The snow in Johannesburg this week was a rare winter wonder, in an icy snap unrelated to climate change. But the early flowering of jacarandas in spring is a sign of shifting seasons influenced by a warming planet.
Professor Jennifer Fitchett, a Wits University biometeorologist, says humans do not register the the 1.1°C rise in average global temperature that has occurred in the post-industrial era.
“But if you look outside at the plants, you see jacarandas flowering in September which used to flower in November. September temperatures are starting in July and August and spring is coming earlier. Plants identify triggers such as temperature to bloom.”
Namaqualand daisies are flowering earlier and butterflies are migrating sooner as South African summers get longer and hotter, and weather patterns become more intense and less predictable.
Physical geographer Adriaan van der Walt from the University of the Free State says that spring is getting shorter and summer is extending into March, yet this is not the full picture of changing weather. South Africa is also having less frequent, though more intense, cold snaps.
“Thousands of species in hundreds of countries” are being affected by phenological change — shifts in seasonal and cyclical natural events — that are a direct result of the climate crisis, says Fitchett.
She studied records dating from 1914 and found that brown-veined white butterflies, which migrate from the Kalahari to Mozambique through Johannesburg in summer, are now starting their trip about 30 days earlier than 100 years ago.
“We have found [changes] in three diverse types of species. When you see this for one species, you start to notice it everywhere,” she says. Each species has its own set of cues and climate change can cause a mismatch, for example, if caterpillars hatch before new leaves and buds appear on plants.
An entire generation of a species may struggle to survive because of global warming and loss of habitat due to human activity, triggering local and mass extinctions.
A rare stag beetle that lives at high altitude in Western Cape mountain ranges is one of hundreds of species at risk of local extinction if their home ranges get too hot and they have “nowhere to go”, says Ian Little, head of conservation at the Endangered Wildlife Trust (EWT).
He warns that more sedentary species, such as endemic insects or reptiles found in specific climate belts, may be unable to adapt. To prevent this South Africa needed to establish large protected areas and support its neglected provincial reserves.
This would trigger a cascade of extinctions, not only of the plants but the pollinators and the mammals, the whole ecosystem
— Guy Midgley
Stellenbosch University professor Guy Midgley, acting director of the school for climate studies, says thousands of indigenous plant species in the winter rainfall region could go extinct locally if that rainfall pattern changed. “This would trigger a cascade of extinctions, not only of the plants but the pollinators and the mammals, the whole ecosystem,” says Midgley, noting that fynbos was a major attraction for tourists.
“We’re seeing the collapse of several endemic plant populations. In the last five years some populations have really declined,” he says, naming one of the dwarf succulents commonly known as “baby’s bums”, Argyroderma delaetii, as an example.
But species that have an extensive range can make up for stress in one region by thriving in another area with different conditions; the quiver tree, for example, is becoming more common in cooler southern Namaqualand.
“This combination of certain populations dying back in hotter, drier conditions and expanding in cooler conditions can be seen as a fingerprint of climate change,” says Midgley of the striking desert aloe found in South Africa and Namibia.
Another visible marker of climate change are shifting biomes, like the encroachment of bush into Africa’s grassland savannah. “Rising carbon levels act as an aerial fertiliser for woody trees and shrubs,” says Midgley.
“With bush encroachment you can’t graze cattle, vultures can’t see carcasses and cheetahs struggle to hunt,” he says. Entire groups of bird species and hundreds of geophytes depend on the grasslands, which often also support strategic water sources.
Working with farmers and tribal leaders across the Drakensberg escarpment, Little and EWT partners have secured just over 100,000ha of grasslands for conservation. Less than 3% of South Africa’s grasslands are currently protected.
In December last year South Africa was one of nearly 200 countries that adopted the Kunming-Montreal Global Biodiversity Framework, whose goals include “30x30", protecting 30% of the planet’s lands and waters by 2030.
Little says: “We are the third-most biodiverse country in the world and we signed onto 30x30 as a global concept, but we have not signed onto the [30x30] High Ambition Coalition for Nature and People.”
He says a “host” of NGOs on working on the expansion of protected areas. “We need to make sure provincial reserves have adequate resources from the National Treasury so they are managed properly.”
Not every reserve is national treasure like a Table Mountain or a Kruger National Park, he says, but all are nevertheless important to endemic species.
Falling far short of the 30x30 global targets, only just over a tenth of South Africa’s land and oceans is formally protected.
The climate crisis has profound impacts on marine species as well as those on land.
Penguins, many seabird species, whales, seals and other creatures in the southern Ocean are among those under pressure, running out of food and safe breeding grounds due to rapid, human-induced global warming.
Like plenty of species that used to be abundant under cooler conditions, African penguins are “hanging by a thread” and could be extinct within a decade unless human behaviour and climate change are reined in.
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