What to expect from climate
change in the next 30 to 40 years
Focus on livestock
Kos vir Afrika!
.co.za
L/4179/Pioneer
HEINZ H. MEISSNER, FOR THE RED MEAT PRODUCERS’ ORGANISATION
You’ve heard so much about climate change, but nobody mentions what
the impact of this will really be on the producer and his land.
I worry about the accuracy of predictions. We all know how difficult and
in some cases, how unreliable the prediction of weather patterns can
be. It has to be said however, that the projections with comprehensive
atmospheric computer models which are currently being used, is impres-
sive. I am satisfied that the general trends are most likely reliable. Having
said that, you still have to be aware of the fact that the deviations in an-
nual and monthly predictions, will be considerable.
In practice this means that there will be cold years and months in a gen-
erally warmer country, and wet years and months in a generally drier
country. Also take into account that projections are being done with the
assumption that the politicians will do nothing to cause or lessen the
greenhouse effect, which is responsible for global warming. However,
I still hope that some responsibility will come to the fore. There are also
worldwide efforts from all sectors to reduce their carbon footprint.
Projections indicate that southern Africa will on average be 1,5
o
C to 2
o
C
warmer in the time period of 2020 to 2050, compared to the time period
of 1960 to 1990. The time period of 1960 to 1990 is often used as a com-
parative time period, because global warming was not really detected in
this period.
The 1,5
o
C to 2
o
C average for southern Africa has a wider spread of sea
level to the interior. The deviations in temperature will only be 0,5
o
C at
sea level because of the fact that the ocean acts as a buffer. The devia-
tions in temperature will be 3
o
C in the east of Namibia and the west of
Botswana. It may not sound that severe, but it has to be put in perspec-
tive. These temperatures are an overall average degree. It includes day
and night temperatures as well as summer and winter temperatures. Try
and imagine for yourself precisely how high the day and summer tem-
peratures will have to be in order to realise these overall averages.
There is no doubt that certain days will be unbearably hot for humans and
animals. You will have to take the necessary measures to protect your
animals against heat stress. Also, if night temperatures do not decrease
to below freezing point, imagine how parasites will flourish in these con-
ditions.
Projections indicate that southern Africa will generally be drier than at pre-
sent. The main reason for this is that the high pressure system that exists
in winter time over the interior and which is responsible for keeping out
moisture inflow, will deepen and lengthen. However, this does not mean
that all areas are going to be drier. The central interior and the Eastern Cape
can receive more rain, while the east of Limpopo and Mpumalanga and the
summer rainfall area of the Western Cape could be much drier.
The reason for this is that with the deepening of the high pressure system
over the interior, the cold fronts that bring rain for the Western Cape,
will be pushed eastwards and southwards (over the ocean), resulting in
less rain in the neighbouring area. Although a difference of 10 mm to
40 mm rainfall does not look that serious, the monthly and yearly devia-
tions of the overall averages must be kept in mind. The projections indi-
cate greater variation in dry and wet years, in other words, more wet in
wet years and drier in dry years than what is currently the case.
Furthermore, we also expect heavy storms and a resultant heavier off-
flow and erosion of land. In other words, less water intrusion per rainfall.
A difference in rainfall patterns are also expected. For instance, in the
Drakensberg area, where more rain is generally predicted, the rainfall
season can be shorter with noticeable reductions as early as February.
It will have a real impact for water flow into the Gariep and Caledon riv-
ers and the resultant availability of moisture for keep-over feeding in the
central grassland areas during the winter.
