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Climate in Context: Volcanoes and Climate Change; Assessing Arctic Marine Ecosystems

Arctic Marine Impacts Still Largely Unexplored

Map of the Arctic showing the locations where footprints of climate change impacts on marine biota have been reported. The Arctic shelves and the mean minimum extent of ice (1979–2000) are indicated.
The colors identify the reported organisms: Green: plankton; Red: benthos; Blue: fish; White: birds; Black: mammals.
Credit: Global Change Biology.

The Arctic is often pinpointed as one of the regions most vulnerable to climate change, and the steadily decreasing level of Arctic sea ice cover is one of the hallmarks of a warming planet. However, while researchers know a great deal about the shrinking sea ice extent and thickness, there are few reports of how Arctic marine ecosystems have changed in recent years.

In order to assess how climate change has affected the marine fauna of the Arctic, where warming is two or three times that of the average global rate, a group of researchers has, for the first time, compiled all the known studies of the biological footprint of climate change (you can think of this as the “amount of impact”) on Arctic marine ecology. In doing so, they have uncovered some surprising trends (and some not-so-surprising ones, too). Their synthesis is currently available online in advance of press in Global Change Biology.

Firstly, the research team found that the number of studies on marine biology and ecology in the Arctic is dwarfed by the number of similar studies in Antarctica (though research in both areas has been increasing since the mid-1990s). Furthermore, when you look at a map of the locations where biological impact studies in the Arctic have taken place, it's clear there are large areas where climate change impacts are undocumented. Along most of the northern Russian coastline, much of the northern Canadian coastline and throughout all of the Central Arctic Ocean, there have not yet been any published studies of how Arctic marine ecosystems are being affected by climate change, the researchers found.

In terms of what is currently known about how Arctic marine ecosystems have been affected by climate change, the current report shows, unsurprisingly, that the changes to ice cover and ocean water circulation have caused some marine species to migrate northward in search of cooler waters. In some cases, animal populations are decreasing, as is the case with Arctic seals and snow crab, and in other cases, the migration of predators out of their habitat has boosted populations, which was observed with cod and pollock.

Despite the fact that there is already clear evidence that Arctic marine ecosystems are changing as the region rapidly warms up, the authors of the paper suggest their main takeaway message is that much more research is needed to better gauge the fate of Arctic marine species.

Volcanic Climate Impact is Seasonally-Dependent

Researchers have long known that large volcanoes can have an impact on global climate. For example Mount Pinatubo, which erupted in the Philippines in 1991, is responsible for bringing the following year’s global average surface temperatures down by about one degree Celsius. In fact, as we mentioned earlier this week, the ability of volcanic ash clouds to block out sunlight and cool the planet has inspired researchers to think of ways to simulate this in order to reduce global warming from greenhouse gas emissions. Though the exact characteristics of a climate-altering volcano are not yet well understood, researchers are actively exploring what it takes for an eruption to have a global impact. 

In one recent study, Rutgers University atmospheric scientists Ben Kravitz and Alan Robock analyzed how the seasonal timing of some volcanic eruptions influences how much effect there is on planetary temperatures. Simulating volcanic eruptions above 50 degrees latitude (north of the Canadian-U.S. border and central Europe) Kravitz and Robock found that large volcanoes erupting during the summer months could have a noticeable effect on the global climate. On the other hand, their research found that eruptions during the winter are less likely to have any noticeable impact because the reflective aerosols from the volcano tend to fall out of the atmosphere more readily and because there are fewer hours of sunlight in those regions during the winter months. Their findings are published in a new paper available online from the Journal of Geophysical Research-Atmospheres

And by the way, in case you’re wondering about recent volcanoes, the eruption of Mt. Eyjafjallajökull last spring in Iceland is not expected to cool global temperatures much. Despite the fact that it spewed out enough smoke and ash to ground European planes for weeks, it didn’t generate enough debris to change the climate by any measurable amount. 

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