Fourteen research teams studying the impacts of warming on the Arctic Ocean have issued independent projections of how the sea ice will behave this summer, and 11 of them foresee an ice retreat at least as extraordinary as last year’s or even more dramatic. The other three groups that issued a numerical estimate see the ice extent heading back toward, but not equaling, the average minimum for summers since satellites began tracking the comings and goings of Arctic sea ice in 1979. Five other groups chose not to issue a numerical estimate.

The ice assessments, and explanations, can be found on the Web site of the ongoing Study of Environmental Arctic Change, or SEARCH. The initiative was begun following a workshop on Arctic ice trends in March that was triggered by the “drastic and unexpected sea ice decline witnessed in 2007,” according to the report posted online.

This short animation, from NASA’s Scientific Visualization Studio, puts 2007 in perspective:

As I wrote last fall, even several experts familiar with other recent Arctic warm periods, most notably one in the early 20th century, see no evidence that ice retreated to the extent measured in the last few years. (That story and a sea-ice graphic are at nytimes.com/climate.)

There will be monthly updates through the summer, according to organizers of the effort. The scientists running the project stressed that it is not a formal forecast, but instead aimed at comparing different ways of analyzing what mix of forces — from winds and currents to any long-term contribution from human-caused global warming — is at work.

“The intent is not to issue predictions, but rather to summarize all available information from ongoing observing and modeling efforts to provide the scientific community, stakeholders, and the public the best available information on the evolution of the arctic sea ice cover,” said the coordinators in a statement. The project is being supported in part by the National Science Foundation and the National Oceanic and Atmospheric Administration.