Gina Ziervogel isn’t your average harbinger of doom. In fact, she has a whole new take on that most inconvenient of truths: global warming.
Johannesburg-born Ziervogel, a fellow at Sweden’s Stockholm Environment Institute’s Oxford office, researches how climate change is affecting societies across Southern Africa.
Based at the Climate Systems Analysis Group in the University of Cape Town’s department of environmental and geographical science, Ziervogel last week addressed the audience at the opening ceremony of Sasol SciFest, South Africa’s national science festival held in Grahamstown, on “South Africa’s Vulnerability to Climate Change: Why we Need to Adapt”.
“Southern Africa is already prone to large swings in climate, such as droughts and floods, which are expected to become more frequent as global warming increases,” she warned.
Ziervogel’s research in Malawi and Zambia in 2005 found that the primary activity for all households was agriculture and that one in five farmers had a harvest that year, while the others struggled because of a lack of rain. Indeed, drought was a major cause of reduced agricultural production in Malawi and in Zambia, less land was cultivated in 2005 than in 2004, primarily because of the lack of water and rainfall.
In her report on the research, Ziervogel says that there were many similar factors and key causes of stress across her case studies. Climate, water management and decreased agricultural production came tops, indicating the social pressure that global warming is applying to ÂAfrica’s rural settlements.
“We have a lot of resources to adapt to climate change in both rural and urban areas but they need to be mobilised. There needs to be commitment. And, of course, there are other priorities in Southern Africa so climate change needs to be integrated with ongoing development. We are highly vulnerable,” she says.
They are feelings echoed by a University of Pretoria project on climate change and agriculture in Africa entitled “Climate, Water and Agriculture: Impact on and Adaptation of Agro-Ecological Systems in Africa”. An initiative of the Agriculture and Rural Development Programme, the World Bank Insitute and the African Region of the World Bank, the project has been executed by the university’s Centre for Environmental Economics and Policy in Africa (Ceepa) under the auspices of Climate Change and Agriculture in Africa.
Ceepa endorses Ziervogel’s opinion that Africa is particularly vulnerable to climate change. According to Climate Change and Agriculture in Africa, although our continent has not contributed in a significant way to the build-up of greenhouse gas emissions in the atmosphere, it is anticipated that a given change in climate will result in more adverse socio-economic impacts in Africa than in other parts of the world.
Climate change is already affecting Africa directly. The Earth’s temperature has been steadily rising for the past two decades, and most of the hottest years on record have occurred in the past 10 years.
It is a trend that is expected to continue if we, as a planet, do not take action. The increased concentration of greenhouse gases like carbon dioxide and methane is generally accepted as the major cause of climate change and while greenhouse gases are produced naturally, human activity via exhaust emissions from motor vehicles, burning of fossil fuels such as oil and coal and the destruction of the world’s rain forests are the biggest culprits.
It is generally accepted that climate change will alter rainfall patterns, give rise to extreme weather conditions and a rise in sea levels, and threaten the availability of fresh water. It will also alter ecosystems such as mountain flora and fauna, coral reefs, deserts and coastal regions. As a result, agriculture, fishing, forestry and other industries that depend on the climate will be hit, ultimately affecting human health and endangering animal habitats.
Important factors in South Africa and the rest of the continent that make the impact of global warming harder to bear are a high dependency on biological fuels, agriculture and forest sectors of the economy, restricted population mobility, poor health facilities and high population growth rates.
Sea level shocker
A network of lakes and rapidly moving rivers of water beneath west Antarctica’s thick ice sheet have been discovered, forcing scientists to revise predictions of changes in global sea levels as the global warming melts the ice sheets, writes Alok Jha.
“What we’re seeing here is a lot more movement of stuff underneath the Antarctic ice sheet than we ever dreamt possible,” said David Vaughan of the British Antarctic Survey.
The faster the water moves in the sub-glacial lakes the more quickly any melting ice from the heart of the continent will get into the open sea, causing water levels to rise. “The way we model the ice sheets to predict how they will behave in the future, how they will contribute to sea level rise in the future, doesn’t take into account all of this [new work],” said Vaughan.
The latest scientific report by the Intergovernmental Panel on Climate Change said that an uncertainty about how ice sheets responded to climate change was the biggest unknown in predicting sea levels around the world. “We can’t make faithful predictions of what’s going to happen to Antarctica unless we get this process understood,” said Helen Fricker of the Scripps Institution of Oceanography at the University of California, San Diego.
Fricker used satellite data to map the rise and fall of the overlying ice — which is up to 3km thick — as the lakes emptied and filled with water. “Over a period of three years from 2003 to 2006 we found regions where the elevation had changed dramatically — the first lake we found had deflated by nine metres, which we were just amazed to see,” Fricker said.
“The old paradigm was that most of the Antarctic was frozen to its bed. In a few places there was free water at the bottom and that was lubricating fast ice flow and that was all very steady, nothing changed very much,” Vaughan said. But this view had become out of date. “Water is not moving around in a steady trickle but filling up in one place and bursting through to another and this process is more widespread than we thought,” he said.
Fricker said: “We thought these changes took place over years and decades, but we are seeing large changes over months.” — Â