PALSEA2 - PALeo constraints on SEA level rise 2
PALSEA2 is a PAGES IGBP, INQUA, WUN 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. It is a continuation of PALSEA1, which operated from 2008 to 2012.
The greatest uncertainty in projecting future sea-level rise lies in the responses of Earth’s remaining ice sheets. The observational period of sea level and ice sheet mass balance spans at best only the last century, at least partly exacerbating present uncertainty in future sea-level rise.
In contrast, the geologic record provides valuable archives of how ice sheets and sea level have responded to past climate variability, particularly during periods of climate warming. The information contained in the geological record can therefore help assess the relationship between ice sheets, sea level and climate change, and provide a firm basis for projecting the future.
PALSEA2 will continue to bring together observational scientists and ice-sheet, climate and sea-level modelers in order to better define observational constraints on past sea-level rise and improve our understanding of ice-sheet responses to rapid climate change.
Link to the external PALSEA2 website.
Learn more and participate
To subscribe to the PALSEA2 mailing list or enquire about how to get involved, contact Prof. Anders Carlson.
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 higer 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