Thirty years ago, the impacts of climate change on species were extremely rare. Today, they’re commonplace.
Recent climate change impacts on flying foxes and the Bramble Cay melomys show how quickly climate change can lead to drastic population declines, providing warnings of unseen damage to less conspicuous species, write Wendy Foden and Nicola van Wilgen of SA National ParksNParks, in the latest edition of the biennial Living Planet Report 2020, by the WWF and Zoological Society of London (ZSL).
Foden and van Wilgen describe how the 1999 discovery that the Edith’s checkerspot butterfly in North America was shifting its range poleward and to higher elevations marked the first documented impact of climate change on nature.
“Just two decades later, climate change impacts are widespread, including the (2016) extinction of the Bramble Cay melomys, a small Australian rodent, and the mass die-off of tens of thousands of flying foxes in a single heatwave.”
Foden and van Wilgen, who are among more than 125 global experts who contributed to the biennial Living Planet report, describe how at least 83% of biological processes have been impacted by climate change, “at scales from genes and populations to species, ecosystems and their services to humans” across terrestrial, freshwater and marine habitats.
While some species, like deep sea fishes, are relatively buffered from climate changes, others like Arctic and tundra species “already face enormous climate change pressures including direct physiological stress, loss of suitable habitat, disruptions of interspecies interactions and the timing of key life events including migration, breeding or leaf emergence”.
Every species currently on Earth is the survivor of a “fiercely competitive, treacherous and arduous natural selection contest spanning millennia”.
“The extinction of the Bramble Cay melomys marks the tragic end of a distinctive evolutionary lineage and demonstrates how drastically and unexpectedly climate change can operate. Actions that reduce greenhouse gas emissions, and aid biodiversity adaptation, are clearly urgently needed and are vital for nature’s survival.”
Between 1970 and 2016, the Living Planet report reveals that global population sizes of monitored populations of mammals, birds, amphibians, reptiles and fish have shrunk by average of two-thirds, driven by habitat loss and degradation, including deforestation, to produce food.
The Living Planet Index (LPI), provided by the ZSL, tracked almost 21 000 populations of more than 4 000 vertebrate species, revealing that wildlife populations in freshwater habitats have suffered a decline of 84%, “the starkest average population decline in any biome, equivalent to 4% per year since 1970”.
“The LPI is one of the most comprehensive measures of global biodiversity,” said Dr Andrew Terry, Zoological Society of London’s (ZSL) director of conservation, in a statement. “An average decline of 68% in the past 50 years is catastrophic, and clear evidence of the damage human activity is doing to the natural world... But we also know that conservation works and species can be brought back from the brink. With commitment, investment and expertise, these trends can be reversed.”
Foden, a conservation biologist and world-leading researcher in climate change vulnerability assessments of threatened species, told the Saturday Star, “It’s easy to look at such figures and declines and feel that it’s too horrible to deal with – that it’s someone else’s problem and to just switch off.
“But if Covid-19 taught us anything, it’s that global problems can become really personal really fast. A healthy environment is the foundation of our physical and mental health. It’s a basic human right and that’s what’s slipping away from each one of us.”
South Africans have been blessed with a disproportionate abundance of environmental assets.
“We’re incredibly fortunate because these underpin our economy, livelihoods and well-being. This also gives us enormous responsibility to look after them, as well as a disproportionate opportunity to change these global trends. Personally, I love our wildlife deeply so it’s a privilege to spend my career working to look after it. I’m quite sure most South Africans feel the same and are looking for ways to help conserve nature. And luckily you don’t even have to move out of your home to do so.
“Just choosing not to be a ‘super-consumer’ – to buy less, reuse, repurpose and escape that trap of always needing the next new thing – is an easy first step and is part of the mental shift we all need to make.
“Our resources are finite, we often need far less than we have and use, and we need to leave enough for nature. I’m thrilled to see the shift towards non- or low-consumerism starting to take hold in our communities.”
While globally climate change is not yet the greatest driver of biodiversity loss, in coming decades it will become as, or more important, than other drivers, says the report.
Co-author Professor Guy Midgley, a leading expert in the field of biodiversity and global change science at Stellenbosch University, writes in the report how up to one fifth of wild species are at risk of extinction this century from climate change alone, even with significant mitigation efforts, with some of the highest rates of loss expected in biodiversity hotspots.
South Africa, he told the Saturday Star, has a huge vested interest in making sure the world sticks to a low emissions future.
“This is because of the vulnerability of our biodiversity, of our ecosystems, our agriculture and our wildfire regimes. We have multiple vulnerabilities to climate change. We should really be very interested in sending a signal to the world we favour sustainable energy future,” he said.
“A part from the fact that we know that a renewable energy future creates all sorts of amazing jobs and reduces health risks to large proportions of our population who are exposed to high levels of pollutants from power stations and open-cast mining, it’s also boosts the hi-tech economy.”
Reports like the Living Planet report “really help highlight the pathway that will bring us both environmental prosperity and social and economic prosperity. It’s not purely a nature report. It’s about development”.
“We know that this part of the world is one of the few that still retains a lot of its original biodiversity, and one of the few parts of the world where we have mega-herbivores, carnivores, where we have all this really incredible diversity and ecosystems that are phenomenal attractors of nature-based tourism and provide all sorts of services for people’s livelihoods,” he said.
“We’re still on a development trajectory... where it’s still at a point where we can really do a lot in our decision-making to maximise biodiversity, along a future development path. Our decisions around energy are enormously important for the region as a whole. If we switch on a renewable economy that will filter through the rest of the sub-region.”
Marco Lambertini, the director-general of WWF International, said in a statement that the evidence cannot be ignored.
“These serious declines in wildlife species populations are an indicator that nature is unravelling and that our planet is flashing red warning signs of systems failure. From the fish in our oceans and rivers, to bees which play a crucial role in our agricultural production, the decline of wildlife affects directly nutrition, food security and the livelihoods of billions of people.”