Two degrees spell drought and death
07 Dec 2012 00:00 | Sipho Kings
With the United Nations Conference of the Parties (COP) process pushing any legally binding process to cut global carbon emissions to 2020 and the Kyoto Protocol still only covering a fraction of emissions, the world's temperature is set to rise by at least 2°C by 2050, according to several reports released during COP18 in Qatar this week. So what will this mean for South Africa?
General patterns indicate that the coast will get 2°C warmer and the interior up to 5°C. This will drastically affect the Highveld and change the seasons. Evaporation will speed up, which is a problem when most water is stored in shallow dams.
Rainfall will increase in the eastern and northern parts of the country, leaving the three Cape regions drier. In the summer, rain will fall in more sporadic and dramatic bursts, destroying top- soil. In the process, little water will make it underground to refill aquifers, which are vital for communities that rely on boreholes. In winter, rainfall will cease.
More turbulent river flows will drag more sediment along and, combined with the collapse of sewage works, provide more food to algae.
Of all the provinces the Western Cape will face the most dramatic changes as its winter rainfall drops. KwaZulu- Natal will face flooding.
Gauteng's water crisis will worsen because it relies on water transfer and dams. At present, only 9% of rainfall makes it into dams and rivers and this amount will decrease.
Because the big rivers are shared with neighbours, political pressures will grow as people vie for limited water.
In the agricultural and forestry sphere, biomes will shift along with the rain and temperature. This is a mixed pot for forestry because new areas will open up, but others will be lost. Increased carbon levels will also change the growth rates of trees.
For commercial farmers, certain crops will no longer grow – rooibos is in danger of losing the one habitat in the world where it grows – and they will have to change how they farm. The effects for subsistence farmers will be devastating. People are already moving off the land because traditional crops are failing in certain areas and this will accelerate.
In general, food insecurity will increase as rain becomes more scarce and sporadic.
In the maize sector, a 2°C increase and a 10% drop in rainfall will reduce profits by R500 a hectare. In winter-rainfall areas, wheat crops will give up to a 60% lower yield. Deciduous fruit producers in the Western Cape will be heavily hit.
As far as the coast and sea are concerned, the oceans are a vast heat storage unit that change temperature slowly. They are steadily getting warmer and it is a difficult process to arrest. Warmer seas are breeding grounds for tropical cyclones, and the instances of these will increase.
South Africa is ruled by two ocean currents, the warm Agulhas on the eastern side and the cold Benguela on the west. They are huge drivers of rainfall and projected to start moving about more, which will bring further unpredictability. A warmer Agulhas will mean more rain, as might a warmer Benguela.
Water insecurity will affect more people, as will water-related diseases. Higher temperatures will endanger more vulnerable members of society – heat waves in Europe already kill tens of thousands. This is especially dangerous in cities in which heat islands mean internal temperatures are already several degrees above average.
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