1 of 140

Climate Change and Action Workshop

Arctic ice �on Sept. 12, 2013

Jan-Marcus Nasse

Katja Ovchinnikova

Alberto Bailoni

2 of 140

What is climate?

3 of 140

Weather

Climate

Current state of the atmosphere�minute-by-minute

Average weather/state of the atmosphere in a region�over a long period of time

4 of 140

The climate system

Atmosphere

Biosphere

Lithosphere

Cryosphere

Hydrosphere

Parts of the Earth affected by climate and affecting each other

5 of 140

What is climate change?

Source: IPCC WG1 Ch1

Increase in mean

Increase in variance

Since climate (variables) are the result of an averaging (as we learned on the slide before) there is a range of values around that mean that can occur when e.g. temperature is measured on a specific day with values close to the average being more likely than extreme events. (5°C at christmas in Germany more likely than 20°C). A change in climate can come in two forms (or a combination of both): The average of a variable like temperature could change in one direction (average temperature on christmas day changes from 5 to 7°) or the frequency distribution could change e.g. more temperature extremes could occur while the average stays the same. A change in one of the climate variables is referred to when it is sustained i.e. goes on for a certain time (IPCC uses a decade - see IPCC Glossary on “climate change”)

6 of 140

How do we observe climate change?

Globally averaged temperature anomaly combining land and ocean surface:

3 independent land datasets �(5000 to 7000 stations each)
2 independent interpolated �marine data sets based �on historic observations

Source: IPCC WG1 2013

Morice et al. 2012

Vose et al.2012

Hansen et al. 2010

7 of 140

How do we observe climate change?

Land surface air temperature anomaly (°C) by year

Source: IPCC WG1 2013

8 of 140

How do we observe climate change?

Extent of summer arctic sea-ice by year

Source: IPCC WG1 2013

9 of 140

How do we observe�climate change?

Source: IPCC WG1 2013

Bojinski et al. 2014

Ocean acidification

Atmospheric CO2

10 of 140

How do we observe�climate change?

Source: IPCC WG1 2013

Bojinski et al. 2014

Ocean acidification

Atmospheric CO2

11 of 140

Earth’s energy budget

Source: NASA - https://science-edu.larc.nasa.gov/energy_budget/pdf/EEB_StoryBoard_0616.pdf

12 of 140

Surface temperature for Earth as simple sphere: -18 °C

Source: NASA

13 of 140

Matter emits energy as electromagnetic radiation

Temperature determines

wavelength (colour)

Source: LibreTexts - see comment

Source: Wikipedia

All matter with a temperature above absolute zero (-273,16°C) emits energy in the form of electromagnetic radiation. The radiation is emitted as a distribution of different wavelengths (“colours”). For an idealized body of matter (black body) its temperature determines two things: the distribution of the wavelengths of the radiation (different spectra for different temperatures on the left; illustration of the phenomenon on the right: the colder the rod the more the perceived colour changes towards the red (and vice versa).

https://phys.libretexts.org/Bookshelves/University_Physics/Book%3A_University_Physics_(OpenStax)/Map%3A_University_Physics_III_-_Optics_and_Modern_Physics_(OpenStax)/6%3A_Photons_and_Matter_Waves/6.1%3A_Blackbody_Radiation

https://commons.wikimedia.org/wiki/File:Glowing_metal.jpg

14 of 140

Matter emits energy as electromagnetic radiation

Temperature determines

emitted power P ∝ T⁴

Temperature determines

wavelength (colour)

Source: LibreTexts - see comment

15 of 140

Energy emissions of Sun and Earth

Like every piece of matter, �the Sun and the Earth emit �an electromagnetic spectrum depending on their respective temperatures

Generalic (2018) - see comment

16 of 140

Surface temperature for Earth as simple sphere: -18 °C

Source: NASA

17 of 140

Surface temperature for Earth as simple sphere: -18 °C

→ something is missing

Source: NASA

The rest of the solar radiation is absorbed and thereby heats the Earth. In addition to the radiation from the sun absorbed and reflected, we also have to consider the energy that is emitted by Earth due to its own temperature. As we know, this is emitted in the form of infrared radiation. (The surface temperature of Earth in this simple model is mostly the result of the heating of the surface that occurs when the solar radiation is absorbed. There is a tiny contribution from the interior of the earth where e.g. radioactive decay produces or volcanic activity contributes energy to the surface, but this is only 1-2% of the Sun’s contribution. If in our simple model we now consider Earth as piece of rock (with the same properties as the actual Earth in terms of reflectivity of sunlight) the global average temperature that would be the result of heating by incoming solar radiation and cooling (energy loss) from outgoing radiation would be -18°C. So there clearly something that is missing in this description.

Source: https://science-edu.larc.nasa.gov/energy_budget/pdf/EEB_StoryBoard_0616.pdf

18 of 140

Sunlight comes into the atmosphere

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

19 of 140

A small part of the radiation is absorbed, small part is reflected by the clouds, most of it goes through the atmosphere

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

20 of 140

Another fraction is reflected by the surface

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

21 of 140

Visible spectral range

Source: see comment

22 of 140

Energy is radiated towards space

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

23 of 140

Most of the energy emitted by the surface absorbed by clouds and gases in the atmosphere

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

24 of 140

Clouds and the atmosphere emit radiation in all directions. At a certain altitude the atmosphere becomes transparent (again)

Altitude of transparency

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

25 of 140

Visible spectral range

Infrared spectral range

Source: see comment

26 of 140

Trapped energy emitted from clouds and gases goes in all directions. Some comes back to further warm the surface. This is the greenhouse effect.

Altitude of transparency

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

Infrared radiation that can escape into space is emitted in all directions by the gas molecules in the atmosphere which get the energy for this emission from the absorption of radiation from below. Since temperature decreases with altitude, to total amount of energy emitted from higher up in the atmosphere is smaller than from the surface of the Earth. The portion of energy emitted by the gas molecules back towards the surface increases the surface temperature, which is the greenhouse effect. The gases in the atmosphere that lead to it (i.e. that absorb in the infrared) accordingly are called greenhouse gases. The natural greenhouse effect (mainly due to water vapour and natural CO2) leads to an average temperature of 15C (compared to the -18C Earth would have without an atmosphere).

Based on: https://web.archive.org/web/20140421050855/http://science-edu.larc.nasa.gov/energy_budget/

27 of 140

Energy from the surface is also emitted as warm air and condensing water vapor.

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

28 of 140

How can climate be influenced?

29 of 140

This system is in balance

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

30 of 140

This system is in balance

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

31 of 140

Surface became brighter →

more radiation is reflected

Loeb et al. 2009

Trenberth et al. 2009

Graphics based on NASA poster (see comments)

32 of 140

This system is in balance

33 of 140

This system is in balance

34 of 140

Add greenhouse gases

to the atmosphere → atmosphere only becomes transparent higher up where it is colder → less energy emission

35 of 140

How big is the anthropogenic influence?

Source: IPCC WG1 2013

36 of 140

How big is the anthropogenic influence?

Source: IPCC WG1 2013

Gas emissions

37 of 140

How big is the anthropogenic influence?

Source: IPCC WG1 2013

Aerosol particles (formation)

38 of 140

How big is the anthropogenic influence?

Source: IPCC WG1 2013

Land use change

39 of 140

How big is the anthropogenic influence?

Source: IPCC WG1 2013

Natural solar �irradiance variation

40 of 140

How big is the anthropogenic influence?

CO2 → +1.68 +/- 0.35 W/m2

Source: IPCC WG1 2013

Well understood:�

Doubling of CO2 → Increase of �radiative forcing by 3.7 +/- 0.4 W/m2

41 of 140

How to determine the influence of CO2?

Atmospheric CO2 at Mauna Loa Observatory

42 of 140

How to determine past CO2 concentrations?

Credit: NASA's Goddard Space Flight Center/Ludovic Brucker

Back in time

Atmospheric observations

Observations in climate records

‘Relative to 1750’

43 of 140

CO2 dramatically increased

44 of 140

How do we know it is anthropogenic CO2 ?

Fossil fuel and cement emissions

Source: IPCC WG1 2013

45 of 140

Anthropogenic CO2 emissions

Source: IPCC WG1 2013

46 of 140

Anthropogenic CO2 emissions

Source: IPCC WG1 2013

Partitioning of the emissions

Half of the emissions ends up in the atmosphere

47 of 140

Total anthropogenic radiative forcing

Source: IPCC WG1 2013

2.29 +/- 1.16 W/m2

48 of 140

From radiative forcing to climate change

49 of 140

Response of the climate system:

Climate sensitivity

Source: IPCC WG1 2013

To get an idea of the consequences of the anthropogenic influence on the climate system we need connect the radiative forcing of the different effects to the climate variables from the first slides. This connection is called the climate sensitivity, which is often expressed as the long-term temperature response of the climate system to the radiative forcing of a doubling of CO2 concentrations. This is not straight forward to do. The IPCC AR5 (2013) states that: “there is high confidence that ECS (=Equilibrium climate sensitivity: equilibrium temperature change for sustained doubling of CO₂) is extremely unlikely less than 1°C and medium confidence that the ECS is likely between 1.5°C and 4.5°C and very unlikely greater than 6°C"

The difficulty to pin this relation down is mainly due to feedbacks in the climate system.

50 of 140

Imbalance in the system

51 of 140

The system will heat up until the radiation at higher transparency altitude balances the radiation budget.

52 of 140

This system heated up and

is in balance

53 of 140

Positive feedback: temperature rises → ice melts → less reflection → imbalance

54 of 140

Positive feedback: temperature rises → more water vapor → transparency altitude even higher → imbalance

55 of 140

Negative feedback: temperature rises �→ trees grow faster and absorb CO2 �→ less greenhouse gases → imbalance

56 of 140

Can we determine the climate sensitivity from observations?

IPCC WG1 2013

Problem: system takes a very long time �to equilibrate

57 of 140

Climate models

ETH Zürich

Quantitatively simulate the influence of climate drivers in the different compartments of the climate system.��
Applications:

attribution of observed change
projections of future developments

To analyse the climate system and to project future responses of the system to our current influence Earth System Models (ESM) are an important tool in climate science. ESMs are coupled atmosphere–ocean general circulation models in which a representation of the carbon cycle is included, allowing for interactive calculation of all atmospheric processes relevant to the climate system. The basis of these models is the solution of physical equations incorporating basic physical principles (conservation of mass, energy and momentum). Since especially the conservation of momentum is impossible to calculate for all molecules in the atmosphere, the climate system is represented in a 3D grid. The differential equations describing the fundamental physics is solved at the grid points whereas processes occurring within the grid cells have to be represented by empirical descriptions. The grid size, which is limited by the available computational power then determines which processes are described with what degree of precision. While global phenomena like the rise of global mean temperatures are well represented, regional effects like local precipitation are harder to represent correctly. Since such processes via the feedbacks mentioned before can influence the the entire climate system, the results of climate systems have to be assessed carefully. Not all climate model are suited to answer all questions. For projections the IPCC uses a whole range of different models, which due to different representations of the empirical effects inside the grid cells, give slightly different results. The combination of different models then can be used to assess the uncertainty of the projections.

Climate model can be used for two types of analysis: 1: The attribution of observed change to specific factors 2: the projection of future climate conditions

https://iac.ethz.ch/group/climate-physics/research.html

58 of 140

Attribution of climate change to different factors

IPCC 2013 WG1

Simulate with and without a specific factor and compare to observations

59 of 140

Global temperature rise limit

2°C target - not exceeding max historical observations, linked to doubling of CO2 (economist Nordhaus in 1977)
1,5°C target - 2009 demand of Alliance of Small Island States based on studies of consequences of a 2° warming for their islands

60 of 140

Carbon budget for temperature increase below 1.5°C

IPCC Global Warming of 1.5°C. (2018)

Budget for increase below 1.5°C: �

420 GtCO_{2 �}

�

Global emissions (2017):�

42 ± 3 GtCO₂per year

�~ 20 years left

(with a linear decrease of emissions)

IPCC WG1 2013

(66% probability)

61 of 140

60 million years

350.000 years

300 years

Earliest bipedal

Homo sapiens

Agriculture

Industrialization

Burke et al. 2018

62 of 140

We risk to cross thresholds of no-return

Steffen et al. 2018

Another arguments for the 1.5 C temperature threshold is the fear that thresholds within the system could be passed that lead to an irreversible change of the climate system. If the state of the climate system is represented by a landscape through which Earth moves like a marble, the interchanging ice ages and inter-glacials can be imagined as the change of position between areas/states of relative stability. If the system through the anthropogenic influence deviates too far from the past path, it might enter new areas of relative stability that might lead to fundamentally different conditions in the system. Once certain thresholds towards such areas are crossed, a recovery through human activity (stopping of emissions etc might no longer be possible).

An example for this are the permafrost soils in the Arctic which store large amounts of methane, a very potent greenhouse gas. If temperatures would rise in way that would lead to the melting of the permafrost, this methane would be released to the atmosphere increasing the radiative forcing leading to further melting and further release and so on. This process would be extremely hard to impossible to counteract.

So far the response of the climate system to anthropogenic radiative forcing has been fairly linear. However, with rising tempertures the risk to pass such threshold increases.

63 of 140

We risk to cross thresholds of no-return

Steffen et al. 2018

64 of 140

Land use change

65 of 140

Greenhouse gases

Forests, wetlands, peatlands, mangroves and grasslands efficiently absorb and store CO2.

Clearing forests and draining peatlands releases carbon from the land into the atmosphere.

Wolosin & Harris 2018, World Resources Institute

66 of 140

Biogenic volatile organic compounds

Forests release biogenic volatile organic compounds (BVOC), which have both positive and negative radiative forcing. In sum, lower BVOC emissions after deforestation result in warming.

Wolosin & Harris 2018, World Resources Institute

67 of 140

Non-radiative forcing

Forests drive movement of air, water, and heat

Accumulating water in roots and soil, humidifying the air causes surface cooling
Transpiration can cause building clouds and rainfall
Impact on the texture of the Earth’s surface, which influences how and where heat and water are distributed
Nonradiative forcing impacts of deforestation in the tropics show net local warming

Wolosin & Harris 2018, World Resources Institute

68 of 140

Land use change impact

CO2 emissions from fossil fuels far exceed those from land use change

But:

IPCC WG1 2013

Land use change emissions

Deforestation/wetlands drainage emissions

MINUS

Carbon sequestration by forests and wetlands

69 of 140

Mitigation potentials by 2030 to limit warming below 2°C

Land sector can offer 37% of the solution

Wolosin & Harris 2018, World Resources Institute

70 of 140

Land sector can offer 37% of CO2 mitigation by 2030

Griscom et al. 2017; Wolosin & Harris 2018, World Resources Institute

Conservation, restoration, and improved management of tropical forests, mangroves, and peatlands -

23% of total mitigation till 2030.

Fossil fuel mitigation

Land sector mitigation

71 of 140

CO2 emissions caused by tropical deforestation

Gibbs et al. 2018

Fritts 2018, World Resources Institute, https://www.wri.org/blog/2018/10/numbers-value-tropical-forests-climate-change-equation

72 of 140

Causes of deforestation

Seymour & Harris 2019, Science

Primary forest loss (million hectares per year)

73 of 140

Deforestation alerts right now

Forest Watch www.globalforestwatch.org

74 of 140

Forest fires right now

Forest Watch www.globalforestwatch.org

75 of 140

Impact of climate change

76 of 140

Impact on humans

IPCC report AR5: Impacts, Adaptation, and Vulnerability

77 of 140

How are we affected by climate change?

Health
Food and water supply
Infrastructure
Economy
Security

http://impact.gocarbonneutral.org (University of Hawaii at Manoa)

https://maps.esri.com/MoraLab/CumulativeChange/

78 of 140

Warmer temperatures, extreme heat, drought

Death
Insufficient water supply
Loss of agricultural productivity
Increased water and air pollution
Forest fires
Water transportation disruption
Reduced learning and worker productivity

79 of 140

Sea level rise, extreme rains, floods

Death, injury
Loss of homes and infrastructure
Loss of food supplies and drinking water

80 of 140

Ocean acidification, CO2 in the soil

Reduced growth and survival of�commercially valuable marine animals
Loss of agricultural productivity

81 of 140

Warmer climate, dirty water, more rains

Expansion of transmission season and geographical range (malaria, dengue)

Infectious diseases, including water-borne ones, spread with rising temperature (cholera, diarrhea)

82 of 140

Loss of homes, infrastructure, resources

Displacement, migration, poverty

Conflicts, violence

Mach et al. 2019, Nature

83 of 140

Vulnerability to climate change: ND-GAIN index (2017)

https://gain-new.crc.nd.edu/

worse

29.6

better

76.0

84 of 140

Example: Dem. Rep. of the Congo is most vulnerable

https://gain-new.crc.nd.edu/

Water

Food

Ecosystem

Infrastructure

85 of 140

CO2 emissions per capita (2017)

https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions

86 of 140

Share of global CO2 emissions (2017)

https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions

87 of 140

Cumulative emissions from 1751 to 2017

https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions

88 of 140

Proposed solutions

Stop fossil fuel emissions

Replace fossil fuels by green energy

Change agriculture/fishing practices

Stop deforestation, start afforestation
Farming instead of mass production, agroforestry, no fishing zones

Remove CO2 from the atmosphere and ocean

Plant trees
Bio-energy with carbon capture and storage, direct air capture, ...

Adapt to rising temperatures

Build infrastructure (e.g. sea walls)
Set up emergency funds

89 of 140

Proposed solutions

Stop fossil fuel emissions

Change agriculture/fishing practices

Remove CO2 from atmosphere and ocean

Adapt to rising temperatures

90 of 140

PARIS AGREEMENT 2015

91 of 140

Paris agreement: key points

Keep global temperature increase well below 2℃, try to limit to 1.5℃
Achieve carbon neutrality (no increase of greenhouse gases)
Set goals for each country and review contributions every 5 years
Developed countries set up “Climate Fund” for developing countries: �at least $100 billion a year
Adaptation: reduce vulnerability to climate change, address damage
Climate change education, public awareness

https://unfccc.int/process-and-meetings/the-paris-agreement/what-is-the-paris-agreement

92 of 140

In Paris agreement: 179 parties, 89% of emissions

Climate Watch https://www.climatewatchdata.org/ndcs-content

93 of 140

Paris agreement pledges

CAIT Climate Data Explorer http://cait.wri.org/pledges

Countries submit their goals (pledges)�
There’s no penalty for not meeting the goals

94 of 140

Germany misses the goal of 40% emission reduction by 2020

https://www.cleanenergywire.org/factsheets/germanys-greenhouse-gas-emissions-and-climate-targets

95 of 140

ec.europa.eu/eurostat, www.cleanenergywire.org/factsheets/germanys-greenhouse-gas-emissions-and-climate-targets

96 of 140

CO2 emission scenarios

https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions

97 of 140

98 of 140

99 of 140

https://www.fridaysforfuture.org/events/map

100 of 140

FFF demands in Germany

Long term:

By 2035, Germany should have net-zero greenhouse gas emissions
By 2030, Germany should cease all coal mining
By 2035, all of Germany's energy should come from renewable sources�

Till the end of 2019:

Cut government subsidies for fossil-fuel energy sources
Shut 1/4 of German coal power plants
Introduce tax on CO2 emissions, 180 Euro per CO2 tonne

https://fridaysforfuture.de/forderungen

101 of 140

How to reduce individual carbon footprint?

Germany 2014

11 tonnes per capita

per year

Globally 2050

2 tonnes per capita

per year

Calculate your CO2 footprint:

https://offset.climateneutralnow.org/footprintcalc

https://uba.co2-rechner.de

102 of 140

Average individual CO2 footprint in Germany

https://uba.co2-rechner.de

103 of 140

Mobility

https://uba.co2-rechner.de

104 of 140

Transportation

23% of total energy-related CO2 emissions + indirect emissions of manufacturing of vehicles, infrastructure, etc.

IPCC report AR5, Chapter 8

105 of 140

Which ways of traveling leave the least carbon footprint?

106 of 140

Travel

IFEU http://www.ecopassenger.org

European Environment Agency, 2014

107 of 140

Tourism - 8% of global CO2 emissions and growing

> 50% of emissions caused by tourism are related to transportation

Lenzen et al. 2018, Nature Climate Change

Residence-based total CO2 footprint (MtCO2), top-ranking countries (2013)

domestic

international

108 of 140

Travel - what can we do?

Travel less
Fly less
Drive less
Use transportation powered by green energy

109 of 140

Other consumption

https://uba.co2-rechner.de

110 of 140

Shopping - what can we do?

Buy:�

local (freight transport ca. 45% of total transport energy, biggest impact - last kilometers)
environmentally friendly manufactured
second hand
long lasting things

Repair instead of buying

111 of 140

Shopping - IT sector

CO2 footprint of devices like PCs, laptops, monitors, smartphones, tablets > 2.5% of global emissions in 2017 and rapidly growing (14% by 2040)�

Belkhir & Elmeligi 2018, Cleaner Production

	CO2 footprint increase from 2010 to 2020
Smartphones	735%
Data centers	310%

112 of 140

Food

https://uba.co2-rechner.de

113 of 140

Which food products leave the most carbon footprint?

114 of 140

Food

Poore & Nemecek 2018, Science, https://www.bbc.com/news/science-environment-46459714

CO2 emissions from food

Kg of emissions per serving

115 of 140

Food waste

Waste - 5% of global emissions, food waste - 44% of waste emissions

FOA 2015, http://www.fao.org/3/a-bb144e.pdf

Wastage

Carbon emissions

116 of 140

Food - what can we do?

Eat less meat
Buy local
Choose diet with less carbon footprint
Don’t waste food

117 of 140

Electricity & heating

https://uba.co2-rechner.de

118 of 140

Electricity and heating

Real time electricity production, consumption, CO2 emissions: https://www.electricitymap.org

42% of global CO2 emissions

119 of 140

Which energy source produces the most carbon emissions?

120 of 140

Electricity and heating

Real time electricity production, consumption, CO2 emissions: https://www.electricitymap.org

Germany, 24 hours

consumption

CO2 emissions

121 of 140

Electricity and heating - what can we do?

Employ green electricity �providers (Ökostrom)�
Save energy (use less electricity, �heating, water)�
If we own a house, insulate it, electrify, install solar panels

122 of 140

Investment - what can we do?

“Green” banks (Ökobanken)�
“Green” pension funds�
...

123 of 140

What is carbon offsetting?

124 of 140

Carbon offsets

Financial contributions to projects reducing CO2 emissions that are made in order to compensate for emissions made elsewhere.

Typical projects:

Planting trees
Supporting renewable energy
Methane collection from farms, landfills, industrial waste
Energy efficiency (e.g. passive buildings, low-energy lightbulbs)
...

125 of 140

Carbon offsets

How to choose a project:

How can the project impact be evaluated?
Would the project occur anyway without selling carbon offset credits?
Does the project cause higher emissions/other side effects outside its boundary?
Does the project permanently reduce emissions?
Are there other benefits in addition to the carbon emissions reduction?
Certification: Quality Assurance Standard

126 of 140

Lifestyles and carbon footprint

https://www.umweltbundesamt.de/sites/default/files/medien/378/publikationen/klimaneutral_leben_4.pdf

CO2 emissions per person

average German person

infrastructure

food

shopping

electricity

heating

transportation

127 of 140

Activism - what can we do?

Participate in protests (https://www.fridaysforfuture.org/events/map)
Vote for environmentally conscious politicians
Influence our organization
Educate ourselves and our colleagues/neighbours/family/friends �(IPCC reports, https://skepticalscience.com)

128 of 140

Upcoming events

September 20

Global Earth Strike

September 27

Heidelberg

Climathon

October 25-27

129 of 140

Changes are needed on the level of

global politics
countries
organizations
individuals

130 of 140

Our hearty thanks for

role game materials to

feedback and promotion to colleagues and friends from

131 of 140

Backup slides

132 of 140

Attribution of climate change to anthropogenic activities

133 of 140

How do we know it is anthropogenic CO2 ?

Description???

Source: IPCC WG1 2013

134 of 140

Forcing through well mixed GHGs

Source: IPCC WG1 2013

135 of 140

Forcing through short lived gases

Source: IPCC WG1 2013

136 of 140

Forcing through aerosols

Source: IPCC WG1 2013

137 of 140

Forcing through land use change

Source: IPCC WG1 2013

138 of 140

Forcing through natural influence

Source: IPCC WG1 2013

139 of 140

Total anthropogenic radiative forcing

Source: IPCC WG1 2013

140 of 140

Climate change and anthropogenic activities

IPCC 2013 WG1