IPCC 5th Assessment Report Impacts and adaptation

Global overview and key findings for Australia

Andy Reisinger

Coordinating lead author, WGII (Impacts, Adaptation, Vulnerability) Ch. 25 Core Writing Team member, Synthesis Report

The Review Process

• One informal, two formal expert reviews, final government review

• Total review comments on WGII: 48,142 (plus 2350 on final SPM)

• 1729 expert reviewers from 84 countries, 49 governments

2590 page report → 30 page Summary (SPM)

(Working Group II only!)

A CHANGING WORLD

WARMING OF THE CLIMATE SYSTEM IS UNEQUIVOCAL,

WITH WIDESPREAD OBSERVED IMPACTS

WGII Summary for Policymakers

AROUND THE WORLD

VULNERABILITY AND EXPOSURE

William West / AFP / Getty Images

THE LIKELIHOOD OF

INCREASING MAGNITUDES OF WARMING INCREASE

SEVERE AND PERVASIVE IMPACTS

IPCC 5th Assessment Report Reasons for Concern

Alternative climate futures entail very different risks

WGII Summary for Policymakers

8

IPCC 5th Assessment Report Mitigation Pathways

Limiting warming to 2°C requires substantial and rapid emissions reductions

Based on WGI and III Summaries for Policymakers, calculations using MAGICC

what emissions path- way is consistent with limiting warming to 2°C? do all decision-makers really understand the magnitude of the challenge?

?

9

IPCC 5th Assessment Report Mitigation Pathways

Limiting warming to 2°C requires substantial and rapid emissions reductions

GHG-intensive emissions pathways may be difficult or very costly to change – major benefit of early action

Delay increases risks and costs. Country pledges for 2020 are not on a cost-effective path to limit warming to 2°C

Based on WGI and III Summaries for Policymakers, calculations using MAGICC

Emissions pathway consistent with 2°C goal

Working Group II Chapter 25 Australasia (IPCC) = Australia + NZ

Observed and projected climate

WGII Chapter 25 – based on CMIP5 model results

Days >40°C (unmitigated emissions)

~ 1990 40°C

WGII Chapter 25 – based on CSIRO report

Days >40°C (unmitigated emissions)

~ 2050 40°C

WGII Chapter 25 – based on CSIRO report

Days >40°C (unmitigated emissions)

~ 1990 ~ 2050 ~ 2100 40°C

WGII Chapter 25 – based on CSIRO report

Days >40°C (unmitigated emissions)

~ 1990 ~ 2050 ~ 2100 40°C

WGII Chapter 25 – based on CSIRO report

Regional Key Risks for Australasia

Impacts that appear difficult to avoid entirely even with mitigation ◦ coral reefs, montane ecosystems (Australia)

Impacts amenable to risk reduction by mitigation and adaptation (the less mitigation, the more transformative adaptation required)

◦ flooding, wild fire (Australia and New Zealand)

◦ water resource constraints, heat waves (Australia)

Impacts subject to large climate uncertainty, with major risk at upper end of changes and associated adaptation challenges ◦ widespread damages from sea level rise

(Australia and New Zealand; at upper end of projected changes)

◦ significant reduction in agriculture production (Australia; at dry end of projected changes)

WGII Chapter 25

Identified based on biophysical impacts, likelihood, timing and persistence, vulnerability of the affected system based on exposure, magnitude of harm, significance of the system and its ability to cope with or adapt to changes

Regional Key Risks for Australasia Key risk (example): increased frequency/intensity of flood damages

risks with current adaptation

risk reduced with high adaptation

WGII Chapter 25

Adaptation pathways

WGII Chapter 25

Adaptation pathways

WGII Chapter 25

Adaptation pathways

WGII Chapter 25

Incremental: doing better/more of what we do now

Transformational: accept that something has to give; re-assess objectives and change course • balance protection / accommodation / retreat

• relocation of industries, diversification

• balance of social, environmental, economic objectives

Needs coordination across decision-makers

Need to protect vulnerable parts of society

Building stable consensus takes (a long, long) time

Adaptation: transformation

EFFECTIVE CLIMATE CHANGE ADAPTATION

A MORE VIBRANT WORLD

Challenges and reflections

A comprehensive regional assessment in 25 pages?

Engagement by the science community is critical – but be careful what you wish for

Is Australia more vulnerable or New Zealand less studied?

Integrating inputs from different science communities into a single document is vital but very challenging

No country is an island – but very limited work on flow-on effects from impacts and responses overseas

Thank you www.ipcc.ch Working Group I: Physical Science Basis

Working Group II: Impacts, Adaptation, Vulnerability

Chapter 25: Australasia (ipcc-wg2.gov/AR5)

Working Group III: Mitigation (reducing emissions)

andy.reisinger@nzagrc.org.nz