Nature’s warning flares told of climate breakdown years ago (Part 1)
Some 15 years ago, science writer Leonie Joubert travelled into the desert north of Cape Town to write one of her first stories on climate change: an investigation into the mass die-off of tree aloes and how this could be the sign that the desert was spreading south towards the beleaguered Mother City. Now, as the United Nations’ global collective of climate scientists issues its most strident warning yet, that we have 12 years in which to bring planetary carbon emissions in check or face run-away climate breakdown, it seems the world might finally be waking up to the fact that nature has been sending out warning flares for decades. The planet is, in fact, burning. Why have we taken so long to respond?
The year was 2001 and biology masters student Wendy Foden was heading off into the desert with a case full of historic photographs of tree aloes and a theory. The epicentre of the story was up in the Brandberg Mountains in Namibia, a few hours’ drive north-west of Windhoek. Farmers up there had been reporting for years that the iconic quiver trees of the desert were toppling over. In those harsh desert conditions, the dead trees lay like fallen tombstones, preserved in the heat and dryness. But there was more to it than that. In many places, there were no younger aloes either, because seedlings weren’t surviving. Was it disease? Was it baboon damage? Hungry grazing game?
Foden wanted to test an idea. Using old photographs of quiver tree forests from across the tree’s range, her mission was to track down the exact site where each picture was shot and re-take the photo. Then she counted the aloes that she found at various sites. From the north of the aloe’s range at the Brandberg, to the southern-most stand of these aloes at Nieuwoudtville, about four hours’ drive from Cape Town, she took pictures, counted trees and did her before-and-after comparisons.
What she found was that in the northern-most parts of the tree’s range, the aloe were dying en masse. Some places looked like graveyards; not a living aloe in sight. In parts of the Richtersveld, where South Africa and Namibia meet at the Orange River and about the centre-point of the aloe’s natural range, she counted a 60 to 70 percent die-off. But as she trekked further south, the populations seemed to be healthier. By the time she reached Nieuwoudtville, she found the desert forests here were still thriving.
This ‘ground truthing’ exercise seemed to support what climate scientists had been theorising for a long time: that as the globe warms up, the climate ‘envelopes’ that are home to specific suits of species, will shift towards the poles, north in the northern hemisphere, south in the southern hemisphere. Elsewhere on the globe, this was already happening: the red fox had been seen moving up into the range of the Arctic fox in Canada; in the UK, some butterfly species were shifting north. In Antarctica, some penguin species seemed to be moving south and polewards.
The tree aloe of our western desert also appeared to be on the move: dying in the north of its range and thriving in the south, as the climate envelope of the desert was effectively spreading south, Foden concluded. This is a sign of the climatic envelope of the desert moving south, it’s not a sign of desertification, where human-caused land-use change denudes a landscape of vegetation and turns it to desert. On its own, this doesn’t necessarily mean anything but together with so many other signals from the natural environment, something, clearly, was shifting.
Since the 1960s, average air temperatures at various weather stations around South Africa have shown a small but clear rise; there’s been a notable increase in the number of warmer days and fewer cooler days overall. In the Western Cape, there’s been an increase of between 1°C and 2°C in the minimum temperature since the 1960s and wind speed along the coast seems to be up by between 1 to 3km per hour.
Across South Africa, from different locations and documented by different scientific disciplines, nature seemed to be sending up warning flares that things were changing. And alarmingly, they’ve been changing for decades. Climate scientists then started to look forward in time, running sophisticated computer models to try and understand what might happen if these changes continued as they were, with sea and air temperatures warming and causing a disruption in the ocean-atmosphere circulation systems that drive regional weather conditions. A grim picture emerged: the whole country, they said, would probably get hotter. While the cooling effects of nearby sea-air might dampen this effect for coastal areas, keeping the temperature increase to just over a degree, the biggest increases would be by 4°C or more in the northern interior. The Northern Cape, they estimated, could see an average increase of between about 2,5°C to 4,5°C in the height of their summers. The eastern escarpment area of the Drakensberg would probably get wetter. The south-west could see shorter winters with a slight increase in rainfall intensity but fewer actual rain days and an overall drying in the far west. Heat stress and changed rainfall would likely cause greater water runoff, evaporation and drying out of soils. This, together with faster south-easterly winds in the Cape, would increase the risk of ‘fire weather’.
That was 15 years ago. Since then, climate knowledge has become more sophisticated, with scientists tuning the dials on their models to pick up a better signal of what lies ahead. So while the UN’s Intergovernmental Panel on Climate Change (IPCC) now warns that we have 12 years in which to get our shared global emissions to level off if we want to stop the average temperature from creeping beyond 1,5°C relative to the pre-industrial era, the picture is more bleak for us here in southern Africa where many parts of the region are already near-desert. Semi-arid places like Botswana, for instance, are heating up faster than this global average. Some recent modelling from the University of Cape Town suggests that Botswana is already committed to step across the threshold of a 2°C average increase in temperature, just five years from now. Nothing we do will stop that juggernaut. The extreme warming and drying expected to hit here, a region where temperature increases aren’t tempered by the cooling effect of a nearby ocean or large body of trees like a tropical forest – will not tuck themselves neatly into Botswana’s national boundaries but will ripple out across the entire semi-desert region. The only response for us now is to find ways to support each other as communities grapple with surviving in this new, extreme climate.
In the timeline of nature (millions to billions of years), the 15 years since the quiver tree story broke is the blink of an eye. Even the timeline of the industrial age (300-odd years) feels ancient, relative to this short 15-year chapter. But in political terms, a decade or two is almost an eon. How much has changed in the political landscape since the turn of the century? And how little has changed in terms of our country squaring up to face our obligations to tackle our contributions to the emissions that are driving climate breakdown (we’re the biggest emitter on the African continent). How little we have done to help communities learn to live in a climate that is quickly shifting to something that is unlike anything in which human ‘civilisation’ has evolved in.
“Over the past decade, we’ve passed crucial climate change markers, such as a CO2 level of 400ppm, reached and passed some years ago, with increasing rapidity,” says Mandi Smallhorne, president of the South African Science Journalists Association and board member of the World Federation of Science Journalists. “The small handful of journalists reporting on climate change have watched the unfolding crisis, kept pace with the science and listened to scientists lay out the implications with huge frustration – because there’s been so little appetite for reporting on climate change in South Africa. And yet we knew all the time that climate change is going to take an exceptionally heavy toll of us in South and Southern Africa, thanks to some unique and not very kindly climatological and geographical features. We knew that we as a country should be, should have been, years back, making urgent, vital policy decisions to stave off the worst blows.”
Here we are, today, with Cape Town facing the worst drought in a century, almost becoming the first developed city to run out of water. We got to see how politically and economically unstable a city and its surrounds can become if political infighting, bureaucratic mismanagement and day-to-day development pressures collide with an environmental shock like this sort of unprecedented drought that is ramped up by human-caused climate change.
We need urgent societal and policy response if we’re going to survive in the uncertain future. As Smallhorne points out, it’s about making sure we’re able to feed ourselves. “It’s about having enough clean water and safe air to breathe. It’s about avoiding the impacts like massive wildfires and dust-storms, the healthcare and productivity burden of heat exhaustion and renal failure and much more, impacts which are costly, dangerous and obstacles to our wellbeing as a country… all of these things require us to jack up our governance, to do the nitty-gritty of running a country really well.”
The back-to-back extreme weather events of the past three years, Cape Town’s recent water crisis and the IPCC’s shock report on the 12 year window left to try and slow this monster down, seem suddenly to have shaken the world awake. But what took us so long to respond?
Part 2 to follow.
Source: Daily Maverick