Climate change has already hit southern Africa. This is how we know

Many people still believe that climate change is a phenomenon that we will only face in the distant future. This may be in part because climate change projections for rising temperatures and extreme weather events are tied to future dates: 2030, 2050 or 2100, for example.

But it’s important to realize that we are already experiencing climate change, and have been for some time now. Over the past century, global temperatures have risen by about 1 ° C. Rising sea levels are already starting to affect some low-lying coastal communities. The world is experiencing more frequent and intense extreme weather events.

The 6th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC): Basis of the Physical Sciences, released in September 2021, contains a comprehensive – and largely grim – assessment of the state of recorded climate change and projected into the world. The IPCC is the United Nations body responsible for assessing the science of climate change – a group of scientific experts from around the world who write scientific reports on the state of Earth’s climate and projections of future changes. climatic.

Its latest report compiles research from 1,400 articles and will serve as an important background document for the COP26 meeting in Glasgow, Scotland, from October 31 to November 12. This is where science is transformed into politics.

Such a policy is critical for the whole world – and urgent for southern Africa, which is particularly vulnerable to climate change. The region is already experiencing faster climate change with more severe impacts than the global average. It also suffers from a low adaptive capacity: there is little capital available to invest in protective measures against future climate hazards, and very pressing immediate human rights needs for a large part of the population. .

It is impossible to avoid the reality that Southern Africa is in the throes of a climate emergency. By identifying trends in the frequency of weather events and their intensity over a period of several decades, and exploring the changes in related biological systems in light of this, it is clear that the region has already been shaken by the change. climate and related effects.

An increase in extreme temperatures

Extreme temperature events can be defined by the maximum temperature, the deviation from the norm, or the duration of temperatures above the threshold. A number of indices have been developed by the World Meteorological Organization to identify and quantify these extreme temperature events.

Hot events, when they meet specific criteria, are called heat waves. These are particularly dangerous for people, animals and plants, and are a direct cause of death.

In southern Africa, there has been an increase in the severity and frequency of heatwave episodes in recent decades. Interestingly, for a few places there has also been an increase in the frequency of extreme cold events. While this is not a feature of global warming, it is driven by changes in regional climate patterns, such as the number of cold fronts moving over South Africa.

Severe drought

Drought is defined as a significant and prolonged deviation from the average precipitation totals. The most serious and well-known drought in southern Africa in recent years has been the “Day Zero” crisis in Cape Town. While increasing water pressure in the city of Cape Town has played a role in this, a longer term shift to the poles in westerly winds carrying winter rain that bring cold fronts and rain in Cape Town during the winter months contributed significantly to this drought.

Southern Africa more broadly is also sensitive to droughts induced by El Niño. El Niño refers to warmer-than-usual conditions in the eastern Pacific that persist for a few months to several years, due to weakening trade winds and a resulting reduction in upwelling colder water at the top. sea ​​surface just off South America. . This was the cause of the 2015-2016 drought in South Africa’s Kruger Park, which resulted in the drying up of waterholes and the widely publicized deaths of hippos and later the culling of other large mammals. .

High intensity tropical cyclones

The South African subcontinent is relatively well protected from tropical cyclones by the island of Madagascar. However, some tropical cyclones form in the Mozambique Channel, and sometimes some tropical cyclones pass through Madagascar. These storms can – and do, as we saw recently with tropical cyclones Idai, Kenneth and Eloise – make landfall in Mozambique.

Read more: Tropical Cyclone Idai: The storm that knew no borders

Over the past decades, tropical cyclones in the southwest Indian Ocean have increased in intensity; the first category 5 tropical cyclone for the sub-ocean basin was recorded in 1994.

Tropical Cyclone Idai, whose intensity was between categories 3 and 4 on landing, provides compelling evidence of the damage caused by high-intensity tropical cyclones in populated areas.

There is also evidence that tropical cyclones have extended their range towards the poles in recent decades, affecting a larger region of southern Africa.

Changes in the timing of phenological events

In addition to the weather conditions that we experience as a result of climate change itself, climate change also has an impact on biological systems. Phenology, which refers to the calendar of recurring biological events each year, is one of the most sensitive bioindicators of climate change.

Read more: Explanation: why phenology is the key to monitoring climate change

In South Africa, scientists have recorded progress in the timing of the flowering of apples and pears in the southwestern Cape, and the flowering of jacarandas in the Gauteng city area. Warmer sea surface temperatures have also caused a delay in the race of sardines along the southern coast of KwaZulu-Natal.

These changes have an impact on agriculture and tourism, but above all demonstrate that climate change has an effect on the natural environment. These schedule changes cannot continue indefinitely. Plants and animals have thresholds beyond which the stresses of climate change will lead to at least local extinction.

The picture seems hopeless, but with mitigation and adaptation strategies and policies driven, among others, by COP26, Southern Africa can reduce the impacts of climate change on local livelihoods. It is important at this stage to invest in adaptation to reduce the impacts of climate change, and to do everything possible to reduce our dependence on carbon to slow climate change.

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