Hothouse Earth

<p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman"></font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><a href="https://mail.google.com/mail/u/0/#inbox/KtbxLxGPqcmVCfTVnCTTMZMFzGDgqrNngB?projector=1&messagePartId=0.1"><font size="4" face="Times New Roman" color="#000000">https://mail.google.com/mail/u/0/#inbox/KtbxLxGPqcmVCfTVnCTTMZMFzGDgqrNngB?projector=1&messagePartId=0.1</font></a></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman"><b>Trajectories of the Earth System in</b></font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman"><b>the Anthropocene</b></font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">Will Steffena,b,1, Johan Rockström</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">, Katherine Richardsonc</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">, Timothy M. Lentond</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">, Carl Folkea,e, Diana Livermanf</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">,</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">Colin P. Summerhayesg</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">, Anthony D. Barnoskyh</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">, Sarah E. Cornella</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">, Michel Crucifixi,j, Jonathan F. Dongesa,k,</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">Ingo Fetzera</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">, Steven J. Ladea,b, Marten Schefferl</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">, Ricarda Winkelmannk,m, and Hans Joachim Schellnhubera,k,m,1</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">Edited by William C. Clark, Harvard University, Cambridge, MA, and approved July 6, 2018 (received for review June 19, 2018)</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px;"><font size="4" face="Times New Roman" style="background-color: rgb(255, 255, 102);">We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary</font></p><p style="margin-top: 8px; margin-bottom: 8px;"><font size="4" face="Times New Roman" style="background-color: rgb(255, 255, 102);">threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and</font></p><p style="margin-top: 8px; margin-bottom: 8px;"><font size="4" face="Times New Roman"><span style="background-color: rgb(255, 255, 102);">cause continued warming on a “Hothouse Earth” pathway even as human emissions are reduced</span><span style="background-color: rgb(255, 255, 255);">. Crossing</span></font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">the threshold would lead to a much higher global average temperature than any interglacial in the past</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Col-</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">lective human action is required to steer the Earth System away from a potential threshold and stabilize it in a</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere,</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">climate, and societies—and could include decarbonization of the global economy, enhancement of biosphere</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">
</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">carbon sinks, behavioral changes, technological innovations, new governance arrangements, and trans-</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman">formed social values....</font></p><p style="margin-top: 8px; margin-bottom: 8px; background-color: rgb(255, 255, 255);"><font size="4" face="Times New Roman"></font></p>