User:Chrizzy 23/sandbox

South Africa is known to be one of the most species-rich and biodiverse areas of the world. A large number of species, animals as well as plants, are only found in South Africa, and nowhere else on the planet. The marine ecosystems of the country are habitat for almost 15 % of all known marine and coastal species. 10 % of the world's plants have their home in South Africa and 65 % of the plants growing in South Africa do not grow anywhere else on the planet. Almost 70 % of the world's invertebrates, and 56 % of the world's amphibians have their home in South Africa.

In addition to the species biodiversity, South Africa is also very rich in different ecosystems and biozones due to different climatic conditions. These conditions come among others from the Atlantic and Indian Oceans framing the country. Also the country's big surface contributes to the wide diversity, so the varieties reach from dry desert over grasslands, savannas, forests and mountain regions up to suptropical wet weather. The National Spatial Biodiversity Assessment (NSBA) referred to 65 % of the marine biozones of the country as threatened back in 2004.

The predictions concerning the climate change for South Africa in general prognosticate increases of temperatures of 1-3°C. Some predictions even talk about a maximum of temperature change, up to 2050, when nothing about the greenhouse gases emissions will be done in the near future, the interior of South Africa could warm up up to 5-8 °C. Nevertheless, the coastal regions will not be affected that much.

It is suspected that there will be less rain in the West and it gets drier in general, but wetter with an increase of the intensity of rainfalls and floods in the East. Also there probably will be more nature events like droughts or floods, storms, wildfires with increased intensity. This has already been seen during the last years. These kind of nature events are expected to happen more frequently in this high intensity.

Climate models for predictions of the future have measured temperatures since 1900. There are different scenarios, which depend on the economoy and global politics concerning for example limiting greenhouse gas emissions. The best-case scenario's goal is to keep the change until 2100 below 2°C; it projects the temperature in Cape Town raising between 1,4 and 1,6 °C by the end of the century. A medium-low scenario, which would decline the emissions starting from 2040, predicts a temperature rise between 2,1 and 2,4 °C. A medium-high scenario, which assumes the greenhouse gases decline starting aroun 2080, prognosticate a rise between 2,4 and 2,8 °C. Finally, the worst-case scenario, which does not contain any decline of greenhouse gases, projects a temperature rise between 3- 5 °C by 2100.

This even can vary because it is not sure yet how the atmosphere will cope with more carbondioxide in the air.

The RCP4,5 scenario predicts a change in annual mean temperature between 1,5 - 2,5 °C for Southern Africa for the period of 2071- 2100 compared with 1971- 2000. A high scenario's projection (RCP8,5) speaks from a change between 2,5 – 4,5 °C.

This is based on the mean of nine different global climate models for each scenario. Thereby the middle scenario (RCP4,5) assume the world working on reducing greenhouse gases to stabilise radiative at 4.5 W/m² before the year 2100. The scenario RCP8,5 works analogously to that approach with 8,5 W/m².

Another model projects an increase of 2,3 °C of the warmest month in Cape Town in 2050 compared to the temperature in 2000. Whereas the increase in the coldest month is only 0,3 ° C.

This fits to the projection of another source that predicts a rise of temperature of 1 °C by 2050 for RCP4,5 and a rise of 2°C by 2100. The RCP8,5 scenario here says that the temperature will rise 2 °C by 2050 and until 2100 there will be a change of 4°C.

Of course, with all the different models and scenarios, it is almost impossible to really predict the future changes, they are only allowing approaches and ideas of how the climate could develop. Therefore it is better for projecting the future climate change with several models and scenarios. These are based on decisions and measurements of the past and techniques of the present. And they only allow a certain assistance in deciding about strategies to reach or not to reach the predicted climate.

Of course, until 2100, many things can happen, new techniques can develop, new solutions can be found, political and economical situations can completely change, so there is still a high uncertaintiy about the predictions.

Also the environment can show unpredicted reactions concerning the rising amount of carbondioxode in the atmosphere for example, or ocean acidification. Land-use changes and ecological effects concerning species and organism communities may also have a larger effect than guesses by now.

But anyway, it is certain that there will be a change in climate in the whole world, concerning a temperature change and shifts as well as intensities of extreme events.

As South Africa is the home for many ecosystems with many different plant and animal species, the climate change will probably have a large impact on the country's biodiversity. There have already been noticable changes during the last decades.

The long coastline of South Africa is ecological unique, with two big currents that define the marine ecozones: the Agulhas and the Benguela currents. The Benguela current in the East is guiding cool, nutrient-rich water towards the equator, along the West coast there are also strong winds coming and mixing South Atlantic water with the current water. The intermediate water temperatures are 16-21 °C, whereas the Agulhas current at the East coast creates temperatures from 20-25 °C. Also, the rocky coasts of South Africa result in high wave energy. Along the South-western coast the diversity of marine animals is quite wide.

Climate change causes general warming of the oceans, also of the Bengula currents along the West coast, which of course also affects the organisms living there and their food chains which reach over many participants. Seabirds are already seen to have shown a decrease in several studies.

One of them, which is marked as red-listed endangered since 2010, is the African penguin, Spheniscus demersus, who is endemic to Southern Africa, and lives along the coast.

The rise in temperatures of the ocean result in higher chick mortality because of less food. The breeding penguins have to leave their nests to travel much further to catch fish for their families. The success of breeding was estimated only 0,23 chicks per pair in 2000 while it was 0,62 ±0.19 every other year between 1989 and 2004 (Crawford 2006 ).

Another negative side-effect of the food either dying or shifting along the coast results in an decrease of ocean productivity which is a economic cause and then leads to overfishing and even less food for the penguins.

The amount of for example sardines fell sharply since 2002 at the location with the largest penguin breeding islands in the west of Cape Town (Crawford 2007 ).

Scientists use the term „Ecological trap“ to define the problem the penguins have because of their original prey like sardines either dying or shifting. There has been a 80% decline in the penguin population of the Benguela ecosystem.

Juvenile penguins have been tracked by scientists and it was found out that they still travel quite far to regions northward or eastward where there used to be a high richness of sardines and anchovies earlier. Nowadays, because of the overfishing in these regions and the climate change, there are not many fish left in these regions, and many juveniles do not find enough prey. The decision for a destination of the young penguins is dependent on environmental factors, such as a cool water temperature, a certain chlorophyll a concentration and clues like the smell of diemethyl sulfide which usually would speak for prey-rich regions. Adult birds later on learn to avoid these habitats but because of getting into the trap many juveniles die during their first year.

There was also a decrease in the general amount of habitats because of many other species and predators shifting and the birds shifting their habitats itself following their food. Birds were forced to nest in more open ground areas, and as a result the penguins suffered from heat stress and had to abandon their nests or the nests got flooded by increased rainfalls or increased sea levels and storms, which would approximately kill around 40 % of eggs and chicks.

The rise of temperature or the higher amount of hotter days in summer do also have effects on the hatching of baby penguins from their eggs. A model has shown that a longer heat period in summer reduces egg and chick survival rates to only 50 %.

Anyway, there is not only a rise in the temperatures of the ocean. Certain areas along the west coast as well as the south and south-east coast have been recorded to cooling seasonally too, usually in winter because of stronger winds for example. Many marine coastal species are known to be very sensitive concerning the temperature. It was recorded that a temperature change that is too sudden can be lethal for a mass of fish (Hanekom et al. 1989 ).

Climate change is predicted to have sea level rise as a consequence, too, and a rise at the West coast of South Africa has already been recorded with a mean of 1,87 mm per year (Mather et al. 2009 ). This then results more weight of water hitting the shores. The higher intensity of storms or the increasing frequency of them can then cause a higher wave energy. There might be effects on erosion-deposition cycles and many organisms may be affected, die or have to shift their range.

As a result of the increase of CO2 in the atmosphere, there is more air-sea gas exchange and the seawater gets more acid, the pH decreases. This acidification is projected to have a large impact on marine and coastal ecosystems (Harley et al. 2016 ).

There are predictions that the pH of the sea water on the surface will decrease by 0,3 – 0,5 units by the end of the century due to the rise of atmospheric CO2 (Caldeira & Wickett 2003 ). There have been several studies about marine organisms that showed that acidification has a large impact on their behavior, their physiology and their development, which of course also has then a large impact on their predators, e.g. birds like the penguin.

All these changes cause shifts of habitats and also changes in the distribution of species such as changes in the communities and food chains of several ecosystems.

Anyhow, there are already many projects concerning the rescue of the biodiversity and species-richness of South Africa that try to find ways to help different organims to survive. Especially concerning the penguin, there are restrictions about fishing in several areas, to avoid more overfishing and more loss of potential prey.

South Africa already started planning mitigation and adaptation strategies and want to use more natural solutions than engineered, one example is rather to exchange expensive desalination plants by clearing invasive alien plants in mountain areas. As one major problem in South Africa about the climate change which will affect the socioeconomy will be the water supply.

Also concerning the connection between biodiversity and climate change, South Africa is for example trying to stop the loss of landscapes due to economy to let the plants adapt to the new conditions, regarding land-use there are many laws from the government.

Anyhow, many strategies that came up for working against the climate change and the loss of biodiversity might collide with economical requirements or issues about the society. Therefor the politics try to work for a change in general to help the whole ecology to allow adaptation but cannot save and find approaches for every single species.

With all the new formed policies and the strategy of „ecosystem-based adaptation to climate change“, it is still hard to keep track about all the landscapes and there are probably still many private farmers (in rural areas) that do anything illegally.

There has to be products and sources for the biodiversity projects, maps have to be created and kept actual. There has to be made decisions all the time again, the processes have to be developed continously. This is a large effort. Also money of course plays a critical role here, too. To accomplish the goals done for the biodiversity and climate change projects it takes much financial resources. Scientists need money to work on their developing strategies. Therefor it is quite hard to convince certain decision-makers to provide and invest the money, the projects and concepts have to show a certain risk-freedom and promise a certain success rate. So, donor institutions also play a major role and it all goes between the interaction of them, the government and the civil society.

One important approach against the climate change is also the usage of renewable energy sources. Economically, the whole continent of Africa would benefit from less import from other countries that sell sources quite expensive. Even though Africa itself is a great export country, for example concerning oil.

With using more renewable energy sources, the resources used so far would be conserved. For Africa, the new sources furthermore would be cheaper and faster, the costs will be reduced over time.

But the management of renewable sources needs a good planning, and in the social side public awareness and education. In some rural areas of South Africa, this might be harder than in Cape Town for example. But there is a programm called EEDSM whose function is to create a higher awareness about energy efficiency.

Solar energy and wind energy might have the highest potential in South Africa regarding the renewable energy sources. The Northern Cape of South Africa counts as one of the best solar resource spot of the world. Also the costs for renewable energy sources decline during the last decade. Nevertheless there are many problems with the storage of the energy gotten from solar and wind energy sources in South Africa which then create new and high costs on the other hand again. But in general, more investments for renewable sources and sharpening the public awareness should be done.