Towards climate stabilisation: understanding changes in climate, climate variability, and impacts

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The aims of the Paris Agreement state that global warming should be limited to 2 degrees of warming above pre-industrial and 1.5 if possible. The implication of the Agreement is that global temperatures should permanently stay at or below this threshold. To stabilise global temperatures at a given level in the long-term, warming at the global scale must be halted. This can only be achieved by reducing emissions of greenhouse gases to net-zero. If all existing climate policies are successfully implemented, the world is currently on track for between 2.5 and 3 degrees of global warming. Given the explicit aims of the Paris Agreement to limit warming to less than 2 degrees, it is important to study what stabilising temperatures at specific global warming levels would mean for regional climate in different regions across the globe.Research into stabilised climates is still in its early stages. Evidence is beginning to emerge that a stabilised climate could be very different from a rapidly warming climate, even at the same global warming level. However, the physical mechanisms explaining these differences in the mean state remain poorly understood. Beyond the mean state, even less is known about how internal modes of climate variability might differ in a warmer, stabilised climate. Changes in the pattern, frequency, or amplitude of modes of variability would have severe impacts across much of the world. Changes in the mean state and in internal climate variability must be quantified and understood, and incorporated into future climate change risk assessments. In addition to needing to include stabilised climate projections, climate change risk assessments also need to account for natural influences on climate. An often overlooked risk with significant consequences is the possibility of a series of large volcanic eruptions occurring in a future warmer climate. Several successive large volcanic eruptions occurred in the 19th century, and a similar sequence of eruptions could occur again. A storyline where a series of large volcanic eruptions occur in a stabilised climate will be explored in this fellowship.This fellowship will fill an important gap in our assessments of possible future climate change and regional climate risk. Climate model simulations are an important tool to explore possible future climates and investigate the mechanisms of future climate change. Currently, only very few experiments designed to study stabilisation at specific global warming levels exist. Novel ensembles designed to study climate stabilisation and the response to volcanic eruptions in a warmer, stabilised climate will be produced in this fellowship. This highly novel approach will generate important insights into the risks of a future world where temperatures have stabilised and produce a valuable resource to be shared with the broad science community at the end of this fellowship. The outcomes of this fellowship will inform policy and adaptation discussions over the next decade and beyond.