Jiggling the tropical thermostat in the Cretaceous hothouse
Abstract
Modern open-ocean sea-surface temperatures rarely exceed ∼28 29 °C, and the same has been thought to represent a rough maximum for past tropical climates. However, new isotopic estimates from the uppermost Cenomanian in the tropical western North Atlantic suggest that mixed-layer temperatures reached ∼33 34 °C (±2 °C) during the middle Cretaceous hothouse. Uppermost Cenomanian tropical sea-surface temperatures may have been as much as 4 7 °C warmer than the highest modern mean annual temperatures. Such extreme conditions suggest that warm tropical oceans could have driven substantially intensified atmospheric heat transport near the Cenomanian-Turonian boundary. The tropical “thermostat” was set higher than today, challenging the hypothesis of tropical climate stability.
- Publication:
-
Geology
- Pub Date:
- April 2002
- DOI:
- 10.1130/0091-7613(2002)030<0299:JTTTIT>2.0.CO;2
- Bibcode:
- 2002Geo....30..299N