Module 1
Introduction to Climate Change Science
One UN Training Service Platform
on Climate Change: UN CC:Learn
1

One UN Training Service Platform
on Climate Change: UN CC:Learn
Learning Objectives
1. Explain the basic concepts
of climate change science
2. Identify the anthropogenic
drivers of climate change
4. Analyze different climate
change scenarios and their
implications
3. Explain observed and
projected trends in the climate
By the end of the
module participants
will be able to:
Module 1: Introduction to Climate Change Science
2

One UN Training Service Platform
on Climate Change: UN CC:Learn
OVERVIEW
Section 1
Introduction to
Climate Change
Science
Section 2
Anthropogenic
Drivers of Climate
Change
Section 3
Observed Trends
and Impacts of
Climate Change
Section 4
Projected Trends
and Impacts of
Climate Change
Section 5
Sources of
Scientific Data
Overview
Module 1: Introduction to Climate Change Science
3

One UN Training Service Platform
on Climate Change: UN CC:Learn
Introduction to Climate Change
Science
Section 1
Module 1: Introduction to Climate Change Science
4

One UN Training Service Platform
on Climate Change: UN CC:Learn
What Is Climate?
Weather
“What is happening
in the atmosphere at
any given time”
Climate
“Average weather
over longer time
frames”
Section 1: Introduction to Climate Change Science
Source: World Meteorological Organization
5

One UN Training Service Platform
on Climate Change: UN CC:Learn
Complexity of the Global
Climate System
Section 1: Introduction to Climate Change Science
Source: IPCC 2007, p96. Further information: WMO Website
6

One UN Training Service Platform
on Climate Change: UN CC:Learn
What Is the Greenhouse Effect?
Section 1: Introduction to Climate Change Science
Source: IPCC 2007. Further info: WMO Website
7

One UN Training Service Platform
on Climate Change: UN CC:Learn
NASA Video on the
Greenhouse Effect
URL: http://www.youtube.com/watch?v=ZzCA60WnoMk
Section 1: Introduction to Climate Change Science
8
Video: Understand how water vapor, carbon dioxide,
and other gases cause the Earth’s greenhouse effect

One UN Training Service Platform
on Climate Change: UN CC:Learn
Factors Shaping the Climate –
“Climate Forcings”
Section 1: Introduction to Climate Change Science
Source: NOAAA National Climatic Data Center
9

One UN Training Service Platform
on Climate Change: UN CC:Learn
Natural Climate Fluctuations –
Example of El Niño and La Niña
Section 1: Introduction to Climate Change Science
Source: NOAA. Further information: WMO Website
10

One UN Training Service Platform
on Climate Change: UN CC:Learn
Climate Change and Global Warming
Global Warming
Refers to the overall
warming of the planet,
based on average
temperature over the
entire surface of the Earth
Climate Change
Refers to changes in
climate characteristics,
including temperature,
humidity, rainfall, wind,
and severe weather events
over long term periods
Section 1: Introduction to Climate Change Science
11
Further information: WMO Website

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Change in Surface
Temperature (1901–2012)
Source:
Source: IPCC 2013, p4
12
Section 1: Introduction to Climate Change Science

One UN Training Service Platform
on Climate Change: UN CC:Learn
Tools to Predict and Project Changes in
the Climate
• A climate prediction or climate “forecast” is an attempt to produce an estimate of the actual
evolution of the climate in the future.
Climate Prediction
• Emissions scenarios describe future releases to the atmosphere of greenhouse gases, aerosols,
and other pollutants and, along with information on land use and land cover, provide inputs
to climate models.
Emissions Scenario
• A numerical representation of the climate system based on the physical, chemical and
biological properties of its components, their interactions and feedback processes, and
accounting for some of its known properties.
Climate Model
• A climate projection is the simulated response of the climate system to a scenario of future
emission or concentration of greenhouse gases and aerosols, generally derived using climate
models.
Climate Projection
Section 1: Introduction to Climate Change Science
Source: IPCC 2013 and IPCC Website. Further info: WMO Website
13

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Change in Average Surface
Temperature
Source: IPCC 2013, p20
Scenario RCP 8.5Scenario RCP 2.6
Section 1: Introduction to Climate Change Science
14
Time Period: 1986-2005 to 2081-2100

One UN Training Service Platform
on Climate Change: UN CC:Learn
Climate Change Has an Impact on:
• Biodiversity, carbon storage,
habitats, …Ecosystems
• Agriculture, fresh water, health, …Human systems
• Transport, buildings, lifestyle, …Urban systems
• Energy, manufacturing, natural
capital industries, …Economic systems
• Equity, migration, peace and
conflict, …Social systems
Section 1: Introduction to Climate Change Science
15

One UN Training Service Platform
on Climate Change: UN CC:Learn
Climate Change Science Allows Us to:
 Understand how and
why the climate is
changing
 Assess how humans are
influencing the climate
 Project how the climate
may change in the
future
 Support
policy/decision-making
and changes in
behaviors
Section 1: Introduction to Climate Change Science
Source: National Science Foundation
Photo Credit: Niwot Ridge lter site/John W. Marr
16

One UN Training Service Platform
on Climate Change: UN CC:Learn
Why is Climate Change Science
Important?
 Sound weather data and forecasts
important for:
 Short-term planning
 Emergency response
 Climate models help to forecast long
term climate scenarios
 Important input for vulnerability assessments and adaptation
planning
 Fosters climate resilient development and avoids mal-adaption
Section 1: Introduction to Climate Change Science
17

One UN Training Service Platform
on Climate Change: UN CC:Learn
History of Climate Change Science
• Argument raised that the temperature of the Earth can be
augmented by the interposition of the atmosphere1824
• Indication that CO2 and H2O can cause changes in the climate1861
• First proposal of the idea of a man-made greenhouse effect1895
• Proof that doubling of atmospheric CO2 concentration resulted
in an increase in the mean global temperature of 2°C1938
• Start of interdisciplinary field of carbon cycle science1950s
• The high-accuracy measurements of atmospheric CO2
concentration1958
• Other greenhouse gases widely recognised1970s
• The first World Climate Conference in Geneva1979
• Establishment of Intergovernmental Panel on Climate Change
(IPCC)1988
• The first IPCC report1990
Section 1: Introduction to Climate Change Science
18
Further information: BBC Website

One UN Training Service Platform
on Climate Change: UN CC:Learn
Anthropogenic Drivers of
Climate Change
Section 2
Module 1: Introduction to Climate Change Science
19

One UN Training Service Platform
on Climate Change: UN CC:Learn
IPCC Video on the Human
Influence on the Climate System
URL: http://www.youtube.com/watch?v=6yiTZm0y1YA&feature=youtu.be
Video: The video summarizes the main findings of the
2013 IPCC Report on the physical science basis of
climate change.
20
Section 2: Anthropogenic Drivers of Climate Change

One UN Training Service Platform
on Climate Change: UN CC:Learn
Overview of Greenhouse Gases
Regulated under the Kyoto Protocol
21
Greenhouse Gas Global Warming Potential
(GWP) (over 100 years)
% of Total Anthropogenic
GHG Emissions (2010)
Carbon dioxide (CO2) 1 76%
Methane (CH4) 25 16%
Nitrous oxide (N2O) 298 6%
Hydrofluorocarbons (HFCs) 124-14,800 < 2%
Perfluorocarbons (PFCs) 7,390-12,200 < 2%
Sulphur hexafluoride (SF6) 22,800 < 2%
Nitrogen trifluoride (NF3) 17,200 < 2%
Source: Reproduced from IPCC 2007 and UNEP 2012
Section 2: Anthropogenic Drivers of Climate Change

One UN Training Service Platform
on Climate Change: UN CC:Learn
Important Greenhouse Gases:
Carbon Dioxide (CO2)
 Most important greenhouse gas (contributes
~64% to total radiative forcing by long-
lived GHGs)
 Half of CO2 emitted by human activities is
being absorbed in the biosphere and in the
oceans
 Rest remains in the atmosphere for hundreds
to thousands of years
Source: WMO 2013
22
Section 2: Anthropogenic Drivers of Climate Change

One UN Training Service Platform
on Climate Change: UN CC:Learn
CO2 Concentration in the Atmosphere
and Annual Growth Rates
Source: WMO 2013
23
Section 2: Anthropogenic Drivers of Climate Change
Since 1750
CO2 concentration in the
atmosphere has increased
by 40%.

One UN Training Service Platform
on Climate Change: UN CC:Learn
Important Greenhouse Gases:
Methane (CH4)
 Second most significant greenhouse gas
(contributes ~18% to total radiative
forcing by long-lived GHGs)
 Approximately 40% of methane is
emitted into the atmosphere by natural
sources
 About 60% comes from human activities
 Stays in the atmosphere for
approximately 12 years
24
Section 2: Anthropogenic Drivers of Climate Change
Source: IPCC 2007 and WMO 2013

One UN Training Service Platform
on Climate Change: UN CC:Learn
CH4 Concentration in the Atmosphere
and Annual Growth Rates
25
Section 2: Anthropogenic Drivers of Climate Change
Source: WMO 2013
Since 1750
CH4 concentration in the
atmosphere has increased
by 150%.

One UN Training Service Platform
on Climate Change: UN CC:Learn
In Focus: The Carbon Cycle
Source: UNEP
Section 2: Anthropogenic Drivers of Climate Change
26

One UN Training Service Platform
on Climate Change: UN CC:Learn
Important Greenhouse Gases:
Nitrous Oxide (N2O)
 The third most significant greenhouse gas
(contributes ~6% to total radiative
forcing by long-lived GHGs)
 Stays in the atmosphere for
approximately 114 years
 Nitrous oxide is emitted into the
atmosphere from both natural (about
60%) and anthropogenic sources
(approximately 40%)
27
Section 2: Anthropogenic Drivers of Climate Change
Source: IPCC 2007 and WMO 2013

One UN Training Service Platform
on Climate Change: UN CC:Learn
N2O Concentration in the Atmosphere
and Annual Growth Rates
28
Section 2: Anthropogenic Drivers of Climate Change
Source: WMO 2013
Since 1750
N2O concentration in the
atmosphere has increased
by 20%.

One UN Training Service Platform
on Climate Change: UN CC:Learn
Important Greenhouse Gases:
Fluorinated Gases
 Global warming effect up to 23,000
times greater than carbon dioxide
 Stay in the atmosphere up to 50,000
years
 Three main groups: hydrofluorocarbons
(HFCs), perfluorocarbons (PFCs), and
sulfur hexafluoride (SF6)
 Mainly developed as substitutes for
ozone-depleting substances
29
Section 2: Anthropogenic Drivers of Climate Change
Source: IPCC 2007. Further info EPA, EC

One UN Training Service Platform
on Climate Change: UN CC:Learn
Greenhouse Gases Controlled by the
Montreal Protocol
 Montreal Protocol aimed to phase
out substances that deplete the
ozone layer
 Substances regulated under the
Montreal Protocol are also powerful
greenhouse gases
 For example, chlorofluorocarbons
(CFCs) contribute ~12% to radiative
forcing by long-lived GHGs
30
Section 2: Anthropogenic Drivers of Climate Change
Source: IPCC 2007 and WMO 2013. Further info: NOAA Website
Source: EPA

One UN Training Service Platform
on Climate Change: UN CC:Learn
Concentration of SF6 and Halocarbons
in the Atmosphere
31
Section 2: Anthropogenic Drivers of Climate Change
Source: WMO 2013

One UN Training Service Platform
on Climate Change: UN CC:Learn
It is extremely likely
that more than 50%
of the warming since
1951 is due to the
increase in greenhouse
gases and other
anthropogenic forcings
together.
Human Influence on the Climate System
Source: IPCC 2013. Further info: WMO website
32
Section 2: Anthropogenic Drivers of Climate Change

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Trends and Impacts of
Climate Change
Section 3
Module 1: Introduction to Climate Change Science
33

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Surface Temperature
Anomaly (1850-2012)
Source: IPCC 2013, p4
Section 3: Observed Trends and Impacts of Climate Change
34
Globally averaged land and ocean
surface temperature
Each of the last three
decades has been
successively warmer at
the Earth’s surface
than any preceding
decade since 1850.

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Change in Annual
Precipitation Over Land
Source: IPCC 2013, p6
Section 3: Observed Trends and Impacts of Climate
Change
35

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Ocean Warming
(1950-2010)
Section 3: Observed Trends and Impacts of Climate
Change
Source: IPCC 2013, p8
36
More than 60% of
the net energy
increase in the
climate system is
stored in the upper
ocean (period
1971-2010).

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Ocean Acidification
Section 3: Observed Trends and Impacts of Climate
Change
Source: IPCC 2013, p10
37

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Sea Level Rise
(1900 to 2010)
Section 3: Observed Trends and Impacts of Climate
Change
Source: IPCC 2013, p8
38
Over the period
1901 to 2010,
global mean sea
level rose by
0.19m.

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Decrease in Arctic Sea Ice
Extent (1900-2010)
Section 3: Observed Trends and Impacts of Climate
Change
Source: IPCC 2013, p8
39

One UN Training Service Platform
on Climate Change: UN CC:Learn
Observed Changes in Physical and
Biological Systems
Section 3: Observed Trends and Impacts of Climate
Change
40
Source: UNEP 2009, p13

One UN Training Service Platform
on Climate Change: UN CC:Learn
In Focus: Is Climate Change to Blame
for Extreme Weather Events?
Source: UNEP
2009, p12.
Further info:
WMO Website
Section 3: Observed Trends and Impacts of Climate
Change
41
Year
NumberofEvents

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Trends and Impacts of
Climate Change
Section 4
Module 1: Introduction to Climate Change Science
42

One UN Training Service Platform
on Climate Change: UN CC:Learn
In Focus: Representative Concentration
Pathways (RCPs)
Section 4: Projected Trends and Impacts of Climate
Change
43
 Set of four new scenarios defined by the scientific community
for the Fifth IPCC Assessment Report.
 Four RCPs include:
 one mitigation scenario leading to a very low forcing level
(RCP2.6),
 two stabilization scenarios (RCP4.5 and RCP6), and
 one scenario with very high greenhouse gas emissions
(RCP8.5).
 RCPs represent a range of 21st century climate policies.

One UN Training Service Platform
on Climate Change: UN CC:Learn
Global surface temperature change for the end of the
21st century is likely to reach 4°C if no action is taken.
Projected Change in Average Surface
Temperature
Source:IPCC2013,p19
Section 4: Projected Trends and Impacts of Climate
Change
44

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Change in Average
Precipitation
Source: IPCC 2013, p20
Scenario RCP 8.5Scenario RCP 2.6
Section 4: Projected Trends and Impacts of Climate
Change
45
Time Period: 1986-2005 to 2081-2100

One UN Training Service Platform
on Climate Change: UN CC:Learn
Temperature and Precipitation
Projections for the 21st Century
URL: http://www.youtube.com/watch?v=bFqO3_2dYxA
Video: This NASA video shows how temperature
and precipitation patterns could change
throughout the 21st century.
Section 4: Projected Trends and Impacts of Climate Change
46

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Change in Ocean Surface pH
Source: IPCC 2013, p20
Scenario RCP 8.5Scenario RCP 2.6
Section 4: Projected Trends and Impacts of Climate
Change
47
Time Period: 1986-2005 to 2081-2100

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Sea Level Rise
Source: IPCC 2013, p24
Section 4: Projected Trends and Impacts of Climate
Change
48
Global mean
sea level will
continue to rise
during the 21st
century.

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Northern Hemisphere
September Sea Ice Extent
Source: IPCC 2013, p20
Scenario RCP 8.5Scenario RCP 2.6
Section 4: Projected Trends and Impacts of Climate
Change
49
Average 2081-2100

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Impacts of Climate Change
in Africa
Source: UNEP 2009, p32
Section 4: Projected Trends and Impacts of Climate Change
50

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Impacts of Climate Change
in Asia
Section 4: Projected Trends and Impacts of Climate
Change
51
Source: UNEP
2009, p34

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Impacts of Climate Change
in Latin America
Section 4: Projected Trends and Impacts of Climate Change
52
Source: UNEP
2009, p37

One UN Training Service Platform
on Climate Change: UN CC:Learn
Projected Impacts of Climate Change
on Small Islands
 Sea level rise exacerbating
inundation, storm surge,
erosion and other coastal
hazards
Section 4: Projected Trends and Impacts of Climate Change
Source: UNEP 2006, p185
53
 Reduced freshwater resources
 Invasion by non-native species
 Effects on food and income
security

One UN Training Service Platform
on Climate Change: UN CC:Learn
54
“Carbon Crossroads”
Source: Cambridge
University 2013, p 14
Section 4: Projected Trends and Impacts of Climate
Change

One UN Training Service Platform
on Climate Change: UN CC:Learn
Global Warming by 2100 and Beyond:
A Function of Cumulative CO2 Emissions
Section 4: Projected Trends and Impacts of Climate
Change
55
Limiting climate
change will
require
substantial and
sustained
reductions of
greenhouse gas
emissions.
Source: IPCC 2013, p26

One UN Training Service Platform
on Climate Change: UN CC:Learn
Sources of Scientific DataSection 5
Module 1: Introduction to Climate Change Science
56

One UN Training Service Platform
on Climate Change: UN CC:Learn
The Intergovernmental Panel on
Climate Change (IPCC)
Leading body for the
assessment of climate
change
Established in 1988 by
UNEP and WMO
Assesses relevant
scientific, technical and
socio-economic
information
Does not conduct any
research itself
Thousands of scientists
from all over the world
contribute to its work
Section 5: Sources of Scientific Data
57

One UN Training Service Platform
on Climate Change: UN CC:Learn
Important Reports Published by the IPCCAssessmentReports
• First
assessment
report (FAR)
• Second
assessment
report (SAR)
• Third
assessment
report (TAR)
• Fourth
assessment
report (AR4)
• Fifth
assessment
report (AR5)
SpecialReportson:
• Renewable
energy
sources
• Extreme
events and
disasters
• Emission
scenarios
• Aviation
• Carbon
capture and
storage
MethodologyReports
• Guidance
for national
greenhouse
gas
inventories
• Guidance
for assessing
impacts of
climate
change
• Land use,
land-use
change and
forestry
TechnicalPapers
• Climate
change and
water
• Implications
of proposed
CO2
emissions
limitations
• Technologies,
policies and
measures for
mitigating
climate
change
58
Section 5: Sources of Scientific Data

One UN Training Service Platform
on Climate Change: UN CC:Learn
World Meteorological Organization
(WMO) – Global Climate Programmes
59
Section 5: Sources of Scientific Data
 World Climate Programme (WCP)
 World Climate Research Programme
 Global Climate Observing System
 World Climate Services Programme
 Programme of Research on Climate Change
Vulnerability, Impacts and Adaptation
 Atmospheric Research and Environment Programme (AREP)
 Global Framework for Climate Services (GFCS)
 Advisory Body: Commission for Climatology (CCI)

One UN Training Service Platform
on Climate Change: UN CC:Learn
In Focus: Global Framework for
Climate Services (GFCS)
60
URL: http://www.gfcs-climate.org/content/about-gfcs
Section 5: Sources of Scientific Data

One UN Training Service Platform
on Climate Change: UN CC:Learn
WMO Global Atmosphere Watch:
Measurement Stations Worldwide
61
Section 5: Sources of Scientific Data

One UN Training Service Platform
on Climate Change: UN CC:Learn
WMO Regional Climate Centers and
Outlook Forums
62
Section 5: Sources of Scientific Data
 WMO Regional
Climate Centres
(RCCs)
 WMO Regional
Climate Outlook
Forums (RCOFs)

One UN Training Service Platform
on Climate Change: UN CC:Learn
National Climate Data
 National Meteorological
and Hydrological
Services (NMHS)
 Collect and manage
national climate data to
help with forecasting and
predictions
Norfolk Island Meterological Office,
Source: Australian Government: Bureau of Meteorology
63
Section 5: Sources of Scientific Data

One UN Training Service Platform
on Climate Change: UN CC:Learn
Annex Additional Resources
Module 1: Introduction to Climate Change Science
64

One UN Training Service Platform
on Climate Change: UN CC:Learn
Module Summary
65
Additional Resources
 Weather and climate are the results of complex interactions between
anthropogenic and natural factors.
 Evidence of global climate change include higher average temperatures,
changes in precipitation, ocean warming, ocean acidification, sea level
rise, decreasing sea ice, and changes in physical and biological systems.
 Observed climate change can be linked with the increase of greenhouse
gase concentrations in the atmosphere since the industrial revolution.
 Global surface temperature change for the end of the 21st century is
likely to reach 4°C if no drastic mitigation actions are taken.
 Various sources of climate data exist that can support planning for climate
change.

One UN Training Service Platform
on Climate Change: UN CC:Learn
Useful Links
IPCC Website WMO Climate Pages
Global Framework
For Climate Services
(GFCs)
World Climate
Programme (WCP)
World Bank Climate
Change Knowledge
Portal
NASA Global
Climate Change
ESA Climate Change
Initiative
NCAR Community
Data Portal
Max Planck: The
Atmosphere in the
Earth System
The Guardian
Climate Change
Pages
The National
Geographic - Global
Warming
UN CC:Learn
Additional Resources
66

One UN Training Service Platform
on Climate Change: UN CC:Learn
Recommended Readings
 Cambridge University (2013). Climate Change: Action, Trends and
Implications for Business
 IPCC (2013). Climate Change 2013, The Physcial Science Basis - Summary
for Policymakers
 UNEP (2009). Climate Change Science Compendium
 UNEP (2009). Climate in Peril, A Popular Guide to the Latest IPCC Reports
 WMO (2013). The Global Climate 2001–2010, A Decade of Climate
Extremes
Additional Resources
67

One UN Training Service Platform
on Climate Change: UN CC:Learn
Main References
 IPCC (2007). Climate Change 2007 - Synthesis Report
 IPCC (2013). Climate Change 2013, The Physcial Science Basis - Summary
for Policymakers
 UNEP (2009). Climate in Peril, A Popular Guide to the Latest IPCC Reports
 UNEP (2012). The Emissions Gap Report 2012
 WMO (2012): Greenhouse Gas Bulletin
 WMO (2009). A History of Climate Activities
 WMO Website: Climate
Additional Resources
68