PALSEA - PALeo constraints on SEA level rise

Phase 1	Phase 2		Phase 3

2008-2012	2013-2017	2018	2019-2022

Image: Free stock photo from pexels.com

Summary

The PALSEA Working Group was active from 2008-2022.

The greatest uncertainty in future sea-level rise is the responses of Earth’s remaining ice sheets. The geologic record provides archives of how ice sheets and sea level responded to past climate warming. PALSEA provides constraints on past sea-level rise and ice-sheet change to improve understanding of future sea-level rise.

This group is open to anyone who is interested, and early-career researchers are encouraged to be involved:

- Read more on the external website

- Sign up to the PALSEA mailing list

- Follow the group on Twitter: https://twitter.com/palseagroup

- Contact the group leaders

Goals

- Develop and refine dataset of relative sea level with improved age and elevation uncertainties, from which rates of sea-level change may be estimated.
- Develop a better understanding of the physical processes involved in ice sheet collapse and its solid earth response.
- Provide constraints on the timing, and drivers, of ice-sheet contribution to periods of Quaternary and Pliocene sea-level rise, to provide validating constraints for future developments in coupled climate ice-sheet models.

PALSEA is a PAGES and INQUA working group focused on using past changes in sea level and Earth’s cryosphere to constrain future sea-level rise in response to climate change.

PALSEA is a continuation of PALSEA1, which operated from 2008 to 2012, and PALSEA2, which operated from 2013-2017.

This third phase of the group ran from 2019-2022 (extended for one year due to coronavirus disruptions).

Overview

Sea-level rise due to polar ice-sheet retreat in a warming world is one of the most important, and uncertain aspects associated with future climate change. The geologic record, features major, and sometimes rapid, changes in ice sheets and sea level that offers an excellent opportunity to assess the rates, magnitudes, and processes involved in ice-sheet and sea-level change, as well as their connection to climate forcings.

Significant scientific developments have occurred over recent years, deepening understanding, but also discovering new complexities in reconstructions of local sea level, processes of solid Earth deformation and ice-sheet collapse. The new phase of PALSEA aims to embrace and overcome these complexities by improving the analysis, documentation, and interpretation of sea-level and ice-sheet observations through interdisciplinary collaborations.

PALSEA will establish an interdisciplinary network of researchers that is equipped to target critical research gaps around the development of paleo-records and the physical processes of sea-level change. The group will develop and update datasets of ice and sea-level proxies and results of earth and ice models, making them available to the broader community through data-sharing platforms; and connect with stakeholders, who are concerned with present and future sea-level change, to translate the results of past sea-level reconstructions into actionable information.

Learn more and participate

This group is open to anyone who is interested, and early-career researchers are encouraged to be involved:

- Read more on the external website

- Sign up to the PALSEA mailing list

- Follow the group on Twitter: https://twitter.com/palseagroup

- Contact the group leaders

Past highlights

Published: 9 July 2015

In a review paper in Science, PALSEA2 have analyzed sea levels during recent warm periods in Earth’s history when global average temperatures were similar to or slightly warmer than today – about 1°C above preindustrial temperatures.

They concluded that global average temperatures similar to today, but slightly higher polar temperatures, resulted in more than 6 metres of global average sea-level rise due to polar ice-sheet loss.

The study confirms that our present climate is warming to a level associated with significant polar ice-sheet loss in the past and even our present temperature targets may commit Earth to at least 6 metres of sea-level rise.

Figure 1: Small increases in global average temperature may eventually lead to sea-level rise of 6 metres or more according to evidence from past warm periods in Earth’s history. Temperatures shown are relative to preindustrial levels. Present day temperature is around 0.8°C higher than pre-industrial levels.

Reference: "Sea-level rise due to polar ice-sheet mass loss during past warm periods", Dutton et al., Science, 10 July 2015, DOI: 10.1126/science.aaa4019

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