Climatic Change (2009) 95:219–230DOI 10.1007/s10584-008-9519-5

Cartographic design and the qualityof climate change maps

Jean E. McKendry · Gary E. Machlis

Received: 13 February 2008 / Accepted: 22 September 2008 / Published online: 21 November 2008© Springer Science + Business Media B.V. 2008

Abstract Maps are essential in climate change research and policymaking, and areprimary tools for communicating climate change information to the public. Theconsequences of cartographic design are potentially significant to understandingclimate change and effectively informing policymakers. Yet, the cartographicdesign and quality of climate change maps have not been critically assessed norsystematically evaluated. We suggest that evaluating the quality of climate changemaps is both timely and essential, and offer one approach as a demonstration. We usecartographic design principles to evaluate a ‘high visibility’ climate change map fromthe 2007 report of the Intergovernmental Panel on Climate Change. Our specificgoals are to demonstrate the need and value of cartographic critique, describe howsuch evaluation can be accomplished, and make a case for cartographers’ engage-ment with climate change scientists in mapping activities. We suggest a research andpolicy agenda for the cartographic evaluation and design of climate change maps.

1 Introduction

Maps are essential to climate change research and policymaking, and their use issubstantial: Working Group I of the Intergovernmental Panel on Climate Change(IPCC) included over 130 maps in its 2007 report (IPCC 2007a). Climate changemaps are used by the scientific community to display results of general circulationmodels (GCMs), projected sea level rise, temperature change, migration of flora andfauna habitat ranges, and more. Policymakers use climate change maps to compare

J. E. McKendry · G. E. MachlisCollege of Natural Resources, University of Idaho,Moscow, ID 83844-1133, USA

J. E. McKendry (B)c/o AAAS, 1200 New York Avenue, NW (Room 637),Washington, DC 20005, USAe-mail: jeanm@uidaho.edu

220 Climatic Change (2009) 95:219–230

costs/benefits of adaptive responses, analyze policy options, and develop mitigationplans. Maps are also primary tools for communicating climate change information tothe public.

Hence, an important question arises for the producers and users of climate changemaps: what is the quality of cartographic design used in climate change maps? Here‘quality’ refers not to the accuracy or reliability of the underlying data but to howdata are cartographically displayed. The question is relevant because: (1) maps, in-cluding climate change maps, are increasingly made by individuals not trained in mapdesign, (2) poor map design can hinder effective data analysis, understanding, anddecision-making, and (3) poorly designed maps can distort information and misleadusers (see Lilley 2007; Cassettari 2007; Carter 2004; McKendry 2000; Monmonier1996).

Mapmaking and cartography have been transformed by technology (see Arikawaet al. 2007; Gartner et al. 2007; Monmonier 2007; Butler 2006; Taylor and Caquard2006). These technological developments have made it easier to produce maps.Geographic Information Systems (GIS), remote sensing, Global Positioning Sys-tems (GPS), interactive web mapping (including ‘mashups’), inexpensive computingplatforms, and plentiful data and data delivery options have made mapmakinga commonplace activity beyond the realm of the trained cartographer. Today’smapmakers often do not have specialized education or training in the principles ofcartographic design. As a result, maps made by non-cartographers vary in quality(as do maps by cartographers, of course), and are often poorly designed (Cassettari2007; Plewe 2007; Monmonier 2006; Field 2005; Wood and Keller 1996).

The consequences of poor quality map design can be significant. Maps have thepower to inform or misinform, lead or mislead, clarify or confuse through the useor misuse of design principles (Lilley 2007; Carter 2004; McKendry 2000; Buttenfield1996; Monmonier 1995; Buttenfield and Beard 1991; Petchenik 1983). For example,Tufte (1990, 1983) analyzes a broad range of information graphics (including charts,diagrams, graphs, tables, and maps) and documents the prevalence of ‘graphicmediocrity’ (due to lack of skill). Importantly, he describes how the quality of graphicdesign can directly impact decision-making by revealing or obscuring information(Tufte 1997).

Given the urgent challenges created by climate change and the importance ofmaps in climate change research and policymaking, the role of map design deservesattention. Surprisingly, the cartographic design and quality of climate change mapshave not been critically assessed nor systematically evaluated.

We suggest that evaluating the quality of climate change maps is both timelyand essential. We offer one approach as a demonstration. First, we select a ‘highvisibility’ climate change map to evaluate, in this case a map used in the “Summaryfor Policymakers” report issued by Working Group II of the IPCC (IPCC 2007b).We then present a brief overview of selected cartographic design principles thatcan be used to evaluate this and other climate change maps. This overview is nota comprehensive ‘primer’ on cartographic design; there are many resources availableto introduce cartographic design (see Section 3 below). The purpose of this overviewis to provide specific examples of agreed-upon design principles established throughcartographic research. Next, we systematically apply these cartographic principlesto the selected climate change map and report the results. We conclude with aproposed research and policy agenda for the systematic cartographic evaluation of

Climatic Change (2009) 95:219–230 221

climate change maps. We acknowledge that this small case study approach is limited.However, our specific goals are to demonstrate the need and value of cartographiccritique, describe how such evaluation can be accomplished, and make a case forcartographers’ engagement with climate change scientists in mapping activities.

Figure SPM.1. Locations of significant changes in data series of physical systems (snow, ice and frozen ground; hydrology; and coastal processes) and biological systems (terrestrial, marine, and freshwater biological systems), are shown together with surface air temperature changes over the period 1970-2004. A subset of about 29,000 data series was selected from about 80,000 data series from 577 studies. These met the following criteria: (1) ending in 1990 or later; (2) spanning a period of at least 20 years; and (3) showing a significant change in either direction, as assessed in individual studies. These data series are from about 75 studies (of which about 70 are new since the Third Assessment) and contain about 29,000 data series, of which about 28,000 are from European studies.White areas do not contain sufficient observational climate data to estimate a temperature trend. The 2 x 2 boxes show the total number of data series with significant changes (top row) and the percentage of those consistent with warming (bottom row) for (i) continental regions: North America (NAM), Latin America (LA), Europe (EUR), Africa (AFR), Asia (AS), Australia and New Zealand (ANZ), and Polar Regions (PR) and (ii) global-scale: Terrestrial (TER), Marine and Freshwater (MFW), and Global (GLO). The numbers of studies from the seven regional boxes (NAM, …, PR) do not add up to the global (GLO) totals because numbers from regions except Polar do not include the numbers related to Marine and Freshwater (MFW) systems. Locations of large-area marine changes are not shown on the map. [Working Group II Fourth Assessment F1.8, F1.9; Working Group I Fourth Assessment F3.9b].

Fig. 1 Map, legend, and caption of Figure SPM.1., reprinted from IPCC Working Group II“Summary for Policymakers” (2007b, p. 10), used with permission

222 Climatic Change (2009) 95:219–230

2 Selecting a climate change map to evaluate

A climate change map from a recent report of the IPCC was selected to demonstratehow climate change maps can be cartographically evaluated. Selecting an IPCCmap is appropriate for several reasons. Since 1988, the IPCC has released fourcomprehensive scientific assessments of climate change. IPCC reports are consideredby policymakers and the scientific community to be a definitive source of informationon climate change and its impacts (Kintisch and Kerr 2007).

The map shown in Fig. 1 was published in the “Summary for Policymakers”completed by Working Group II for Climate Change 2007: Impacts, Adaptation andVulnerability. Contribution of Working Group II to the Fourth Assessment Report ofthe Intergovernmental Panel on Climate Change (IPCC 2007b, p. 10). The title of themap is “Changes in physical and biological systems and surface temperature 1970–2004.” Figure 1 is the only map included in this summary report for policymakers.We consider this map appropriate for a case example given that: (1) the IPCC is alegitimated source of climate change information, (2) the IPCC’s fourth assessmentreport (AR4) is a major consensus technical effort to summarize current climatechange knowledge, (3) the policy summary is an important stand-alone document,and (4) Fig. 1 is the sole map in the policy summary approved by Working Group II.

The map published in the report is 184 mm wide by 194 mm tall, accompanied bya caption 184 mm wide by 41 mm tall, and printed in color on a page 215 mm wideby 279 mm tall. The map was also made available as a separate color graphic (thoughwithout its title or caption) on the IPCC website (IPCC 2007b). Since its originalpublication, the map has been distributed through other reports of the IPCC and inthe public media in both its original and modified form.

The map appears in the draft copy of the “Summary for Policymakers of theSynthesis Report of the IPCC Fourth Assessment Report”—the overall summary ofthe IPCC’s work (IPCC 2007c). It was published in modified form in the WashingtonPost (print and online) on 18 November 2007, page A10 with the caption excluded,title changed, and legend edited and rearranged (Struck 2007). The map was adaptedand split into two separate maps by the Organization of Ibero-American States(Organización de Estados Iberoamericanos 2007). The resulting two maps wereposted on the organization’s website with substantial changes made to the legend(see http://www.oei.es/decada/presentacioneurop.htm).

The color version of the map published in the final summary report of WorkingGroup II and shown in Fig. 1 is evaluated in this demonstration, downloaded fromthe IPCC website 21 November 2007 (IPCC 2007b, p. 10).

3 Selected principles of cartography to use in evaluating climate change maps

Research and practice in the field of cartography have produced a set of fundamentalprinciples that are essential to good cartographic design—principles that deal withmap layout and symbolizing data and features. Cartographic design principles guidedecisions about how to represent locations on a map and attributes of those locations,using graphic symbols such as color, size, shape, typography, and other symbols.Principles describe how points, lines, and areas should be symbolized based onthe underlying data (i.e., attributes of features). For example, the selection of

Climatic Change (2009) 95:219–230 223

Tab

le1

Sele

cted

prin

cipl

esfo

rca

rtog

raph

icde

sign

and

layo

utw

ith

desc

ript

ions

(ada

pted

from

Bre

wer

2005

and

Kry

gier

and

Woo

d20

05)

Car

togr

aphi

cpr

inci

ple

Des

crip

tion

ofca

rtog

raph

icpr

inci

ple

Map

proj

ecti

onA

llm

appr

ojec

tion

sha

vedi

stor

tion

s(d

ista

nce,

area

,dir

ecti

on,a

nd/o

rsh

ape)

.An

equa

l-ar

eam

appr

ojec

tion

isa

good

sele

ctio

nfo

rm

ost

smal

l-sc

ale

map

s(e

.g.,

man

yw

orld

map

s)an

dsh

ould

beus

edfo

rm

aps

show

ing

data

dist

ribu

tion

s.G

ener

aliz

atio

nSm

all-

scal

em

aps

shou

ldsh

owm

ore

area

,les

sde

tail,

and

mor

ege

nera

lizat

ion

offe

atur

es.L

arge

-sca

lem

aps

shou

ldsh

owle

ssar

ea,m

ore

deta

il,an

dle

ssge

nera

lizat

ion

offe

atur

es.T

heco

astl

ine

ofa

coun

try

ona

larg

e-sc

ale

map

issy

mbo

lized

bya

line

wit

hm

ore

deta

iled

curv

esth

anth

esa

me

coas

tlin

eon

asm

all-

scal

em

ap.

Dat

acl

assi

ficat

ion

Qua

litat

ive

data

show

diff

eren

ces

inki

nd(e

.g.,

fore

stve

rsus

urba

nla

ndco

ver)

.Qua

litat

ive

data

shou

ldbe

grou

ped

soth

atfe

atur

esin

the

sam

egr

oup

are

mor

esi

mila

rth

andi

ssim

ilar

and

feat

ures

indi

ffer

entg

roup

sar

em

ore

diss

imila

rth

ansi

mila

r.Q

uant

itat

ive

data

show

diff

eren

ces

inam

ount

(e.g

.,po

pula

tion

dens

ity)

.Qua

ntit

ativ

eda

tash

ould

begr

oupe

dby

spec

ific

exte

rnal

crit

eria

(e.g

.,qu

anti

les)

orby

the

char

acte

rist

ics

ofth

eda

ta(e

.g.,

natu

ralb

reak

s).

Map

layo

uta

Foc

usM

apla

yout

shou

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ide

read

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thro

ugh

the

map

elem

ents

and

help

them

focu

son

the

mos

tim

port

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arts

ofth

em

ap.

Vis

ualv

aria

bles

b

Col

orhu

eC

olor

hue

(suc

has

red,

gree

n,bl

ue)

shou

ldbe

used

toca

tego

rize

feat

ures

that

are

qual

itat

ivel

ydi

ffer

ent,

such

asa

rive

ran

da

road

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olor

valu

eC

olor

valu

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htne

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shou

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tore

pres

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uant

itat

ivel

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ffer

entd

ata

(eit

her

rank

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data

ornu

mer

ical

amou

nts)

,suc

has

popu

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onde

nsit

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pica

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.g.,

light

gree

n)an

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mbe

rs(e

.g.,

dark

gree

n)in

sequ

enti

alda

tase

ts,s

uch

asa

data

seto

fpop

ulat

ion

chan

gefr

om0%

to10

0%.F

ordi

verg

ing

data

sets

wit

han

impo

rtan

tm

idpo

int(

betw

een

nega

tive

and

posi

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valu

es),

such

aspo

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chan

gefr

om−5

0%to

+50

%,h

uean

dva

lue

can

vary

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etw

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rect

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inth

eda

tase

t.T

hem

idpo

intf

rom

0%to

−50%

can

besy

mbo

lized

usin

ga

light

toda

rkco

lor

hue.

The

mid

poin

tfro

m0%

to+

50%

can

besy

mbo

lized

usin

ga

diff

eren

t,co

mpl

emen

tary

light

toda

rkco

lor

hue.

Col

orsa

tura

tion

Col

orsa

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tion

(or

inte

nsit

yof

hue,

such

asbr

ight

red

com

pare

dw

ith

adu

ll,gr

ayre

d)ca

nbe

used

for

qual

itat

ive

orqu

anti

tati

veda

ta.

Itis

diffi

cult

tous

eon

its

own

tosy

mbo

lize

data

.Sat

urat

ion

isty

pica

llyus

edto

rein

forc

ech

ange

sin

valu

efo

rqu

anti

tati

veda

taor

tore

info

rce

chan

ges

inhu

efo

rsm

alla

reas

ona

map

that

are

qual

itat

ivel

ydi

ffer

ent.

Size

Size

shou

ldbe

used

tore

pres

entq

uant

itat

ivel

ydi

ffer

entd

ata

(eit

her

rank

-ord

ered

data

ornu

mer

ical

amou

nts)

.Ala

rger

squa

resi

gnifi

esa

grea

ter

quan

tity

than

asm

alle

rsq

uare

.Sh

ape

Shap

esh

ould

beus

edto

cate

gori

zefe

atur

esth

atar

equ

alit

ativ

ely

diff

eren

t.A

squa

reis

notm

ore

orle

ssth

ana

circ

le,

buti

sdi

ffer

enti

nki

nd.

Vis

ualh

iera

rchy

Vis

ualh

iera

rchy

shou

ldem

phas

ize

the

mos

tim

port

antm

apel

emen

ts.L

ess

impo

rtan

tele

men

tssh

ould

bele

ssno

tice

able

.Vis

ualh

iera

rchy

shou

ldcl

earl

yco

mm

unic

ate

the

inte

llect

ualh

iera

rchy

and

purp

ose(

s)of

the

map

.a F

orK

rygi

eran

dW

ood

(200

5)‘f

ocus

’is

one

elem

ent

ofm

apla

yout

that

also

incl

udes

map

piec

es(t

itle

,le

gend

,bo

rder

,et

c.),

bala

nce

(sta

bilit

y),

and

the

grid

(und

erly

ing

grid

ofve

rtic

alan

dho

rizo

ntal

lines

that

help

sw

ith

bala

nce)

.bB

erti

n(1

981)

init

ially

desc

ribe

dse

ven

visu

alva

riab

les.

Car

togr

aphe

rsha

vead

apte

dan

dm

odifi

edth

islis

t.F

ive

visu

alva

riab

les

are

pres

ente

dhe

re.

224 Climatic Change (2009) 95:219–230

appropriate color schemes is determined by whether the attributes are qualitative(use different colors to symbolize different ecotypes) or quantitative (use the samecolor with variation from light to dark to symbolize changes in temperature overtime). Cartographic principles guide decisions about how to group (‘classify’) datafor representation. For example, a map showing temperature ranges may havetemperature data assigned to groups using equal intervals (same data range foreach class) or quantiles (same number of data points in each class). Cartographicprinciples guide decisions about how to arrange all the graphic symbols included ona map so that there is clarity in the overall design and layout. Numerous texts reviewand explain cartographic principles (see, for example, Slocum et al. 2005; Kimerlinget al. 2001; Dent 1999; Robinson et al. 1995; MacEachren 1994; Monmonier 1993).There is strong consensus within the cartographic community about basic principles.

Contemporary map design also demands understanding the constraints and op-portunities determined by the media on which a map will be reproduced. Forexample, maps designed for digital display are limited by screen resolution comparedwith maps designed for printing on paper, and ‘endless zoom’ options carry with themunique problems of data accuracy and cartographic design (see Lobben and Patton2003, for a comparison of design issues for digital and printed maps).

Table 2 Selected introductory resources on cartographic design

Books (full citations are listed under references)Cynthia Brewer, Designing Better Maps: A Guide for GIS UsersBorden Dent, Cartography: Thematic Map Design, 5th editionJon Kimerling, Philip Muehrcke, and Juliana Muehrcke, Map Use: Reading, Analysis, and

Interpretation, 5th editionJohn Krygier and Denis Wood, Making Maps: A Visual Guide to Map Design for GISAlan MacEachren, Some Truth with Maps: A Primer on Symbolization and DesignMark Monmonier, How to Lie with Maps, 2nd editionTerry Slocum, Robert McMaster, Fritz Kessler, and Hugh Howard, Thematic Cartography

and Geographic Visualization, 2nd editionJournals

Cartographic Perspectives (Journal of the North American Cartographic Information Society;http://www.nacis.org)

Cartography and Geographic Information Science (Journal of the Cartography and GeographicInformation Society; http://www.cartogis.org)

Cartographica (Journal of the Canadian Cartographic Association; http://www.cca-acc.org/)The Cartographic Journal (Journal of the British Cartographic Society;

http://www.cartography.org.uk/)Websites

http://www.colorbrewer.org(an interactive online tool designed to assist in selecting good color schemes for maps andother graphics)

http://www.typebrewer.org/(an online tool designed for people who want to learn more about map typography)

http://www.progonos.com/furuti/MapProj/Normal/CartProp/cartProp.html(an introduction to map projections, with examples of distortions, and a discussion of matchingprojection to a map’s purpose)

http://mappingcenter.esri.com/(a website that focuses on cartographic resources, examples, and assistance for users of ArcGIS)

Climatic Change (2009) 95:219–230 225

Table 1 includes selected cartographic principles adapted from two recent booksthat focus on map design (Brewer 2005; Krygier and Wood 2005). Specifically,Table 1 describes principles concerning map projections, generalization, data clas-sification, map layout, visual variables (such as color), visual hierarchy (importantinformation is visually prominent in the map’s design), and more. The sources wereselected because their focus is on teaching GIS users how to make better maps, andcan introduce non-cartographers to the basics of good map design.

The list of principles, though not exhaustive, deals with common design issuesencountered in mapping. For example, all maps displayed in two dimensions requiremathematical transformation of spherical coordinates to plane coordinates throughthe use of a map projection. All map projections have distortions of distance, area,direction, and/or shape. Such distortions are particularly noticeable on small-scalemaps, such as maps of the world. A map projection that preserves relative areasshould be used for maps showing data distributions. While these principles are basicand straightforward, their application in the overall design and layout of a map isoften complex and challenging, can involve design tradeoffs, and is a requirementfor high quality map design.

For climate change scientists interested in learning more about cartographicdesign, Table 2 provides a list of selected resources that include numerous examplesof good and poor map design.

4 Evaluating the IPCC climate change map: an example approach

Figure 1 from the IPCC Working Group II summary report for policymakerscan be evaluated using the selected principles in Table 1. Each principle can besystematically applied to the map with the result rated as good, satisfactory, or poorfollowed by a brief explanation. We applied this method to the IPCC map shown inFig. 1.

Table 3 includes the rating of the map for each selected principle with itsexplanation. Our preliminary and limited evaluation indicates that the map publishedin the summary report of Working Group II for policymakers ranges from poor tosatisfactory in its use of selected cartographic principles. For example, we rated maplayout and focus as poor. The map legend is complex and includes data not evendisplayed on the map, i.e., the number and percentage of significant changes in theseries of four-celled tables with arrows. The legend is also the same size as the map,and they visually compete with each other for importance on the page. Informationabout the white areas on the map is included in the caption but not in the map legend.Meaningful relationships between changes in physical and biological systems andchanges in surface temperature are difficult to see.

We rated the generalization of features on the map as satisfactory. The map showscoastlines and boundaries between nations. The black linework to symbolize coast-lines and boundaries is more detailed than needed for the scale of this map. The highlevel of detail for the southern tip of Chile means that the black boundaries blend inwith the point locations (blue circles with black outlines). Table 3 summarizes resultsfor each of the selected cartographic principles.

Overall, our evaluation is that the map does not clearly and effectively displayinformation about its intended topic, “changes in physical and biological systems and

226 Climatic Change (2009) 95:219–230

Tab

le3

Res

ults

ofev

alua

ting

map

from

IPC

Cw

orki

nggr

oup

IIsu

mm

ary

repo

rtus

ing

sele

cted

prin

cipl

esfo

rca

rtog

raph

icde

sign

and

layo

ut

Car

togr

aphi

cpr

inci

ple

Rat

ing

Exp

lana

tion

Map

proj

ecti

onP

oor

The

map

show

ste

mpe

ratu

rean

dot

her

stat

isti

cali

nfor

mat

ion.

The

proj

ecti

onsh

ould

beeq

ual-

area

.Ins

tead

,iti

sa

cylin

dric

aleq

uidi

stan

tpro

ject

ion.

Are

ais

dist

orte

das

wel

las

shap

e.T

heco

lore

dsq

uare

son

the

map

are

equa

lin

size

,bu

tthe

ydo

notr

epre

sent

the

sam

ear

eaon

the

eart

h.G

ener

aliz

atio

nSa

tisf

acto

ryT

hem

apsh

ows

coas

tlin

esan

dbo

unda

ries

ofna

tion

s.T

hege

nera

lizat

ion

ofar

eas

(not

hing

smal

ler

than

aco

untr

y)is

appr

opri

ate.

Lin

ewor

kto

sym

boliz

eth

eco

astl

ines

and

boun

dari

esis

too

deta

iled

for

the

scal

ean

dpu

rpos

eof

the

map

.A

rgen

tina

,Chi

le,A

ntar

ctic

a,an

dSo

uthe

astA

sia

are

exam

ples

whe

reto

om

uch

deta

ilin

terf

eres

wit

hth

ear

eas

and

data

bein

gsh

own.

Dat

acl

assi

ficat

ion

Sati

sfac

tory

The

map

disp

lays

quan

tita

tive

and

qual

itat

ive

data

that

are

clas

sifie

d.T

heob

serv

atio

nlo

cati

ons

for

phys

ical

syst

ems

are

com

bine

din

toa

sing

legr

oup.

Obs

erva

tion

loca

tion

sfo

rbi

olog

ical

syst

ems

are

com

bine

din

toa

sing

legr

oup.

The

yar

esy

mbo

lized

asqu

alit

ativ

ely

diff

eren

tgro

ups

usin

gdi

ffer

entc

olor

hues

.T

heda

taon

tem

pera

ture

rang

ear

ecl

assi

fied

into

five

grou

ps,l

owto

high

.Iti

sun

know

nho

wth

ecl

ass

brea

ksw

ere

esta

blis

hed.

The

read

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term

ine

that

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size

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plex

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ally

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pete

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rtan

ceon

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edby

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area

son

the

map

isin

clud

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but

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nth

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aple

gend

.

Climatic Change (2009) 95:219–230 227

Vis

ualv

aria

bles

Col

orhu

eSa

tisf

acto

ryP

oint

obse

rvat

ions

for

phys

ical

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biol

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ffer

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olor

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sis

appr

opri

ate

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ping

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itat

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sfac

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cle

sym

bols

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izes

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appr

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chy

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plet

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een

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les

(bio

logi

cals

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ms)

inm

ostl

ocat

ions

,whi

legr

een

circ

les

cove

rbl

ueon

esin

afe

wlo

cati

ons.

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cles

that

only

chan

gesi

zein

Eur

ope

are

conf

usin

g.A

ctua

lcha

nges

inph

ysic

alan

dbi

olog

ical

syst

ems

(em

phas

ized

inth

em

apti

tle

and

inth

ele

gend

)ar

eno

tdis

play

edon

the

map

.Als

o,th

eco

lor

hues

ofth

eci

rcle

s(b

lue

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gree

n)ar

eve

rycl

ose

toth

ebl

uean

dgr

een

colo

rhu

esus

edto

show

tem

pera

ture

rang

e.

228 Climatic Change (2009) 95:219–230

surface temperatures 1970–2004.” For the only map published in an IPCC summaryreport for policymakers, the evaluation reveals specific issues of cartographic qualitywith this ‘high-visibility’ map. Our evaluation is of course subjective, and reflects: (1)our choice of selected design principles, (2) the evaluation categories, (3) the lack ofmultiple reviewers, and (4) the reviewers’ expertise in applying the design principlesto the evaluated map. Nevertheless, this kind of cartographic evaluation can provideuseful insights into the quality of climate change maps.

5 Toward a research and policy agenda for evaluating climate change maps

We have demonstrated how a climate change map can be evaluated. Other climatechange maps are likely to vary in quality and could benefit from such evaluation.Poor quality climate change maps have implications for climate change researchand policymaking. We suggest a modest but important agenda to improve thecartographic quality of climate change maps.

(a) Systematic evaluation of the cartographic design and quality of climate changemaps should be undertaken to assess and improve climate change maps.

Our evaluation was a preliminary demonstration. Evaluation methods should berefined to include: (a) carefully designed sampling plans to select a population ofclimate change maps to evaluate, (b) expanding the criteria (cartographic principles)to apply in the evaluations, including possible weighting of criteria, (c) assemblinga panel of expert cartographers to assess map design using established evaluationtechniques, and (d) developing more elaborate and varied evaluation rankings. Suchevaluations could provide an important inventory of the state of climate changemap design, identify key examples of good design, educate climate scientists aboutcartographic principles, and help target efforts to improve climate change maps.

(b) The impact of climate change maps on climate change research and policymakingshould be researched to better understand their specific role and influence.

Such research on the impact of climate change maps includes cartography of course,but could usefully extend to psychology, sociology, and political science. There areseveral key questions. How do maps influence or direct scientific efforts and researchpriorities? What assumptions do scientists make about the audiences for whom theyproduce the maps, do these assumptions need to change, and if so, how? Howeffective are climate change maps for synthesizing and interpreting climate changedata for policymakers? How are specific maps being used to guide decision-making?What are the implications of inserting inaccurate or misleading maps (purposefullyor not) into the policymaking process? What are the cumulative effects of mapsproduced by scientific organizations when reprinted and propagated through thepopular media (unchanged or modified)? How can the cartographic design andpersuasiveness of climate change maps be improved? Research to address thesequestions can illuminate the role of climate change maps, help identify key traitsof effective maps, and improve research, policy analysis, and public communicationrelated to climate change.

Climatic Change (2009) 95:219–230 229

(c) Climate change scientists should encourage cartographers to become more di-rectly engaged with climate change research and cartographers should be respon-sive to such engagement.

Cartographers can and should be more effectively engaged in climate science ac-tivities. Climate change research teams should include cartographers or personnelwell-trained in cartography. Climate change scientists and cartographers should workcollaboratively to actively advocate and implement good quality map layout anddesign. Potential collaborations include (but are not limited to) training of climateresearch teams, regular map critiques, and experimentation with new cartographicmethods, technologies, and map designs.

6 Conclusion

Climate change is the most pervasive environmental challenge facing contemporarysocieties. Its local, regional, and global impacts are (and will increasingly be) extraor-dinary in scope, complexity, and consequence. The scientific community has a wide-ranging and intense research effort underway, focused on climate change dynamics,impacts, adaptation, and mitigation alternatives. The results increasingly dependon maps as tools of visualization and analysis, instruments of policy and decision-making, and ways of communicating climate change science to the public. As we havesuggested, maps have the power to inform or misinform, lead or mislead, clarify orconfuse through the use or misuse of design principles. Successful application of goodmap design is a necessary step in the development of the climate change sciences.

Acknowledgements The authors thank the anonymous reviewers for their review and comment onearlier drafts of this manuscript. Wayde Morse and Jim Snyder provided valued assistance. An earlierversion of this paper was presented at the 23rd International Cartographic Conference, Moscow,Russian Federation, August 2007.

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