Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate Data, Climate Modeling, and Modern Observations Implies that 2°C Global Warming Above the Preindustrial Level Would Be Dangerous

Abstract

We use numerical climate simulations, paleoclimate data, and modern observations to study the effect of growing ice melt from Antarctica and Greenland. Meltwater tends to stabilize the ocean column, inducing amplifying feedbacks that increase subsurface ocean warming and ice shelf melting. Cold meltwater and induced dynamical effects cause ocean surface cooling in the Southern Ocean and North Atlantic, thus increasing Earth"s energy imbalance and heat flux into most of the global ocean"s surface. Southern Ocean surface cooling, while lower latitudes

Upper Pleistocene parabolic ridges (i.e. ‘chevrons’) from the Bahamas: Storm‐wave sediments or aeolian deposits? A quantitative approach

“…The LIG is commonly known as one of the warmest interglacial periods of the last 800 kyr (Past Interglacials Working Group of PAGES, 2016) with a global average temperature estimated at 1.5 to 2.0°C warmer than the pre-industrial one (Hansen et al, 2016), and a sea level rise of 6 to 9 m above present associated with significantly reduced ice sheets (Dutton et al, 2015). As such, it has been used as a potential analogue for future climate models (Masson-Delmotte et al, 2013;Hansen et al, 2020). Prolonged anomalies of the ITCZ position have long-term effects on the climatic conditions in the tropics, which have been linked with changes in sea surface temperature (SST) and salinity (SSS), Atlantic Meridional Overturning Circulation (AMOC) and ice sheets extent (Peterson & Haug, 2006;Gibson & Peterson, 2014;Hoffman et al, 2017;Zhuravleva & Bauch, 2018).…”

“…Finally, sandy storm deposits are systematically thinning landward with slopes ranging from 1°to 5°whereas 'chevrons', like parabolic dunes, are thickening as they progress inland ( Figs 5 and 6) with the highest elevation lying near the ridge apex (Hearty et al, 1998;Hearty & Tormey, 2017;Vimpere et al, 2019). Hearty et al (1998Hearty et al ( , 2002, Hansen et al (2016Hansen et al ( , 2020, Hearty & Tormey (2017) and Tormey (1999) excluded an aeolian origin for the 'chevrons' because of the scarcity of steeply dipping foresets in these landforms. However, as emphasized by Goudie (2011), high-angle strata are relatively rare among the foreset beds of aeolian parabolic dunes.…”

“…Up to now called 'chevrons', the peculiar V-shaped and U-shaped oolitic ridges of Late Pleistocene age exposed on several Bahamian islands have drawn the attention of numerous researchers for almost two decades (Hearty et al, 1998(Hearty et al, , 2002(Hearty et al, , 2015Tormey, 1999;Kindler & Strasser, 2000Bourgeois & Weiss, 2009;Hansen et al, 2013Hansen et al, , 2020Engel et al, 2015;Tormey et al, 2016Tormey et al, , 2018Rovere et al, 2017Rovere et al, , 2018Hearty & Tormey, 2017, 2018aMylroie, 2018a,b;Vimpere et al, 2019). However, despite the numerous studies pertaining to these landforms, both their formation mechanism and their climatic significance remain uncertain and controversial.…”