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Higher Antarctic temperatures bad news for South Africa’s climate

Researchers have noted that the Antarctic has experienced a temperature spike as part of a warming climate trend that could impact on South African weather.

Researchers measured a record temperature of 20.75°C on Seymour Island, a chain made up of 16 major islands near the Antarctic Peninsula.

“There is a warming trend in the Antarctic. The day on which the measurement was made was a weather event, but this sits in the warming trend,” UCT Climate Systems Analysis Group scientist Dr Chris Lennard told News24.

He said from 1970 to 2000 the average temperature in Antarctica increased, and it resulted in daily temperature spikes.

“So it is more correct to say that the daily temperature recorded is a weather event, but this would very likely not have happened unless the regional climate was warming.”

African Climate and Development Initiative post-doctoral research fellow Dr Kamoru Abiodun Lawal said that temperatures in Antarctica can range from 10°C in summer to -40°C in winter.

“Therefore, the recently observed high temperature of about +18°C is one of the weather extremes. It can only become part of the climate trends if it becomes normal occurrences, year in year out,” said Lawal.

Rainfall patterns

And this could have serious impacts for rainfall in SA.

“On the macro scale the heating Antarctic reduces the temperature gradient between the tropics and polar region, which should impact the way mid-latitude cyclones (cold fronts) we experience behave.

“They could become more erratic in how they move from west to east and may also reduce in intensity,” said Lennard, though he added that there was still some doubt about direct effects.

“Also it is not only the Antarctic that is important here, it is also warming in the tropics that has increased the size of something called the Hadley circulation that is causing a poleward shift of the mid-latitude systems.”

The Hadley circulation refers to the thermal shift of warm air from the equatorial region to a height of about 15km, which is transported to the poles and descends at the subtropics. Flow returns near the surface.

December and January were among the hottest months on record, data from international research institutions found.

December was 1.05°C above the 20th century average, according to the US National Oceanic and Atmospheric Administration.

In Europe, the Copernicus Programme found that January was the hottest on record, with temperatures 1.2°C above the 1981 to 2010 normal.

These high temperatures could have significant impacts on the polar glaciers.

“Scientific findings have shown that higher temperatures over, for example Antarctica, may lead to massive melting of glaciers. Thereby, leading to a rise in the heights of sea levels. This poses negative consequences for coastal areas, especially in South Africa,” said Lawal.

Rise in sea levels

The long-term weather forecast for South Africa indicates higher than normal temperatures, according to the South African Weather Service.

Scientists are concerned that increased warming will result in a rise in sea levels which could inundate coastal cities.

“Rainfall wise, South Africa may benefit from general increase in rainfall if the temperatures in Antarctica keep rising. However, the rainstorms may become more violent in nature due to an increase in the kinetic energy of the wind coming from the Antarctica. These may lead to an increase in loss of life and property worth billions of rand,” said Lawal.

Lennard said that there is ongoing intensive research into how warming may impact rainfall in SA.

“We are actively researching this because obviously the fronts are important for winter rainfall in the Western Cape but also for the summer rainfall through what we call tropical-temperate troughs, which are cloud bands that stretch from the tropics to the mid-latitudes and are important for summer rainfall.”

He added that “warming of the Antarctic will likely impact the position and intensity of cold fronts with consequent negative consequences for winter rainfall in the Western Cape and potentially in the summer rainfall region”.

In his State of the Nation Address, President Cyril Ramaphosa acknowledged that climate change posed a threat to SA and promised a low carbon transition.

“We will finalise the Climate Change Bill, which provides a regulatory framework for the effective management of inevitable climate change, by enhancing adaptive capacity, strengthening resilience and reducing vulnerability to climate change – and identifying new industrial opportunities in the green economy,” said Ramaphosa.

Eskom

Environmental groups were supportive of the move.

“Restructuring the electricity supply industry away from a polluting monopoly is a step in the right direction. However, it falls short of solving Eskom’s addiction to dirty coal, which is creating our current ‘managed’ blackouts while devastating communities with toxic air and grotesque water wastage,” said Greenpeace Africa in response.

Lawal suggested that fossil fuels will be with us for the foreseeable future.

“We cannot see an end to the utilisation of fossil fuels, even in the nearest future as long as it is still the cheapest source of energy that is readily available; notwithstanding its contribution to climate change.

“In terms of climate change, mitigation and adaptation goes hand in hand. Governments must continue to help people to alleviate the effects of climate change while people must be ready to embrace adaptation strategies.”

Lennard said that in terms of adaptation, a hotter climate seemed inevitable.

“So for us mitigation is about Eskom and the move to renewables for energy. But in a climate change context most of our effort will be about adaptation to a hotter country with either drier or no rainfall change conditions.”

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