ALBERT

Description: In the northeastern tropical Atlantic, a region of high potential vorticity (PV) determines the size of the exchange window for the interior thermocline flow of the subtropical cell via its variations in strength and extent. Variability of this PV barrier has the potential to impact the ventilation of the tropical Atlantic on decadal timescales. Here, the impact of the North Atlantic Oscillation (NAO) on the PV barrier related to isopycnals within the thermocline of the subtropical-tropical Atlantic Ocean is assessed from Argo observations for the time period of 2006-2022. Relative to the negative NAO phase (2009-2010), during the positive NAO phase (2014-2019), the North Atlantic subtropical high and the northeast trades are intensified. Satellite-derived wind stress curl shows increased upwelling/downwelling on the equatorward/poleward side of the trade wind zone, respectively. In the subtropical-tropical Atlantic, a symmetric pattern of isopycnal heave is observed: rising isopycnals within 20 degrees N and 20 degrees S and sinking poleward of that. With rising isopycnals, the PV barrier in the northeastern tropical Atlantic becomes stronger. Analyses of geostrophic velocities and the Sverdrup streamfunction show that during the positive NAO phase there are increased equatorward velocities at thermocline level along the western boundary and reduced velocities through the interior as a result of intensified northeast trades and therefore a strengthened PV barrier. Intensified trades lead to enhanced subduction of thermocline waters and, independent of that, to a strengthened Equatorial Undercurrent transport as observed at the mooring site at 0 degrees, 23 degrees W, likely via the pulling effect of the subtropical cells. In the North Atlantic Ocean, subducted water from the subtropics has two possible pathways within the thermocline toward the equatorial region: the interior pathway and the pathway along the western boundary. The size of the exchange window between subtropics and tropics depends on the extent of a barrier zone in the eastern part of the basin that is associated with wind-driven upwelling of density surfaces. The North Atlantic Oscillation (NAO) is the dominant atmospheric climate mode in the North Atlantic and in this study, we show how the NAO impacts the barrier for the equatorward thermocline flow in the tropical Atlantic Ocean. During positive NAO phases (e.g., 2014-2019), density surfaces become shallower and strengthen the barrier, while during negative NAO phases (e.g., 2009-2010) the barrier weakens. Geostrophic velocity analysis reveals that during positive NAO phases more thermocline water is transported equatorward via the western boundary and less via the interior pathway. Additionally, observations from a mooring site at 0 degrees, 23 degrees W show stronger Equatorial Undercurrent transport as a result of intensified trade winds during positive NAO phases. Trade winds in the northeastern tropical Atlantic strengthen during positive phases of the North Atlantic Oscillation (NAO+) Potential vorticity barrier for the interior equatorward thermocline flow of the North Atlantic Subtropical Cell strengthens during NAO+ Annual subduction of thermocline water and Equatorial Undercurrent transport increase simultaneously from 2008 to 2018

Description: Technologien für CO₂-Abscheidung und -Speicherung machen Hoffnung, werden aber gleichzeitig als Rechtfertigung für die geringe Reduktion von Emissionen aus fossilen Energiequellen genutzt. Das ist nicht vereinbar mit dem Ziel, die Erderwärmung auf 1,5 oder 2 °C zu begrenzen.

Description: Digitalisation has transformed the way we communicate and collaborate with friends, family, and colleagues. In a similar vein, digitalisation in industry – the so-called industry 4.0 – is expected to transform the way firms and their suppliers collaborate in global supply chains. Considering that 25 percent of global emissions in 2021 were generated by industry (IEA): Can industry 4.0 play a role in greening industrial supply chains? Researchers at the Research Institute for Sustainability (RIFS) at the Helmholtz Centre Potsdam explored the opportunities and risks of digital supply chains for environmental sustainability. In short: sustainability does not simply occur as a by-product of digitalization. Firms should aim to increase sustainability levels in their supply chain – whether through digital or non-digital means.

Description: What to expect of the incoming Lula government’s environmental policy

Description: As we start off the new year and set our sights on new goals and projects, we also want to take stock of the many activities and achievements of the RIFS “Justice in Sustainability” focal topic team during 2022.

Description: The term “triple crisis” loomed large in 2022: The interlinking crises of the pandemic, the climate and energy crises, and the war in Ukraine took many people to their existential limits this past year. Geopolitically, we now face a fragmented world in which power relations are increasingly contested. This was evident at the Sharm el-Sheikh Climate Change Conference (COP 27) in November, where familiar lines of conflict shaped negotiations. Tensions between countries of the Global North and South, for example: Who bears how much responsibility for the climate change that is already occurring (not least of all financial responsibility!) and who (still) counts as a developing country and should be granted support? Debate also continues to rage around the exploitation and use of fossil fuels, which many countries wish to continue for as long as possible – even under the Paris Agreement.

Description: Let's close our eyes for a moment and travel back in time to childhood. Try to remember a time when you felt scared or devastated, the feeling of losing someone you truly love. And now, let’s imagine that these moments begin to multiply and persist. They stay in our minds for days and weeks.

Description: For years now the international community has been negotiating an agreement that will cover more than half of the Earth's surface and establish rules for the conservation and sustainable use of marine biodiversity. Will they succeed?