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Climate Effects Consolidated Reportfor River Scheme Sustainability Project

May 2015

Bay of Plenty Regional Council5 Quay StreetPO Box 364Whakatane 3158NEW ZEALAND

Prepared by Ingrid Pak, Environmental Engineer

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Document information

Document name: Climate Effects Consolidated Report for River Scheme Sustainability Project

Contact person: Ingrid Pak

Status: For presentation to Council workshop

Document review

Review timeframe: n/a

Reviewers: n/a

Document history

Author Description of change Date Version

Ingrid Pak First draft report April 2015 V1

Ingrid Pak Comments from RSS project team and steering group

May 2015 V1.1

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Person Role Date of issue Version

Mark Townsend Engineering Manager November 2015 V1.1

Authorised by: Mark Townsend Date: 3 November 2015

Reviewed by: Ken Tarboton Date: 3 November 2015

Climate Effects Consolidated Report – River Scheme Sustainability Project i

Acknowledgements

Katalin Maltai and Mark James for their support and guidance. Ken Tarboton, David Boothway, Roger Waugh, Sandra Barnes, Justine McLeary, Martin Butler and Michelle Lee for their valued reviews. Rachael Musgrave and Gail McKee for formatting and the colourful schematic. Trig Yates for producing the rainfall projections maps.

Climate Effects Consolidated Report – River Scheme Sustainability Project iii

Executive summary

This report summarises what we know about climate change and climate cycles in the Bay of Plenty. It consolidates findings from a range of reports on an international, national and regional level, and provides guidance as to how Council could or should use this information in its policy, guidelines and projects. It forms the deliverable part of the Climate Effects Workstream of Bay of Plenty Regional Council’s (BOPRC) River Scheme Sustainability Project.

Generally, the climate in the Bay of Plenty is likely to be warmer and drier in the future. We can expect:

Warmer winters, reduced frequency of frost inland and at higher elevations and a longer growing season.

Drier average conditions will lead to increased drought risk.

More frequent and intense rainfall events, with an associated increase in risk of flooding and erosion.

Climate change will likely impact on the coastal margins of the Bay of Plenty, by altering coastal processes such as erosion and sediment supply.

Current advice for future sea level for New Zealand is a base rise of 0.5 m and potential rise of at least 0.8 m by 2090, based on Ministry for the Environment Guidelines (MfE, 2008). It is expected that these forecast rises will increase with the new MfE guide due out next year.

Bay of Plenty Regional Council already incorporates the effects of climate change in natural hazard risk assessments through the Operative Regional Policy Statement. It uses a projection of a base sea-level rise of at least 0.6 m (above the 1980–1999 average) for infrastructure and developments that are relocatable, a projection of a base sea-level rise of 0.9 m (above 1980–1999 average) for structures where future adaptation options are limited, such as regionally significant infrastructure and developments which cannot be relocated, and an additional sea-level rise of 10 mm per annum for infrastructure with a life span beyond 2112.

In addition to climate change, there are four large-scale climate cycles that affect the climate in New Zealand and the Bay of Plenty. These are the Interdecadal Pacific Oscillation (IPO), the El Nino Southern Oscillation (ENSO), the Southern Annular Mode (SAM), and the Indian Ocean Dipole (IOD).

Analysis of river flows and extreme rainfall records show some evidence that the IPO and ENSO phases influence the observed temporal clustering of floods in some Bay of Plenty rivers, but the relationship is not always clear. Therefore, designers of permanent structures such as bridges and stopbanks need to use records extending beyond the phases of the IPO, if possible. There is not enough evidence to delay infrastructure spending based on the timing and effects of climate cycles.

Bay of Plenty Regional Council aims to future-proof the region against climate change by providing advice and developing policy to help the region adapt and become more resilient to the effects of climate change. Some examples of what Council is doing to manage/address climate change are outlined in this report.

Climate Effects Consolidated Report – River Scheme Sustainability Project v

Contents

Acknowledgements iii

Executive summary v

Part 1: Purpose 1

Part 2: Introduction 3

2.1 What is climate change? 3

2.2 Climate change at international, national and regional levels 3

2.3 Report structure 5

Part 3: Research summary 7

3.1 International 7

3.2 National 7

3.3 Regional 7

Part 4: Climate Change for Bay of Plenty 9

4.1 Climate change science 9

4.2 Climate change projections for the Bay of Plenty 12

Part 5: Sea level rise for Bay of Plenty 15

5.1 Impacts on coastal margins 15

5.2 Sea level rise 15

5.3 Council Policy – Operative Regional Policy Statement 15

Part 6: Climate cycles in the Bay of Plenty 17

6.1 Rainfall regime and trends 17

6.2 Impacts of climate oscillations 18

6.3 Climate change and other variables 20

6.4 Conclusion 20

Climate Effects Consolidated Report – River Scheme Sustainability Project vii

Part 7: Regional application of climate change and sea level rise in policy and guidelines and projects 21

7.1 Local Government role 21

7.2 Council policy and guidelines 21

7.3 Council projects 24

Part 8: Application of climate change 27

8.1 Effects of climate change on river schemes 27

8.2 Recommendations for future work 27

Part 9: Conclusion 29

Part 10: References 31

Appendix 1 – Glossary 35

Appendix 2 – Rainfall projection maps 37

viii Climate Effects Consolidated Report – River Scheme Sustainability Project

Part 1: Purpose

This report summarises what we know about climate change and climate cycles in the Bay of Plenty, based on several commissioned reports and international and national documents. It forms the deliverable part of the Climate Effects Workstream of BOPRC’s River Scheme Sustainability Project (RSS). It consolidates findings and summarises the implications of these findings on the river schemes.

As we expect the climate to change over the next 100 years, this will affect the management of the river schemes. This report will help us better understand the impact of weather cycles and climate change on the river schemes.

Climate Effects Consolidated Report – River Scheme Sustainability Project 1

Part 2: Introduction

2.1 What is climate change?

Climate change has taken place over thousands of years but there is now an influence on climate from a rapidly increasing world population and its use of resources. In the past few generations humankind has been exhausting fossil fuel reserves that were generated over several hundred million years. More greenhouse gases such as carbon dioxide in the atmosphere are enhancing the natural greenhouse effect. The result of the enhanced greenhouse effect is called “anthropogenic climate change”, or climate change that is a result of human activity.

The long term effects of climate change are additional to the short and medium term variability in climate, caused by large-scale climate cycles, such as the Interdecadal Pacific Oscillation (IPO) and El Nino Southern Oscillation (ENSO).

2.2 Climate change at international, national and regional levels

Climate change research is carried out at an international level by the Intergovernmental Panel on Climate Change (IPCC). The findings of the international research then feed into national guidance documents published by the Ministry for the Environment (MfE), which in turn feed into regional investigations and assessments, most of which are carried out by the National Institute of Water and Atmospheric Research Limited (NIWA). Figure 1 shows schematically the climate and climate change information available to Council (top section of Figure 1). Findings of these regional reports then feed into regional policy and guidelines and are applied in regional council projects (bottom section of Figure 1).

The role of Local Government is defined in a draft report on “Climate Change and Local Government” (Dickie, et al, 2015) to the Society of Local Government Managers (SOLGM) through consideration of various acts, namely the Local Government Act (LGA), the Civil Defence and Emergency Management Act (CDEMA), the Building Act (BA) and the Resource Management Act (RMA) (SOLGM, 2015).

This report focuses on the available information that relates to the river schemes. Other climate change work exists within Council, such as implications on pest management, water quality, and working with the industry, which is not included herein.

Climate Effects Consolidated Report – River Scheme Sustainability Project

Figure 1 Schematic of available climate and climate change information and its use within Council.


2.3 Report structure

The report structure generally follows the schematic in Figure 1 and is outlined below:

Part 3 outlines the available climate and climate change information at an international, national and regional level. It lists the research reports Council has available. These are also shown on the schematic in Figure 1.

Part 4 summarises the NIWA 2011 report on climate change projections for theBay of Plenty. It explains the scenarios and modelling approaches used in the climate change assessment, and summarises the key climate change projections for future temperature, rainfall, wind, drought, and pasture growth.

Part 5 summarises sea-level rise projections and climate change impacts on the coastal margins in the Bay of Plenty from the NIWA 2006 report, IPCC estimates, and MfE guidelines. It also shows how the sea-level rise estimates are applied in the Regional Policy Statement.

Part 6 summarises the NIWA 2014 report on climate cycles in New Zealand and the Bay of Plenty. It describes the main climate cycles affecting the Bay of Plenty region and the impacts they have on rainfall, river flow and resulting flood risk. It also gives recommendations as to how to consider climate cycles in infrastructure design.

Part 7 outlines how Council uses the available information on climate change as part of its statutory role through regional policy, guidelines and projects.

Part 8 outlines the application of climate change in the RSS project and lists recommendations for further work in this field in the future.

Part 9 concludes the consolidated report.

Part 10 contains references to the reports used in this consolidated report.

A Glossary is included in Appendix 1.

Appendix 2 shows rainfall projection maps for the Bay of Plenty for the four seasons.


Part 3: Research summary

This section summarises the available research at an international, national and regional level. It generally follows the top section of the schematic shown in Figure 1.

3.1 International

3.1.1 Intergovernmental Panel on Climate Change

The Intergovernmental Panel on Climate Change (IPCC) is an international scientific body that assesses predictions of future climate based on published research. The IPCC is an internationally accepted authority on climate change, that produces reports that have the agreement of leading climate scientists and the consensus of participating governments. The IPCC has published five comprehensive assessment reports reviewing the latest climate science, the most recent being the Fifth Assessment Report (Ar5) in 2014 (IPCC, 2014).

3.2 National

3.2.1 Ministry for the Environment

The Ministry for the Environment (MfE) prepared three comprehensive technical reports, following the release of the Fourth Assessment Report on the science of climate change by the IPCC (IPCC, 2007). These are: “Climate Change Effects and Impacts Assessment” (MfE, 2008), “Coastal Hazards and Climate Change” (MfE, 2008a) and “Tools for Estimating the Effects of Climate Change on Flood flow” (MfE, 2010). Based on these technical reports, MfE has published guides for Local Government to help to adapt to climate change (MfE, 2008b; MfE 2009; and MfE, 2010a). These guides focus on increases in temperature, rainfall and sea level throughout New Zealand. It is expected that these guides will be updated, based on the IPCC Fifth Assessment Report by about 2016.

3.2.2 NIWA

The National Institute of Water and Atmospheric Research Ltd (NIWA) has published “Coastal Adaptation to Climate Change – Pathways to Change” in 2011 as part of a study aiming to create the necessary information and tools, to adapt to the impacts of climate change in the New Zealand coastal environment (NIWA, 2011). It is a thorough collection of available information on climate change, sea level rise and coastal hazards at the time, and outlines an adaptation pathway with a step–by-step guide for local authorities and communities.

3.3 Regional

3.3.1 NIWA

A number of reports have been commissioned by BOPRC over time to assess climate, climate trends and climate change projections in the Bay of Plenty. These are briefly outlined below.

In 2003, NIWA reported on the climate variability and trends in the Bay of Plenty and presented scenarios for future climate change in its report “The climate of the Bay of Plenty: Past and Future” (NIWA, 2003).

The climate change assessment part of the NIWA 2003 report was updated in 2011 in “An Updated Climate Change Assessment for the Bay of Plenty” (NIWA,


2011) and draws on a significant body of climate change modelling and knowledge, developed both internationally and by NIWA. It collates modelling information, projections for temperature, rainfall, and storminess and associated impacts on droughts and pasture growth for the Bay of Plenty region. Findings of the report are summarised in detail in Part 4.

In 2006, NIWA reviewed the effect of climate change on the Bay of Plenty coastline in “Impacts of climate change on coastal margins of the Bay of Plenty” (NIWA, 2006). The report assesses the potential climate change impacts on the drivers of coastal hazards that may affect the coastal margins of the Bay of Plenty coastline over the next 50-100 years. A brief summary of the report’s findings are presented in Part 5.

The National Institute of Water and Atmospheric Research Limited also provided an “Assessment of Effects of Large-Scale Climate Oscillations on The Flood Risk in the Bay of Plenty” in 2014 (NIWA, 2014). The report describes the main climate cycles affecting New Zealand and the Bay of Plenty region, the impacts they have on rainfall, river flow and resulting flood risk and their predictability. It also includes a recommendation on whether and how infrastructure planning for river schemes should consider climate cycles. The report is summarised in detail in Part 6.

Lastly, NIWA has recently prepared a report on the “Climate and Weather of the Bay of Plenty”, which summarises climate data collected from 1981-2010 (NIWA, 2013). This report is not discussed further as it focuses on the past climate.

3.3.2 Earthwise

Earthwise Consulting has prepared a report on the “Biotic Effects of Climate Change in the Bay of Plenty” (Earthwise Consulting, 2006). This report focuses on the effects of climate change on biosecurity threats (pest animals and plants), indigenous biodiversity, and economic land uses. This work draws on the findings of the NIWA 2003 report and looks specifically at effects in the Tauranga Harbour Catchment, on Rotorua Lakes, and on the Rangitaiki Plains.

For more detail please refer directly to these reports, listed in the references, Part 10.


Part 4: Climate Change for Bay of Plenty

An initial climate change assessment was undertaken by NIWA in 2003 (NIWA, 2003). It presented scenarios for future climate change and commented on temperature, rainfall, and wind changes for the Bay of Plenty for the next 50 to 100 years. Based on this report, changes in climate that are likely to occur in the Bay of Plenty include:

Warmer winters, reduced frequency of frost inland and at higher elevations, and a longer growing season.

Drier average conditions will lead to increased drought risk.

More frequent and intense rainfall events, with an increased risk of flooding and erosion.

Possibly more tropical cyclones and periods of intensive storminess.

In 2011 the climate change assessment for the Bay of Plenty has been updated by NIWA. This updated report draws on a significant body of climate change modelling and knowledge undertaken internationally and by NIWA, over the intervening eight years. Below is a summary of this report.

4.1 Climate change science

At BOPRC’s request, NIWA selected three “what-might?” scenarios to investigate in its climate change assessment, based on emission scenarios described in the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) (Figure 2):

If the middle-of-the-road greenhouse gas emission scenario (known as A1B) occurred, what might the climate of the Bay of Plenty look like at mid-century (2030-2049)?

If the middle-of-the-road greenhouse gas emission scenario (known as A1B) occurred, what might the climate of the Bay of Plenty look like at century-end (2080-2099)?

If the high greenhouse gas emission scenario (known as A2) occurred, what might the climate of the Bay of Plenty look like at century-end (2080-2099)?


For convenience, these time periods are shortened to “2040” (equivalent to 2030-2049) and “2090” (2080-2099).

Figure 2: Example of “what-might?” scenarios; IPCC projections of global temperature increase. Solid coloured lines are multi-model global averages of surface warming (relative to 1980-1999) for emission scenarios B1, A1B and A2, shown as continuations of the 20th century simulations (black line). The coloured shading denotes the ±1 standard deviation range of individual model annual averages. The grey bars at right indicate the ‘likely range’ of temperature increase at 2090-2099 relative to 1980-1999, along with the best estimate (coloured horizontal line within each grey bar), for six scenarios that span the full range of all IPCC emission scenarios. (Adapted from Figure SPM-5, IPCC 2007).

Three spatial scales were used to inform these “what might” questions:

The Bay of Plenty average (i.e. the region as a whole), for seasonal and annual mean rainfall and mean temperature.

The within-Bay-of-Plenty response; namely gridded data provided as GIS layers, with data on a 5 x 5 km grid across the Bay of Plenty Regional Council area of responsibility, for seasonal mean rainfall and seasonal mean temperature (Figure 3).

Site-specific information (for example assessing air frosts at Rotorua), for a range of extremes, such as air frosts, hot days, cold nights, drought and pasture modelling, at sites selected by Council.


Figure 3: Example of gridded GID layer; The 10-model average projected summer temperature change between 1980-1999 and 2080-2099, under an A1B emission scenario (NIWA, 2011).

Lastly, two modelling approaches were used to inform the “what might” questions:

The average (mean) of 10 Global Climate Models (GCMs) empirically downscaled to the Bay of Plenty region is the primary output given in this report, for tabular data and all of the GIS layers containing gridded 5 x 5 km data. Comparisons between observational data and multiple climate models (Lambert and Boer, 2001) show the group mean tends to have a lower error than most, if not all, of the individual models. Therefore, the 10-model average is the recommended “result” for Councils to use, if not using an “envelope” approach. To cater for an “envelope” approach, the lowest and highest response from the empirically downscaled GCM models, as well as the single result from the Regional Climate Model (see below) are given, for a selection of sites and variables.

The National Institute of Water and Atmospheric Research Limited’s Regional Climate Model (RCM) was run, nested under one GCM, and the single RCM result was incorporated into the report where relevant in Tables and Figures. In particular, the RCM outputs were downscaled to the same 5 x 5 km grid as the GCM data, and to selected station observations, and used to model drought and pasture growth at selected sites, since there are more daily climate variables available under the RCM projection than just temperature and rainfall. Key differences between the GCM and RCM results were noted, and these contributed to the overall synthesis of likely future climate in theBay of Plenty.


Climate change science is complex, as is interpreting and using the results found. Results can be viewed qualitatively for “big-picture” understanding of the likely climate of a future, warmer Bay of Plenty - such as understanding, for example, that drier winters are likely overall. Quantitative results are also available as GIS layers, with data on a 5 x 5 km grid across the Bay of Plenty region. There are 32 GIS layers available to BOPRC. Eight of these are climatological layers (i.e. reflect the present climate), quantifying present seasonal mean rainfall and seasonal mean temperatures, and 24 layers are future (seasonal) projections of likely change in mean rainfall and temperature, based on the three “what-might?” situations outlined previously. All the future layers are based on the (GCM) 10-model average.

4.2 Climate change projections for the Bay of Plenty

Climate change projections for the Bay of Plenty are:

4.2.1 Key temperature

Projections show an increase in temperature with time for the Bay of Plenty as follows:

Warm by about 1.2°C by 2040 under the A1B scenario,

Warm by about 2.7°C by 2090 under A1B,

Warm by about 3.2°C by 2090 under the higher A2 emission scenario, and

Warm slightly more in winter than the annual mean.

4.2.2 Key rainfall

In contrast to projected temperature changes, the projected rainfall changes show marked spatial variation across the Bay of Plenty. In summary, rainfall projections for the Bay of Plenty include:

For the region as a whole, virtually no change in the 10-model average annual precipitation by end-century, but a range across the models from a 10 percent decrease to a 15-20 percent increase (A1B and A2 combined),

A weak tendency for decreased precipitation by 2090 along the coast (about 5 percent),

A marked trend to winter rainfall decreases, especially for coastal locations,

A similar rainfall trend in spring to that in winter (i.e. a decrease),

A trend to increasing rainfall in the summer season, which is more marked for inland locations than at the coast,

A similar rainfall trend in autumn to that in summer (i.e. an increase).

4.2.3 Key circulation, storminess and extreme wind results

A shift in the low pressure/storm track near New Zealand in a future warmer climate is projected with drier winters but wetter summers. Daily extreme winds generated by large-scale weather systems (such as fronts and lows) are projected to decrease in summer but increase in winter, while small-scale convection will increase, which is likely to affect small-scale extreme winds associated with thunderstorms and gust fronts.

12 Climate Effects Consolidated Report – River Scheme Sustainability Project

4.2.4 Extreme temperature

The projected frequency of an air frost (air temperature below 0°C) becomes very small by century-end at the selected Bay of Plenty sites, under GCM projections. At present, the frequency of air frosts ranges from about five per year in Opotiki to 20 per year in Rotorua. By the end of the century, Rotorua is projected to experience an air frost only one to two days a year under the A1B scenario, and is projected to go some years without seeing a frost at all under A2. The frequency of cold nights is also projected to become significantly smaller in all the future scenarios.

Hot days (recording 25°C or more) are projected to become the norm during the summer months by the end of the century. For example, Whakatane has an average of 22 hot days occur per year, but by 2090 between 80 and 100 hot days per year are projected. It should be noted that the RCM estimates a larger number of air frosts and hot days, both under current climate and into the future.

4.2.5 Extreme rainfall projections

Since the water-holding capacity of the atmosphere increases with the temperature (by about 7-8 percent more for every 1°C rise in temperature), it is widely accepted that extreme rainfalls will also increase in a future warmer climate. A recent New Zealand study suggests that increases in extreme precipitation events are likely to be seen in nearly all regions of the country under a warmer climate, and may well show increases larger than 7-8 percent for every 1°C rise in temperature. Global Climate Models and RCM projections of extreme 24-hour rainfall at selected sites within the Bay of Plenty, show a general increase in the magnitude of extreme events in the future, although there are differences between the model projections.

4.2.6 Key drought results

On average, under current climate, droughts lasting more than a month are infrequent in the Bay of Plenty. Low-intensity droughts lasting more than 14 days are currently experienced in summer (on average) around 30 percent of the time at Katikati and Te Puke, and about 20 percent of the time at Whakamarama and the eastern sites Te Teko and Opotiki.

Projections under A1B and A2 by century-end show the largest changes are likely to occur in droughts lasting longer than a month. At the five sites analysed, increases of between 9 percent and 17 percent in time spent in low-intensity summer drought, lasting one month or more, are likely at 2090 under A1B (compared to 20-26 percent under A2, with the exception of Opotiki). Notably, under A2 at 2090, the time spent in moderate and high-intensity droughts lasting a month or more is also generally increased (by between 0-8 percent across all five sites), which is consistent with the predictions in previous national drought analyses.

4.2.7 Key pasture growth modelling results

The relatively warm, dry summers and cool, wet winters in the Bay of Plenty yield an annual pasture growth curve with a distinct, reliable, spring growth peak, variable autumn growth peak and low winter growth (due to cool temperatures limiting growth rates). Near the ranges, winter growth is lower and summer growth is higher than along the coast, due to the lower temperatures and higher summer rainfall observed.


A coupled soil-water balance and pasture production model of stock-grazed ryegrass pasture was used to model future pasture growth (with no adaptation). Projections at 2090 show little change in annual pasture biomass but significant changes in the seasonality of pasture growth in the Bay of Plenty. Projected higher summer temperatures reduce summer pasture growth significantly at 2090 under both A1B and A2. Milder winter temperatures result in large increases in winter growth (double current levels along the coast, and treble inland by 2090). Total spring growth and reliability of spring growth are unchanged.

In contrast, at mid-century under A1B, there is a projected reduction of low growth years, giving a slightly higher median summer pasture growth, which reflects the RCM and GCM 10-model average projection of increased summer rainfall under A1B at 2040. This is most likely to be due to inter-decadal climate variability (i.e. wet and/or dry decades), based on natural climate cycles.

4.2.8 Specific sites results

Whilst the previous section concentrated on results for the Bay of Plenty as a whole and across the region based on gridded data, this section presents results at selected sites within the Bay of Plenty.

Temperature: increased temperature, little spatial variation, i.e. Tauranga warms about the same as Whakatāne.

Rainfall: rainfall projections show marked spatial variation across Bay of Plenty. Maps of NIWA’s rainfall projections for the region are available as GIS layers. Rainfall projections to end of century for the high end scenario (A2) are shown in Appendix 2.

Air frosts: generally less air frosts (e.g. Rotorua now: 20 days per year; end of century: 1-2 days per year.

Cold nights: fewer cold nights.

Hot days (>25℃¿ and very hot days (more than 30ºC): more hot days (e.g. Whakatāne now: 22 per year, end of century: 80-100 per year). More very hot days (e.g. Rotorua now: once every five years, end of century: twice a year).

Rainfall extremes: general increase in magnitude of extreme rain events.

Drought: a general increase in time spent in low-, moderate- and high-intensity droughts lasting one month or more.

Pasture growth: little change in annual pasture biomass, but significant changes in the seasonality of pasture growth in the Bay of Plenty.


Part 5: Sea level rise for Bay of Plenty

5.1 Impacts on coastal margins

The NIWA report on impacts of climate change on the coastal margins of the Bay of Plenty (NIWA, 2006) confirms that climatic variation can influence storminess, wave conditions, sediment supply and coastal processes such as erosion. Future changes in climate will alter these processes in the coastal environment, but in many instances there needs to be more data to accurately assess impacts. This also applies to sea level rise, which has been increasing at a historical rate of around 1.8 mm/year. Accurate local impact assessment is not possible until more information becomes available on rates of vertical land movement throughout the Bay of Plenty and any acceleration that could occur with global climate change. In the meantime, the current global estimate is considered appropriate and it is recommended that, for planning purposes, an allowance of 0.5 m for 2100 is used.

5.2 Sea level rise

Global sea level rise estimates vary. The IPCC Fourth Assessment Report (IPCC, 2007) states that computer modelling has suggested a range of projected sea level rise from 0.18-0.59 m by the end of the century, assuming contributions from ice flow from Greenland and Antarctica remain at rates observed from 1993-2003. An extra 0.1-0.2 m rise would be expected if these ice-sheet contributions were to grow, in line with global temperature increases. Future sea level advice for New Zealand is a base rise of 0.5 m and potential rise of at least 0.8 m (both are relative to the 1980-1999 average) with an allowance of 10 mm per year beyond 2100, based on Ministry for the Environment Guidelines (MfE, 2008a).

The Intergovernmental Panel on Climate Change has released its Fifth Assessment during 2014 (IPCC, 2014) and the Ministry for the Environment is expected to update its guidelines during 2016 to reflect the IPCC5 findings. Current sea level rise advice in Pathways to Change (NIWA, 2011) advises a minimum of 1.0 m rise by 2115. Current climate change guidance from Ministry for the Environment (MfE, 2008a) projects forward to the year 2090. This is no longer a 100-year future projection period. It is expected that the updated MfE Guidelines of 2016 will include an updated 100-year projection period.

5.3 Council Policy – Operative Regional Policy Statement

The Operative Regional Policy Statement – Natural Hazard Policy NH11B: Providing for climate change states:

Incorporate the effects of climate change in natural hazard risk assessment. Authoritative up-to-date projections of changes in sea level, rainfall, temperature, and storm frequency and severity will be used as updated scientific data become available.

Use the following projections as minimum values when undertaking coastal hazard assessments:

(a) A 100-year time frame,

(b) A projection of a base sea-level rise of at least 0.6 m (above the 1980–1999 average) for activities/developments which are relocatable,


(c) A projection of a base sea-level rise of 0.9 m (above the 1980–1999 average) for activities where future adaptation options are limited, such as regionally significant infrastructure and developments which cannot be relocated, and

(d) An additional sea-level rise of 10mm per annum for activities with life spans beyond 2112.

Explanation

Climate change has implications for many natural hazards including coastal hazards, landslip, sedimentation, wind, drought, fire and flooding.

Policy NH 11B seeks to ensure a consistent approach to identifying and assessing coastal hazards, which aligns with the most recent and internationally accepted scientific knowledge on climate change risk. This Policy and Policy IR 2B set out minimum values for climate change projections, to be taken into account when assessing natural hazards and identifying the types of natural hazards likely to be exacerbated by climate change. Current sea-level rise projections have been derived from: Coastal Hazards and Climate Change: A Guidance Manual for Local Government in New Zealand, Ministry for the Environment, May 2008a.

Rationale for RPS policy NH 11B numbers differing from MfE guidance referenced in the Explanation [Ministry for the Environment 2008. Coastal Hazards and Climate Change. A Guidance Manual for Local Government in New Zealand. 2nd edition. Revised by Ramsay, D, and Bell, R. (NIWA). Prepared for Ministry for the Environment. viii+127 p. ISBN: 978-0-478-33118-9 (print), 978-0-478-33119-6 (electronic), ME number: 89]:

The values in Policy NH 11B were set in line with the New Zealand Coastal Policy Statement, which requires a 100-year timeframe (minimum) and the guidance and policy itself, which requires a rate of increase of 10 mm per year beyond 2100,(to 2012, when Policy NH 11B was finalised) as follows:

For paragraph (b) of Policy NH 11B:

The current base sea-level rise of 0.5 m was set in 2007. Five years have elapsed. 10 mm per annum x 5 = 50 mm. So the 2012 base should be 0.5 + 0.05 = 0.55 m, rounded to 0.6 m.

For (c):

The current base sea-level rise of 0.8 m was set in 2007. That guidance is for the 2090s (2090–2099). A minimum of 100 years, to 2112, requires an additional 13 years, 12 of which are “beyond 2100”.

10 mm per annum x 12 = 120 mm. So the 2012 base should be 0.8 + 0.12 = 0.92, rounded to 0.9 m.

For (d):

Change “beyond 2100” to “beyond 2112”.

When taken to 2015, the (c) value, to two decimal places, would be 0.92 + (10 mm x (2115-2112) = 0.92 + 0.03 = 0.95 m or 1.0 m to one decimal place.


Part 6: Climate cycles in the Bay of Plenty

The National Institute of Water and Atmospheric Research Limited’s 2014 Climate Cycles report describes the main climate oscillations affecting New Zealand and the Bay of Plenty region, and the impacts they have on rainfall, river flow and resulting flood risk. It also describes the rainfall regime of New Zealand and recent trends in the Bay of Plenty rainfall record. The report is summarised below.

6.1 Rainfall regime and trends

Precipitation in the region is highly variable spatially and temporally. Several trends are identified:

Total rainfall generally decreased in the Bay of Plenty since the 1960s or 1970s, but this reduction was only statistically significant at the 95 percent level at Tauranga. Year to year variability of total annual rainfall was found to be large in the region.

Typically there are about 95 rain days per year in the Bay of Plenty at coastal sites such as Tauranga and Ōpōtiki, but his has risen to up to 134 days per year during extreme years.

There has been a significant, long-term trend towards fewer rain days at some stations in the Bay of Plenty over the study period (1900-2002), with much of this reduction occurring since the 1960s or 1970s. In very wet years, the number of rain days was typically high, with the converse also true.

An extreme rain index was calculated measuring the fourth largest rainfall amount per year. Extreme (large) daily rainfall has not changed significantly over the 20th century in the Bay of Plenty. However, in the short-term, the years from 1970-2002 have been atypical in that extreme daily rainfalls have been generally lower than seen elsewhere in the historical climate record (at least at coastal or lower evaluation stations). For this reason, planning or policy decisions should not be made based on this part of the record alone. Variability in extreme rainfall in the region remains very large and needs to be considered.

The frequency of extreme daily rainfall has decreased across the Bay of Plenty over the past 100 or so years, but the decrease is significant only at Tauranga. Regardless, the climate from circa 1970-2002 was atypical, in that extreme daily rainfalls were less frequent than recorded elsewhere in the historical climate record.

The average magnitude of the top four (very extreme) daily rainfalls per year has not significantly changed in the past 100 years across the Bay of Plenty except at Tauranga, which shows a small decrease over the period 1910-2002. However, the 1980s and 1990s have been unusual at some stations in the region in that extreme daily rainfalls have been generally smaller in magnitude than seen at other times in the past. These stations exhibit a large decrease in the extreme intensity index after the early 1970s, and therefore recent climate is not generally representative for long-term planning.

Over the 50-year period 1951-2000, seasonal rainfall has decreased over most of the region in most seasons. Decreases have been larger in the west (Tauranga westwards) than in the east (Whakatāne eastwards) and south. Tauranga rainfall has decreased by about 10 percent in winter to 30 percent in summer since 1951.

6.2 Impacts of climate oscillationsClimate Effects Consolidated Report – River Scheme Sustainability Project 17

The report reviews four large-scale natural climate cycles and their corresponding impacts on rainfall and flood flow in New Zealand and specifically the Bay of Plenty:

Interdecadal Pacific Oscillation (IPO).

El Nino Southern Oscillation (ENSO).

Southern Annular Mode (SAM).

Indian Ocean Dipole (IOD).

6.2.1 Interdecadal Pacific Oscillation

The Interdecadal Pacific Oscillation (IPO) is a natural fluctuation in climate over parts of the Pacific Ocean. It shows characteristic circulation patterns for phases of about 20-30 years. During the 20th Century, three major phases of the IPO were identified – a positive drier phase (1922-1945) for the Bay of Plenty, a negative wetter phase (1947-1977), and another positive phase (1978-1999). The start of the 21st Century has seen a return to negative, wetter, IPO conditions (Figure 4).

Figure 4 Phases of the IPO. Positive = dry; Negative = wet in the Bay of Plenty (NIWA, 2014; Data courtesy of the Hadley Centre, UK Meteorological Office).

These patterns are the “average” response and do not mean that every year of a particular IPO phase will behave in the same way.

No scheme for predicting when a shift may occur is known.

6.2.2 El Nino Southern Oscillation

The El Nino Southern Oscillation (ENSO) is a natural fluctuation of the global climate and refers to the variation in sea surface temperature across the equatorial Pacific Ocean and in surface air pressure in the tropical western Pacific. El Nino and La Nino refer to opposite extremes of the ENSO cycle and occur every three to seven years. A common measure of the intensity and state of the ENSO events is the Southern Oscillation Index (SOI) (Figure 5).


Figure 5 Southern Oscillation Index from 1930-2014. La Nina = positive = wetter; El Nino = negative = drier for Bay of Plenty (NIWA, 2014).

In general, during an El Nino, New Zealand experiences a stronger than normal south-westerly airflow leading to drier than normal conditions in the east of the country (i.e. the Bay of Plenty). Conversely, during La Nina, more north-easterly flows ensue, leading to wetter than normal conditions in the north and east of the North Island. Individual events can differ substantially from this pattern. El Nino Southern Oscillation can occur at any time of the year, but its peak usually occurs during spring and summer. Once El Nino or La Nina events have commenced, their evolution is partly predictable for the coming few months.

6.2.3 Southern Annular Mode

The Southern Annular Mode (SAM) is a ring of climatic variability circling the South Pole. It influences the South Island more dominantly than the North Island. The positive phase of the SAM during summer induced wetter conditions along the east of the North Island. Likewise, the positive of the SAM in winter brings wetter conditions to the Bay of Plenty.

6.2.4 Indian Ocean Dipole

The Indian Ocean Dipole (IOD) is a coupled ocean-atmosphere phenomenon in the Indian Ocean, defined by the difference in sea surface temperature between a western pole in the western Indian Ocean and an eastern pole in the eastern Indian Ocean. A general effect of increased rainfall in the Bay of Plenty during a negative phase is likely.

The SAM and IOD have less influence on rainfall and river flow in New Zealand, with limited studies encompassing the Bay of Plenty region.

6.2.5 Analysis of river flows

Bay of Plenty river flows for the larger rivers have been well monitored. A study of these records showed partial support for the concept of the IPO phases influencing flood magnitude of some Bay of Plenty rivers (Rangitāiki, Tarawera and Whakatāne). Analysis of extreme rainfall records for the region also offers some supporting evidence of the IPO phases, although this effect is not evident in the records of other rivers (Kaituna, Waioeka, Mōtū).


6.3 Climate change and other variables

Climate cycles will be superimposed on top of the impacts of climate change. Therefore, adaptation to changes in rainfall and flood flow will need to incorporate both the shorter-scale natural climatic variations as well as long-term trends.

The combination of climate change, interacting natural climate oscillations and other variables such as land use change, make long-term impacts to flood risk difficult to determine. There is some supporting evidence for the long-term climate cycles (ENSO and IPO) likely to have an influence on the observed temporal clustering of floods but the relationship is not always clear. Designers of permanent structures such as bridges and stopbanks need to use all available records, particularly those extending over two or more phases of the IPO.

6.4 Conclusion

At present, NIWA suggest there is insufficient evidence for delaying infrastructure expenditure based on the timing and effects of climate cycles. They strongly recommend to continue the collection of river flow, rainfall and other climate data throughout the region, and re-examine relationships between flood flow and climate cycles regularly. The continued monitoring will also be vital in any future assessment of the potential impacts of climate change.


Part 7: Regional application of climate change and sea level rise in policy and guidelines and projects

This section outlines how Council uses the available information on climate change as part of its statutory role. It generally follows the bottom section of the schematic shown in Figure 1.

7.1 Local Government role

The statutory role of Local Government with respect to climate change, comes from the Resource Management Act and sub-ordinate national policy statements. The role can be liberally interpreted as assisting communities adapt to the foreseeable effects of a changing climate. Central Government has the role for setting national greenhouse gas emission targets and developing the market mechanisms to achieve these (SOLGM, 2015).

7.2 Council policy and guidelines

The findings of the reports listed in Part 3, particularly projections on future temperature, rainfall and sea level, are then used within BOPRC policy and guidelines documents, such as the Regional Policy Statement Natural Hazards (RPS Nat. Haz.), Position Statement on Climate Change in the Long Term Plan 2015-2025 (BOPRC, 2015), Regional Coastal Policy Statement (RCPS), Bay of Plenty Regional Coastal Environment Plan, Hydrological and Hydraulic Guidelines, Stormwater Guidelines, and the Asset Management Plan. More detail on sea level rise predictions included in the Regional Policy Statement Natural Hazards (RPS Nat. Haz.) is given in Part 5.

Bay of Plenty Regional Council aims to future-proof the region against climate change by providing advice and developing policy to help the region adapt and become more resilient to the effects of climate change. Some examples of what Council is doing to manage/address climate change are outlined below. It should be noted that the projects are integrated and draw off the learnings of each other.

7.2.1 Set policy and rules

The Bay of Plenty Regional Policy Statement (RPS) (BOPRC, 2014) requires the effects of climate change to be recognised and provided for in integrated planning and natural hazard risk assessment, noting that setting policy and rules for coastal communities requires robust evidence. The Bay of Plenty RPS and the Regional Coastal Environment Plan (BOPRC, 2014a) implements the Ministry for the Environment (MfE) current guidance manual. Since it became operative in 2003, the Regional Coastal Environment Plan has required sea-level rise to be taken into account in identifying coastal hazards. This has in turn been included in relevant city and district plans in the region.

7.2.2 Rivers and drainage schemes

Bay of Plenty Regional Council’s Infrastructure Strategy (2015 – 2045) (BOPRC, 2015a) and Rivers and Drainage Asset Management Plan (2014/2015) (BOPRC, 2015b) identified climate-change-related sea level rise and increased intensity and frequency of storm events as significant issues. The Infrastructure Strategy proposes to set aside $8.4M over the next 30 years, specifically for climate change capital works for four rivers and drainage schemes that provide flood protection in the region.


7.2.3 Regional flood risk management

Bay of Plenty Regional Council is working collaboratively with territorial authorities in the region and other key stakeholders to establish a better way of mitigating flood risk across the region. Current mechanisms tend to have a structural focus. A 100-year catchment-wide focus, similar to the River Scheme Sustainability Project, will be used to steer decision-making.

7.2.4 Provide guidance

Bay of Plenty Regional Council has prepared guidance documents that include reference and design advice for the effects of climate change, referenced back to MfE current guidance. These include the Hydraulic and Hydrological Guidelines (BOPRC, 2012) and the Stormwater Guidelines (BOPRC, 2012a). Note: guideline documents are non-statutory documents and are therefore non-enforceable.

7.2.5 Share local climate change projections with our communities

Bay of Plenty Regional Council commissioned NIWA (2011) to assess and model the potential changes on temperature, rainfall, wind, drought, frost days and pasture growth as a result of selected climate change scenarios as per IPCC4 projections. This generated local-scale information (32 scenario combinations in GIS format) of potential climate change impacts across the Bay of Plenty. This information was shared with primary industries and research communities (e.g. Zespri, avocado growers and HortResearch) and territorial authorities in our region for their use. The information was also made into an easy-to-read and easy-to-relate-to pamphlet and website material available for the wider community.

7.2.6 Provide technical advice - coastal calculator

Bay of Plenty Regional Council has commissioned NIWA to apply its latest coastal science to the Bay of Plenty, to create a tool that calculates the height of the sea at 21 locations around the region. The tool calculates storm surge, wave set-up and wave run-up, plus adds a linear sea-level rise elevation increase. The National Institute of Water and Atmospheric Research Limited has completed similar analysis for other New Zealand councils and translated results into coastal inundation maps for some of them. The National Institute of Water and Atmospheric Research Limited has completed inundation mapping of the Auckland Council using 1 and 2 m SLR projections and this work is before the Environment Court, with NIWA being expert witness for Auckland Council. We have been advised that the 1 m SLR projected inundation levels, appear to have generated little public feedback but the 2 m SLR inundation zone is creating a vocal response.

7.2.7 Provide technical advice – floodplain mapping

Bay of Plenty Regional Council undertakes modelling to generate flood hazard maps for areas associated with Council rivers and drainage schemes as part of floodplain management strategies (EBOP, 2001; EBOP, 2008; EBOP, 2008a). The mapping includes allowance for climate change derived rainfall and sea level rise. Flood levels are used for flood scheme design and providing minimum floor-level advice.


7.2.8 Feedback to MfE for climate change guideline updates

Bay of Plenty Regional Council has participated in a workshop and provided feedback to MfE, about what the industry requires from updated MfE Climate Change Guidance documents. We have requested that more numbers, levels and real applicable information be included in updated guidance, and that guidance is updated in a timelier manner so it remains current and relevant. We have been advised that MfE may not issue the update to the 2008 guidance to include IPCC5 for another year. The 2008 guidance provides projections to the year 2090 but the 100-year future window is now 2115, making the MfE guidance projections 25 years too short, compared to 100-year statutory requirements in the RPS.

7.2.9 Advice to territorial authorities

Bay of Plenty Regional Council advises our territorial authorities on district plan changes associated with flooding, climate change impacts and areas to be released for development, so that we collaboratively create safer and more resilient communities (one of our Community Outcomes).

7.3 Council projects

Current BOPRC projects that use the research findings are the River Scheme Sustainability Project (RSS), the Water Programme and the Spatial Plan.

7.3.1 River Scheme Sustainability Project

Council’s River Scheme Sustainability Project incorporates climate change for future decision-making in a 100-year framework for each flood scheme catchment. This project aims to explore the best long-term sustainable solutions for the future of the river schemes in the Bay of Plenty. Climate change factors increase the cost of hard engineering solutions, so the Council project also considers “working with nature”, soft engineering solutions and non-structural options where applicable.

7.3.2 Water Management Programme

The Water Management Programme is also including climate change within its long-term planning.

7.3.3 Spatial planning

Bay of Plenty Regional Council is undertaking spatial planning analysis. The current status is that layers of information are being developed and assessed, including projected climate change impacts. Over the next six months the layers will be integrated to develop a clear understanding and a document prepared detailing findings.

7.3.4 Seek opportunities to build understanding

Bay of Plenty Regional Council is also taking part in case studies and sharing information and knowledge with research institutions, to better understand how to adapt to climate change. Current research partners include the International Global Change Institute (IGCI, University of Waikato), LandCare Research, and NIWA.


Bay of Plenty Regional Council is participating in a case study in a Government-funded four-year targeted research project called “Climate Change, Impacts and Implications for New Zealand”. This project aims to generate new knowledge about likely climate change impacts, including those on ecosystems and primary production.

One of the case studies is focused on wetlands in the lower Kaituna River Catchment. The case study is looking into key pressures, critical time steps and potential responses. The project is also exploring the increasing relevance of climate change science and decision-making capacity to consider climate change risks through collaborative learning process.


Part 8: Application of climate change

8.1 Effects of climate change on river schemes

The River Scheme Sustainability project’s goal is to set direction for sustainable management of the five major river and drainage schemes (Kaituna Catchment Control Scheme, Rangitāiki-Tarawera River Scheme, Whakatāne-Waimana River Scheme, Waioeka-Otara River Scheme and Rangitāiki Drainage Scheme) for the next 100 years. The goal is to reduce long-term risk of flood hazards while encouraging environmentally and economically sustainable land-use practices, and raising awareness and changing attitudes and behaviour in the communities.

As we expect the climate to change over the next 100 years, this will affect the management of the river schemes. This report will help us better understand the impact of weather cycles and climate change on the river schemes. Future climate change impacts to consider are:

Sea level rise: affects all schemes similarly. Drainage, pumping, decreased level of service of coastal flood protection.

Rainfall/storms: increased flood risk, decreased level of service of flood protection and increased erosion, coastal storms effects and sediment transport to estuaries and harbours. Increased drought risk may affect future land use.

8.2 Recommendations for future work

To better manage river schemes sustainably in the long term, this report has highlighted the following recommendations for further work in future:

Review NIWA’s Coastal Calculator: the coastal calculator is a tool developed by NIWA to calculate design wave run-up levels for specific coastal areas (review is currently under way).

IPCC 2014: The IPCC’s Fifth Assessment is published but waiting for summary and guidance by MfE.

MfE 2016: an updated guidance document is due now, based on the IPCC Fifth Assessment. It is expected to be available in 2016. Once the new guidance document is available, regional applications documents should be reviewed to ensure they are aligned with the new guide.

Climate change projected expenditure in the AMP and Infrastructure Strategy should be updated once the new MfE guidance document is available. This will quantify the climate change implications on the river schemes.

Review Climate Change projections: The climate change projections for the Bay of Plenty (NIWA, 2011) should be reviewed and updated with any new and significantly different climate change guidance from IPCC/MfE.

Maintain climate monitoring sites and regime to ensure trends in climate change are captured.

Review climate cycles data in 10 years’ time.

Incorporate climate change information into planning/regulatory documents.


Part 9: Conclusion

Bay of Plenty Regional Council aims to future-proof the region against climate change by providing advice and developing policy to help the region adapt and become more resilient to the effects of climate change. The consolidated report outlines how the council uses the research information in its policy, guidelines and projects.

International, national and regional guidance on climate change and its effects on the Bay of Plenty are documented in this report, which looks at climate change and cycles for the Bay of Plenty. Specific effects of climate change and climate effects in the Bay of Plenty are presented in the context of their application to river schemes for consideration in the long-term sustainability of these schemes.

The information summarised within this report presents a good starting point for further investigating climate change considerations and incorporating climate change into our planning and operation. In particular the River Scheme Sustainability project will utilise the updated information when undertaking analysis of options for the future within a 100-year framework for each scheme.

We expect additional climate change information from other agencies will become available in the near future, including:

Ministry for the Environment - Coastal hazard and climate change guidance.

Parliamentary Commissioner for the Environment - Sea level rise.

Once available, this information should be incorporated into the development of a strategic approach to climate change in the Bay of Plenty.


Part 10: References

BOPRC, 2012; Hydrological and Hydraulic Guidelines. Guideline 2012/02.

BOPRC, 2012a; Stormwater Management Guidelines for the Bay of Plenty region. Guideline 2012/01.

BOPRC, 2014; Operative Regional Policy Statement for the Bay of Plenty. Strategic Policy Publication 2013/04.

BOPRC, 2014a; Proposed Regional Coastal Environment Plan. Strategic Policy Publication 2014/01.

BOPRC, 2015; Long Term Plan 2015-2025.

BOPRC, 2015a; Draft Infrastructure Strategy 2015-2045.

BOPRC, 2015b; 2014/2015 Draft Rivers and Drainage Asset Management Plan.

Earthwise Consulting, 2006. Biotic Effects of Climate Change in the Bay of Plenty. Prepared for Environment Bay of Plenty, March 2006.

Environment Bay of Plenty and Ōpōtiki District Council, 2001. Waioeka-Otara Floodplain Management Strategy.

Environment Bay of Plenty, 2008. Whakatāne-Waimana Floodplain Management Strategy. Operations Publication 2008/09.

Environment Bay of Plenty, 2008a. Rangitāiki-Tarawera Floodplain Management Strategy. Rivers and Drainage Publication 2008/01.

IPCC, 2007. Climate Change 2007: Fourth Assessment Report of the Intergovernmental Panel on Climate Change.

IPCC, 2014. Climate Change 2014: Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

MfE, 2008. Climate Change Effects and Impact Assessment: A Guidance Manual for Local Government in New Zealand; Ministry for the Environment, May 2008.

MfE, 2008a. Coastal hazards and climate change: A guidance manual for Local Government in New Zealand; Ministry for the Environment, July 2008.

MfE, 2008b. Preparing for Climate Change: A guide for Local Government in New Zealand; Ministry for the Environment, July 2008.

MfE, 2009. Preparing for Coastal Change: A guide for Local Government in New Zealand; Ministry for the Environment, March 2009.

MfE, 2010. Tools for estimating the effects of climate change on flood flow: A guidance manual for Local Government in New Zealand; Ministry for the Environment, May 2010.

MfE, 2010a. Preparing for Future Flooding: A guide for Local Government in New Zealand; Ministry for the Environment, May 2010.

NIWA, 2003. The Climate of the Bay of Plenty: Past and Future?; NIWA Client Report AKL2003-044, prepared for Environment Bay of Plenty, June 2003.


NIWA, 2006. Impacts of climate change on coastal margins of the Bay of Plenty. NIWA Client Report HAM2006-031, prepared for Environment Bay of Plenty, May 2006.

NIWA, 2011.Coastal Adaptation to Climate Change – Pathways to Change. November 2011.

NIWA, 2011a. An updated climate change assessment for the Bay of Plenty. NIWA Client Report AKL2011-019, prepared for Bay of Plenty Regional Council, December 2011.

NIWA, 2013. The climate and weather of Bay of Plenty. NIWA Science and Technology Series Number 62. 3rd edition, 2013.

NIWA, 2014. Assessment of the effects of large-scale climate oscillations on the flood risk in the Bay of Plenty. NIWA Client Report AKL2014-035, prepared for Bay of Plenty Regional Council, December 2014.

SOLGM, 2015. Climate Change and Local Government; DRAFT Report to the Society of Local Government Managers, Sector Futures Working Party.


Appendices


Appendix 1 – Glossary

AMP – Asset Management Plan.

BA – Building Act.

BOPRC – Bay of Plenty Regional Council.

CDEMA – Civil Defence and Emergency Management Act.

Climate – the weather conditions prevailing in an area in general or over a long period.

Climate Change – a change in global or regional climate patterns, in particular a change apparent from the mid-20th Century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels.

Climate Cycles – a recurring cyclical oscillation within global or regional climate, and a type of climate pattern.

CPS – Coastal Policy Statement.

ECL – Earthwise Consulting Limited.

ENSO – El Nino Southern Oscillation.

FMS – Floodplain Management Strategy.

H&H Guidelines – Hydrological and Hydraulic Guidelines.

IOD – Indian Ocean Dipole.

IPO – Interdecadal Pacific Oscillation.

IPCC – Intergovernmental Panel on Climate Change.

LGA – Local Government Act.

LTP – Long-Term Plan.

MfE – Ministry for the Environment.

NIWA – National Institute of Water and Atmospheric Research Limited.

RF – Rainfall.

RFRMF – Regional Flood Risk Management Framework.

RMA – Resource Management Act.

RSS – River Scheme Sustainability Project.

SAM – Southern Annular Mode.

SLR – Sea Level Rise.

SOLGM – Society of Local Government Managers.

SW guidelines – Stormwater Guidelines.


Temp – Temperature.

Weather – a state of the atmosphere at a particular place and time as regards heat, cloudiness, dryness, sunshine, wind, rain etc.


Appendix 2 – Rainfall projection maps

Figure 6 Bay of Plenty projected spring (September-November) mean rainfall change (%) to end century – high end scenario (A2)


Figure 7 Bay of Plenty projected summer (December-February) mean rainfall change (%) to end century – high end scenario (A2)


Figure 8 Bay of Plenty projected autumn (March-May) mean rainfall change (%) to end century – high end scenario (A2)


Figure 9 Bay of Plenty projected winter (June-August) mean rainfall change (%) to end century – high end scenario (A2)


Documents

Environment B·O·P - Home - Bay of Plenty Regional … · Web viewEnvironment Bay of Plenty 8Climate Effects Consolidated Report – River Scheme Sustainability Project Climate Effects