Climate change: Drought in the Amazon rainforest | nd-aktuell.de

The news quickly spread around the world: more than 100 dead river dolphins washed ashore in the Brazilian rainforest at the beginning of October. The rare animals were recovered from Lago do Tefé, a tributary of the Amazon. Videos from the Mamirauá Institute, a research facility run by the Ministry of Science, showed vultures preying on the carcasses. Experts suspect: The dolphins and thousands of fish have fallen victim to water temperatures of up to 40 degrees Celsius.

The river dolphins, called “botos” in Brazil, are not only revered in indigenous mythology. They are also considered an indicator of the health of the region. Amazonia is currently experiencing a massive dry phase. There is hardly any rain, temperatures are above average, rivers are drying up. »The entire ecosystem is out of balance due to the drought,” says geology professor at the University of São Paulo (USP), Pedro Luiz Côrtes, to “nd”.

Extreme weather is becoming more frequent

Brazil is experiencing the effects of an El Niño. This climate phenomenon, known in technical jargon as the El Niño Southern Oscillation (ENSO), changes the ocean currents and the climate. Parts of the eastern Pacific will be warmer, western parts will be cooler. This leads to heavy rain in some regions and droughts in others. This is also the case in Brazil.

There have been heavy rains in the south of the country in recent weeks. In some regions, it rained more than usual in a month in one day. A number of people died in floods and landslides.

At the same time, there was much less rain in the north and northeast of the country. »The consequences of such weather phenomena are becoming more and more extreme. When it rains, it rains very heavily. When it’s dry, it’s very dry,” says Côrtes, who has been researching environmental issues for many years and coordinates the master’s program in environmental studies. For him, this has to do with climate change: “At normal temperatures, water evaporates gradually and clouds have longer to spread. The greenhouse effect leads to more energy and higher temperatures. This means that evaporation happens much faster and clouds form more quickly. This leads to an imbalance and extreme weather events become more frequent. Researchers are worried because the dry phase in Amazonia has only just begun. Temperatures are expected to rise even further in the next few weeks.

Amazonia is a habitat of superlatives. The world’s largest tropical rainforest grows here with a huge diversity of animals and plants, many of which have not even been discovered yet. The gigantic forest stretches across nine countries, with the largest part belonging to Brazil. And the longest and richest river in the world flows there: the Amazon. The complex ecosystem has an impact on the entire planet. Most researchers are certain: changes in the region could have dramatic consequences for the global climate.

Due to the current drought, the level of the Amazon has fallen by almost 30 centimeters every day in the past few weeks. Tributaries have turned into small streams. The lack of rain also threatens the tropical wet forest, which is heavily dependent on water. If it doesn’t rain enough, the entire ecosystem could fall apart. Many animal species are in danger of dying and the flora is also in danger. The drier the trees, the more vulnerable they are to the forest fires that destroy large parts of the rainforest every year.

Researchers have observed that the time intervals between extreme droughts are becoming shorter and shorter. There were dry phases in 2005 and 2010, each of which was classified as a “drought of the century”. However, even more extreme droughts followed in 2015 and 2016. According to scientific calculations, above-average dry years could occur every two years from 2025 onwards – and become the new normal from 2050. According to scientists at the Potsdam Institute for Climate Impact Research (PIK), this would have serious consequences: large parts of the rainforest are in danger of turning into a savannah. This would have devastating consequences for biodiversity and ultimately the global climate.

Without rivers, there are no transport routes

Although large parts of the jungle are inaccessible, more than 20 million people live in the Brazilian Amazon region alone. On the river banks, deep in the jungle, but also in vibrant cities like Manaus and Belém. The current drought is also hitting them hard. Since there are no roads in much of the Amazon, people rely on the rivers to transport food, go to the doctor or attend school. A number of villages are currently cut off from the outside world because the rivers are not deep enough for ships to sail due to the drought. Production is also suffering as a result, especially in the megacity of Manaus. Many raw materials cannot be delivered and manufactured products cannot be transported.

The state governments of the affected states declared a state of emergency in some areas. Vice President Geraldo Alckmin traveled to the region and Environment Minister Marina Silva ordered aid deliveries to the cut-off regions. In January, the government under the social democrat Luiz Inácio Lula da Silva took office and promised a radical change in environmental policy. According to geologist Pedro Luiz Côrtes, the Lula government is acting in a much more coordinated manner than the previous administration of right-wing extremist Jair Bolsonaro. “Unfortunately, politicians usually only react to such extreme weather events instead of preparing for them,” he criticizes. Both local, state and federal levels failed to take preventative measures. The forecast of an El Niño has been around for a long time and the last weather phenomena of this kind have shown that the effects are becoming increasingly extreme.

What also worries many people is that, according to calculations, the El Niño climate pattern could reach its peak this winter. Scientists at the US Oceanographic and Meteorological Administration (NOAA) believe that one of the most intense El Niños ever recorded could develop by December: a Super El Niño. Other researchers urged people not to panic – the fluctuations between El Niño events made it difficult to predict the intensity of such phenomena.

Nevertheless, the heat in the South American spring was not primarily due to El Niño, according to a report just published Attributionsstudie shows. “Although ENSO has influenced large-scale weather patterns, the direct contribution to extreme heat is small compared to the climate change signal,” says the summary at World Weather Attribution. Without man-made global warming, spring temperatures would have been 1.4 to 4.3 degrees Celsius lower than those actually measured. The likelihood of an early heat wave has increased at least a hundredfold with climate change. Under current climate conditions, such a heat wave would statistically occur once every 30 years. However, with further warming, these waves could become even more frequent and temperatures could become even higher.

Danger to the monsoon

A few days ago, more bad news for the rainforest made the rounds. In the specialist journal »Science Advances« The results of a study were published: Researchers from the Potsdam Institute for Climate Impact Research and the Norwegian University of Tromsø (UiT) found that global warming, deforestation and intensified land use could lead to a critical destabilization of the South American monsoon. If a tipping point is exceeded, significantly less precipitation can be expected. Although it is not possible to determine an exact period for such a destabilization, the scientists nevertheless issue an urgent warning. “Forest losses due to direct deforestation, droughts and fires can therefore significantly change the climate in South America and cause the complex coupling mechanisms between the Amazon rainforest and the South American monsoon circulation to exceed a critical point of destabilization,” explained climate scientist and lead author of the study Nils Bochow the website of the Potsdam Institute for Climate Impact Research. “The results presented here suggest an impending shift in the Amazon ecosystem if deforestation and global warming are not stopped.”

Moisture exchange via precipitation and evaporation is fundamental for the climate and preservation of the Amazon rainforest. Some of the rain in Amazonia comes from evaporation from trees. Deforestation could cause lasting damage to this exchange that the rainforest needs to survive. “A collapse of the coupled rainforest-monsoon system would lead to a significant decrease in precipitation in large parts of South America,” wrote PIK researcher and co-author Niklas Boers. The prevailing drought provides a foretaste of what this could mean for the region.

Deforestation has shifted

Since the Lula government took office, deforestation in the Amazon has declined significantly. “We are doing our homework,” Environment Minister Silva announced. However, studies show it has increased in other regions of Brazil, such as the central Cerrado savannah. Deforestation remains big business and the agricultural sector, which is largely responsible for the destruction, continues to have a lot of influence in the country despite Bolsonaro’s election: 300 of the 513 MPs are assigned to a non-factional agribusiness interest group. Excavators are still rolling through the rainforest, cattle farmers are still carrying out slash-and-burn agriculture, gold diggers are still encroaching on indigenous territories.

At the Amazon summit in the Brazilian city of Belém in early August, the heads of state of the Amazon states presented a plan to stop the destruction of the rainforest. An expert panel is to be created, inspired by the United Nations IPCC, as well as a regional observatory for better exchange of information. In addition, a police investigation center is to be set up in the Brazilian Amazon city of Manaus in order to be able to prosecute environmental crimes more effectively across borders. Nevertheless, many criticized the final declaration because it contained few clear and concrete commitments.

Brazil’s President Lula insists that industrialized nations make $100 billion available annually to protect the rainforest. This was already promised at the World Climate Conference in 2009. The South American states are likely to represent this demand at the Cop 28 world climate conference, which starts in Dubai at the end of November.