Latest science on projected climate change and potential

impacts in Namaqualand NDM and CSA Partners’ Conference 13

and 14 March 2012Kokerboom Conference Centre, Springbok

Prof Guy Midgley

Chief Director South African National Biodiversity Institute; IPCC co-ordinating lead author

Key points• Climate change not “doom & gloom”• Simple in principle, complex in detail• Namaqualand is ecologically special

because of stable climate history• Regional understanding of climate

change and impacts is now advancing• Climate change adaptation: useful to

consider short, medium and long term vulnerabilities and responses

FundamentalsCO2 makes up only

0.0375%!Why is an extra

0.0002% per year important?

~78% Nitrogen~21% Oxygen ~0.09% Argon

Trace gases do ALL the warming

Recent Global Fossil Fuel EmissionsCO

2 em

issio

ns (P

g C

y-1) CO

2 emissions (Pg CO

2 y-1)

Growth rate1990-1999

1 % per year

Growth rate2000-2009

2.5 % per year

Time (y)

2009: Emissions:8.4±0.5 PgCGrowth rate: -1.3%1990 level: +37%

2000-2008Growth rate: +3.2%

2010 (projected):Growth rate: >3%1990 1995 2000 2005 2010

9

8

7

6

Most observed warming since the mid-20th century

is very likely the result(confidence >90%)

of the observed increase in anthropogenic greenhouse

gas concentrations –

warming is unequivocal

IPCC (2007)

Climate change is happening

Change

Warming oceansSea surface temperature

• Trend in SST since 1982 using the more reliable Reynolds SST• Combination of observation and satellite remote sensing

Satellite remote sensing for oceans, high resolution for the last 30 years. Some regions have warmed, some have cooled due to stronger wind.

The warming is clearly not uniform.

South African land based measurements show warming (1960 to 2003)

Trend in Max. TemperatureTrend in TemperatureTrend in Min. Temperature

Significant Positive trendNon-significant Positive trend

Significant Negative trendNon-significant Negative trend

No trend

Trend in Max. TemperatureTrend in TemperatureTrend in Min. Temperature

Significant Positive trendNon-significant Positive trend

Significant Negative trendNon-significant Negative trend

No trend

Adapted from Kruger and Shongwe (2004)

© CSIR 2007 www.csir.co.za

Hadley Center:CRU 3.1 linear

temperature trend 1961-2009

Strong warming has occurred over the central parts of

southern Africa, including the central interior of South Africa

Warming more moderate along the coastal areas,

except south-western SA and southern Mozambique

sciencephotolibrary

Namaqualand is special

Paleo-climate stability and ecological implications

Karoo endemic bird species richness

Present 6000 ya 21000 ya 24000 ya (weaker upwelling)

Rainfall variability, coastal fog, El Nino and Namaqualand

Region 4 annual rainfall

400

600

800

1000

1200

1400

1600

1900 1920 1940 1960 1980 2000 2020

Year

Rai

nfa

ll (m

m)

Sea surface temperature change during EL NINO

Orange warmer than normal blue colder than normal

Rainfall change during EL NINO

Blue/green is wetter than normal, yellow/red is dryer than normal.

El Nino effects on wind

Change in wind speed and direction during EL NINO in austral summer

Or periodicity ?

Cumulative N/S wind anomalies

-50

-25

0

25

50

75

Jan-

61

Jan-

64

Jan-

67

Jan-

70

Jan-

73

Jan-

76

Jan-

79

Jan-

82

Jan-

85

Jan-

88

Jan-

91

Jan-

94

Jan-

97

Jan-

00

Jan-

03

Jan-

06

nort

h/so

uth

win

d an

omal

ies

Lüderitz wind

Mowe wind

Neville Sweijd ACCESS/CSIR and Anja van der Plas Namibia, Min. FMR

Climate: Future projections

• Under relatively unmitigated global emissions scenario

• Air temperature: Coastal regions warm 1-2°C ~ 2050

3-4°C ~ 2100Interior regions warm

3-4°C ~ 2050 6-7°C ~ 2100

Climate: Future projections• Rainfall change – uncertainty due to lack of credible regional modelling

efforts, of decadal variability, reliance on statistical extrapolation

Summer Autumn Winter Spring

Upper 75%

Median

Lower 25%

~ 2050

-15 mm 20 -10 mm 30

-20 mm 20 -15 mm 20 5 mm 35 -5 mm 40

-55 mm 0 -25 mm 5 -30 mm 10 -20 mm 30

5 mm 40 5 mm 45