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Climate change:

the scientific essentials for a future framework

Diana Ürge-Vorsatz

March 13, Budapest

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Outline

Introduction Evidence of CC Future scenarios and impacts Costs of CC Emission reduction needs and

Fundamentals of mitigation Sharing the burden (opportunity?) in

CEE

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Introduction: the scientific basics

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Greenhouse effect

Greenhouse effect is a natural mechanism, which maintains the temperature of the Earth 33°C warmer than if it had no GHG “layer” (global average temperature is 15 °C).

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Global-average radiative forcing estimates and ranges:

Used to compare different drivers of climate change

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Global Warming Potential (GWP) weighted global greenhouse gas

emissions 1970-2004

Source: IPCC AR4 2007

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The Evidence - Direct Observations of Recent Climate Change

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.

The global average surface temperature has increased at the 100-year trend (1906–2005) of 0.74°C ± 0.18°C.

Source: Pachauri and Jallow, 2007.

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Projections of change and impacts

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Projections of Future Changes in Climate

For the next two decades a warming of about 0.2°C per decade is projected for a range of SRES emission scenarios.

Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C per decade would be expected.

The commitments to climate change after stabilisation of radiative forcing are expected to be about 0.5 to 0.6°C, mostly within the following century.

Source: Pachauri and Jallow, 2007.

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Projections of future changes in climate (selection)

Anthropogenic warming and sea level rise would continue for centuries due to the timescales associated with climate processes and feedbacks, even if greenhouse gas concentrations were to be stabilized.

Temperatures in excess of 1.9 to 4.6°C warmer than pre-industrial sustained for millennia…eventual melt of the Greenland ice sheet. Would raise sea level by 7 m.

Source: IPCC, AR4, WG I. 2007

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UNIVERSITYSource: Stern Review, 2007.

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Projected warmingin 21st century expected to be greatest over land and at most high northern latitudes

and least over the Southern Ocean and parts of the North Atlantic Ocean

Projections of Future Changes in Climate

Source: IPCC, AR4, WG I. 2007.

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Projected change in precipitation for the period 2080 to 2099 relative to 1980 to 1999, SRES

A1B

Source: IPCC, AR4, WG I. 2007.

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Ecological vulnerability to future climate change

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Agro-economic vulnerability to future climate change (2061–2070) based on loss of agricultural productivity. Solar radiation, atmospheric CO2 concentration, temperature, soil moisture, nutrient availability, andfarming practices are represented using nonlinear (process-based or empirical) functions, implemented through the agricultural crops component in the LPJ model (Bondeau et al., 2007). Adaptation of farming practices is considered by allowing shifts in planting dates, varieties, and irrigation (Rosenzweig and Iglesias, 2003). If a significant yield loss in at least one important crop was identified in a country where the GDP share of agriculture is greater than 5%, then vulnerability was ranked as “high.” In the case of low dependency on agriculture and a decrease in only one significant crop yield (or no decrease at all), vulnerability was ranked as “low.” The remaining two combinations were ranked as “medium.”

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Temperature

This map illustrates what can be expected in

Europe by the end of the century, according to the IPCC scenario (SRES A2)

whereby no action is taken to reduce greenhouse gas

emissions, so that the global mean temperature increases by about 3.4°C by the 2080s compared

to 1990 levels. Under this scenario, nearly all

European regions are expected to be

negatively affected and up to half of Europe’s plant species could be

vulnerable or threatened by 2080.

Source: Commission Adaptation Green Paper; 2007.

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European heat-wave 2003 - estimation of return periods

extremelyrare

event

10 y10 y

1000 y1000 y

100 y100 ymean

Swiss Temperature Series 1864-2003 (mean of 4 stations)

More elaborate analysis shows it likely that most of the risk of the event due to increase in greenhouse gases - also that by 2050, likely to be average event and by 2100 a cool event (Stott et al 2004, Nature 432 610-614).

Source: Johansson, 2006, CEU lecture.

(Schär et al. 2004, Nature, 427, 332-336)

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This map illustrates what can be expected in

Europe by the end of the century, according to the IPCC scenario (SRES A2)

whereby no action is taken to reduce greenhouse gas

emissions, so that the global mean

temperature increases by about 3.4°C by the

2080s compared to 1990 levels. Under this

scenario, nearly all European regions are

expected to be negatively affected and up to half of Europe’s plant species could be

vulnerable or threatened by 2080.

Source: Commission Adaptation Green Paper; Marr, SUN presentation, 2007.

Precipitation

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Scenarios for future emissions and stabilisation targets

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Stabilisation and commitment to warming

Source: Stern Review, 2007.

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Projected CO2 emissions leading to stabilisation at different levels

IPCC AR4 (2007), WGI. The first figure shows the assumed trajectories of CO2 concentration (SP scenarios); the second shows the implied CO2 emissions, as projected with the Bern2.5CC EMIC. The upper and lower bounds are indicated by the top and bottom of the shaded areas. Alternatively, the lower bound (where hidden) is indicated by a dashed line.

The lower the stabilisation level the earlier global CO2 emissions have to peak

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Long term mitigation (after 2030)

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

[1] The best estimate of climate sensitivity is 3ºC [WG 1 SPM].[2] Note that global mean temperature at equilibrium is different from expected global mean temperature at the time of stabilization of GHG concentrations due to the inertia of the climate system. For the majority of scenarios assessed, stabilisation of GHG concentrations occurs between 2100 and 2150.[3] Ranges correspond to the 15th to 85th percentile of the post-TAR scenario distribution. CO2 emissions are shown so multi-gas scenarios can be compared with CO2-only scenarios.

Source: IPPC, AR4, WG III, 2007.

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Stabilisation targets

Current evidence suggests a stabilisation need of 450 – 550ppm CO2-eq Anything higher has very harmful impacts Anything lower raises costs significantly and may

not even be feasible any more However, little can now be done to change

the likely adverse effects that some developing countries will face in the next few decades, and so some adaptation will be essential.

Strong and early mitigation is the only way to avoid some of the more severe impacts that could occur in the second half of this century.

Source: Stern Review, 2007. www.sternreview.org.uk

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Key challenge for appropriate response to climate change

Exceeding 2-2.5° C above 1750 levels would entail sharply increasing risk of intolerable impacts

Avoiding this will require prompt action

Two-pronged strategy: avoid the unmanageable (mitigation) and manage the unavoidable (adaptation)

Mitigation and adaptation measures should be integrated and reinforcing

Source: Urge-Vorsatz. 2007. Presentation of the UN SEG Report

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Costs of climate change

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Total cost of CC

The total cost of BAU CC is app. a 20% reduction in consumption per head, “now and into the future” (Stern Review, Executive summary, p. x)

Source: The Stern Review, 2007. www.sternreview.org.uk

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Illustration of costs numbers for stringent mitigation

GDP without mitigation

GDP with stringent mitigation

GDP

Time

80%

current

77%

~1 year

Source: IPPC, AR4, WG III, 2007.

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Mitigation strategies

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The Three Key Pillars of Mitigation Strategies

1. Lowering the energy intensity of economic activity through increases in the efficiency of vehicles, buildings, appliances, and industrial processes

2. Lowering the carbon-emissions intensity of energy supply through additions of renewable and nuclear energy supply and through modifications to fossil fuel technologies that enable the capture and sequestration of CO2

3. Reducing the carbon emissions from land-use change by means of reforestation, afforestation, avoided deforestation, and improved soil-management practices in agriculture

Source: Urge-Vorsatz. 2007. Presentation of the UN SEG Report

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Sectoral economic potential for global mitigation for different regions as a function of carbon price,

2030

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Estimated potential for GHG mitigation at a sectoral level in 2030 in different cost

categories , transition economies

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Buidlings Industry Agriculture Energy supply Forestry Waste Transport

Gton CO2eq.

<20 <0 0-20 20-100

Cost categories* (US$/tCO2eq)

* For the buildings, forestry, waste and transport sectors, the potential is split into three cost categories: at net negative costs, at 0-20US$/tCO2, and 20-100 US$/tCO2. For the industrial, forestry, and energy suppy sectors, the potential is split into two categories: at costsbelow 20 US$/tCO2 and at 20-100 US$/tCO2.

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Mitigation portfolio for electricity, 2030

Improved energy-efficiency in buildings can supply the largest Improved energy-efficiency in buildings can supply the largest mitigation reduction, comparable to all renewable energy generation, mitigation reduction, comparable to all renewable energy generation,

and to other measures combinedand to other measures combined

Source: IPPC, AR4, WG III, 2007.

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Sharing the burden – or the opportunity?

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Per Capita and Total Emissions of Greenhouse Gases in Year 2000

Source: UN SEG 2007, www.confrontingclimatechange.org

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CO2 emissions per capita

0 5 10 15 20 25

Nepal

Bangladesh

Kenya

India

Kyrgystan

Iraq

Thailand

Azerbaijan

China

Macedonia

Romania

Hungary

Bulgaria

Belarus

Serbia & Montegro

Slovakia

South Africa

EU-25

Greece

Israel

Japan

Czech Republic

Canada

US

tonnes per cap.

Source: IEA Key Statistics, 2007

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CO2 per TPES

0 0.5 1 1.5 2 2.5 3 3.5

Nepal

Kenya

Bangladesh

India

Kyrgystan

Slovakia

Canada

Thailand

Hungary

EU-25

Azerbaijan

Belarus

Japan

Romania

Bulgaria

US

Czech Republic

South Africa

Iraq

China

Israel

Macedonia

Serbia & Montegro

Greece

t CO2/ toe

Source: IEA Key Statistics,2007

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Emission reductions for Eastern Europe under different regimes

in comparison to baseline

2025

-70

-60

-50

-40

-30

-20

-10

0Preference

Score

Multi-Stage

BrazilianProposal

Per CapitaConvergence

Jacoby Rule

% 2050

-120

-100

-80

-60

-40

-20

0

BrazilianProposal

MultiStage

Per CapitaConvergence

PreferenceScore

Jacoby Rule

%

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Fossil CO2 emissions in Eastern Europe and FSU: different regimes

The purple line is the baseline

Source: Den Elzen et al 2003.

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Conclusion

The evidence of anthropogenic climate change is now unequivocal

All countries in CEE are and will be badly affected, although severity and type of impacts vary

Avoiding dangerous impacts requires urgent and strong action today

Emission reduction needs for CEE in 2025 are 30 – 50%, while for above 80% for 2050

However, the AR4 concludes that this is feasible, and The costs of even the more ambitious stabilisation targets are not substantial if action starts today

Many mitigation options are associated with economic and social benefits. For instance, capturing the cost-effective potential in buildings can supply 38% of mitigation needs in 2030 for a 3C target. CEE has especially high potential.

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THANK YOU FOR YOUR THANK YOU FOR YOUR ATTENTION!ATTENTION!

For more questions:For more questions:Vorsatzd@ceu.hu

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References Publications: UN SEG. (2007). Confronting climate change challenge: Avoiding the

unmanageable, managing the unavoidable. Scientific Expert Group report on Climate Change and Sustainable Development. URL: http://www.unfoundation.org/files/pdf/2007/SEG_Report.pdf

Presentations: Johannson, T. B. (2006). Greenhouse Gas Emissions and Climate Change.

Lecture at the CEU, October 30, 2006. Pachauri, R. K. and Jallow, B. (2007). Climate change 2007: The Physical

Science Basis. Working group I contribution to the Fourth Assessment Report of the IPCC. Nairobi, 6 February, 2007. URL: http://www.ipcc.ch/present/presentations.htm Accessed on September 8, 2007.

Manning, M. (2007) Climate Change 2007: Observations and Drivers of Climate Change.

Graphics: Planets and atmospheres. (2000). In UNEP/GRID-Arendal Maps and Graphics

Library. Retrieved 02:48, September 9, 2007 from http://maps.grida.no/go/graphic/planets_and_atmospheres.

Greenhouse effect. (2002). In UNEP/GRID-Arendal Maps and Graphics Library. Retrieved 15:16, September 8, 2007 from http://maps.grida.no/go/graphic/greenhouse_effect.

Cooling factors. (2000). In UNEP/GRID-Arendal Maps and Graphics Library. Retrieved 23:29, September 10, 2007 from http://maps.grida.no/go/graphic/cooling_factors.