Wetlands cover only 4–9% of Earth’s land surface, but contribute to more than 20% of ecosystem services globally. They are also among the most vulnerable ecosystems on Earth, and are now under threat from both climate change and human activity. The impacts of such threats as well as different natural and manmade drivers influencing wetland conditions are not limited to just the local scale of each individual wetland, but extend over larger landscape areas that integrate multiple wetlands and their total hydrological catchment – the wetlandscape. However, our understanding of these interactions has been limited because data and knowledge of conditions and changes over entire wetlandscapes are still scarce. Bolin Centre researcher Navid Ghajarnia and co-authors have now developed a new global database that maps how these factors have changed at 27 wetlandscapes during a 30-year period. This new database makes it easier for researchers to study changes in wetlandscapes that are due to climate change and human activity.

Glaciers and ice sheets around the world have been losing more than 700,000 Olympic swimming pools of water every day. Glaciers form by the transformation of snow into ice, which is later melted by the atmosphere in summer, or slides slowly all the way into the sea. With climate change, glaciers are melting and breaking up into icebergs, which feed into the ocean at an accelerating pace. Exactly how fast depends to a large extent on the shape of the seafloor and on the bed below all the ice. New bathymetric and oceanographic data collected by an international team of marine geoscientists provide important insights into the processes that are controlling the rapid loss of the Greenland Ice Sheet over the last four decades.

If we go back to a period ~23–5 million years in the past, we will find ourselves in the Miocene epoch. There, we find a world with significantly higher temperatures than today, while CO2 levels were just slightly higher than modern day levels. This can point to that relatively low, near future, CO2 levels can cause a larger warming of Earth’s systems than today’s climate models can reproduce. In their review paper, titled “The Miocene: The Future of the Past”, Bolin Centre researcher Margret Steinthorsdottir and co-authors use climate-reconstructions from the Miocene to test their knowledge about Earth’s systems under conditions where both temperatures and CO2 are higher than they are today. In this way, it gives us the rare opportunity to see into the future.

Often called “the lungs of our planet”, tropical forests play a crucial role in global carbon storage and sequestration. They are some of the most varied environments on Earth, and are under threat from both deforestation and global warming. A study by Arie Staal and co-authors finds that with growing greenhouse gas emissions, there is a chance that a larger part of the Amazon rainforest loses its natural resilience and turns into a savannah-like ecosystem. It could take decades for tropical forests to recover from this, which could have devastating consequences for plants and animals.

Permafrost is one of Earth’s largest terrestrial carbon stocks. It stores around 1,500 billion tonnes of carbon, which is near twice the amount of carbon in the atmosphere. But rising temperatures cause permafrost thaw and ground surface collapse, leaving behind dramatic changes in the landscape. In a study that was selected one of the most important insights in climate science 2020, Bolin Centre researcher Gustaf Hugelius and colleagues shows that the emissions of greenhouse gases from permafrost will be larger than earlier projections because of abrupt thaw processes affecting frozen peatlands, which are not yet included in global climate models.

Aerosols – small, invisible particles in the air around us – plays a significant role in the climate system. They affect the radiative balance of the Earth both directly, by scattering and absorbing light, and indirectly, by influencing cloud properties, which in turn influences the temperature. Aerosols can also influence remote atmospheric circulation and rainfall patterns. Currently, these aerosol interactions are one of the largest sources of uncertainty when trying to look into future climates. A team of Bolin Centre researchers at the Department of Meteorology and the Department of Environmental Sciences, Stockholm University, took a closer look at how aerosols affects the Arctic climate.

In an effort to better predict what future environmental changes will most likely influence biodiversity, Bolin Centre researcher Johan Ehrlén and co-authors conducted a study to investigate which of multiple environmental drivers (abiotic, biotic, and/or anthropogenic) affected wild plants the most. This information can aid in identifying the major threats of environmental and climate change to biodiversity.

How sensitive is the climate to carbon dioxide emissions, more precisely? Will a doubling of atmospheric carbon dioxide from preindustrial levels result in a 1.5°C or 4.5°C warmer Earth? The answer has far reaching consequences, since the uncertainty range includes both the merely troubling and the catastrophic. In 2018, 25 scientists were challenged by the World Climate Research Programme (WCRP) to narrow the climate sensitivity and three years later they presented a range between 2.6°C and 3.9°C, updating the climate sensitivity range that has been used for over 40 years.