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Impacts, Vulnerability and Adaptation in Key South African Sectors

An input into the Long Term Mitigation Scenarios process

Prepared for: Department of Environment Affairs and Tourism

South Africa

Authors:

G Midgley, R Chapman, P Mukheibir, M Tadross, B Hewitson, S Wand, R Schulze, T Lumsden, M Horan, M Warburton, B Kgope, B Mantlana,

A Knowles, A Abayomi, G Ziervogel, R Cullis and A Theron

LTMS input Report 5 (Summary report)

October 2007

ENERGY RESEARCH CENTRE

University of Cape Town

Assessing impacts, vulnerability and adaptation in key South African sectors

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Ten free-standing chapters make up this report, and this Executive Summary and supporting Synthesis Report serve to draw together the main findings in both an abbreviated and an extended and illustrated format that focuses on main findings, but also adds a level of detail for the purpose of communicating the key results, and the uncertainties associated with them, for the benefit of a policy maker. The chapters that make up this report are compiled as separate documents as follows. These are generally reviews of the literature available, but in some cases comprise new work that has been carried out to provide information in an area that is lacking an assessment.

1 Summary (incorporating Executive Summary and Synthesis

Report)

22 pages

2 Introduction 4 pages

3 Adaptation concepts 9 pages

4 Retrospective analysis of climate change 19 pages

5 Climate science and new scenarios 16 pages

6 Water and Hydrology 77 pages

7 Agriculture

A) Winter rainfall

B) Summer rainfall

57 pages

45 pages

8 Forestry, Environment, Biodiversity and Ecosystem services 36 pages

9 Human Health 15 pages

10 Rural Livelihoods 14 pages

11 The Urban Environment 25 pages

The following citation should be used for this report:

Midgley GF, Chapman RA, Mukheibir P, Tadross M, Hewitson B, Wand S,

Schulze RE, Lumsden T, Horan M, Warburton M, Kgope B, Mantlana B,

Knowles A, Abayomi A, Ziervogel G, Cullis R and Theron A. (2007)

Impacts, vulnerability and adaptation in key South African sectors: An input

into the Long Term Mitigation Scenarios process, LTMS Input Report 5,

Energy Research Centre, Cape Town

The suite of reports that make up the Long Term Mitigation Scenario study include the

following:

A Long Term Mitigation Scenarios for South Africa

B Technical Summary

C Technical Report

C.1 Technical Appendix

D Process Report

The study was supported by the following inputs:

LTMS Input Report 1: Energy emissions

LTMS Input Report 2: Non-energy emissions: Agriculture, Forestry and Waste

LTMS Input Report 3: Non-energy emissions: Industrial Processes

LTMS Input Report 4: Economy-wide modeling

LTMS Input Report 5: Impacts, vulnerability and adaptation in key South African sectors


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PrefacePrefacePrefacePreface

Risk and uncertainty statement

Much of the impacts assessment work reviewed in this report does not deviate far from the

recently published IPCC estimate that the most likely range for global temperature response to

CO2 doubling is from 2 to 4.5ºC, with the median response (the “climate sensitivity”) not far

below 3ºC. The approach of making assessments guided by the median climate sensitivity, as we

have done here, may appear to be logical and justifiable, but it is important to point out that this

approach significantly underestimates the risks of larger impacts due to the uncertainty inherent

in the climate sensitivity. We have found that, in general, the apparently less likely scenarios of

climate change are poorly explored in the impacts literature, and thus that this high risk region

remains largely unquantified.

The IPCC fourth Assessment Report provides the most recent and comprehensive estimate of the

likelihood that human activities are causing currently observed temperature and climate change.

Their essential conclusions are that:

“Warming of the climate system is unequivocal, as is now evident from observations of increases

in global average air and ocean temperatures, widespread melting of snow and ice, and rising

global mean sea level”

and that

“Most of the observed increase in globally averaged temperatures since the mid-20th century is

very likely due to the observed increase in anthropogenic greenhouse gas concentrations”.

This level of certainty translates to a >90% probability (9/10 chance) that human activities are

responsible for the global warming observed since the 1950’s.

This finding itself provides some level of support for a policy response, but the urgency of the

response needed is better judged on what the projected warming is likely to be, given a range of

societal choices regarding fossil fuel use, land cover change and then a range of other less critical

decisions. It is these projections that depend on the estimate of climate sensitivity. A truly risk-

averse strategy should consider fully the impacts of higher climate sensitivities, especially

because certain key feedbacks to climate from the biosphere are not yet incorporated in climate

models. But we find that these are lacking in the literature, thus providing us with published

material that yields what may be conservative estimates of impacts.


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Contents

1.1 EXECUTIVE SUMMARY 1

1.2 SYNTHESIS REPORT 6 1.2.1 Observed climate trends during modern human history 6 1.2.2 Climate science and new scenarios 7 1.2.3 Adaptation to climate change 10 1.2.4 Impact on water resources and hydrology 11 1.2.5 Impact on agriculture 12 1.2.6 Impact on forestry 14 1.2.7 Impact on terrestrial ecosystems and biodiversity 15 1.2.8 Impact on health 16 1.2.9 Impact on rural livelihoods 17 1.2.10 Impact on the urban environment 18 1.2.11 Indicative costs of climate change impacts 18


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1.1.1.1. SummarySummarySummarySummary

1.11.11.11.1 EXECUTIVE EXECUTIVE EXECUTIVE EXECUTIVE SUMMARYSUMMARYSUMMARYSUMMARY

The IPCC Fourth Assessment Report (AR4) concluded in 2007 that there is a greater than 90% chance that human

activities such as fossil fuel burning and deforestation are changing the earth’s climate system. The evidence for

climate change is clear and unambiguous. Changes in climate have already been observed that are generally

consistent with model projections, and are likely to continue to occur for many decades to come even if mitigation

efforts are successful, because of lags and inertia in the global biosphere response. The global projections for a range

of assumptions of climate sensitivity and societal development scenarios are for between a 1.2º and 5.8ºC rise in

global temperature by 2100. The range of climate change projected clearly remains broad even at the global level, and

the potential impacts remain uncertain to a greater or lesser degree depending on the affected sector in question.

However, it is possible to assess sensitivities, vulnerabilities and risk associated with climate change at the national

and sub-national levels. It is also possible to explore potential adaptation options and estimate their possible costs in

relation to the costs of inaction.

Modelling studies project a range of possible scenarios and impacts in South Africa, given the uncertainties in global

greenhouse gas emissions scenarios and in the response of the climate system. Some of these projected impacts are

alarming and of immediate societal relevance – for example, a projected change in available water supply in South

Africa would have major implications in most sectors of the economy, but especially for urban and agricultural

demands. The set of studies presented here reviews currently available information on observed climate trends,

projected changes and the vulnerability to climate change across an array of key sectors that are known to show

sensitivity to climatic drivers. Where possible, adaptation responses have also been reviewed per sector, and the costs

of adaptation and damage costs due to a lack of action have been extracted – although examples of this level of work

are currently very few. The projected impacts of anthropogenic climate change in South Africa provide an important

motivation for the Long Term Mitigation Scenario project (LTMS). The main findings are summarised as follows:

▪ Climate observations and trends: Analysis of climates during the last 10 000 years, at least, indicate that the

current levels of temperature in this region have seldom, if ever, been significantly exceeded. Extended dry spells in

various regions of South Africa, on the other hand, have induced severe drought conditions in living memory and

recorded history that have had major disruptive effects on society, prior to the onset of anthropogenic climate

change.

▪ Changes in regional climates based on records from several thousand weather stations are unequivocal and are very

likely to be at least partly attributable to anthropogenic climate change. Air temperatures over the past thirty years

have increased and statistically significant trends of increased maximum temperatures have been recorded for the

western and southern half of the country, and the north-west region. There are fewer frost days, particularly on the

inland plateau. No strong trends have been detected in southern African rainfall amounts over the last 100 years of

record, but there is weak evidence of drying in the north-west, and a wetting in the north-east since the 1950s.

Significant increases in the intensity of extreme rainfall events have been identified over more than two thirds of

the country, and are broadly consistent with climate change projections.

▪ Projected climate scenarios: Scenarios of regional climate change remain uncertain, particularly with regard to

rainfall projections. International scientific consensus even on the sign of projected rainfall change in southern Africa

has not been achieved. Regional downscaling approaches may reduce this uncertainty somewhat, but it is important

to stress the current wide range of possible rainfall scenarios, especially in summer rainfall region. Projections of

temperature can be made with a far higher level of confidence than those of rainfall.

▪ Air temperature is virtually certain to continue to increase by between ~1°C and 3°C across the country over the next

three to five decades at least, with the greatest increases towards the interior, and strongest trends in the daily


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minimum. Regional rainfall scenarios project a general drying in most seasons in the SW parts of the western Cape,

and between 5 and 30% reductions during autumn and winter months. In summer and autumn the northern and

eastern regions of the country are likely to become wetter, especially over regions of steep topography around the

escarpment. This projection, based on developments in downscaling results to regional level, does not concur fully

with previously proposed scenarios that were biased towards drying projections. The projected changes in the

intensity and frequency of precipitation events remain uncertain.

▪ Hydrology: A general increase of evapotranspiration by ~ 5 – 15%, projected throughout the region by ~2050,

threatens sustainable water resources directly. South Africa is projected to have a higher relative irrigation water

demand by ~2050. Indirect implications through reduced soil moisture levels could impact runoff generating

mechanisms and dryland agriculture quite markedly, although all those processes will occur in interplay with as yet

uncertain rainfall changes.

▪ The annual number of stormflow events is projected to decrease by ~2050 over most of the country, including some

of the most crucial source regions of streamflows in southern Africa such as the Lesotho highlands. Future increases

in stormflow events per year are simulated over much of the Northern Cape (where few stormflow events currently

occur), as well as in the Northwest of the country. Greater rates of soil erosion are projected by ~2050 over much of

the interior in median and especially in wet years. Much of South Africa is projected to have more variable

streamflows despite higher predicted flows overall. However, parts of the Western Cape are projected to have

considerably lower variability relative to the present, and lower overall predicted streamflows.

▪ Agriculture: Both summer and winter rainfall regions face challenges to agricultural production by ~2050. Winter

rainfall agriculture faces imminent significant threats particularly due to projected increasing water shortages,

resulting in greater competition with urban use of water, and lower yields and greater yield variability in both irrigated

and rain-fed crops. Additional heat stress will reduce the productivity of perennial and annual crops, especially chill

unit-dependent deciduous fruit, and livestock.

▪ Net water requirements for crops in the summer rainfall region are projected to increase by between 10 and 30%

throughout southern Africa by ~ 2050. Projections for profitability of maize production are sensitive to temperature,

rainfall and CO2 fertilization scenarios. A 2°C temperature increase alone is projected to reduce profits by around

R500/ha across the highveld maize region, but CO2 fertilization may mitigate this loss almost completely.

▪ Many autonomous adaptation options in agriculture exist that are simply enhancements of existing risk management

or production enhancement activities. Where crops are near climate tolerance thresholds, or where multiple stresses

exist (e.g. soil degradation), or where producers’ capacity for autonomous adaptation is exceeded, deliberate

planned measures (i.e. acclimation-type adaptation) will become necessary. The secondary impacts of projected

climate changes on the broader rural and regional economy could be substantial, but have not yet been adequately

quantified.

▪ Forestry: The formal forestry sector faces a wide range of potentially plausible outcomes that are very sensitive to

projected rainfall change. Drought during 1991/92 caused the loss of approximately R450 million to the industry. With

expected temperature increases by ~2050 of 2ºC and a reduction in rainfall of 10%, most forestry species show

reduced viable production area of between 40% and 100%, but an increase of between 50% and 90% in planting

area if rainfall increases by 10% with 2ºC warming.

▪ Biodiversity and ecosystems: Updated climate scenarios and the application of improved modelling techniques

indicate that some key ecosystems may not be as imminently vulnerable (i.e. by ~2050) to climate change impacts as

reported previously. Nonetheless, earlier projections of enhanced extinction risk for several tens of percent of

endemic species remain within the range of possible outcomes, but probably represent an extreme outcome by ~

2050.

▪ Several savanna woodland and grassland ecosystems may store between ~20 and 600% more carbon than currently

stored due to temperature, rainfall and CO2 fertilization effects, but this is likely to depend to a large extent on future

fire regimes. Fire regimes typical of several of South Africa’s dominant ecosystems, such as Fynbos, Grasslands and


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Savanna, are projected to show a greater frequency, and possible increase in mean size with projected regional

climate change, due to the prevalence of higher fire risk conditions for longer periods of time.

▪ Human health: The immediate health impacts of extreme climatic events are well established and documented, but

the impacts of gradual changes in temperature and precipitation are less tangibly measurable. The pattern of

increasing extreme rainfall events and rising temperature favour the geographical expansion of the borders of vector

borne diseases such as malaria. This is supported by several mathematical models as well as surveillance and direct

observations in many quarters. Climate impacts on human health will interact with those on rural livelihoods, in

particular.

▪ Rural livelihoods: The impact of climate variability on assets links directly to the impact on livelihood activities.

Production and income activities are likely to be significantly affected by climate change and increased climate

variability by ~ 2050 at least, particularly in rural areas where changes in rainfall directly affect agriculture and natural

resources that underpin many production and income activities. In South Africa, there is growing evidence of how

changes in rainfall impact on livelihoods by increasing vulnerability of farming systems.

▪ Adapting to climate change at the rural livelihood scale will be a critically important. It is particularly important to focus

on the most vulnerable groups, so that their livelihoods are not eroded by climate events but rather to facilitate

resilience to the expected changes in climate. This requires an integrated approach of both acclimation type and

resilience type adaptation responses that address multiple sectors whilst combining the knowledge of vulnerable

groups together with specialist insights.

▪ Urban environment: Increasing frequency and intensity of extreme precipitation events will result in higher risk of

flooding episodes in urban settings, and drought induced water shortages and fire risk, particularly in the Western

Cape. Enhancement of resilience-type adaptation responses such as disaster management will become increasingly

important to cope with this growing challenge. Whilst more gradual, the potential of sea level rise impacts, especially

when accompanied by high tidal and storm events, are relevant for key coastal areas that are identified as vulnerable

due to high population densities and settlements and infrastructure of all types.

▪ Extreme events such as heat waves are expected to increase in frequency and severity with increased risk of

mortality amongst the elderly and sick, and attendant risk of fire in informal settlements. Acclimation type adaptation

responses to reduce urban heat loads, such as through greening programs, could help in reducing this threat

▪ Adaptation: It seems useful to define two main types of adaptation, namely “resilience-type” adaptation, which

addresses the potentially damaging effects of changing climate extremes on sectors, and “acclimation-type”

responses, which address strategies to cope with the gradual changes in background climate such as slow rates of

warming that may ultimately require new behaviours and practices in human society. Differentiating adaptation

responses into “resilience-type” and “acclimation-type” adaptation responses might allow adaptation strategies,

implementing agencies and financing sources to be more effectively allocated to where needs are most urgent

▪ A number of potential barriers to implementing a adaptation plans include:

Low local (site-based) human capacity to undertake adaptation planning

Limited financial resources and competing priorities

They require a longer time horizon than the typical political and development framework

The absence of a legislative framework


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▪ Estimated costs: The costs of impacts and adaptation options are summarised in the tables below:

Cost of damages i.e. the cost of inaction due to low adaptive capacity and resilience

Impacts Magnitude of costs

Historical:

Flood damage event in the Western Cape due

to extreme rainfall events in2003, 2004, 2005,

2006 and 2007, all caused by cut-off low

presure weather systems

100’s of millions of Rands/event with

accumulated losses ~ R 1 billion

Coastal storm damage along the Durban coast

due to extreme weather event (2007)

Infrastructure costs in greater Durban ~ R100

million

Forestry losses during 1991/92 drought where

followed up with Forestry South Africa

~R 450 million

Forestry losses due to wild fire in Mpumulanga

and KwaZulu Natal

~ 60,000 ha of plantations destroyed worth

~R 500 million

~R 70 million of sawmilling infrastructure and

assets destroyed

Drought impacts on agriculture

1983/84

1991/92

Dryland crops in South Africa declined to about

30% of average production, resulting in a loss

of about R2.2 billion. South African GDP

dropped by about 7%

Total losses to agriculture about R3.5 billion.

DP dropped about 1.8%,

Potential:

Damage to residential property in the Western

Cape due to sea level rise.

10’s -100’s millions of Rand

Deaths due to malaria Death rates have been declining since 1999,

because of spraying and other control

programmes (406 died in 1999, 96 in 2002).

Most deaths occur in Limpopo Province. The

advent of multi-drug resistant malaria is a

serious concern

Deaths due to cholera (the Cholerae vibirio

lives in sea-borne zooplankton, which responds

to phytoplankton blooms in warmer nutrient-

enriched waters. The faecal-oral

contamination route on land is prevalent during

high-rainfall seasons).

82,275 cases of cholera resulted in 171 deaths

in 2001. Costs of treatment and lost

productivity are ~ 10s of millions of Rands.

Increased morbidity due to schistosomiasis 13 deaths in 2004. Infection rates along the

east coast of KwaZulu Natal can be very high,

ranging from 25-90% of school-going children

with significant adverse long-term

consequences for health (infertility and cancer)

and reduced disability-adjusted life years –


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meaning economic productivity decreases.

Increase morbidity due to increasing frequency

of photochemical smogs in Cape Town

10’s of millions of Rands.

Increased temperature on winter rainfall

agriculture: 2-3oC

5-20% fruit crop losses (Varying losses

depending location and crop type.) calculate

rand costs and downstream impacts

Lower rainfall on winter rainfall agriculture over

time.

Marginal areas – 15-60% crop reduction

Productive areas – 5-12% crop reduction

2°C temperature increase reduces profits by

~R500/ha across the highveld maize region

100’s millions of Rand per annum

Table 3: The potential cost of acclimation adaptation

Interventions and adaptations Magnitude of costs

Large-town water provision in the western

Cape as a response to climate change by 2035

100’s of millions of Rands for the Cape Town

Metropolitan area for increasing storage,

reducing leakage, more sophisticated

treatment and reuse of water, increased

efficiencies of use and desalination

Small town water provision in the western

Cape under climate change by 2035.

10’s of millions of Rands per small municipal

area (up to 3.5 times more costly than prior to

climate change impact)

Conserving biodiversity – gene and seed

banking.

100’s of thousands of Rand per annum

Conserving biodiversity – reserves and off-

reserve management.

10’s – 100’s of millions of Rands

Higher-efficiency irrigation 10’s – 100’s of millions of Rands. Farmers are

particularly sensitive to sudden increased costs

because of low profit margins and volatile

weather conditions and market prices

Urban greening to reduce heat island 10’s of millions of Rands

Air conditioning 100’s of millions of Rands, but confounded by

growing shortages of power in South Africa for

the forseeable future

Emissions and air pollution control Billions of Rands, including large-scale

electrification of the public transport system.

100’s of millions in Cape Town, where brown-

haze conditions are likely to worsen

Control of vector borne disease 100’s of millions of Rands

Improved housing and urban drainage systems

to prevent flooding impacts

Billions of Rands. Supply of land for housing is

limited and dwellings tend to be built on low-

lying areas where vulnerability to flooding is

higher.


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1.21.21.21.2 SYNTHESIS REPOSYNTHESIS REPOSYNTHESIS REPOSYNTHESIS REPORTRTRTRT

1.2.1 Observed climate trends during modern human history

A short review of trends and changes in changes in South Africa’s historical climate forms an important backdrop to this

report. These trends are derived from a number of sources that have been carefully quality-controlled. Precipitation trends

have recently been analysed using a data set of approximately 3 000 rainfall stations records across South Africa, a data

set in which high-altitude stations tend to be under-represented. Temperature trends have likewise recently been

analysed using records from 1053 stations which passed quality control, but of these only 23 had a record length of

greater than 50 years of daily temperature data, and only four stations exceeded 75 years record length of daily data. The

network of temperature stations is densest in the KwaZulu-Natal, Gauteng and Western Cape provinces, and sparsest in

the Northern Cape province and Lesotho.

No strong trends have been detected in southern African rainfall amounts over the last 100 years of record, but there is

weak evidence of drying in the north-west, and a wetting in the north-east since the 1950s. Significant increases in the

intensity of extreme rainfall events between 1931–1960 and 1961–1990 have been identified over more than two

thirds of the country. The intensity of 10-year high rainfall events has increased by over 10% over much of the

country, except in parts of the north-east, north-west and the winter rainfall region. These observed increases in

extreme rainfall events are broadly consistent with climate change projections. Air temperatures are increasing and

statistically significant trends of increased maximum temperatures have been recorded for the western and southern half

of the country – the drier region of the country. The north-west region also has become warmer. There are fewer frost

days, particularly in the Highveld and inland plateau areas, but little if any change in the lower altitude, coastal regions,

with an exception along the north-east coast where a warming trend has been detected. Analysis of climates during the

last 10 000 years indicate that the current regional air temperature means have seldom, if ever, been exceeded.

South Africa seems prone to climatic and especially rainfall variability at a range of time scales. After the end of the

Medieval Warm Period (from about 800-1200 AD) the climate became somewhat cooler and drier (called the Little Ice Age

and lasting from about 1300 – 1800 AD). Substantial droughts are known to have occurred, leading to famine and

substantial social disruption of populations from the 1400s through to the early 1800s. There is evidence that the biggest

flood that left physical evidence of its occurrence, took place at some time in the 1400s in the Orange River system. Very

severe droughts in the early 1800s and deep famines caused social dislocations to populations in southern Africa that are

still evident to this day. This naturally-driven variability occurred prior to the current era that seems increasingly subject to

anthropogenic climate change trends.

Wet and dry phases in the southern African region, with associated droughts and floods, continue to this day. Their

occurrence appears to be strongly influenced by El Niño / Southern Oscillation (ENSO) events. An El Niño is caused by

changes in the sea surface temperature across the equatorial Pacific Ocean, which together with changing atmospheric

pressure and wind patterns, creates regional shifts in rainfall and winds across the Pacific, affecting Australasian rainfall

and the Asian monsoon. The related effects of these changes (sometimes termed “tele-connections”) are felt in the

southern African region where strong El Niño events tend to be associated with dry phases and droughts in parts of

southern Africa, usually but not always limited to the summer rainfall region. The deep drought of 1983 coincided with a

strong El Niño, for example. La Niña events, which involve equatorial atmospheric and oceanic conditions of opposite sign

to those during El Niño events, tend to be associated with wet phases and regional flooding, especially in the summer

rainfall region. It is now understood that regional rainfall is also controlled to some extent by other sea-surface

temperature conditions in the western Indian Ocean (the Indian Ocean Dipole) and the South Atlantic Ocean (informally

known as a Benguela Niño). These linkages are still not well understood and are a focus of ongoing research.


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Extreme rainfall conditions in South Africa are also associated with cut-off low pressure systems in the winter rainfall

region, and cyclones occasionally moving onto the north-eastern parts of South Africa from the western part of the Indian

Ocean during late summer. These events bring very substantial rainfalls and consequent flooding, leading to great

damage and severe loss of lives. Cyclone Domoina in 1983 caused great damage in KwaZulu Natal and the flooding

after Cyclone Eline in 2000 devastated Limpopo Province and southern Mozambique.

Global warming has been predicted to have an effect on the frequency of ENSO and cyclone events. If the Southern

Oscillation Index (the SOI is a measure of the intensity of the changes in the temperature and wind patterns in the Pacifica

Ocean region) becomes negative more frequently, or even on a semi-permanent basis, as has been hypothesized as a

consequence of global warming, it could induce semi-permanent drier conditions in Southern Africa. Such concerns have

also been expressed in eastern Australia, which suffered a failed rainfall season in 2007 even under La Nina conditions

that normally bring relief from drought, and Western Australia, which has apparently experienced a permanent drop in

long term mean rainfall over the past thirty years.

While considerable effort has been made to link rainfall fluctuations at roughly twenty year frequencies to natural cycles

such as the solar sunspot cycle, the evidence supporting this explanation is weak, and does not explain rainfall variability

to any real extent, nor does it explain temperature trends observed over the past thirty years in particular. The effects of

the ~21-year sunspot cycle on rainfall appear small to indetectible and certainly not significant at a level of statistical

confidence that could inform long term hydrological planning at this stage. An apparent 18-year cycle in rainfall has been

identified at mid-latitudes in southern Africa, but its cause remains unattributed, and its susceptibility to climate change

impacts is not known.

1.2.2 Climate science and new scenarios

Policy-relevant assessments of climate change impacts, vulnerability and adaptation to climate change are dependent on

projections of change in key measures such as mean annual rainfall, seasonal shifts in rainfall, changes in rainfall

variability, changes in air temperature and to a lesser extent on other aspects of weather. However, it is important to note

that the ongoing development and refinement of climate change projections leads the development of impacts scenarios

by up to several years. This leads to a disjunction between the most up-to-date generation of climate projections, and

impacts assessments commonly completed on an older generation of climate scenarios.

The most recent scenarios generated for the IPCC fourth assessment report (AR4 – see http://www.ipcc.ch/) are referred

to here. These scenarios have been processed (statistically downscaled) to generate regional scenarios at a spatial scale

that is relevant for impacts assessments in South Africa, and these are summarised and compared with older generation

scenarios on which much of the impacts work reported here is based.

The most recently developed climate scenarios, as is to be expected, include some differences from the previous

generations of scenarios used in key regional studies such as the SA Country Study on Climate Change (SACSCC,

published in part in 2000 see http://www.sanbi.org/countrystudy/). The climate scenarios most recently produced in the

IPCC process have not yet been fully assessed by the impacts community in this country to ascertain the implications for

impacts, vulnerability and adaptation responses. This makes an assessment of overall implications for South Africa

particularly difficult to carry out at this time, especially when different sectors have applied independent and more or less

distinct scenarios.


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Figure 2.1 Projected change in total annual rainfall (mm month

-1) for July and December from a new generation

GCM used in the most recent IPCC assessment

December – February (DJF) March – May (MAM)

June – August (JJA) September – November (SON)

Figure 2.2: Multimodel (8 IPCC AR4 GCMs) projected median change in maximum surface temperature for the

DJF, MAM, JJA and SON seasons by ~2050.

Most recently developed downscaled rainfall scenarios project a general drying in most seasons in the SW parts of the

Western Cape, particularly during autumn and winter months and in line with a shorter winter rainfall season, concurring

with the patterns identified in the SACSCC. In summer and autumn the northern and eastern regions of the country are

likely to become wetter, especially over regions of steep topography around the escarpment. This projection, based on


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developments in downscaling results to regional level, does not concur fully with the SACSCC scenarios which were

biased towards drying projections. The projected changes in the intensity and frequency of precipitation events remain

uncertain. Overall, the winter rainfall region is projected to experience a drying trend, and the summer rainfall a

moistening trend (see Figure 2.1) with possible increases in both rainfall intensity and drought duration. Temperature is

virtually certain to continue to increase across the country (see Figure 2.2), with the greatest increases towards the

interior, and strongest trends in the daily minimum. Near the coast the projected increases are very likely to be

moderated by the proximity of the ocean. Closer to the mountains and towards the interior temperature increases are

likely to be greater. The increase in air temperature is likely to be of the order of 1ºC to 3ºC (by approximately 2055)

depending on location and season, and be most apparent in the daily minimum temperature. Arid and semi-arid regions

towards the western interior are very likely to experience greater increases in maximum temperature than the rest of the

country.

Most of the impacts studies that use explicit climate scenarios are based on the HadCM1 (used in the SACSCC) and

HadCM2 generated scenarios that updated these. It is now clear that these scenarios project conditions drier in southern

Africa than many other general circulation models. These HadCM scenarios are not “wrong” in relation to more recent

emissions scenarios and climate projections, but are useful in representing what South African policy makers could

consider the higher percentile of risk relative to the overall ensemble of updated projections. Thus, many of the impacts

projections that follow can be seen as tending away from median and towards the more extreme negative in many

instances, especially for the summer rainfall region. In the case of certain summer rainfall crop and forestry projections,

however, a useful approach for risk assessment has been followed that provides a wide range of impacts projections. This

is based on assessing impacts in response to spatially uniform climate shifts that capture the uncertainty in the amount

and sign of the change in rainfall and temperature (see Table 1).

Table 1 Climate Change Scenarios adopted for the analysis of the impacts of climate change

on agriculture and forestry.

Scenario Parameter Change

Scenario 1 Temperature + 1°C

Scenario 2 Temperature + 2°C

Scenario 3 Rainfall + 10%

Scenario 4 Rainfall -10%

Scenario 5 Temperature + 2°C; rainfall - 10%

The science behind climate change projection is far from complete, and there is a critical need to sustain the momentum

and capacity achieved to date to enable policy on adaptation, in particular, to evolve as the climate continues to change in

ways that are somewhat unpredictable. The current regional assessment of climate change reflects the most recent

advances in understanding by the international community. Critical uncertainties remain regarding feedbacks between

land surface and regional climate, and possible thresholds and tipping points in the climate system that may lead to

sudden and rapid changes, such as the rainfall reductions that seem to have occurred in Western Australia. Skill in

projecting climate change at very fine spatial and temporal scales is still evolving, and at this time is not yet able to

address all the questions and needs of those affected.

There is also an urgent need to stabilise and expand the observation of core climate measures, and to reverse the trend

of a declining coverage of the observation network. Understanding regional responses to global climate change and

variability depends heavily on high quality observations to quantify climate risks and quantify thresholds that indicate

increased vulnerability (such as fire danger indexes), and to enable the development of improved climate projections.


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1.2.3 Adaptation to climate change

The biosphere is committed to a certain amount of anthropogenic climate change above that already measured even if

greenhouse gas (GHG) concentrations were to have been stabilised at 2000 levels. This “constant composition”

commitment is estimated by a range of methods to be around 0.5-0.6° with an uncertainty range of 0.3-0.9°C.

Accelerating emissions are virtually certain in the short term at least, and thus there is little doubt that a certain amount of

anthropogenic climate change will be essentially unavoidable even if GHG emissions are successfully reduced through

effective international action. Thus most sectors will need to adapt since much of the change that will occur in the first half

of this century, at least, that has been pre-determined by past and current GHG emissions.

The practical concepts needed to address adaptation are currently unnecessarily confused, thus limiting more rapid

advances in planning and implementation responses. In this report two types of adaptation are recognised and defined

(see Figure 2.1). These are “resilience-type” adaptation, which addresses the potentially damaging effects of changing

climate extremes on sectors, and “acclimation-type” responses, which address strategies to cope with the gradual

changes in background climate. These include slow rates of warming that may ultimately require new behaviours and

practices in human society. Differentiating adaptation responses into “resilience-type” and “acclimation-type” adaptation

responses may allow adaptation strategies to be better prioritised, and implementing agencies and financing sources to

be more effectively allocated to where needs are most urgent.

Figure 2.1 Graphical representation of the need for resilience-type adaptation and acclimation-type adaptation in

relation to a changing climate, as represented by a change in global mean temperature. It is noted that at under

baseline climate conditions (for example, 1960-1990 mean conditions, the origin of the graph) no need exists for

acclimation-type adaptation. However, due to inherent climate variability and the incidence of extreme events, a

regionally dependent need exists for resilience-type responses to cope with this risk. As climate changes (as

represented by increase in global mean temperatures), the need for both adaptation response types is likely to

increase in most regions, but with far higher levels of uncertainty (represented by the question marks) in the case of

resilience type adaptation than in acclimation type adaptation.

Requirement for adaptation =

potential damages or loss

Change in global mean temperature

Impacts of changing mean;

requires acclimation-type

adaptation

Impacts of changing extremes;

requires resilience-type

adaptation

??


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A number of potential barriers to implementing adaptation plans have been identified and include:

o Low local (site-based) human capacity to undertake adaptation planning

o Limited financial resources and competing priorities

o They require a longer time horizon than the typical political and development framework

o The absence of a legislative framework

1.2.4 Impact on water resources and hydrology

South Africa is a water-stressed country with an average annual rainfall of ~500mm (60% of the world average), and

stream flow in South African rivers is at a low level for most of the year. Due to low rainfall, exacerbated by forestry and

agricultural land use, only 9% of rainfall reaches rivers, compared to a world average of 31%. Total societal water

requirements closely approached availability limits by 2000. Rainfall variability is historically responsible for water-related

disasters such as floods and droughts. Impacts of projected climate change on water resources and hydrology therefore

occupy a key position in assessments of vulnerability and adaptation responses.

A downscaled Regional Climate Model, the Conformal-Cubic Atmospheric Model (C-CAM), was applied using daily data

at a resolution of 30’ x 30’ (~ 50 - 60 km) enabling hydrological impacts to be evaluated at a fine temporal and spatial

scale. A general increase of evapotranspiration by ~ 5 – 15% is projected throughout the region by ~ 2050 (assuming a

doubled pre-industrial atmospheric CO2), with the lowest increases along the humid south and southeast coasts and parts

of the arid Northern Cape, and highest increases are projected to occur on the interior plateau. Direct implications are

likely to be severe for irrigation and reservoirs, while the indirect implications through reduced soil moisture levels are

likely to impact runoff generating mechanisms and dryland agriculture, although in a complex interplay with rainfall

changes.

The annual number of stormflow events is projected to decrease in a future climate in the winter rainfall region, the

southern coastal zone, the northern and eastern parts of Limpopo province and almost the entire KwaZulu-Natal, Lesotho,

Free State and coastal half of the Eastern Cape. These areas include some of the most crucial source areas of

streamflows in southern Africa. Future increases in stormflow events per year are simulated over much of the Northern

Cape (where few stormflow events currently occur), as well as Mpumalanga, Swaziland and the remainder of Limpopo.

Much of South Africa is projected to have more variable streamflows despite higher predicted flows overall. However,

parts of the Western Cape are projected to have considerably lower variability relative to the present, and lower overall

predicted streamflows. The Lesotho highlands also show decreases in streamflow variability. Streamflows are projected to

shift between one and two months earlier over much of Limpopo and the interior, while shifting a month later in parts of

KwaZulu-Natal and Swaziland. It is striking that the transitional area between the summer and winter rainfall regions is

seen to be in a state of considerable flux with projected climate change and is likely to present major challenges to water

resource planners in those regions.

Greater rates of soil erosion (represented by catchment sediment yield) are projected over much of the interior in median

and especially in wet years, with relative reductions in a future climate modelled along the east coast and the winter

rainfall region. South Africa is projected to have a higher relative irrigation water demand under a plausible future climate

scenario. More than 90% of South Africa is projected to show increases in days with the topsoil at wilting point, with the

Free State, southern Mpumalanga and KwaZulu-Natal showing a doubling and more of this stress factor. Lesotho and the

northeast coast of KwaZulu-Natal are likely to experience amongst the highest increases in dry topsoils in a future climate.


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BOX 1 Projected impacts of climate change on groundwater recharge

The projected impacts of climate change on groundwater recharge are expected to be

beneficial for groundwater resources in certain areas. Groundwater recharge occurs

under heavy, intense rainfall events, and these have been observed to increase over the

past few decades, mainly in the summer rainfall region. An increase in recharge events

per year, by a factor of 1.5 to over 3, is projected for a future climate, in particular in the

southern and eastern Free State, Lesotho, northern parts of the Eastern Cape and much

of KwaZulu-Natal. Unfortunately, these are not areas which depend as heavily on ground

water resources as the arid and semi-arid western parts of South Africa. Thus the benefits

of greater ground water recharge are projected to accrue to currently less water-stressed

regions, with the accompanying increased risk of flood damage due to the extreme

rainfall events.

1.2.5 Impact on agriculture

The socio-economic value and role of agriculture in South Africa is substantial, including contributing 3.7% to

annual GDP and its relatively unquantified but large role in supporting mainly rural livelihoods. Agriculture is

dependent on the temperature and moisture conditions being near-optimal during the growing season for both

annual and perennial crops. Climate change affects agriculture by imposing temperature and moisture

excursions from current median conditions to new conditions, which may benefit or reduce agricultural

productivity, as well as having important implications for pest vigour. Indices of growth potential relevant to crops

may show a greater responsiveness to climate change relative to underlying changes in base measures such as

rainfall or temperature. For example, the duration of temperature an organism experiences between upper and

lower thresholds is related to its growth rate. The Heat Unit concept captures this dependence, and is important

for predicting harvest dates of many fruit crops, planting dates of annual crops, for determining phenelogical

growth stage, for dry matter accumulation and importantly, when and how often to apply pest control.

Projected climate change will alter the rate at which heat units accumulate, affecting crop yields, timing of farming

operations and pest vigour. With a 2°C increase in temperature, on average, most of the agriculturally important

parts of the country will experience a 15-35% increase in heat units, with most significant increases on the

Highveld and eastern Escarpment which are currently amongst the coolest regions.

Chill units represent a concept that is similar to heat units, but is related to the period of accumulated minimum

temperatures below a threshold. Exceedance of this threshold resets the accumulation of chill units to zero,

making this measure highly sensitive to warming trends. Chill units affect hormonal response in plants (deciduous

crops) relating to completion of seasonal dormancy (rest period), budbreak, leaf developments, flowering and

fruit-setting. Climate change-induced warming is predicted to reduce the accumulation of chill units, making it

more difficult to produce chill-dependent deciduous fruits such as apples.

Western Cape agriculture faces imminent significant threats particularly due to projected increasing water

shortages, resulting in greater competition with urban use of water, and lower yields and greater yield variability in

both irrigated (see Box 2) and rain-fed crops. Additional heat stress will reduce the productivity of perennial and

annual crops, especially chill unit-dependent deciduous fruit, and livestock.


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BOX 2 Climate change and winter rainfall region agriculture

Most vulnerable crops climate change-induced warming are those dependent on winter

chilling (apples and pears), and those dependent on rainfall amount and distribution. The

SACSCC did not consider impacts of climate change on winter rainfall agriculture, thus

unfortunately ignoring this climate change-sensitive sector. Simulations suggest,

assuming continuing orchard irrigation but no other adaptive response, that apple

production areas in the Western Cape will shrink with progressive warming and finally

be restricted to the high-lying Koue Bokkeveld. By the end of the 21st century (with mean

warming >3°C) this crop could be entirely non-viable without the development and

adoption of new heat-tolerant varietals.

Pears are less chill-dependent than apples. Initial moderate warming (1-1.5°C) could

lead to slight gains (e.g. in the cooler Elgin/Grabouw region) or slight losses (in the

warmer Ceres and Wolseley regions). With continued warming (2-3°C) losses are

estimated at between 5% and 20% depending on cultivar and region. Should irrigation

water not be sufficiently available, losses would be substantially higher for all fruit crops.

Grapevines are likely to be resilient to some warming and drying. With moderate

warming (1-1.5°C), irrigated vineyards will maintain yields, and yield increases may

result for medium/standard quality wine. Small reductions (2.5-5%) in yield and quality

may accompany greater warming (2-3°C) especially in the warmer production regions

(Olifants River, Worcester, Robertson). Non-irrigated vineyards will show slight losses

under moderate warming, but more serious losses (10-15%) with stronger warming.

Wheat production potential varies widely across the winter rainfall region. Greatest impacts (without adaptation) are

expected given changes expected by ~2030-2050 in the most marginal areas (Sandveld and Rooi Karoo) in the north-

west (low total rainfall, projected losses of 15-60% of yield depending on the amount of warming and drying) and the

Heidelberg Vlakte in the south-east (irregular winter rainfall, losses of 20-70% yield estimated). Yield variability will also

increase over time. The most productive wheat producing areas of Klipheuwel/Hermon and Goue Rûens are likely to

sustain lower losses of yield (5-12%). A distinct increase in prevalence of optimum climate conditions for major pests,

codling moth (on apples) and chilo stem-borer (on the summer rainfall crop sugar cane, but likely representative of a pest

typical of annual crops), is projected for each degree of warming. From these findings the implications of temperature

projections alone are likely to be profound by as early as 2030 for affected annual and perennial crops of the winter

rainfall zone, and the many thousands of jobs associated with this industry.

Net water requirements for crops in the summer rainfall region are projected to increase throughout southern Africa (see

Figure 2.2). In the south and north predicted increases are less than 10%, but along the KwaZulu-Natal coast and the

Lesotho/central Free State area these are around 30%. Projections for profitability of maize production are sensitive to

temperature, rainfall and CO2 fertilization scenarios (CO2 fertilisation occurs as rising atmospheric CO2 levels boost

photosynthesis and primary production of crops, mainly of annuals). A 2°C temperature increase alone is projected to

reduce profits by around R500/ha across the highveld maize region, but CO2 fertilization may mitigate this loss almost

completely. Even for a 10% rainfall decrease, the CO2 fertilization effect increases profits by up to ~R1500 per hectare.

CO2 fertilization effects are however very uncertain and no local experiments exist through which these projections can be

tested.


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Many autonomous adaptation options in agriculture are enhancements of existing risk management or production

enhancement activities. Where crops are near climate tolerance thresholds, or where multiple stresses exist (e.g. soil

degradation), or where producers’ capacity for autonomous adaptation is exceeded, deliberate planned measures (i.e.

acclimation-type adaptation) will become necessary. The secondary impacts of projected climate changes on the broader

rural and regional economy could be substantial, but have not yet been adequately quantified.

Figure 2.2 Ratios of future to present mean annual net irrigation requirement and its inter-annual variability,

derived from ACRU simulations with C-CAM RCM daily climate outputs (right), and compared with baseline

climate values (left) simulated with the ACRU hydrological model using daily data for present climatic conditions

1.2.6 Impact on forestry

Formal employment in forestry is estimated at between 80,000 and about 140,000 people, with an estimated 120,000

people employed in industries that process wood. About 40% of these are employed in sawmills, 30% in pulp and paper

manufacture, and 30% in secondary processing. In addition, forestry-related employment is found in less formal activities

such as making poles and charcoal production. The formal forestry and forest products industry contributes ~2% to GDP

in South Africa, earning ~R1 billion per annum in net foreign exchange. The role of indigenous forests and their

contribution to rural livelihoods is not considered in this report, but deserves attention in a future assessment.

The potential impacts of climate change on the formal forestry sector are potentially significant, but these are projected by

climate suitability models to be highly dependent on rainfall scenarios. Recent evidence supports this contention, showing

for example that drought during 1991/92 caused the loss of approximately R450 million to the industry. With expected

temperature increases by ~2050 of 2ºC and a reduction in rainfall of 10%, Acacia mearnsii, Eucalyptus dunnii, E.

grandiflora (see Figure 2.3), E. nitens, E. smithii and Pinus elliottii, P. patula, P. taeda and certain hybrids, show a

reduction of between 40% and 100% in viable planting area. By contrast, these commercially important species and

hybrids show an increase of between 50% and 90% in planting area if rainfall increases by 10% with 2ºC warming.


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Given the uncertainty relating to summer rainfall projections, the forestry sector faces a wide range of potentially plausible

outcomes, indicating the critical need for reducing uncertainties of rainfall projections in this region. However, threats of

greater fire frequency with rising temperatures are clearly an important risk regardless of the rainfall scenario.

Selection and testing of new hybrids that are more drought-tolerant and efficient in water use seems to be an appropriate

means of implementing acclimation-type adaptation in this sector, while fire control may be important in improving

resilience-type adaptation.

Figure 2.3 Climatic suitability for Eucalyptus grandis under current climate, and scenarios of temperature (T) and

rainfall (P) change relative to current climate. These scenarios broadly encompass the range of climate simulations

for ~2050 as projected by general circulation models. Maps show optimal areas, non-viable areas, and areas of

intermediate suitability revealing which limiting factors reduce optimal productivity.

1.2.7 Impact on terrestrial ecosystems and biodiversity

The economic value of ecosystems and biodiversity is increasingly being recognized and quantified. Globally, ecosystem

services have been suggested by certain approaches to have a value equivalent to the global gross national product. In

South Africa, which has the fifth highest level of plant species richness in the world, the economic value of wild

ecosystems in the Cape Floristic Region biodiversity hotspot alone, for example, has been estimated to be greater that R9

billion per annum in 2000 in consumptive use, non-consumptive use and indirect use value.

Medium and longer term risks due to climate change for terrestrial species appear high in South Africa. Several studies

have projected significant loss of geographic range and even elevated species extinction risks for a notable proportion of

South Africa’s endemic fauna and flora. Early evidence for negative impacts of observed climate change on the desert

tree Aloe, the quiver tree or kokerboom, has been identified, and a threat to a large portion of its geographic range in

Namibia and parts of South Africa has been quantified.

The species-rich winter rainfall biomes appear particularly vulnerable, with some tens of percent of their endemic species

threatened by elevated extinction risk this century. This risk is exacerbated by current trends in land use change and

conversion of wild habitat. Updated climate scenarios and the application of improved modelling techniques indicate that

Presentt

T +1°C T +2°C

T +2°C, P –10% T +2°C, P +10%


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some key ecosystems (e.g. the Nama-Karoo Biome) may not be as imminently vulnerable (i.e. by ~2050) to climate

change impacts as reported previously in the SACSCC (see Figure 2.4). Nonetheless, the SACSCC projections and

earlier projections of species extinction risk remain within the range of possible outcomes, but probably represent an

extreme outcome by ~ 2050.

Figure 2.4 Projected changes in (left hand panels) major South African Biomes (Succulent Karoo, brown; Fynbos,

red; Nama-karoo, orange; grassland, green; savanna, yellow) by ~2050 according to the General Circulation

Model CSM given the IS92a emission scenario used in the SACSCC; (right hand panel) ranges of four major

southern African Biomes by 2050 (dark green = high suitability, medium green = low suitability, light green =

unsuitable), given climate projections of HadCM3 under SRES A2 scenarios, and applying a Generalised additive

Modelling approach

In terms of ecosystem services and carbon sequestration, several savanna and arid grassland ecosystems found in the

summer rainfall region may store between ~20 and 600% more carbon due to temperature, rainfall and CO2 fertilization

effects, but this may depend to a large extent on future fire regimes. Fire regimes are typical of several of South Africa’s

dominant ecosystems, such as Fynbos, Grasslands and Savanna, and are projected to show a greater frequency, and

possible increase in mean size with projected regional climate change, due to the prevalence of higher fire risk conditions

for longer periods of time.

While there exist a few key fire control experiments that provide important information on ecosystem structural responses

to this disturbance, there is currently no field-based experiment or other clear evidence to assess the important role of

atmospheric CO2 enrichment in increased sequestration potential and possible shift in ecosystem structure. While thismay

have positive carbon sequestration benefits, there are attendant negative implications for the biodiversity of open

grassland and savanna habitats.

1.2.8 Impact on health

Southern Africa is grappling with socio economic and demographic issues that are historically unique to the region,

coupled with huge health burdens of AIDS and a growing TB epidemic. The potential contribution of climate change in this


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arena is currently largely implicit, but shifts in climate regime may have a key impact on the already delicate balance that

exists between health, economic productivity, livelihoods and prosperity.

The immediate health impacts of extreme climatic events with longer term psychosocial consequences and loss of

livelihoods are well established and documented, but the impacts of gradual changes in temperature and precipitation that

are observed and predicted in the region are less tangibly measurable. The pattern of increasing extreme rainfall events

and rising temperature favour the geographical expansion of the borders of vector borne diseases such as malaria. This is

supported by several mathematical models as well as surveillance and direct observations in many quarters.

Health effects due to climate change can be attributed to the following external impacts:

o Temperature (changes in mean and extremes)

o Extreme rainfall events – drought and floods

o Air pollution

o Vector and rodent borne diseases

Adaptations of both acclimation- and resilience-type are needed that will guarantee adequate and reasonable healthcare

delivery services particularly in the rural setting, and resilient housing and infrastructure both in the rural and urban

communities aimed at reducing the tendency towards migration and improving the lot of rural citizens. Such adaptations

could include:

o Advancing a multi-faceted approach to health management as an acclimation-type adaptation

o Efficient and effective meteorological and weather forecasting services as a key resilience-type

adaptation response.

1.2.9 Impact on rural livelihoods

An assessment of the impact of climate variability on rural livelihoods (where livelihoods comprise the various activities,

assets and capabilities of people’s daily lives) facilitates an integrated view of the multitude of ways in which human

societies that are poverty stricken or poverty prone may be affected by climate.

Natural capital, such as timber, plants, land and water will be affected by changing rainfall and temperature, with impacts

on water the likely most imminent challenge. Human capital, such as people’s skills, knowledge, health and ability to

labour, might be affected through increased pressure on water availability, food supplies due to higher prices or lower

productivity of land. Health is affected by changing pollution levels, the quality of water and changes to vector-borne

diseases such as malaria. As resource availability becomes increasingly limited, so does the ability to secure income, and

economic assets can be eroded over time. There is also evidence that extreme events place pressure on social

networks, because it becomes more onerous to maintain social reciprocity under higher levels of resource stress.

The impact of climate variability on assets links directly to the impact on livelihood activities. Production and income

activities are likely to be significantly affected by climate variability, particularly in rural areas where changes in rainfall

directly affect agriculture and natural resources that underpin many production and income activities. In South Africa,

there is growing evidence of how changes in rainfall impact on livelihoods, often increasing vulnerability of farming

systems. Extreme events, such as drought and flood, also affect production and income activities.

Changes in climate and climate variability are also likely to increase the risk to assets and activities. Increased

temperatures and drier conditions, for example, increase fire risk, and this is currently a major threat in informal

settlements, causing major damage to livelihoods assets as well as threatening lives.

Adapting to climate change at the rural or poverty prone livelihood scale will be a critically important undertaking. It is

particularly important to focus on the most vulnerable groups, so that their livelihoods are not eroded by climate events but


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rather to facilitate resilience to the expected changes in climate. This requires an integrated approach that addresses

multiple sectors whilst combining the knowledge of vulnerable groups as well as the specialist.

1.2.10 Impact on the urban environment

Climate change has the potential to reduce available water resources through reduced rainfall and higher

evapotranspiration in mainly the western parts of the country, and also to increase consumption patterns due to

temperature increase. This likely to increase the risk of water shortages, and raise the cost of providing water by relevant

authorities. Early adoption of acclimation type adaptation responses by relevant authorities, such as demand

management, hold promise for countering this challenge.

Longer term projections support the view that the frequency and intensity of future extreme precipitation events will

increase during the twenty-first century, with result of more flooding episodes in urban settings. Enhancement of

resilience-type adaptation responses such as disaster management will become increasingly important to cope with this

growing challenge.

Whilst more gradual, the potential of sea level rise impacts for enhanced damages are real. This is especially so when

they are accompanied by high tidal and storm events, and relevant for key coastal areas that are identified as vulnerable

due to high population densities and settlements and infrastructure of all types, such as the Saldanha area, parts of

greater Cape Town, and along the southern Cape and East coast. For example, a combination of the Highest

Astronomical Tide (HAT - every 19 years), and an intense storm in the south-west Indian Ocean resulted in wave

conditions with a return period of about 1:500 years, resulting in significant damage to buildings and infrastructure along

the KwaZulu Natal coast in 2007. Rising sea levels as a result of the global warming is likely to add 0.4m to mean sea

level by 2100. This will bring similar sea level conditions experienced during the HAT once every 19 years to once every

two weeks (the normal lunar cycle), making the joint probability of high tide levels and an intense storm much more likely.

Combined with the intensifying development of the South African coastline, the cost of damages is likely to rise

substantially.

Other extreme events such as heat waves are expected to increase in frequency and severity in a warmer world with the

consequential mortality amongst the elderly and sick, and attendant risk of fire in informal settlements. The frequency of

brown haze air pollution events (photochemical smog) in Cape Town, fro example, are expected to increase during winter

months as the number of rain days decreases and the number of temperature inversions increases. Particulate matter is

the main pollutant and has been linked to serious respiratory health problems. Maximum thresholds are already being

exceeded in some parts of Cape Town. Total direct health costs of respiratory illness have reached about 930 million

Rand and global warming over the next 50 years could be expected to add 46-92 million Rand to that value. Acclimation

type adaptation responses to improve air quality, and to reduce urban heat loads, could help in reducing these threat.

1.2.11 Indicative costs of climate change impacts

Very few studies in South Africa have attempted to quantify costs of climate impacts and cost:benefit calculation of

interventions are even fewer. The following tables provide an indicative estimate of the potential costs under two main

assumptions; firstly of damages due to inaction as a result of low levels of adaptive capacity through human and

financial constraints; and secondly of the costs to accommodate climate impacts in the relatively few sectors in which

these have been estimated, such as water resource planning and the conservation of biodiversity. The cost on health

and livelihoods are difficult to estimate, given that there are multiple influences and impacting factors.


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Table 2: Cost of damages i.e. the cost of inaction due to low adaptive capacity and resilience

Impacts Magnitude of costs

Historical:

Flood damage event in the Western Cape due

to extreme rainfall events in2003, 2004, 2005,

2006 and 2007, all caused by cut-off low

presure weather systems

100’s of millions of Rands/event with

accumulated losses ~ R 1 billion

Coastal storm damage along the Durban coast

due to extreme weather event (2007)

Infrastructure costs in greater Durban ~ R100

million

Forestry losses during 1991/92 drought where

followed up with Forestry South Africa

~R 450 million

Forestry losses due to wild fire in Mpumulanga

and KwaZulu Natal

~ 60,000 ha of plantations destroyed worth

~R 500 million

~R 70 million of sawmilling infrastructure and

assets destroyed

Drought impacts on agriculture

1983/84

1991/92

Dryland crops in South Africa declined to about

30% of average production, resulting in a loss

of about R2.2 billion. South African GDP

dropped by about 7%

Total losses to agriculture about R3.5 billion.

GDP dropped about 1.8%,

Potential:

Damage to residential property in the Western

Cape due to sea level rise.

10’s -100’s millions of Rand

Deaths due to malaria Death rates have been declining since 1999,

because of spraying and other control

programmes (406 died in 1999, 96 in 2002).

Most deaths occur in Limpopo Province. The

advent of multi-drug resistant malaria is a

serious concern

Deaths due to cholera (the Cholerae vibirio

lives in sea-borne zooplankton, which responds

to phytoplankton blooms in warmer nutrient-

enriched waters. The faecal-oral

contamination route on land is prevalent during

high-rainfall seasons).

82,275 cases of cholera resulted in 171 deaths

in 2001. Costs of treatment and lost

productivity are ~ 10s of millions of Rands.

Increased morbidity due to schistosomiasis 13 deaths in 2004. Infection rates along the

east coast of KwaZulu Natal can be very high,

ranging from 25-90% of school-going children

with significant adverse long-term

consequences for health (infertility and cancer)

and reduced disability-adjusted life years –

meaning economic productivity decreases.

Increase morbidity due to increasing frequency

of photochemical smogs in Cape Town

10’s of millions of Rands.


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Increased temperature on winter rainfall

agriculture: 2-3oC

5-20% fruit crop losses (Varying losses

depending location and crop type.) calculate

rand costs and downstream impacts

Lower rainfall on winter rainfall agriculture over

time.

Marginal areas – 15-60% crop reduction

Productive areas – 5-12% crop reduction

2°C temperature increase reduces profits by

~R500/ha across the highveld maize region

100’s millions of Rand per annum

Table 3: The potential cost of acclimation adaptation

Interventions and adaptations Magnitude of costs

Large-town water provision in the western

Cape as a response to climate change by 2035

100’s of millions of Rands for the Cape Town

Metropolitan area for increasing storage,

reducing leakage, more sophisticated

treatment and reuse of water, increased

efficiencies of use and desalination

Small town water provision in the western

Cape under climate change by 2035.

10’s of millions of Rands per small municipal

area (up to 3.5 times more costly than prior to

climate change impact)

Conserving biodiversity – gene and seed

banking.

100’s of thousands of Rand per annum

Conserving biodiversity – reserves and off-

reserve management.

10’s – 100’s of millions of Rands

Higher-efficiency irrigation 10’s – 100’s of millions of Rands. Farmers are

particularly sensitive to sudden increased costs

because of low profit margins and volatile

weather conditions and market prices

Urban greening to reduce heat island 10’s of millions of Rands

Air conditioning 100’s of millions of Rands, but confounded by

growing shortages of power in South Africa for

the forseeable future

Emissions and air pollution control Billions of Rands, including large-scale

electrification of the public transport system.

100’s of millions in Cape Town, where brown-

haze conditions are likely to worsen

Control of vector borne disease 100’s of millions of Rands

Improved housing and urban drainage systems

to prevent flooding impacts

Billions of Rands. Supply of land for housing is

limited and dwellings tend to be built on low-

lying areas where vulnerability to flooding is

higher.

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