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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

    i

    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

  • Assessing impacts, vulnerability and adaptation in key South African sectors

    ii

    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.

  • Assessing impacts, vulnerability and adaptation in key South African sectors

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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

  • Assessing impacts, vulnerability and adaptation in key South African sectors

    1

    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 disr