One of the major concerns with a potential change in climate is that an increase in extreme events will occur. Results of observational studies suggest that in many areas that have been analyzed, changes in total precipitation are amplified at the tails, and changes in some temperature extremes have been observed. Model output has been analyzed that shows changes in extreme events for future climates, such as increases in extreme high temperatures, decreases in extreme low temperatures, and increases in intense precipitation events. In addition, the societal infrastructure is becoming more sensitive to weather and climate extremes, which would be exacerbated by climate change. In wild plants and animals, climate-induced extinctions, distributional and phenological changes, and species' range shifts are being documented at an increasing rate. Several apparently gradual biological changes are linked to responses to extreme weather and climate events.

1 991)] showed a large-scale antcyconc gyre In the general v c n t y of the gyre shown in F g 1 C However. Red's gyre and the one depicted n F g. 1 C have substanta dfferences In their verica structure and horizontal substructure 7. Southward flow of North Atlantic Deep Water on the eastern side of the Md-Atantc Ridge IS supported by P. M. Saunders [J. Mar. Res. 40, 641 (1982)], S. Gana and C. Provost [J. Mar. Syst. 4, 67 (1 993)], and J Pallet and H Merc~er (Deep-sea Res., Pan I, n press) 8 Topographc s depths of -1 000 m are a barrer for flow of t h s densty Into the Nordic Seas. 9. L V Worihngton, Johns Hopkins Oceanogr. Srud. 6, (1976); R. A. Clarke. H. VV. Hill, R F Re n'nger, 3 A. Warren. J. Phys. Oceanogr. 10. 25 (1 980); M S McCanney, Prog. Oceanogr. 29. 283 (1 992): VV. J. Schrntz and M. S. McCariney, Rev. Geophys, 31. 29 11993'1. 10 R S. ~l c k a r t and w M. Smethe. J Phys Oceanogr. 23. 2602 (1 993). 1 1 . J. Pallet, M. Arhan, M. S. McCariney, In preparaton. 12. P B. Rhnesand W. R. ~o a n d , ~y n :~r r n o s . Oceans 3. 289 (I 979) 13. VV, R. Holland. Geophys. Fluid Dyn. 4, 187 (1 973). 11. R. Gerdes and C. Koberle. J. Phys. Oceanogr 25, 2624 (1 995). 15, These gyres at intermedate depths are dstnct from the smaller scale gyres at abyssal depths that are more clearly assocated w~t h the basn topography. 16. P. 5 .