Present effects, future impacts: what scientific research in Antarctica has to say on climate change

Science | Studies aim to assess the complexity and interconnections of phenomena, as well as emphasize the need for practical attitudes and urgent policies

*First published in January 16, 2025
*Photo: Ronaldo Bernardo, from the UFRGS Polar and Climate Center, holds a frozen ice testimonial collected at the Mertz Glacier (International Antarctic Coastal Circumnavigation Expedition – ICCE. Photo/Video © Anderson Astor and Marcelo Curia)

This article is part of Antarctica Special (Especial Antártica, in Portuguese), which compiles six articles spanning from the research and understanding of climate change to the daily routine of a crew who spent 60 days in an icebreaker ship. 

Climate change consists of long-term alterations in the temperatures and weather patterns of our planet. It might be propelled by natural causes, such as big volcanic eruptions, or human causes. The latter is the current leading factor – according to scientists, human activity has intensified climate change’s growing pace since the 1800s. 

An 1.2ºC increase of the Earth’s average surface temperature – related to the burning of fossil fuels, deforestation, unplanned urban development, among other factors – is highlighted by the United Nations (UN) as the largest in the last 100,000 years. Research shows that the last four decades were warmer than any other decade after 1850, and the period between 2011 and 2020 registered the highest temperatures on record.

“Humankind has worked on causing this change, especially over the last 120 to 150 years. It is slower to overturn it than to initiate it,” declares climatologist Venisse Schossler, professor at the Geosciences Institute at the Federal University of Rio Grande do Sul (UFRGS) and research associate of the National Institute of Science and Technology of the Cryosphere (INCT Cryosphere) and the Polar and Climate Center (PCP/UFRGS). Schossler, along with 60 researchers from seven other countries, is part of the team that has been leading the circumnavigation expedition around the coast of Antarctica since 2024. 

The researcher mentions the steep reduction in ozone concentration, known as the “ozone hole”, as an example of the atmospheric regeneration process complexity. The ozone layer, located in the stratosphere, is responsible for absorbing 90% of ultraviolet (UVB) radiation. Human exposure to this type of radiation is linked to the development of skin cancer, suppression of the immune system and premature aging, as well as damage to the eyesight. UVB rays also harm many life forms’ early developmental stages, such as planktons, which are the foundation to aquatic food chains, thus provoking environmental imbalances. The 1987 Montreal Protocol banned the production and consumption of substances responsible for the destruction of the ozone layer. CFCs (chlorofluorocarbons) are among the many substances which have been extensively used as cooling agents and in aerosol sprays. They can remain active for 80 to 100 years after their release into the atmosphere. Therefore, as Schossler highlights, even with a ban, recovery is slow.

When it comes to global warming, the climatologist indicates that decreasing greenhouse gas emissions is only the starting point and stresses that an energetic transition is urgent. “No climatologist ignores it won’t to be instantaneous. We know it is a transition, that is, society must slowly move towards not using fossil fuels anymore,” she emphasizes. 

The second point relates to how urban areas are developed. The current vertical model allows for the creation of islands where the heat gets trapped and cannot escape. The scientist further explains that, in order to be adopted, energetic transitions need government incentives such as lowering taxes on solar power technology and services. 

“Many countries are on the forefront already, especially European ones and China. They are running on this transition front and creating jobs and technologies. This is important for the world as a whole, even for developing countries that do not contribute as much to the emission of greenhouse gases.”

Venisse Schossler

Climate teleconnections

Schossler is also a member of Notos – Climatology Laboratory, a UFRGS Polar and Climate Center group that studies the relationship of climate change in the connections between Antarctica and the tropics. One of the goals is to understand how alterations in the Southern Hemisphere atmospheric circulation have affected Brazil and South America as a whole, with a special focus on states in southern Brazil. 

“Rio Grande do Sul and Santa Catarina are exactly on the threshold of polar air mass inflows that come from Antarctica and warm air mass inflows filled with humidity from the equatorial region. When they meet, the worst storms, cyclones, and extreme events are formed.”

Venisse Schossler

The researcher draws attention to the climate teleconnection phenomenon: a link between events that occur in one place and influence other events in places further away. The calculations for these connections are determined through statistics based on atmospheric and oceanographic data from specialized websites. Local sample collection, such as snow samples, is necessary to prove these connections. “We interpret the events from previous years through them, like how the snow precipitates and holds bubbles that are atmospheric samples,” Schossler affirms. 

“Ice cores” are being collected from 16 glaciers that have been moving in rapid speed and show ice mass loss. These samples will be melted for an analysis of water, gases, and other elements. Through this process, it is possible to identify, for example, connections between warm air masses or soot from the fires in the Amazonian rainforest and the Cerrado biome. The extracted material will also serve to understand how events such as El Niño influence the surrounding area of the Antarctic continent and, consequently, the rest of the planet. Moreover, it will be used to understand climate change associated to increased temperatures, carbon dioxide (CO₂) emissions, and the hole in the ozone layer. 

“This data is essential not only for us to understand extreme events in the Southern Cone (Conesul, in Portuguese), but to predict weather periods that affect agriculture and the course of our food so intensely, for example. These are not only climate connections, but social and economic, too.” 

Venisse Schossler

Marine biological carbon pump

Pedro Augusto Mendes de Castro Melo, professor of the Oceanography department at the Federal University of Pernambuco (UFPE), is part of the expedition for the first time. He is a researcher at Project Mephysto, which integrates 7 Brazilian institutions across three different regions (4 in the Northeast; 2 in the Southeast; 1 in the South). There are also 2 institutions from the United States, 1 from Japan and 1 from Italy. 

The main goal of Mephysto is the interdisciplinary investigation of physical, chemical, and biological processes in the structuring of planktonic ecosystems and biogeochemical cycles in the Brazil-Malvinas Confluence (BMC), a phytoplankton diversity hotspot. Melo’s research is linked to the ecology of plankton in general (phyto and zoo). Phytoplankton are microalgae that produce energy by removing CO₂ from the atmosphere in order to produce oxygen through a process called photosynthesis. “It is estimated that in every two breaths we take, one contains oxygen produced by a phytoplankton,” declares the professor.

Zooplankton are the next in line, as they are the organism that links the energy produced by phytoplankton with the rest of the trophic chain. Hence, observing how zooplankton are present in the Antarctic surroundings and how such presence is related to matters of climate change becomes a fundamental task. The concept of a marine biological carbon pump, that is, sequestering and removing carbon from the atmosphere through biological processes and transferring it to the deep ocean, is a key-point in understand the process. Up to 30% of carbon excess is removed from the atmosphere through this process. Zooplankton’s participation in the marine biological carbon pump begins the moment they consume phytoplankton, using part of the energy generated by photosynthesis. 

Although they are the same size as a grain of rice, zooplankton are capable of long migrations and can travel up to 500,000 meters in a day. “It is like doing an IronMan Triathlon every day,” compares Melo. The researcher explains that when zooplankton migrate, they feed on phytoplankton present in light zones of the ocean. When they move to deeper zones, they take carbon with them.

“Our role is to observe the composition of the structure, if changes have occurred and how this relationship between zoo and phytoplankton is happening. Our goal is to understand how the marine biological carbon pump is working and if it is being affected by climate change.”

Pedro Augusto Melo

Melo’s expedition group is collecting zooplankton samples in order to study their taxonomy and ecology. They also conduct experiments on herbivory or grazing. “We are going to assess this interaction, if the process is happening or not in an ideal way, and how it reflects the composition of phytoplankton herbivory rate,” says the professor.

Another study will be conducted on mortality. It is possible to distinguish the proportion of dead and alive organisms in the sample on the moment of collection by applying pigment to the sample. As a result, the contribution of the carcasses to the marine biological carbon pump can be estimated.

Melo highlights that plankton are excellent indicators to water quality and mass because temperature is a crucial factor to changes in the metabolism and the growth rate in a plankton community. The warmer the temperature, the more stratified the water column will be, a scenario that compromises nutrient circulation. With fewer nutrients, the phytoplankton growth rate decreases; and, as a consequence, it supports less zooplankton, impacting the entire trophic chain. 

“Plankton, in general, are excellent indicators because they encompass great diversity. From viruses and bacteria that are part of them, to chordates like fish and fish larvae. Many of these organisms have close relationships with certain temperature, salinity, and depth conditions. This way, we can understand a little bit of what is happening in the system or even notice a change in the community based on any physio-chemical alterations in the water.”

Pedro Augusto Melo

The researcher points out that the ocean current that flows down the coast of Brazil to Antarctica is warm and nutrient-poor whereas the one that flows upwards from the Malvinas is cold and nutrient-rich. When the two meet, they create a diverse environment with two communities that mix in an area called a biodiversity hotspot.

Since it is a coastal expedition, the four Mephysto researchers’ idea is to access the zones where the main interactions are happening, as the thaw or ice formation process and pre-melting layers occur mainly in this region. Their project also focuses on the Brazil-Malvinas Confluence and the Antarctic peninsula to understand how these changes are affecting extreme events and the interrelation between the physicochemical environment and biological behaviors. 

“As an example, we have a completely different environment in Pernambuco. There are river flows, rain water, pollution, urban areas. We need to observe an ocean region that offers the most stability, like in Antarctica. The big achievement of this expedition is being able to really look and assess this planktonic communities that occur exactly where there is an intensification of this process”

Pedro Augusto Melo

The impact of climate change

In an 2022 interview to the university radio, Antarctic Expedition coordinator Jefferson Simões talked about the losses that can already be felt and warned about the future impacts climate change can cause. Among them are the processes happening at the edge of the frozen part of the ocean, which stem from carbon dioxide absorption. Simões highlighted ocean acidification, which threatens shell formation for many microorganisms, and the effort of many species in adapting to water that is becoming sweeter. 

The scientist reported that a northern part of Antarctica is becoming greener. As a result, some islands exhibit expansion of grassy fields, which caused penguin species to migrate south in search of survival. In addition, some fish species that were not present before are penetrating the Antarctic ocean. “Emperor penguins as a species are already considered to be endangered for the next 50 to 100 years. There have been changes in atmospheric circulation, with a tendency of stronger winds around Antarctica,” said the coordinator. 

To Simões, the most significant consequence is the rise in sea levels. “The ice that is on the continent is what matters: in some scenarios, until 2100, losing mass represents an average increase in sea level ranging from 30cm to 90cm,” he highlights. To him, either case represents the best and the worst outcome. However, they do not account for a non-linear behavior that might occur, that is, the process happening faster due to the destabilization of West Antarctica, which might lead to sea levels rising a few meters in the next 200 or 300 years. The challenge here is to make the countries comply with the Paris Agreement.

“Kyoto [Protocol] has been ‘dead’ for over 10 years, and Paris risks the same fate. If nothing is done, global climate change rate will surpass social, political, and economic responses that facilitate the adaptation.”

Jefferson Simões

He reinforces that, depending on the degree of said transformations, human society and other species have more resilience to its impacts. However, it is crucial to follow negotiations on a political level globally. If not, there are no means of resolving the situation. “We cannot go into negationist mode when it comes to such changes. Antarctica, because of its sensitivity to climate, works as an early warning to the changes that are happening on a global scale,” Jefferson Simões warns. 

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Translated into English by Luiza Estivalet Pinto, undergraduate student enrolled in the course “Supervised Translation Training I (English)” of the Undergraduate Program in Language and Literature, under the supervision and translation revision of Professor Elizamari R. Becker (P.h.D.) – IL/UFRGS.

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:: Read in portuguese

Efeitos no presente, impactos para o futuro: o que a pesquisa científica na Antártica tem a dizer sobre as mudanças climáticas