Climate and transformation
Anthropogenic climate change is no longer a distant forecast—it is a present reality. Global average temperatures are setting new records with alarming frequency, and extreme heatwaves, droughts, storms, and heavy rainfall events are becoming more common and more intense. Climate research has demonstrated that these extreme events are becoming increasingly likely due to global warming. Whether this trend continues unabated depends largely on humanity's commitment to climate protection moving forward. Researchers from various Max Planck Institutes are not only working to improve the accuracy of climate forecasts, but are also investigating how humanity can adapt to the consequences of climate change. Their efforts focus on developing strategies to mitigate climate impacts and limit global warming to manageable levels.
Is climate change caused by human activity?
There is overwhelming agreement among climate researchers that human activity is causing global warming and that we are already experiencing its effects. This scientific consensus confirms the predictions and warnings made by Klaus Hasselmann, who first demonstrated the link between human activity and climate change as early as 1995. In recognition of this pioneering work, Hasselmann was awarded the 2021 Nobel Prize in Physics.
However, when it comes to detailed predictions of how much the climate will change in the coming decades and what impact this will have, some uncertainties remain. For instance, it is still unclear whether critical tipping points exist within Earth's systems—like the Amazon rainforest or the Arctic and Antarctic ice sheets—beyond which their collapse would become irreversible
How far has global warming progressed, and what are the consequences?
In 2023, the global average temperature surpassed pre-industrial levels by 1.5 degrees Celsius for the first time. While this may not seem like much, the reality is more complex. Some regions, such as the Arctic and parts of the continents, are warming significantly faster than others. Additionally, this seemingly small increase is already driving more frequent and severe extreme weather events. The European Xaida consortium, using attribution research, has shown that human-induced climate change increases the likelihood of events like droughts and heatwaves. By comparing scenarios with and without human influence, researchers can calculate just how much more likely these events have become.
The impact of droughts or heavy rainfall events depends on numerous factors. For instance, southern slopes naturally dry out much faster than northern ones. In the summer of 2021, the Ahr Valley experienced a devastating catastrophe after several days of heavy rainfall, while similar rainfall in northeast Germany that same year had relatively mild effects. Researchers at the Max Planck Institute for Biogeochemistry are now leveraging artificial intelligence to predict the precise consequences of climate extremes and extreme weather events for specific locations.
The current understanding and uncertainties surrounding climate forecasts are assessed by the Intergovernmental Panel on Climate Change (IPCC). This global body includes numerous scientists from around the world, including researchers from the Max Planck Society. These experts analyse studies on various aspects of climate change and compile their findings into comprehensive assessment reports
Which countries are most affected by climate change?
As global warming causes the Arctic and Antarctic ice sheets to melt, sea levels are rising, putting some island nations and coastal cities at risk of submersion if climate change continues unchecked. Researchers at the Max Planck Institute for Comparative Public Law and International Law are studying the implications of this growing threat for affected nations in terms of international law.
Rising sea levels, along with extreme heat and drought, are already forcing people to leave their homes, and as climate change worsens, these factors are expected to become even more significant drivers of migration. To address this growing challenge, the international community must establish clear regulations under international law to protect and support climate migrants.
In Germany and across Europe, the effects of climate change are already evident through increasingly frequent heatwaves and droughts on the one hand, and heavy rainfall, and severe storms, on the other. Forests, in particular, are suffering significantly from these changes. In some parts of Germany and Europe, forests are expected to transform dramatically, and in certain regions, they may even disappear entirely.
How extreme will climate change become?
The future severity of climate change depends largely on whether humanity can eliminate fossil fuel use. However, feedback loops and potential tipping points in the Earth’s system will also play a critical role. For example, changes in the Arctic and Antarctic ice sheets, which are melting due to global warming, will in turn influence the climate. Rising sea levels will not only threaten to submerge island nations and coastal cities but will also introduce large amounts of freshwater into the oceans, potentially disrupting global ocean currents. There are ongoing concerns that the North Atlantic circulation, which includes the Gulf Stream and is crucial for maintaining mild temperatures in Europe, could collapse. Such an event would radically alter Europe's climate. Climate scientists are closely examining potential tipping points for both the ice sheets and the North Atlantic circulation, beyond which changes would become irreversible. In the case of the West Antarctic ice sheet, it’s possible that this threshold has already been crossed, with the ice sheet likely to vanish entirely in the coming centuries.
However, researchers at the Max Planck Institute for Meteorology find no indication in measurements or simulations that the North Atlantic circulation could irreversibly collapse, especially not in the near future.
.The Amazon rainforest is a key factor in the Earth system, which may be heading towards a tipping point. This vast rainforest creates its own climate—but only as long as deforestation and climate-change-driven drought don’t push it past a critical threshold. If the forest shrinks below a certain size, it risks crossing this tipping point. Should it disappear, rainfall across South America would decrease significantly, and around 550 gigatonnes of CO2 would be released—about 15 times the amount humanity currently emits in a year.
Feedback mechanisms, whose effects are not yet fully understood, impact Siberian permafrost and cloud formation, particularly in the tropics. When the permafrost thaws, immense quantities of methane—a greenhouse gas 25 times more potent than CO2 — can be released. Researchers at the Max Planck Institute for Biogeochemistry are studying how these processes respond to climate change.
Whether climate change causes more or fewer clouds to form because a warmer atmosphere can absorb more water, and whether the clouds then have a cooling or warming effect, is another uncertainty in current climate models. What is clear is that it depends on the type of clouds and where they form. Clouds in the tropics, for instance, play a crucial role in the global climate and are a focus of research at the Max Planck Institute for Meteorology.
Natural climate fluctuations, such as the El Niño phenomenon and variations in ocean currents, can either amplify or mitigate the effects of global warming.
What happens at the World Climate Conferences?
At the environmental summit in 1992 in Rio de Janeiro, the contracting parties adopted the Climate Framework Convention. Since 1995, countries have been meeting annually at a World Climate Conference. At the climate conference in 2015 in Paris, they adopted the Paris Agreement, in which they agreed to limit global warming to well below 2 degrees Celsius and ideally to 1.5 degrees Celsius.
Today’s climate conferences also focus on who will bear the costs of climate adaptation and protection. Industrialized countries have been the main contributors to climate change, yet many nations in the global South are among the most affected. This imbalance is increasingly leading to conflicts, which international law must help resolve.
Climate protection: How can the transformation to climate neutrality succeed?
Curbing climate change presents immense technical challenges. First and foremost, humanity must shift from fossil fuels to renewable energy sources and sustainable raw materials to sustain and even enhance prosperity. Many scientists at the Max Planck Society are dedicated to enabling this transition to a climate-neutral society. Their research explores effective and efficient use of renewable energies, innovations in energy storage, and the potential of nuclear fusion as a completely new energy source for Earth.
Transitioning to climate neutrality poses particular challenges for certain sectors of the economy, such as the steel and aluminum industries. Researchers at the Max Planck Institute for Sustainable Materials are working to find solutions for these difficult transformations.
Here’s a refined version for clarity: In sectors where avoiding CO2 emissions is currently impossible or challenging, capturing the greenhouse gas could be beneficial. The CO2 could then be stored underground or repurposed as a raw material for basic chemicals or fuels.
Can geoengineering stop or reverse climate change?
Geoengineering is being discussed as a potential means to mitigate global warming. This term refers to measures that directly intervene in the climate, akin to how humanity has altered it through greenhouse gas emissions since industrialization—but with the opposite effect. However, such interventions are highly controversial. They are not only complex and costly, but they also cannot simply reverse global warming. Instead, they may give rise to a new climate with unforeseen effects. Researchers at the Max Planck Institute for Meteorology are exploring the potential consequences of geoengineering. Geoengineering not only raises questions of climate science, but also of international law. For instance, if a country were to unilaterally release sulfate particles into the atmosphere to block sunlight, it could have global repercussions and lead to conflicts with other nations adversely affected by such measures.
Reforestation can help counteract global warming, as trees absorb significant amounts of CO2. While some reforestation efforts are already underway, scientists at the Max Planck Institute for Meteorology are investigating how effective reforestation could be in limiting global warming and whether other geoengineering approaches might be even more impactful. Reforestation represents a form of land-use change that has the potential to slow climate change. However, certain land-use changes often accelerate warming—for instance, when tropical rainforests are cleared for pastures. The effects vary globally: while forests capture more CO2 than grasslands, they have a lower albedo, meaning they reflect less sunlight. Researchers are also debating whether natural forests or managed forests offer better benefits for climate protection.
