No shortcut to understanding climate, scientist warns
Scientists supported by the EU-funded TiPES and TAOC projects warn that tipping points in our climate system may be more difficult to predict than previously thought. By modelling the Atlantic Meridional Overturning Circulation (AMOC), an ocean current system that plays a key role in the climate system, the researchers show that the system’s stability is much more complicated than presumed up to now. In short, we cannot rely on nature giving us clear-cut early warning signs of a climate disaster. As reported in their study published in the journal ‘Science Advances’, the team employed a primitive-equation ocean model to simulate the collapse of the AMOC as a result of increasing glacial melt. Any collapse would be preceded by various intermediate tipping points, or transitions between different stable circulation states in the AMOC. Using 2.75 million years of model simulations, the scientists uncovered what they describe in the study as “a very rugged stability landscape” with up to nine coexisting stable states.
No obvious signs
Study co-author Prof. Valerio Lucarini of TiPES project partner University of Reading, United Kingdom, states in a ‘EurekAlert!’ news release: “Within each state there is a multiplicity of nearby states. Depending on where or what you are observing, you might find some indicators of nearing collapse. But it is not obvious whether this collapse will be contained to nearby states or lead to a major upheaval, because the indicators only reflect the local properties of the system.” The researcher adds: “These states are the different ways that the Atlantic meridional overturning circulation organises itself at large scales, with key implications for the global climate and especially regionally in the North Atlantic. Under some scenarios, the circulation could reach a ‘tipping point’ where the system is no longer stable and will collapse. Early warning indicators tell us that the system might be jumping to another state, but we do not know how different it will be.” Mentioning a similar occurrence in a separate investigation of palaeoclimatic records, Prof. Lucarini notes that “when you change your timescale of interest – just like a magnification lens - you can discover smaller and smaller scale distinct features that are indicative of competing modes of operation of the global climate. Paleoclimatic records of the last 65 million years allowed us to provide a new interpretation of the climate evolution over that time period, and reveal these multiple competing states.” According to Lucarini, the current EU-funded study lays the foundations for exploring our climate system “through the lens of statistical mechanics and complexity theory.” The author further remarks: “It really stimulates a new outlook of climate, in which you have to put together complex numerical simulations, observational evidence and theory in an unavoidable mixture. You have to appreciate and endorse this complexity. There is no shortcut, no free lunch in our understanding of climate, but we are learning a lot from it.” The TiPES (Tipping Points in the Earth System) project ended in February 2024. TAOC (Tipping of the Atlantic Ocean Circulation) ends in September 2027. For more information, please see: TiPES project website TAOC project
Keywords
TiPES, TAOC, climate, tipping point, Atlantic Meridional Overturning Circulation, AMOC, ocean, ocean current, climate system
