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Greenhouse Gas Emissions and Climate Change

Jürgen ScheffranInstitute of Geography, CliSAP/CEN

Universität Hamburg

“Energy and Climate Policy" (63-951) Lecture 6, June 9, 2016

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Connection between energy and climate impacts

CO2 emissions

CO2 concentration in atmosphere

Global mean temperature

Natural resources

Societal stability and conflict

Energy in production and consumption

Human security risks

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Earth‘s mean annual radiant energy and heat balance:The Greenhouse effect

From Houghton et al. (1996: 58).

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Global carbon cycle

Main annual fluxes in GtC/yr: pre-industrial ‘natural’ fluxes in black and ‘anthropogenic’ fluxes in redIPCC 2007: WG1

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IPCC

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Greenhouse gas emission trends(IPCC 2014)

Total anthropogenic GHG emissions have risen more rapidly from 2000 to 2010 than in the previous three decades (high confidence).

CO2 remains the major anthropogenic GHG with 76% of total GHG emissions in 2010 weighed by GWP100 (high confidence).

Over the last four decades total cumulative CO2 emissions have increased by a factor of 2 from about 900 GtCO2 for the period 1750–1970 to about 2000 GtCO2 for 1750–2010 (high confidence).

Regional patterns of GHG emissions are shifting along with changes in the world economy (high confidence).

Current GHG emission levels are dominated by contributions from the energy supply, Agriculture, Forestry and Other Land‐Use (AFOLU)

Industry and building sectors gain considerably in importance (robust evidence, high agreement).

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Total annual anthropogenic GHG emissions by groups of gases 1970-2010

IPCC 2014

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Cumulative CO2 emissions have more than doubled since 1970

IPCC 2014

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Changes in CO2 concentrations overthe last 1000 years

Source: Anderson/Strahler, Visualizing Weather and Climate

p. 10Source: IPCC 2013, WG1

Probability density functions for the effective radiative forcing

Radiative forcing: change in the net, downward minus upward, radiative flux (expressed in W m–2) at the tropopause or top of atmosphere due to a change in an external driver of climate change

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Global air temperature

Source: Anderson/Strahler, Visualizing Weather and Climate

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Observed and projected climate variables for different IPCC reports

Source: IPCC 2013, AR5-WG1

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Total radiative forcing and cumulative carbon emissions since 1751 in baseline scenario compared to RCP scenarios

IPCC-WG3 (2014)

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Global temperature change and cumulative global CO2 emissions

p. 15Source: IPCC 2013, AR5-WG1

Global mean precipitation versus temperature changes relative to 1986–2005

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Anomalies relative to 1880–1919 for surface temperature, 1960–1980 for ocean heat content, 1979–1999 for sea iceSource: IPCC 2013, WG1

Comparison of observed and simulated climate change

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Observed changes in annual average surface temperature

Source: IPCC 2013, WG1

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Projected changes in annual average surface temperature

Source: IPCC 2013, WG1

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Observed changes in annual average precipitation

Source: IPCC 2013, WG1

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Projected changes in annual average precipitation

Source: IPCC 2014, WG1

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Projections of climate change-driven biome shiftsin the context of land use

Source: IPCC 2013, AR5-WG1

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Summary of estimated impacts of observed climate changes on yields over 1960–2013

Number of data points analyzed within parentheses for each category (Source: IPCC 2014)

Source: IPCC 2014, WG2

Data points

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Key terms of climate impacts(IPCC-WG2 2014)

Impacts: Effects on natural and human systems, including effects on lives, livelihoods, health, ecosystems, economies, societies, cultures, services, and infrastructure due to the interaction of climate changes or hazardous climate events occurring within a specific time period and the vulnerability of an exposed society or system.

Exposure: Presence of people, livelihoods, species or ecosystems, environmental functions, services, and resources, infrastructure, or economic, social, or cultural assets in places and settings that could be adversely affected.

Vulnerability: Propensity or predisposition to be adversely affected; variety of concepts and elements including sensitivity or susceptibility to harm, lack of capacity to cope and adapt.

Hazard: Potential occurrence of natural or human-induced physical event, trend or physical impact that may cause loss of life, injury, or other health impacts, damage and loss to property, infrastructure, livelihoods, service provision, ecosystems & environmental resources.

Risk: Potential for consequences where something of value is at stake and where the outcome is uncertain. Risk is often represented as probability of occurrence of hazardous events or trends multiplied by the impacts if these events or trends occur.

Risk = probability x impact

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Vulnerability and risk in climate-society interaction

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Multidimensional vulnerability driven by intersecting dimensions of inequality

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Global temperature and risks

Source: IPCC 2014, WG2

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Global patterns of impacts in recent decades attributed to climate change

Source: IPCC 2014, WG2

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Risks of tropical storms for urban centers

Source: WBGU 2007

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World Map of the Global Climate Risk Index 1995-2014

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Source: Scheffran/Battaglini 2011

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Climate change risks for human security and the interactions between livelihoods, conflict, culture and migration

Source: IPCC 2014, WG2

p. 32Source: Lenton et al 2008

Tipping elements in the climate system

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Long-term time scales for stabilization

Source: IPCC 2001, Synthesis Report.Source: Intergovernmental Panel on Climate Change, Climate Change 2001: Synthesis Report—Summary for Policymakers. www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf