Ecosystems on the Edge

from Lloyd’s Report 2012: Arctic Opening – Opportunity and Risk in the High North

As the prevailing environmental conditions in the Arctic change, so do the living ecosystems adapted to those particular conditions.

Some benefit from climate change: at the bottom of the marine food chain primary production by phytoplankton in the Arctic increased by 20% between 1998 and 2009 (and the increase has been as much as 70% in the Kara Sea and 135% in the Siberian sectors of the eastern Arctic Ocean)¹ . On land, the Arctic is becoming increasingly green.

Some lose: walrus and polar bear populations have tended to decline because of reductions in sea ice, while ocean acidification due to increased carbon dioxide uptake in warmer seas can harm some marine life and the fisheries associated with them² . Others adapt: some fish stocks have moved, and flourished, as a result of warmer waters. In the short term, cod stocks in the Barents Sea and off the coast of Greenland have become more productive, and have moved further north than ever.

Over time, however, the impacts of climate change – and greater economic development – are more complex than identifying winners and losers. As with sea ice, changes in ecosystems can be discontinuous and abrupt. Marine ecosystems inter-relate in previously unexpected ways. Northward-moving fish stocks inevitably alter the balance in the ecosystem into which they migrate, including outcompeting or preying upon established Arctic species³ . Some invasive species – introduced as a result of greater human activity – can destroy existing ecosystems. Though the impact of increased ocean noise from shipping on those is not clear, it is likely to have a negative impact on marine mammals that use acoustics for prey location and navigation.

At the same time, air- and sea-borne pollution from the industrialised south, such as persistent organic pollutants (POPs), can pose a serious challenge to ecosystems that, in the Arctic, tend to be relatively simple, vulnerable and difficult to re-establish. The increasing rate of disruption to Arctic ecosystems makes their future structure increasingly hard to predict. It also makes establishing environmental baseline data – against which change is measured and potential future changes are assessed – even more important.

Charles Emmerson, Glada Lahn, 2012, Ecosystems on the Edge, Lloyd’s.©