The IPCC Fourth Assessment Report and global climate change

Pete Smith

Royal Society-Wolfson Professor of Soils & Global ChangeInstitute of Biological & Environmental SciencesSchool of Biological Sciences, University of Aberdeen,Scotland, UK. E-mail: pete.smith@abdn.ac.uk

SDC Scotland & Scottish Government - Climate Change Seminar & Evening Reception,

Scottish Parliament, Wednesday 29th October 2008

Outline

• What is the IPCC? • Main findings of IPCC on climate• Main findings of IPCC on impacts and

adaptation• Main findings of IPCC on mitigation• The political process• Conclusions

Outline

• What is the IPCC? • Main findings of IPCC on climate• Main findings of IPCC on impacts and

adaptation• Main findings of IPCC on mitigation• The political process• Conclusions

What is the IPCC?

Website: www.ipcc.ch

• IPCC : Intergovernmental Panel on Climate Change

• Created by World Meteorological Organisation (WMO) & United Nations Environment Programme (UNEP) in 1988

• Mandate: assess the science of climate change, impacts and adaptation, mitigation options

• Publishes consensus reports (1990, 1996, 2001, 2007) (Cambridge University Press)

• Advises Climate Change Convention

• Nobel Peace Prize 2007

The three main working groups of IPCC

• WGI – Climatology• WGII – Impacts and Adaptation• WGIII – Mitigation

• Plus:– Special reports– National Greenhouse Gas Inventories

Programme

Outline

• What is the IPCC? • Main findings of IPCC on climate• Main findings of IPCC on impacts and

adaptation• Main findings of IPCC on mitigation• The political process• Conclusions

Current atmospheric concentrations of carbon dioxide and methane far exceed pre-industrial values determined from ice cores spanning the last 650,000 years. The increases in these greenhouse gases since 1750 are due primarily to emissions from fossil fuel use, agriculture, and land-use changes.

Humans are responsible for large increases in atmospheric GHG concentrations in the atmosphere

IPCC, AR4, WGI (2007)

The 100-year linear trend (1906–2005) is 0.74 [0.56 to 0.92]°C. The linear rate of warming averaged over the last 50 years (0.13 [0.10 to 0.16]°C per decade) is nearly twice that for the last 100 years showing that global warming is increasing.

Increases in atmospheric GHG concentrations are leading to pronounced global warming

IPCC, AR4, WGI (2007)

1850 1900 1950 2000

Difference from 1961-1990 long term average

There are different regional trends in temperature increase but they cannot be explained without human GHG emission increases

IPCC, AR4, WGI (2007)

Climate projections without mitigation

IPCC, AR4, WGI (2007)

Main findings of IPCC on climate

IPCC, AR4, WGI (2007)

• Warming of the climate system is unequivocal

• Very high confidence that net effect of human activities since 1750 = warming

• Last 50 years likely to be highest temperature in at least last 1300 yrs

• Most of this warming is very likely due to increase in human greenhouse gases

• Without emission reduction policies, global temperature could increase by 1.1 to 6.4°C, or even higher in 2100 compared to 1990

• Sea level could increase by 18 to 59 cm, or more

• Frequency/intensity of several extreme phenomena due to increase (ex: heat waves, droughts, floods, …)

Outline

• What is the IPCC? • Main findings of IPCC on climate• Main findings of IPCC on impacts and

adaptation• Main findings of IPCC on mitigation• The political process• Conclusions

The Chacaltaya glacier and ski-lift, Bolivia

Skiing was no longer possible after 2004 IPCC, AR4, WGII (2007)

Other effects of regional climate changes on natural and human environments areemerging, although many are difficult to discern due to adaptation and non-climatic drivers.

IPCC, AR4, WGII (2007)

IPCC, AR4, WGII (2007)

• Natural systems are being affected by regional climate changes, particularly temperature increases.

• Some adaptation is occurring now, but on a limited basis.• Adaptation will be necessary to address impacts resulting from the

warming which is already unavoidable due to past emissions.• A wide array of adaptation options is available, but more extensive

adaptation than is currently occurring is required to reduce vulnerability to future climate change. There are barriers, limits and costs, but these are not fully understood.

• Many impacts can be avoided, reduced or delayed by mitigation.• A portfolio of adaptation and mitigation measures can diminish

the risks associated with climate change.• Impacts of climate change will vary regionally but, aggregated and

discounted to the present, they are very likely to impose net annual costs which will increase over time as global temperatures increase.

Main findings of IPCC on impacts and adaptation

IPCC, AR4, WGII (2007)

Outline

• What is the IPCC? • Main findings of IPCC on climate• Main findings of IPCC on impacts and

adaptation• Main findings of IPCC on mitigation• The political process• Conclusions

GHG emissions have increased by 70% since 1970

IPCC, AR4, WGIII (2007)

Emission trends

There is significant mitigation potential at a range of C prices

IPCC, AR4, WGIII (2007)

Energy supply

0

1

2

3

4

5

6

7GtCO2-eq

Transport Buildings Industry Agriculture Forestry Waste

Non-OECD/EI TEITOECDWorld total

US$/tCO2-eq

Global economic mitigation potential for different sectors at different carbon prices

IPCC, AR4, WGIII (2007)

The cost of stabilizing atmospheric GHG concentrations by 2100increases with the stringency of the stabilization target

Stabilizing at 590-710 ppm CO2-eq. will cost -0.6 to1.23% of GDPStabilizing at 535-590 ppm CO2-eq. will cost 0.2 to 2.5% of GDPStabilizing at 445-535 ppm CO2-eq. will cost 3% of GDP

IPCC, AR4, WGIII (2007)

Main findings of IPCC on mitigation

• A significant proportion of GHG emissions can be mitigated at relatively low cost by 2030

• There is significant mitigation potential in all sectors (industry, energy, buildings, transport, agriculture, forestry and waste)

• Lower atmospheric GHG stabilization levels will cost more

• In order to stabilize the concentration of GHGs in the atmosphere, emissions would need to peak and decline thereafter. The lower the stabilization level, the more quickly this peak and decline would need to occur.

• Mitigation efforts over the next two to three decades will have a large impact on opportunities to achieve lower stabilization levels

Outline

• What is the IPCC? • Main findings of IPCC on climate• Main findings of IPCC on impacts and

adaptation• Main findings of IPCC on mitigation• The political process• Conclusions

The Political Process

• UNFCCC (United Nations Framework Convention on Climate Change - since 1992)

• COP (Conference of Parties)• Kyoto Protocol to the UNFCCC (2008-2012) –

only developed countries – significant not ratification by e.g. US, Australia

• Bali Roadmap (what will come after 2012) – will include developing countries as well as (hopefully) non-Kyoto developed countries

United Nations Framework Convention on Climate Change

Talks under the Kyoto Protocol

• 1st commitment period expires in 2012• AWG-KP: to negotiate further commitments for

Annex I Parties for the period beyond 2012– Analysis of mitigation potential for different sectors:

policies, measures and technologies

– Analysis of means to reach emission reduction targets and identification of ways to enhance their effectiveness and contribution to sustainable development

Slide courtesy of Fernando Castellanos Silveira, UNFCCC

United Nations Framework Convention on Climate Change

The Bali Action Plan

• Two-year negotiation process for a broad response to climate change.

• Key elements: – Shared vision – Mitigation– Adaptation– Finance – Technology.

Slide courtesy of Fernando Castellanos Silveira, UNFCCC

United Nations Framework Convention on Climate Change

The Bali Action Plan

Shared Vision

Mitigation Adaptation

Technology

Finance

Catalytic role of the UNFCCC

Slide courtesy of Fernando Castellanos Silveira, UNFCCC

United Nations Framework Convention on Climate Change

Elements of the Bali Action PlanAction by developed

countriesMeasurable, reportable,

verifiable mitigation action/commitments

Implementation of action on adaptation

Support action by developing countries

Action by developing countries

Nationally appropriate mitigation actions supported and enabled by technology, financing and capacity building

Reducing emissions from deforestation

Implementation of action on adaptation

Cooperative sectoral approaches and sector-specific actions on mitigation

Slide courtesy of Fernando Castellanos Silveira, UNFCCC

United Nations Framework Convention on Climate Change

• It is necessary to have a comprehensive, long-term climate change strategy

• There is a need for both adaptation and mitigation– The less we mitigate now, the more we will need

adaptation later – and more resources will be needed.

• There are many challenges but also many opportunities

• The poorest countries are the most vulnerable and will be the most affected by climate change

Slide courtesy of Fernando Castellanos Silveira, UNFCCC

Outline• What is the IPCC? • Main findings of IPCC on climate• Main findings of IPCC on impacts and

adaptation• Main findings of IPCC on mitigation• Climate change in Scotland over the next

century• Conclusions

John Holdren, President of the American Association for the Advancement of Science

• ‘We basically have three choices –mitigation, adaptation, and suffering.

• We’re going to do some of each. The question is what the mix is going to be.

• The more mitigation we do, the less adaptation will be required, and the less suffering there will be.’

Slide courtesy of Jean-Pascal van Ypersele

Conclusions• Climate change is real, human induced and is changing

ever more rapidly• Adaptation will cost money, but not as much as the cost of

the damage caused by climate change. Some will be necessary due to climate change already “in the pipeline”

• Mitigation is possible and a significant proportion can be met by low cost options. Mitigation reduces the amount of adaptation necessary

• The problem is enormous, but there is hope that we can deal with it. Drastic emission reduction targets are necessary (e.g. 80% reduction by 2050) – these will be difficult to achieve and creative, sustainable solutions in all sectors will be needed.

Thank you for your attention