Seasonal variability in a warming climate: Lessons from the Pliocene
Warm Period and beyond
Abstract
One of the most worrisome aspects of anthropogenic climate change is its
potential to enhance the frequency and severity of extreme weather
events and seasonality (van der Wiel et al., 2021). More accurate
reconstructions of short-term climate variability in past warm climates
help improve our projections of this type of variability in future
climate (IPCC, 2013). Here, we apply our recently developed clumped
isotope methodology for absolute seasonal sea surface temperature and
salinity reconstructions (de Winter et al., 2021a; b) on fossil mollusk
shells from the Pliocene Warm Period (3.0 – 3.3 Ma) of northwestern
Europe, an important analogue for equilibrium climate under present-day
radiative forcing (pCO2 ≈ 400 ppmV; Haywood et al.,
2016). Isotope records from well-preserved shells of four different
bivalve species (Arctica islandica, Glycymeris radiolyrata, Angulus
benedeni and Ostrea edulis) reveal warm sea surface temperatures and
high seasonal variability during the key mid-Pliocene PRISM interval,
allowing detailed comparison with long-term geological climate
reconstructions and an ensemble of model simulations (Haywood et al.,
2016). Moreover, our results shed light on sub-annual variability in
water chemistry in the shallow European epicontinental seas during this
crucial period. These new findings highlight the effect of a warming
climate on shallow marine ecosystems and shed light on the seasonal
response to global warming. Haywood, A. M. et al. Integrating geological
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