We have had ice roads for a long time here at the Hailuoto Island. The maintenance of the road has remained the same. But what has changed is the pattern of upkeep due to the changing road conditions because of climate change.
Jarkko Pirinen, Finnish Road Administrator, Oulu Region
Satellite pictures over the last 30 years show a significant reduction in the extent of ice coverage in the Baltic region, and on-the-spot measuring has proved that the ice is also thinner than it used to be. The season of ice cover has dropped by as much as 44 days.
In the past, the Hailuoto ice road would be open from November to mid-April or even mid-May, but in recent years it has only been approved for traffic use from mid-February and has then had to close by mid-April at the latest. Even when it is usable, it’s becoming more difficult to maintain. The ice tends to be eroded by strong winds, and snow has to be swept off more frequently.
Another consequence of the reduced ice road season is that the ferry has to operate once an hour during the rest of the winter, adding to CO2 emissions in the area. On the other hand, the Baltic Sea ice breakers used to have to start work in November, but now only need to go out in December or even January, and return earlier at the end of the season.
Less sea ice in the Baltic has led to more commercial shipping. But the milder winters do not necessarily mean that navigating is safer. Storms are more common, and the winds compress the drift ice into high blocks of hard ridged ice that constitute a hazard for ships and boats.
“We don’t have any hard winters any more in the Baltic Sea.”Jari Haapala, Senior Research Scientist, Finnish Meteorological Institute, Finland
The Baltic Sea was originally a freshwater lake until sea levels rose 8,000 years ago, allowing the North Sea to flow in. Now it’s the largest area of brackish (mixed fresh and saline) water in the world. It’s also extremely shallow, and for this reason is being affected faster by the changing climate than the deeper oceans are. In addition to the shrinking ice cover, more freshwater flows from snow, rain and sleet have been recorded in the Baltic; there has also been a decrease in salt water flowing in from the North Sea. The rising proportion of fresh water is creating an imbalance that has started to change the composition of the marine habitat. The reduction in salinity has led to fewer cod eggs surviving and a decline in the cod larvae’s staple food. If the trend continues, cod may die out altogether in the Baltic.
Scientists see the reduction in ice and the decreasing salinity as clear signs of climate change, such that the Baltic should be considered a test bed for what might happen in the Arctic in the coming decades. If the region becomes ice free in the summer, this could have significant consequences for the circulation of the atmosphere and of the ocean, and for the future of marine ecosystems.
“We don’t know what kind of climate there will be in the future, and that’s a concern for all scientists. But it should also be a concern for all politicians.” Jari Haapala