Franziska Lechleitner
Thomas Opel
Sevasti Modestou
Tobias Braun
Anton Vaks
Gideon Henderson
Pete Scott
Alexander Osintzev
Alexander Kononov
Irina Adrian
Yuri Dublyansky
Alena Maria Giesche
Sebastian F.M. Breitenbach
Stuart Umbo
2025
<p><span>The Miocene provides an excellent climatic analogue for near-future runaway anthropogenic warming, with atmospheric </span><span class="inline-formula">CO<sub>2</sub></span><span> concentrations and global average temperatures similar to those projected for the coming century under extreme-emissions scenarios. However, the magnitude of Miocene Arctic warming remains unclear due to the scarcity of reliable proxy data. Here we use stable oxygen isotope and trace element analyses, alongside clumped isotope and fluid inclusion palaeothermometry of speleothems to reconstruct palaeo-environmental conditions near the Siberian Arctic coast during the Tortonian (8.68 </span><span class="inline-formula">±</span><span> 0.09 </span><span class="inline-formula">Ma</span><span>). Stable oxygen isotope records suggest warmer-than-present temperatures. This is supported by temperature estimates based on clumped isotopes and fluid inclusions giving mean annual air temperatures between </span><span class="inline-formula">+</span><span>6.6 and </span><span class="inline-formula">+</span><span>11.1 </span><span class="inline-formula">°C</span><span>, compared with </span><span class="inline-formula">−</span><span>12.3 </span><span class="inline-formula">°C</span><span> today. Trace elements records reveal a highly seasonal hydrological environment.</span></p><p><span>Our estimate of <span class="inline-formula">></span> 18 <span class="inline-formula">°C</span> of Arctic warming supports the wider consensus of a warmer-than-present Miocene and provides a rare palaeo-analogue for future Arctic amplification under high-emissions scenarios. The reconstructed increase in mean surface temperature far exceeds temperatures projected in fully coupled global climate models, even under extreme-emissions scenarios. Given that climate models have consistently underestimated the extent of recent Arctic<span id="page1534"></span> amplification, our proxy data suggest Arctic warming may exceed current projections.</span></p><p><span><br data-mce-bogus="1"></span></p>
application/pdf
10.5194/cp-21-1533-2025
en
Copernicus Publications
Speleothem evidence for Late Miocene extreme Arctic amplification – An analogue for near-future anthropogenic climate change?
article