2.4. Understanding Arctic Change and Projection of Future States of the Arctic System

A rapid shift in Arctic and alpine plant community distribution, composition and structure is likely as species respond to climate change. In northern alpine tundra ecosystems, like those found in the southwest Yukon, Canada, these movements may have significant impacts on biodiversity, habitat quality and structure as suitable areas diminish in size at higher elevations. We used bioclimatic envelope models to generate current day vegetation-climate relationships.

The freshwater (FW) export variability from the Arctic Ocean is a topic of great interest, as changes in the Arctic FW export have the potential to affect the deep water formation in the North Atlantic. For the 21st century, climate models predict an intensification of the hydrological cycle and a disappearance of the perennial sea-ice cover. Due to the associated freshening of the upper ocean and the phase shift from solid to liquid FW storage in the Arctic, model simulations consistently show an increase in the liquid FW export from the Arctic Ocean.

Changing climate in the Arctic is expected to have significant effects on the pattern and distribution of terrestrial vegetation. Species characteristic of specific zones in the mountains of northern Sweden have been shown to migrate up and downslope with changes in climate over the Holocene. This study evaluates the potential for Scots pine (Pinus sylvestris) to become a treeline dominant at Fennoscandian treelines replacing mountain birch (Betula pubescens ssp. czeropanovii).

Climate projections for the 21st century indicate that there could be a pronounced warming and degradation of permafrost in the arctic and sub-arctic regions. Climate warming is likely to cause permafrost thawing with subsequent effects on surface albedo, soil organic matter degradation, hydrology and greenhouse gas emissions. In order to assess possible changes in the permafrost thermal state and the active layer thickness, the GIPL2-MPI parallel transient model was implemented for the entire Alaskan permafrost domain.

The Gulf of Finland is the most pollute part of the Baltic Sea. Intense human activities are influence on ecosystem of the Gulf of Finland. One of the hot spots of the Gulf of Finland is the Luga Bay. For example, on terminals of the Luga Bay, we can study the impact of harbor installations on the ecosystem of the Gulf of Finland. Infrastructure of the Luga Bay is composed of various harbor installations. There are multi-terminal, plants infrastructure and "New Harbour-Streams".

Are glaciers responding to anthropogenic climate change (temperature and/or precipitation), natural climate variation, or other forcings? Commonly, it is all of the above. Little doubt the total Earth record of glacier changes points to recent anthropogenic climate changes as the major source of glacier area and length shrinkage. In Alaska, a host of variable phenomena is at work.

We invert the image of retreating Arctic sea-ice, and focus on the expanding area of the Seasonal Ice Zone (SIZ): that region that is ice-covered in winter, but exposed to the atmosphere and full sun in the summer. Before about 2004, this region was mostly restricted to the continental shelves. Recently, however, it has grown to include much of the deep Canada Basin, creating a new biome: the deepwater SIZ.

The arctic is a highly sensitive region to be profoundly affected by global warming and would likely experience greater warming than the rest of the world. One immediate consequence of climate change in the Arctic would likely be the widespread permafrost degradation and thus a strong increase in methane emission (via thermokarst lakes and /or wetland expansion).

The arctic climate is modulated by atmospheric aerosols that affect the surface-atmosphere radiation balance through interactions with solar and terrestrial radiation. During April 2009, the Pan-Arctic Measurements and Arctic Regional Climate Model Inter-comparison Project was conducted by Alfred Wegener Institute of Germany, utilizing their research aircraft, Polar-5. Characterizing aerosols was one objective of the campaign. Sun photometric procedures were adopted to quantify aerosol optical depth AOD along the flight track.

Scenarios are valuable tools for decisionmakers. The prediction of the future development of most real systems is inherently complex and usually inaccurate. Scenarios allow us to develop and bring into focus several images of future developments. These images can help decisionmakers to plan for a range of futures. Scenarios can also be a useful tool in identifying early indicators as to what the actual future development will be.