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April 2016
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Facing climate variability and change
C
an you, first of all, cope with varia-
bility? It is important to understand
that there is a difference between
climate change and climate vari-
ability. Climate variability (
veranderlikheid
)
has always been present and is part of
the natural order. It describes year to year
changes.
These variations are not the result of hu-
man activity. Climate change (
verandering
)
may be the result of changes in the natural
order like solar emissions or changes in the
earth’s orbital elements and natural internal
processes of the climate system, however
these changes are also the result of anthro-
pogenic forcing (human activity: Develop-
ment, settlement and industrial activity).
Without doubt the climate is becoming
warmer and the next few decades will be-
come warmer still. This is of great concern
and we need to attend to this matter for the
sake of the future.
The synoptic chart (
Figure 1
) depicts typical
El Niño conditions. The mid-summer rainfall
pattern can be seen across the globe.
The effect is not the same everywhere and
there is also no sign of El Niño in many parts
of the world.
El Niño (The Son – refers to the birth of
Christ) has a significant impact on farming in
southern Africa and forces abnormal warm,
dry conditions while in Equatorial East
Africa it is much cooler and wetter.
La Niña (The Daughter) describes opposite
conditions. Predictions are made by looking
at historic patterns and these predictions
have proven to be very reliable. In August
2015 climatologists were already predicting
the high likelihood of an El Niño phenom-
enon. Our models actually slightly under-
estimated the intensity compared to what
eventually did realise early in 2016. The
actual recorded temperatures (see
Graph 1
)
indicate that this El Niño is the strongest yet
observed.
Notably, most strong El Niño’s (1982/1983
and 1997/1998) were followed by the pres-
ence of La Niña conditions which presents
favourable conditions and good rains. So
what about 2016/2017? It isn’t unreasonable
to anticipate a La Niña late in 2016.
Looking to the future, Landman adds that
climatologists cannot make deterministic
statements, but rather suggest probabili-
ties.
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Graph 1: Historical Niño 3,4 sea surface temperature anomaly.
Figure 1: Typical El Niño conditions.
– Prof Willem Landman
Prof Willem Landman