This document outlines key concepts related to climate and climate modelling. It discusses global climate models (GCMs) which are 3D models of the atmosphere and oceans used to simulate the climate system. It also discusses regional climate models (RCMs) which provide higher resolution outputs than GCMs to better represent regional features. The document then summarizes projected climate changes from the Intergovernmental Panel on Climate Change including increased global temperatures, precipitation changes, and sea level rise under different emissions scenarios through 2100.

1. Pabitra Gurung
PhD Student
gurung@unbc.ca
NRES 804
CLIMATE AND CLIMATE MODELLING

2. OUTLINE
 Climate and Climate Modelling
 Global Climate Models / General Circulation Models (GCMs)
 Regional Climate Models (RCMs)
 Intergovernmental Panel on Climate Change (IPCC)
 Projected Changes (IPCC, AR5)

3. Are you planning to use “Climate and Climate
Change” information in your research?
Is it an important for your study or not?

4. CLIMATE AND CLIMATE MODELLING
(Source: IPCC, 2007 )

5. Forcing agents
 Greenhouse Gases
(CO2, CH4, N2O, O3, CFCs)
 Aerosols
(SO4, Carbon, Nitrate, Dust etc.)
 Land use and Land Cover
 Solar
 Volcano
 etc.
Factors that change the climate
(Source: IPCC, 2013 )
Sources/Actors:
People, Industry, Agriculture, Urbanization, Vehicles, Disaster etc.

6. Important 5 components to
understand climate models
1. Solar Radiation
(absorbed by the atmosphere and
sea)
2. Dynamics
(e.g. movement of energy/heat and
mass by winds)
3. Surface processes
(effects of ice, snow, vegetation,
albedo, and moisture interchanges)
(Source: McGuffie and Henderson-Sellers, 2005)

7. Important 5 components to
understand climate models
4. Chemistry
(Chemical composition of
atmosphere and interactions, e.g.
CO2 exchanges between sea, land
and atmosphere)
5. Resolution in both time and
space
(the timestep of the model and
horizontal & vertical scales
resolved)
Note: Model setup & programming
language and platform
(Source: McGuffie and Henderson-Sellers, 2005)

8. Basic 4 types of climate
model
1. Energy balance models (EBMs)
(Surface temperature as a function
of the energy balance on the Earth)
2. One-dimensional radiative-
convective (RC) models
(the temperature profile based on
the modelling of radiative and a
‘convective adjustment’ which
depend on the predetermined lapse
rate )
(Source: McGuffie and Henderson-Sellers, 2005)

9. Basic 4 types of climate
model
3. Dimensionally-constrained models
(Statistical dynamical (SD) models,
which deal with surface processes
and dynamics)
4. Global climate models (GCMs)
(3-dimensional nature of the
atmosphere and ocean is
incorporated)
(Source: McGuffie and Henderson-Sellers, 2005)

10. A GCMs, a type of climate model, is
a mathematical model of the general
circulation of a atmosphere and ocean;
and based on the Navier–Stokes
equations on a rotating sphere with
thermodynamic terms for various
energy sources (radiation, latent heat).
𝜌
𝐷𝑣
𝐷𝑡
= 𝛻𝑝 + 𝜇𝛻2
𝑣 + 𝑓
(Where, “𝜌” is a density; “𝑣” is a flow
speed; “𝑡” is a time; “𝑝” is a pressure;
“𝜇” is a dynamic viscosity; and “𝑓” is a
body forces)
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Spencer, 2009)

11. 1. Conservation of energy
(the first law of thermodynamics)
i.e. Input energy = Increase in internal energy
+ Work done
2. Conservation of momentum
(Newton’s second law of motion)
i.e. Force = Mass × Acceleration
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Islam, 2013)
Fundamental 4-laws considered in GCMs

12. 3. Conservation of mass
(the continuity equation)
𝜕𝜌
𝜕𝑡
+
𝜕𝜌
𝜕𝑥
𝑢 𝑥 +
𝜕𝜌
𝜕𝑦
𝑢 𝑦+
𝜕𝜌
𝜕𝑧
𝑢 𝑧 = 0
(Where, “𝜌” is a density; “𝑡” is a time; “𝑥, 𝑦, 𝑧”
are the three orthogonal directions; and “𝑢” is
a flow speed)
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Islam, 2013)
4. Ideal gas law
(an approximation to the equation of state – atmosphere only)
i.e. Pressure × Volume ∞ Absolute temperature × Density
Fundamental 4-laws considered in GCMs

13. There are seven primitive equations for all
models, with the prognostic equations being
energy (temperature), moisture (water), the
wind components (u, v, w), mass (air density,
and pressure).
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Islam, 2013)
Fundamental 4-laws considered in GCMs

14. Types of GCMs
1. AGCM (Atmospheric GCM)
Atmosphere and impose sea
surface temperature
2. OGCM (Ocean GCM)
Global sea patterns
3. AOGCM (Atmosphere and Ocean
GCM) or CGCM (Coupled GCM)
Coupled atmosphere-ocean models
(e.g. CCSM4, HadCM3, GFDL)
GLOBAL CLIMATE MODELS (GCMS)
(Source: McGuffie and Henderson-Sellers, 2005; Islam, 2013)

15. REGIONAL CLIMATE MODELS (RCMs)
(Source: Feser et al., 2011; Giorgi, 2008)
RCMs are tools used to achieve high-resolution climate data from coarsely
resolved GCMs.

16.  Higher detail for mountain ranges
and coastal zones
 More detail on differing vegetation
coverage and soil characteristics
 A description of smaller-scale
atmospheric processes
To produce model output that is closer to
the real heterogeneity condition
(Physiographic details) of the nature.
REGIONAL CLIMATE MODELS (RCMs)
(Source: Evans, 2012; Feser et al., 2011; Wang et al., 2012)
The added value of the RCMs in comparison with the GCMs

17.  Higher detail for mountain ranges
and coastal zones
 More detail on differing vegetation
coverage and soil characteristics
 A description of smaller-scale
atmospheric processes
To produce model output that is closer to
the real heterogeneity condition
(Physiographic details) of the nature.
REGIONAL CLIMATE MODELS (RCMs)
The added value of the RCMs in comparison with the GCMs
(Source: Evans, 2012; Feser et al., 2011; Wang et al., 2012)
Temperature
Anomaly

18. Development of Climate Model
 Mid-1970s
 Mid-1980s
 First Assessment Report 1990 (FAR)
 Second Assessment Report 1995 (SAR)
 Third Assessment Report 2001 (TAR)
 Fourth Assessment Report 2007 (AR4)
 Fifth Assessment Report 2013 (AR5)
INTERGOVERNMENTAL PANEL ON CLIMATE
CHANGE (IPCC)
(Source: IPCC, 2013 )

19.  Representative Concentration
Pathway (RCP)
1. RCP2.6
2. RCP4.5
3. RCP6.0
4. RCP8.5
 Reference Period (1986-2005)
 Projected Period (2016-2035,
2046-2065, 2081-2100, ... )
Projection Scenarios (AR5)
(Source: IPCC, 2013 )

20. Global Mean (5% - 95% model ranges)
2046-2065 2081-2100
Scenario Mean Range Mean Range
RCP2.6 1.0 0.4 - 1.6 1.0 0.3 - 1.7
RCP4.5 1.4 0.9 - 2.0 1.8 1.1 - 2.6
RCP6.0 1.3 0.8 - 1.8 2.2 1.4 - 3.1
RCP8.5 2.0 1.4 - 2.6 3.7 2.6 - 4.8
Projected Changes in Temperature (°C)
(Source: IPCC, 2013 )
PROJECTED CHANGES (IPCC, AR5)
Note: Reference/Baseline period: 1986-2005

21. (Source: IPCC, 2013 )
Projected Changes in Precipitation (IPCC, AR5)

22. (Source: IPCC, 2013 )
Projected Changes in Sea Level (IPCC, AR5)

23. Questions ?

24. REFERENCES
Evans, J.P., 2012. Regional Climate Modelling: The Future for Climate Change Impacts and Adaptation Research.
Earthzine. http://www.earthzine.org/2012/02/14/regional-climate-modelling-the-future-for-climate-change-impacts-and-
adaptation-research/. Accessed 7 Mar 2014.
Feser, F., B. Rockel, H. von Storch, J. Winterfeldt, and M. Zahn, 2011. Regional Climate Models Add Value to Global
Model Data: A Review and Selected Examples. Bulletin of the American Meteorological Society 92:1181–1192.
Giorgi, F., 2008. Regionalization of Climate Change Information for Impact Assessment and Adaptation. WMO Bulletin
57:86–92
IPCC, 2007. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth
Assessment Report of the Intergovernmental Panel on Climate Change S. Solomon, D. Qin, M. Manning, M. Marquis,
K. Averyt, M. M. B. Tignor, and H. L. Miller (Editors). Cambridge University Press, Cambridge, United Kingdom and
New York, NY, USA.
IPCC, 2013. The Physical Science Basis Contribution of Working Group I to the Fifth Assessment Report of the
Intergovernmental Panel on Climate Change. T. F. Stocker, D. QIN, G.-K. Plattner, M. M. B. Tignor, S. K. Allen, J.
Boschung, A. Nauels, Y. Xia, V. Bex, and P. M. Midgley (Editors). Cambridge University Press, Cambridge, United
Kingdom and New York, NY, USA.
Islam, S. U., 2013. Role of Modeling and Simulation in Climate Predictions. Presentation at Climate Science Informal
Seminars. University of Northern British Columbia.
McGuffie, K. and A. Henderson-Sellers, 2005. A Climate Modelling Primer. John Wiley & Sons, Ltd, Chichester, England.
Spencer, R.W., 2009. How Do Climate Models Work? Global Warming. http://www.drroyspencer.com/2009/07/how-do-
climate-models-work/. Accessed 7 Mar 2014.
Wang, T., A. Hamann, D.L. Spittlehouse, and T.Q. Murdock, 2012. ClimateWNA—High-Resolution Spatial Climate Data
for Western North America. Journal of Applied Meteorology and Climatology 51:16–29.