THEME 8
Future Trends and Patterns of Change in Climate, Ozone, Ecosystems, and other Systems

The Arctic is undergoing rapid environmental, social and economic change. A changing and variable climate is perhaps the greatest “natural” stressor on Arctic ecosystems and it is in this region where abrupt changes or regime shifts might occur. Theme 9 aims to address those future trends and patterns over a range of time and space scales. Although climate and ecosystem observations and models have improved considerably in recent years there are still many uncertainties in our knowledge of ocean-ice-atmosphere and terrestrial-cryosphere-atmosphere interactions of the Arctic climate system and the associated modelling of Arctic ecosystems. Projection of future changes will be critical.

There is a need to improve our predictive capability, with due consideration of thresholds and feedbacks, of climate variability and change in order to produce improved climate change assessments on a range of time and space scales. Determination of the processes responsible for past variability and change should allow their improved representation in global and regional models. Regional climate modeling of the Arctic region would complement global NWP re-analyses and an Arctic System re-analysis would be most welcome. Diminishing sea ice, thawing permafrost, increased Arctic runoff, reduced snow cover and glaciers/ice sheets all signal change. What will happen in the future? How will stratospheric ozone and other constituents evolve in a changing climate? How will changes in stratospheric composition affect climate? What will be the impact on terrestrial and marine ecosystems?

Improved predictive capability will be essential and will benefit from circumpolar collaboration, which ICARPII can stimulate. Other planned projects will also benefit this initiative. The U.S. led initiative, SEARCH, aims to become international in scope. The World Weather Research Program is planning an international research programme, THORPEX, designed to accelerate improvements in short-range (up to 3 days), medium-range (3 to 7 days) and extended-range (week two) weather predictions. The World Climate Research Programme is planning a Climate System Observation and Prediction Experiment to improve climate predictions from weeks to centuries and on global to regional scales. The latter two international initiatives aim to provide improved information for an increasing range of practical applications of direct relevance, benefit and value to society. Both are considering the Arctic as a region where such studies could have particular benefit. Such initiatives planned for the next 10 years are key in projecting future changes in the Arctic climate and its ecosystems.