at relatively
coarse horizontal resolutions –
namely at typical grid spacings
of about 2° - 3° in both longitude
and latitude. At these resolutions,
the regional details of climate
(such as the characteristics
of orographic precipitation and
thunderstorms) and climate change
cannot be sufficiently described.
Additional uncertainties surrounding climate
projections include the role of natural variability, the
future rate of increase of greenhouse gas concentrations
and the systematic simulation errors associated with
each individual GCM. To improve the detail of the GCM
projections, the methods of statistical and dynamical
downscaling are used to obtain high-resolution
projections of climate change over areas of interest.
Such downscaled scenarios of climate change over the
north-eastern region of South Africa are described in
this section. The current climate variable is compared
with the average future (projected) conditions — first
spatially and then graphically over a monthly time
series. Seasonal changes in precipitation variables (total
rainfall, the duration of dry spells, and the frequency of
rain days) are presented spatially and a graph showing
the envelope of change1 is presented in order to
demonstrate the range of future possibilities.
Future temperature was obtained from two dynamic
regional climate models (PRECIS and MM5) and
future precipitation variables were obtained from ten
statistically downscaled GCMs (IPSL_CM4, GFDL_
CM2_0,
CCMA_CGCM3_1,
MRI_CGCM2_3_2A,
CSIR0_MK3_0, CSIR0_MK3_5, MPI_ECHAM5, GISS_
MODEL_E_R, CNRM_CM3, MIUB_ECHO_G), made
available by the Climate System Analysis Group at the
University of Cape Town.
An envelope of models is used to project different (but equally plausible)
climate futures
1
7
CLIMATE CHANGE PROJECTIONS
Ch an ge s in Te m p e r a t ure
1.Maximum temperature
Increase in annual maximum day temperature of approximately 0.5°C.
A decrease of between 0.27°C and 1.26°C is possible for April, May, June, and July.
Maximum
Present Conditions
8
Future Conditions
Present Conditions
Spring
(SeptemberOctoberNovember)
shows the
greatest change
in mean day
temperature...
Future Conditions
2.Mean temperature
Increase in annual mean day temperature of between 0°C and 0.89°C.
Spring (September-October-November) shows the greatest change in mean day temperature, with an average
increase of 1.28°C expected over the three months.
9
Changes in Temperature
3.Minimum temperature
Increase of between 0.6°C and 1.16°C in the minimum day temperature for all months of the year, with no regions
experiencing below zero temperatures.
Minimum
Present Conditions
10
Future Conditions
Changes in Rainfall
Present Conditions
Future Conditions
Maximum Future Rainfall
Minimum Future Rainfall
4.Total Annual Rainfall
An increase in total annual rainfall is expected for the whole region, with possible distinct increases along the
escarpment.
11
Cha nges in Rainfall
5. Total Monthly Rainfall
Future annual rainfall is expected to range from 301 mm to 758 mm per annum. The majority of this rainfall is
expected to fall during the summer months (December-January-February).
12
6. Seasonal Change in Rainfall
An extension of the rain season may occur into early spring due to the increase in rainfall predicted for
September-October-November. Autumn and winter are also expected to receive more rainfall and this may have
significant consequences for biological triggers and cropping calendars.
Summer
Autumn
Winter
Spring
13
Cha nges in Rainfall
7. Envelope of Rainfall Change
Rainfall is expected to increase by between 85 and 303 mm per year for the region as a whole. The greatest
increase in rainfall is expected during February, April and September with increases of above 30 mm according
to the upper limit of change predicted from the downscaled models. There are however, a range of possibilities
where rainfall could decrease during some months (refer to the lower limit of change).
14
8.Evaporation
Despite the increase in mean annual rainfall, future evaporation is expected to increase. This means that there less
likely be less water available for use in the future.
Present Conditions
Despite the
increase in
mean annual
rainfall,
future
evaporation
is expected
to increase.
Future Evaporation
15
Dry- spell Duration
9.Annual Dry-spell Duration
The numbers of dry days per year are expected to decrease due to the future increase in mean annual rainfall.
Present Conditions
16
Future Conditions
10. Envelope of change in the number of dry days
The greatest change in the number of dry days is projected for June whereas there is little change expected for
the summer and spring months (September - January).
17
Dry- spell Duration
11. Seasonal change in Dry-spell duration
There is little to no change in the dry-spell duration in spring and summer. For the region in general, the dry-spell
duration is expected to decrease in autumn by between half a day and 3 days and in winter by between 1 and 6.7
days. This corresponds with the increase in rainfall expected during these seasons.
Summer
Winter
18
Autumn
Spring
Frequency of Rainfall Events
12. Annual frequency of rainfall events
The number of rain events is expected to increase. This could infer that the chances of floods may increase.
Present Conditions
Future Conditions
13. Monthly frequency of rainfall events
The majority of rain events are expected to occur in November, December and January, which have the highest
number of days experiencing rainfall.
19
Frequency of Rainfall Events
14. Envelope of change in number of rain days
The number of rain days per month is expected to increase by between 1.036 and 2.188 days. This small change
in the number of rain days per month compared with the increase in rainfall demonstrates that the intensity of rain
events and possibly the severity of rain events may increase. The lower limit of change shows a decrease in the
number of rain days for the majority of the year; this may also be a likely possibility.
20
Summer
Autumn
Winter
Spring
15. Seasonal change in number of rain days
In some areas the numbers of days experiencing rain are the same or lower than current numbers despite the
projected increase in rainfall for those areas, inferring an increase in the intensity of rain events.
21
Sect or specifi c i m p a c t s o f
climate change
This section outlines specific information about the nature
of future impacts across a range of sectors, namely forestry
agriculture, conservation and tourism, health, water resources,
and rural development and urban planning.
FORESTRY
South Africa’s forestry sector is sensitive to climate
change as it is based on the plantation of nonindigenous species (species that are not typical of
South Africa). Land availability, water demand as well
as environmental and socio-economic conditions affect
the vulnerability of the sector to climate change.
site conditions are predictable). Alternative forms of
silviculture, such as mixed species forests, agroforestry,
and the use of adapted indigenous tree species
could yield more resilient forests in areas where site
development uncertainty is high or water use restrictions
prohibit the use of fast-growing plantation species.
Commercial forestry plantations occupy approximately
1.1% of South Africa, with Mpumalanga housing one of
the largest forestry plantation areas. The three major
species grown in commercial plantations are pines,
eucalypts and wattle.
Climate change is likely to exacerbate existing
declines in river runoff due to water use by commercial
plantations, agriculture, woody exotic invasive species,
and urban and industrial land use. Consequently, an
integrated ecosystem management approach, or
‘multiple benefits’ approach must be considered. Such
an approach should be able to provide an optimal
portfolio of land-use forms in an area which could
integrate production, environmental, climate change
adaptive, sequestration and mitigation objectives and
socio-economic aspects for sustainable landscape
management.
Given the projected increases in temperature and
changes in rainfall, certain areas may not be climatically
suitable for the production of a specific species (as
different species have different climatic constraints,
such as mean rainfall and mean temperature) and some
areas may no longer be suitable for commercial forestry.
However, areas that are at present not climatically
suitable for forestry may become suitable in the future.
Tree breeding can produce trees that match future
projected site conditions (in regions where future
22
Given the lengthy rotation of commercially grown forest
species (7 – 30 years), it is crucial that decisions on the
most effective climate change adaptation strategies are
developed and implemented in a timely manner.
AG R I C UL T UR E
Projected increasing temperatures and changes in
rainfall timing, amount and frequency, have critical
implications for the full range of agricultural systems
in South Africa. Agricultural production is generally
responsive to current climate variability. Degradation
of South Africa’s natural agricultural capital may be
exacerbated by climate change (as well as existing
challenges to the agricultural sector).
Emerging
agriculture is likely to be particularly adversely affected,
due to, in many cases, lower adaptive capacity.
The agricultural sector is likely to feel the direct and
indirect impacts of projected climatic changes in a
number of ways:
• Crop productivity may decrease for even small
increases in temperature, (despite benefits obtained
through increased photosynthetic activity as a result
of increased carbon dioxide).
• Predicted higher temperatures may negatively
impact organic matter; in an environment where
soil organic matter retention is already affected
by other stressors such as grazing, addition of
fertiliser and manure, burning, and soil cultivation.
• Increased temperatures and resulting evaporation
are likely to increase irrigation demands, in a country
•
•
•
•
where existing water supply and quality difficulties
already provide stress to the irrigated agriculture
sector.
Existing water supply and water quality challenges
already stress irrigated agriculture. Predicted
climate change impacts on water supply and
quality will critically complicate these existing
stresses, increasing existing water competition.
Increasingly exceeding the temperature thresholds
above the thermal comfort zone of livestock, which
could induce behavioural and metabolic changes
including altering growth rate, reproduction and
ultimately mortality.
Conversely, increases in temperature during the
winter months could reduce the cold stress
experienced by livestock, and warmer weather
could reduce the energy requirements of feeding
and the housing of animals in heated facilities.
Higher temperatures may favour the spread of
significant pests and pathogens to a range of
agricultural systems. For example, a number of
pathogens of concern to the highly valuable
vegetable and fruit industries prefer higher
temperatures.
Summary of the possible
impacts of climate change
on livestock production
systems
Socio-economic/livelihood impacts
• Changes in incomes derived from
livestock production
• Shifts in land use (including
consequences of land reform)
• Overall changes in food production
and security
Indirect livestock impacts through
ecological impacts
• Increased frequency of disturbances,
such as wild fires
• Changes in biodiversity and vegetation
structure
• Changes in soil nutrients
Direct livestock impacts
• Changes in forage quality and quantity
• Changes in the length of the growing season
• Changes in water quality and quantity
• Reduction in livestock productivity
• Behavioural and metabolic changes
• Increased prevalence of ‘new animal diseases’
23
C o nser va t i on a n d To u ris m
South Africa is worldrenowned for exceptionally
high levels of biodiversity.
Among areas of comparable
size - 2% of the world’s land
area - Southern Africa has
the richest flora in the world,
being home to 10% of all
known plant species and
7% of all reptiles, birds, and
mammals.
Conservation
agencies,
particularly
state-run
conservation areas have a mandate to maintain
biodiversity, and through several Acts are obliged to
meet a range of biodiversity targets. It is in this sector
that the heaviest impacts may lie, as the projected
changes carry a heavy responsibility of conserving the
country’s biodiversity in spite of such impacts. The
implications are far-reaching as changes in plant and
24
animal ranges and biome shifts, as well as the alteration
of ecosystem functioning, mean that these organisations
have the duty to use the climate change predictions and
plan ahead so as to continue to meet their biodiversity
conservation responsibility. The organisations need
to ensure that areas of future biodiversity hotspots
are incorporated as conservation areas at this stage
to ensure their continued conservation. This involves
expanding or changing the configuration of protected
areas, often at great expense ; and/or working with
land owners to conserve biodiversity outside formal
protected areas.
Several other activities in this sector run as commercial
or semi-commercial concerns, the most common
being hunting and eco-tourism. These sectors will be
affected by changes in the biodiversity of the area and
will also be impacted by factors that will negatively
impact the tourist experience, such as increased bush
encroachment, altered animal and plant assemblages
and an increase in discomfort levels caused by
increased temperatures. Management actions certainly
will be able to mitigate against certain of these impacts,
but such mitigation actions will no doubt result in an
increased cost to this sector.
Impacts on ecosystems and biodiversity:
•
•
•
•
Globally, 20-30% of species assessed to date may
become extinct as temperatures increase.
In South Africa, several studies indicate that
the majority of endemic species are likely to show
contractions of geographic range, and that up to
30% of endemic species may be at increasingly high
risk of extinction. One specific study shows a
significant range contraction in almost 80% of the
179 species (including 34 bird, 19 mammal, 50
reptile, 15 butterfly and 57 other invertebrate
species) included in the research. The majority of
these range contractions are expected to occur
in the eastern half of South Africa.
Rising atmospheric CO2 levels may be increasing
the cover of shrubs and trees in Grassland and
Savanna biomes, with mixed effects on biodiversity,
and possible positive implications for carbon
sequestration. For example, Colophospermum
mopane woodlands are known to have a low density
of herbivores due to the low grass biomass and
the high density of the trees, which increases
ungulates’ susceptibility to predation. An expansion
of C. mopane will have strong negative impacts on
the tourism experience through potentially reduced
numbers of game within these patches, resulting in
reduced game viewing opportunities.
Changes in the timing of plant and animal life
cycles will impact conservation areas as this may in
future change the species assemblages of these
areas. Due to the changing climate a disconnect
may occur between the timing of behaviour and the
available resources on which the behaviour depends.
The individual impacts of these changes will
likely scale up to have several ecosystem responses,
including the range and distribution shifts of
species and communities, the composition of and
interactions within communities, and the structure
and dynamics of ecosystems.
•
•
•
Additional stresses to biodiversity that will interact
with climate change include wildfire frequency
(which has already shown climate change-related
increases in the Western Cape region) and alien
invasive species, which are likely to be advantaged
by changed climates and increased atmospheric
carbon dioxide concentrations.
The combined effects of these and stresses relating
to land use and fragmentation of habitats will further
increase the vulnerability of biodiversity to climate
change.
The ability of ecosystems to adapt naturally to
new conditions may be exceeded in the late century
due to a combination of climate change, fires, floods
and droughts as well as other global change drivers
such as land-cover change and pollution.
Source: Climate Change, CSIR, 2010
25
U r b a n pl an n i n g a nd rura l d evelo p m ent
“Climate
change is
a serious
threat to
development”
As a consequence of the South Africa’s
unique history, the former Bantustan
areas are generally characterised by
densely populated and highly dispersed
settle-ments with high concentrations of
poverty and limited access to employment,
livelihoods and socio-economic services.
Such inequalities increase people’s vulnerability to the
physical impacts of climate change. For example, the
risk of water-borne diseases due to changes in rainfall
patterns and temperature increases expected with
climate change will be increased in households without
proper access to potable water.
The resources spent in the community to deal with
patients affected by water-borne diseases, for example,
may divert funding away from capital investments
necessary for economic development. In addition,
these communities are dependent on a range of natural
resources for firewood, wild fruits and herbs, medicines
and craft materials, which contribute to their livelihoods.
These resources are already under increasing pressure
and future use combined with changes in production
as a result of climate change may lead to unsustainable
levels of harvesting.
People who reside in informal settlements have been
identified as one of the most vulnerable populations
globally. Informal settlements are often vulnerable
to water-related disasters such as floods and severe
storms, particularly in cases where the communities
are located on flood plains and there is an absence of
proper water infrastructure.
The impact of climate change on specific
sector activities reflects on the economic
sustainability of the municipality
AGRICULTURE
COMMERCE
MINING
LOCAL
ECONOMIC
DEVELOPMENT
FORESTRY
MANUFACTURING
TOURISM
26
Key questions for local municipalities are:
• What impact will climate change have on the
capacity of municipalities to deliver the services
and utilities that the communities they serve need
and expect?
• What are the current and potential impacts of
climate change on informal settlements located in
the local and district municipalities?
• Are municipal plans for economic development
viable in light of the projected changes in climate?
• What effect will extreme events such as droughts
and floods have on the life cycle of infrastructure
where design is currently based on historical
observations?
• What are the consequences of climate change for
the segment of the population currently living below
RDP standards?
Planning decisions on the local and district levels are
supported by Integrated Development Plans (IDP) which
serve as a framework that informs decisions related to
development in a specific area. The concentration of
activities in one sector limits flexibility to switch to other
sectors that are less sensitive to changes in climate,
such as manufacturing and services. It is significant
that agriculture has been identified as the sector
through which a number of the local municipalities in
Mpumalanga and Limpopo decided to focus future
economic development. The predicted changes in
climate, however, could force the shutdown or relocation
of agricultural business in vulnerable areas, which would
have an enormous effect on economic development of
the area as well as on a community which is made up
largely of unskilled labour.
Human
HEALTH
The
incidence of
malaria could increase
with the expansion of
habitats suitable
for mosquitoes
that transmit
malaria
The health of humans is closely linked with their
surrounding environment. Climate change is expected
to affect the fundamental requirements for a healthy
society: clean air, safe drinking water, sufficient food
resources and secure shelter.
Documented direct health effects of climate change
include extreme events such as floods, droughts and
thermal stress (such as strokes, rashes and dehydration).
Indirect health effects of climate change include the
spread and/or increase of the incidence of infectious
and vector-borne diseases, water-borne pathogens,
water quality, air quality, and food availability and quality.
Increasing temperatures may favour the geographical
expansion of the borders of malaria and cholera. This
is supported by several predictive models, as well as
surveillance and direct observations in many quarters.
The actual health impacts that will occur in the future are
strongly dependent on local environmental conditions,
the socio-economic status of the area, and the range of
adaptation measures put in place to reduce the threats.
Another important factor that may increase the threat
to human health is population displacements due to
extreme weather events and sea-level rise (affected
populations are termed climate change refugees) as
well as climate-related conflicts.
The vulnerability and capacity of a community or
communities to adapt to health threats depend on
their general health status, for example the prevalence
of cardiovascular diseases, HIV/Aids and TB, chronic
non-communicable diseases, malnutrition or stunting
especially in young children; level of education and
awareness; economic status; general demographic
profile (for example gender and age profiles); migration
patterns and levels, level of infrastructure development
and maintenance; access to and availability of skilled
medical personnel and facilities, and population
density.
One major difficulty in quantifying the impacts of climate
change on human health is the lack of long-term health
data for a specific area or areas that can be linked to
changes in the climate system. The links between
human health, the natural environment and systems
operating at different time and spatial scales contribute
to the complexity associated with distinguishing the
health effects of climate change from other global
environmental changes. In addition, climate change is
one of several factors that can affect human health.
Direct and indirect health effects of climate change
Regional climate changes
• Increased temperatures
• Changes in rainfall regimes
• Heat waves
• Extreme weather events
Modulating influences
Contamination paths
Transmission dynamics
Changes in agro-ecosystems and
hydrology
Socioeconomic and demographic
disruption
Direct health effects
• Temperature-related illness and death
• Extreme weather-related health effects
Indirect health effects
• Air quality and pollution
• Changes in distribution and potency of allergens and mycotoxins
• Water- and food-borne diseases
• Vector- and rodent-borne diseases
• Effects of food and water shortages
• Mental, nutritional, infectious diseases
Source: Redrawn from World Health Organization, Online at: WHO Climate Influences
27
WATER RESOURCES
The close interconnectedness between climate and the
hydrological cycle means that water resources will be
impacted by climate change. This will place increased
pressure on water resources, ultimately threatening the
sustainability of future availability.
Currently, 98% of South Africa’s surface water yield,
as well as 41% of the annual usable potential of
groundwater have been allocated to use.
Water resources are directly impacted by current
climate variability and it is expected that climate change
could impact resources significantly in the future. It
is estimated that an 8% reduction in rainfall results in
a 31% reduction in groundwater recharge and a 30%
reduction in surface runoff. In addition, climate change
is expected to exacerbate the poor state of major rivers
in South Africa.
The major risks to water resources include:
• decreased availability of water in rivers as a result
of net effect of increased temperatures and
increased evaporation, coupled with shifts in the
timing and amounts of rainfall;
• changes in the concentration and timing of high and
low flows due to changes in rainfall;
• increased incidence of floods as the incidence of
very heavy rain events increases; and
• increased risk of water pollution and decreased
water quality linked to erosion and high rainfall
events, which increase the presence of sediments,
nutrients, dissolved organic carbon, pathogens and
pesticides, and increased water temperature, which
promotes algal blooms.
The majority of catchments in South Africa use more
water than is available on an annual basis.
28
The impacts
of climate
change on water
resources are likely
to be exacerbated
by changes in landuse and poor land-use
management.
Currently,
98% of South
Africa’s surface
water yield, as well
as 41% of the annual
usable potential
of groundwater
are allocated
to use.
The political and practical imperative to improve access
to water for both rural and urban poor will create further
stress on the hydrological system as a result of the
increased human demand.
Despite the influence of climate change, it is predicted
that by 2025 South Africa will be using up the majority
of its surface water resources. This is as the sustainability
of water resources and ultimately the availability of
water in the future will depend on both supply and
demand pressures. Supply pressures include climate
change and environmental degradation, where for
example pollution reduces the amount of clean water
available for use. Demand pressures include population
growth and density which lead to increased demand
for domestic, industrial and agricultural water use, as
well as knock-on effects of the management of water
usage.
Res p onses t o t he imp a c ts of c l i ma te c ha nge
Adaptation refers to the “adjustments in
natural or human systems in response to
actual or expected climatic stimuli or their
effects, which moderates harm or exploits
beneficial opportunities” (IPCC 2007).
There are two main types of adaptation:
• Anticipatory Adaptation is adaptation that takes
place before impacts of climate change are
observed. Also referred to as proactive adaptation.
• Reactive Adaptation is adaptation that takes place
after impacts of climate change have been
observed.
Climate change adaptation is a means of responding
to the impacts of climate change. It aims to moderate
the impacts as well as to take advantage of new
opportunities or to cope with the consequences of new
conditions. The capacity to adapt is dependent on a
region’s socio-economic and environmental situation as
well as the availability of information and technology.
Mitigation refers to the measures taken to reduce the
emission of greenhouse gases and to enhance sinks of
greenhouse gases, such as aforestation measures.
Vulnerability refers to the “degree to which a system is
susceptible to, or unable to cope with, adverse effects
of climate change, including climate variability and
extremes. Vulnerability is a function of the character,
magnitude, and rate of climate variation to which
a system is exposed, its sensitivity, and its adaptive
capacity” (IPCC 2007).
Climate change will not be felt in isolation of other
stressors. In many sectors, adaptive strategies appear
to be under way, although most are centred on coping
with short-term risk. Few clear strategies, at present,
consider long-term adaptive planning. Adaptive
possibilities are considered per selected sector in the
table below.
Adaptation strategies that are effective and/or
suitable across sectors need to be prioritised; this is
termed a Multi-Sectoral Approach. This would involve
simultaneously addressing a range of objectives,
which include climate change adaptation, carbon
sequestration, mitigation of greenhouse gas emissions,
biodiversity conservation and sustainable livelihoods.
Many existing strategies and policies may be merely
supported or amended to improve resilience in the face
of climate change implications for key sectors.
Several new adaptation options are emerging. Various
institutions are emerging as key for enhanced facilitation
of adaptation to climate variability and climate change.
Such institutions include those disaster risk reduction
and early warning oriented institutions prompted by
the Disaster Management Act. Further attention and
support needs to be provided for the role of effective
planning and climate change particularly at local
levels (e.g. municipalities). Lastly, critical priority areas
include finding ways to expand the business sector’s
engagement in adaptation as well as mitigation and
improving understanding of the role of behaviour
change and climate change adaptation.
Source: IPCC, Fourth Assessment
29
Selected examples of adaptation
measures by sector
S ec t or
A dapt at i o n o p t i o ns
Agriculture
• Shifts in crop calendars and the switching of crops.
• Soil, water and nutrient conservation practices.
• Improved land management, such as erosion control. Switch to more resilient
livestock production systems.
• Switch to more resilient livestock production systems.
It is important to note that climate change impacts may make agriculture
increasingly unfeasible as a livelihood strategy for the rural poor. This must be
taken into account in developing policy and strategy for the emerging agriculture sector.
Forestry
• Fire frequency and intensity is likely to increase due to the increase in dry
spells and temperature. The commercial forestry industry may respond
through the combination of pro-active fuel reduction and re-active fire
fighting, but this will certainly increase production costs.
• The mitigation potential of the forest-wood sector in South Africa is widely
undeveloped, and can be increased by carbon sequestration3 in forests
on previously not-afforested areas, carbon sequestration in wood products,
an increased forest biomass use for energy production, and also by a further
reduction of the carbon footprint of forest operations and timber transport.
• A ‘multiple benefits’ approach must be considered. Such an approach should
be able to provide an optimal portfolio of land-use forms in an area which
could integrate production, environmental, climate change adaptive,
sequestration and mitigation objectives and socio-economic aspects for
sustainable landscape management.
• Alternative forms of silviculture, such as mixed species forests, agroforestry,
and the use of adapted indigenous tree species could yield more resilient
forests in areas where site development uncertainty is high or water use
restrictions prohibit use of fast growing plantation species.
Conservation and
Tourism
• Climate change projections need to feed into sector long-term management
plans.
• Building partnerships to enable effective management of areas not under
formal protection, and investment in the expansion of key protected areas.
• Increasing awareness of the value of using biodiversity in assisting societal
adaptation to the adverse impacts of climate change.
3
30
the natural removal of carbon dioxide from the atmosphere by the soil and plants
Health
• Adaptations are urgently needed that will guarantee adequate and reasonable
healthcare delivery services – addressing all aspects of South Africa’s complex
health burden, not merely the impacts of climate change.
• Improved housing and infrastructure in both rural and urban communities
should particularly aim to reduce risk of water-borne disease, exposure to
indoor pollution, and support of existing public health infrastructure
initiatives.
• Efficient and effective meteorological, water and air quality monitoring
services are an essential component of an early-warning adaptive and
disease mitigation strategy.
• Primary health activities for disease prevention as well as the collection and dissemination of health information.
Municipality and
Planning
Although national and sectoral policies and plans guide and direct climate
change responses, real, on the ground climate change mitigation and adaptation will be pioneered and driven by local municipalities.
• Describe and prioritise what adaptation interventions must be initiated,
who should be driving these interventions and how implementation will be
monitored.
• Incorporate climate information into all municipal plans
• Comply with obligations as per the Disaster Management Act, veld and
forest fire management.
• Avoid building in floodline areas; and investigate possible revisions to flood
line estimations.
• Investigate and prioritize existing and planned strategies and actions that
indirectly support climate change adaptation.
• Design and maintenance of stormwater infrastructure.
• Demand-side water management
• Municipal developments to include water and energy savings
• Local Economic Development strategies that incorporate climate realities
Water
• Sector-specific strategic adaptation to longer term climate changes include
enhanced water storage capacity and increased water supply for the water
sector, as well as improved catchment management (e.g. removal of invasive
alien species). The Second National Communication states, significantly, that
“The Water Act, the water management institutions that it creates, and the
ongoing commitment to the delivery of basic water supply and sanitation
infrastructure all have high relevance for adaptation”
• Expanded rainwater harvesting, water storage and conservation techniques,
water reuse, desalination, water-use and irrigation efficiency.
• Water conservation (WC) and water demand management (WDM) strategies
are becoming a fundamental part of adaptation at the household level.
• Improved understanding of South Africa’s water balance, water demand
management, as well as strengthening engineering and community based
capacity to respond to new water supply challenges.
• DWAF (2008) states that priority needs to be given to developing robust
strategies to ensure that demand matches supply, even where water
availability is reduced.
• Institutions need to encourage appropriate technology that range from
large-scale water provision for economic growth through to micro-level
processes to provide water to rural development.
31
Furthe r Re ading
IPCC (2001) Climate Change 2001: Synthesis Report. A contribution of Working Groups I, II and III to the Third
Assessment Report of the Intergovernmental Panel on Climate Change. UK: Cambridge University Press.
IPCC (2007) Climate change 2007: Synthesis Report, Contribution of Working Groups I, II and III to the Fourth
Assessment Report of the Intergovernmental Panel on Climate Change. UK: Cambridge University Press.
Steffen, W., Sanderson, A., Tyson, P.D., Jäger, J., Matson, P.A., Moore, B., Oldfield, F., Richardson, K., Schellnhuber,
H.J., Turner, B.L. and Wasson, R.J., 2001: Global Change and the Earth System: A Planet Under Pressure, IGBP
Science Series 4, Springer-Verlag, New York.
U s eful Clim at e C hange Resources
The Kruger to Canyons Project Website
www.sarva.org.za/k2c
The South African Risk and Vulnerability Atlas
www.sarva.org.za
Climate System Analysis Group
www.csag.uct.ac.za
Intergovernmental Panel on Climate Change
www.ipcc.ch
United Nations Framework Convention on Climate Change
www.unfcc.int
Oxfam International
http://www.oxfam.org/climatechange
United Nations Environmental Programme
www.unep.org/climatechange
Greenpeace
www.greenpeace.org/~climate
WWF
www.panda.org/climate
Glossary of Climate Change Terms
http://nsidc.org/arcticmet/glossary/climate_change.html
32
Website: www.sarva.org.za/k2c
Contact:
Claire Davis: [email protected]
Climate Change Research Group,
Natural Resources and the
Environment, CSIR
Nikki Stevens: [email protected]
Climate Change Research Group,
Natural Resources and the
Environment, CSIR

GENERAL Climate Change Handbook for NE South Africa (Gauteng

Transcription

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