As shown later, much of the resultant risk to human populations and the ecosystems upon which they depend comes from the pro- jected extremely rapid rate of change in climatic conditions. Indeed, the prospect of such change has stimulated a great deal of new scientific research over the past decade, much of which is elucidating the complex ecological disturbances that can impact on human well-being and health—as in the following example. The US Global Change Research Program (Alaska Regional Assessment Group) recently documented how the various effects of climate change on aquatic ecosystems can interact and ripple through trophic levels in unpredictable ways. For example, warming in the Arctic.