Keiichi Nomura: Kushimoto Marine Park Center, Kushimoto, Japan.
3. Sediments suggest El Nio variability persists with warming
There has been some debate as to whether global warming could lead to a permanent El Nio state rather than a periodically varying El NioSouthern Oscillation (ENSO), which occurs now. It has also been suggested that ice-free Arctic summers could affect high-latitude and midlatitude circulation patterns and climate variability.
Now sediment records from the Arctic suggest that even as climate warms, the variability of ENSO will continue. Davies et al. analyze the first annually resolved sediment core spanning 1000 years about 70 million years ago during the Late Cretaceous.
The Cretaceous was significantly warmer than present conditions, and the Arctic Ocean was free of ice in the summer. The warmer state during the Cretaceous could be similar to what Earth might look like in the coming decades if climate continues to warm. The sediment record indicates that the ENSO oscillation did occur during that time period, adding to evidence that ENSO is a robust phenomenon likely to continue even as climate warms.
Geophysical Research Letters, doi:10.1029/2010GL046151, 2011
Title: Tropical ocean-atmosphere controls on inter-annual climate variability in the Cretaceous Arctic
Authors: Andrew Davies: National Oceanography Centre Southampton, School of Ocean and Earth Science, University of Southampton, Southampton, UK; Now at Neftex Petroleum Consultants Ltd., Abingdon, UK;
Alan E. S. Kemp and Heiko Plike: National Oceanography Centre Southampton, School of Ocean and Earth Science, University of Southampton, Southampton, UK.
4. Assessing coral reef health
|Contact: Peter Weiss|
American Geophysical Union