Tipping points (TPs) in Earth’s climate system have been the topic of increasing interest and concern in recent years given the risk that greenhouse gas emissions could cause abrupt, potentially irreversible, climate transitions. Paleoclimate records are essential for identifying past TPs.
Scientists have now developed the open source PaleoJump database, which contains a collection of carefully selected, high resolution records originating in ice cores, marine sediments, speleothems, terrestrial records and lake sediments. These records show climate variability on centennial, millennial and longer time scales and cover all the continents and ocean basins.
Many of these records show abrupt transitions, raising the question of whether similarly drastic changes may occur in the near future, as anthropogenic global warming pushes the climate system away from its relatively stable state. Many of Earth’s subsystems exhibit variability and could experience a sudden shift into a new state once certain key thresholds, known as tipping points are crossed.
Records of past climate and environmental changes play a crucial role in identifying potential TPs in the climate system by enabling the reconstruction of Earth’s climatic history. These records, especially those that show abrupt transitions, may provide valuable insights into the past behaviour of Earth’s systems and possible TPs. By using this information, we can have a better understanding of the possible trajectories of future climate change and their environmental impacts.
The PaleoJump database currently holds records from 131 sites, grouped by their geological type: 49 marine-sediment cores, 32 speleothems, 18 lake sediment cores, 20 terrestrial records and 12 ice cores.
The database focuses on indicators that can be directly compared with climate models: oxygen isotopes reflecting changes in past temperatures, sea level and precipitation; carbon isotopes containing information on past vegetation and the carbon cycle; aeolian deposits that include signatures of past precipitation, mineral aerosols, and atmospheric transport patterns; as well as other indicator based estimates of past temperatures.
The broad spatial coverage of the PaleoJump database with its records that differ in nature – ice, marine and land – as well as their length and resolution, will facilitate research on tipping elements in Earth’s climate, including polar ice sheets, the Atlantic Meridional Overturning Circulation and the tropical rainforests and monsoon systems. In addition, it will support establishing improved criteria on where and how to collect data for reliable early warning signals of impending TPs.