Climate change fake?

breaking year of 1976! So much for a waterfall that was said to be at the end of its days!

So often we hear that droughts are now more devastating now than in the past because of climate change. But what criteria are used to make this claim? Is it the actual rainfall that occurred or the effect of the drought on the local population? If the second criterion is used, it may be not too surprising. Over time human populations have increased rapidly in southern Africa and hence there is less water to go round for both people and their livestock.

But there are some aspects of climate change here that are at odds with a hotter, drier climate. Firstly, weather data shows that average annual rainfall over the Ghanzi District has actually increased by some 50mm over the past 50 years.

And frost may now occur after the winter season has passed ( frost occurs when the night temperature falls to zero degrees or below). I recorded temperatures over 30 years ago in Lobatse where frost could be expected between about 15 June and 25 July. Thus May, August and September would normally be frost- free. Now living in Tonota, I have experienced cold conditions after July, and even in September and October.

The South African Department of Meteorological Services has also confirmed this trend. In mid- October 2017, a very strong cold front with sub- zero temperatures affected the Eastern Cape. Many sheep farmers here lost large numbers of sheep at this time. One farmer said that he lost more than 3 000 animals as a result of the cold – he said that he normally shears his sheep at the end of September long after the end of winter. According to him, extreme cold could never occur in October! And another strong cold front passed over the area in early November causing more sheep to die. In fact, record November sub- zero temperatures were recorded in the Free State at the time.

The weather was also unusually cold in Botswana at the time and in November I recorded one night a temperature of just 8C ( the normal night temperature for November is 17C). In November 2018, late frost was also experienced in Mpumalanga! And early October one year I saw a sheet of ice on the roof of my vehicle early one morning!

So, this trend of cold weather occurring after winter might point to global cooling for part of the year here! Such changes in weather has implications for the planting of summer crops such as maize. Normally, farmers could plant maize in August but it seems these days that may not always be possible; perhaps September is a better month now And very cold weather can occur before the normal frost season. In late May 2007, a very strong cold front passed over Botswana sending temperatures plummeting to - 6C in Francistown where farmers lost up to 80 percent of their produce.

Following the evening BTV news bulletin, the Department of Meteorological Services issues the weather forecast for the next 24 hours. On one map, they show the expected night temperatures for selected places in the country. Often, they predict lower temperatures for Francistown than Gaborone, and even the Kgalagadi, especially in winter.

Now this is surprising since Francistown lies in the north of the country and so should be warmer.

And in the past we have always associated the lowest winter night temperatures with only the Kgalagadi. So, could winter night temperatures in the Francistown area be dropping as a result of climate change? I recently spoke to a meteorologist in Gaborone about this – she told me that they are aware of this but, as yet, are unable to explain it. Now in the distant past winter nights must have been warmer in the Francistown area than further south. Evidence for this is to be found in the type of natural vegetation that is to be found in eastern Botswana.

The mopane tree is not found in the south and only grows to the north of Mahalapye. One reason for this is that mopane trees do not tolerate frost which normally would be more severe in the south. But now things have changed!

In the next, and final, article on climate change, we will look at whether lower rainfall and increasing temperatures are a reality in the rest of the world.