What is CRAICC?
The on-going Arctic climate change and cryosphere are interlinked via the following five components (see figure below): A) Radiative forcing, B) Arctic warming, C) Changes in the cryosphere, D) Society and human activities, E) Feedbacks in the climate system. Traditionally, the enhanced warming of Arctic areas, as compared with the Earth as a whole, has been explained by the so-called ice-albedo feedback, which involves the loop A -> B -> C -> A (loop 1).
In CRAICC, we will expand the above thinking to include the roles of society and associated human activities (component D), as well as feedbacks other than the traditional ice-albedo feedback (component E). Related to the component D, two potential feedback loops with different starting points can be identified. First, future reductions in ice and snow cover affect human activities and concomitant emissions in the North through changes in cargo ship traffic, travel and tourism industry, oil exploration and production, fishing and agriculture. This can be described with the loop C -> D -> A -> B -> C (loop 2). Second, the society has a potential to influence Arctic warming via either targeted emission control actions or geoengineering, both corresponding to the loop D -> A -> B -> (C) -> D (loop 3). The Arctic climate system itself involves a number of yet poorly-understood feedback processes initiated by changes in i) the heat balance over surface, ii) moisture budget, or iii) natural emissions of aerosols and their precursors, and formation of secondary aerosols including also ozone which is a potent greenhouse gas. Collectively, these feedbacks can be described with the loop A -> B -> (C) -> E -> A (loop 4).
Our main aim is to quantify the feedback loops 1-4, and especially to address how the loops 2-4 compare with the loop 1 in their potential magnitude. We will focus our attention on the role played by short-lived pollutants (recently also called short-lived climate forcers) and clouds and their linkages with cryospheric changes because i) their role in Arctic warming is potentially very large, yet poorly quantified, ii) their emissions are expected to be changed considerably as a result of future warming and associated changes in human activities, and iii) they might provide an additional mitigation pathway for future Arctic warming