Any Reason to Expect a Tipping Point with Arctic Sea Ice?

by Emil Morhardt

Williamson et al. (2016) examined the satellite data looking for signs of a tipping point in Arctic sea ice loss, but found none (my Jan 1 post). About the same time, Notz and Stroeve (2016) looked at the same data and did a simple linear correlation between September Arctic sea ice area and cumulative CO2 emissions since 1850. Voila! There was a strong negative linear correlation between the two showing a sustained loss of 3 ± 0.3 square meters of September sea ice area per cumulative metric ton of CO2 emission. Their title summarizes the result clearly: Observed Arctic sea-ice loss directly follows anthropogenic CO2 emission. If this linear trend continues and there is no tipping point—and there is no reason to expect one—we can make a pretty good guess about the timing of the future of Arctic sea ice to the extent we can predict CO2 emission levels. At the rate we are going, September Arctic sea ice will be completely gone before mid-century (and global average temperatures will have risen more that 1.5ºC.) Furthermore, we can now get a feeling for how much our personal use of fossil fuels and the energy derived from the directly affects Arctic sea ice; the average CO2 release from personal use is several metric tons,  Continue reading

Environment and Politics: Alaskans Adapt to a Changing Climate

by Russell Salazar

While climate change mitigation must continue, societies are marching on into an inevitably warmer world. The ability for a community to adapt to a new environment will be a crucial characteristic in the coming century. Wilson (2013) presents a study of an Alaskan village to show how political and social changes are correlated with a community’s vulnerability to the impacts of climate change. The paper focuses on the subsistence livelihoods of the Koyukon Athabascan people, describing major changes since the 1950s that altered their climate adaptability. These included an increased emphasis on formal education, a greater exposure to market economies, as well as the legislation and bureaucracy introduced by the government, all of which had a profound impact on the Koyukon Athabascan way of life. Wilson concludes by encouraging more cautious and deeper ethical considerations with regard to placing political constraints on communities. Continue reading

Climate Change and its Effect on Alaskan Inuit Populations

by Margaret Loncki

Ford et al. (2008) explore the vulnerability of two populations of Alaskan Inuits to climate change. The authors begin by explaining the cultural importance of the “procurement, sharing, and consumption” of traditional food. Global climate change plays a very important role in these Alaskan Inuit’s ability to efficiently and successfully harvests viable food sources. As a result, Climate change has the potential to bring about social, cultural, and economic change. Continue reading

Arctic Warming and the Atlantic-Pacific Fish Interchange

by Kyle Jensen

For most of the Quaternary Period the inhospitable environment north of the Arctic Circle has served as a biotic barrier between Northern portions of the Atlantic and Pacific oceans. Through it is known that interchange across the Northwest and Northeast passages has occurred, currently only 135 of over 800 fish species found above 50° of latitude are found in both oceans. Continued warming may result in the reopening of these passages resulting an accelerated interchange of species between the Atlantic and Pacific as species follow favorable conditions into higher latitudes. This may also lead to increased movement of fishing and shipping vessels through these channels, which could facilitate further interchange. This has the potential to impact the food webs and biodiversity of systems in both of these oceans, the consequences of which would affect ecosystems currently comprising 39% of global marine fish landings. To analyze potential impacts of future species interchange, Wisz et al (2015) has made forecasts of potential distributions for 515 fish species. Continue reading

Modeling CO2 and CH4 Fluxes in the Arctic using Satellite data

by Rebecca Herrera

The peatlands and tundras of the Arctic perform vital ecosystem services to the earth through their ability to sequester carbon (CO2) and methane (CH4) and function as a carbon sink. The ability of the permafrost in the peatlands and tundra ecosystems of the Arctic to continue to function as a natural reservoir for carbon and methane may be disrupted by rising global temperatures that increase the rate of soil decomposition. Watts et al. (2014) integrate a terrestrial carbon flux (TCF) model to include a newly developed CH4 emissions algorithm. The new TCF model simultaneously assesses CO2 and CH4 fluctuations and the corresponding net ecosystem carbon balance (NECB), which is contingent upon gross primary productivity (GPP) subtracted from ecosystem respiration. The integrated TCF model uses data gathered through satellite remote sensors to assess fluxes in CO2 and CH4. Continue reading

Red Fox Populations Encroach on Arctic Fox Ranges due to Warmer Temperatures

by Hilary Bruegl

In the nineteenth century Arctic tundra of Finnmark, Norway, the Arctic fox population declined to near extinction and have been recovering minimally despite strict protection. Hamel et al. (2013) investigated potential factors involved in suppressing healthy recolonization of prior territories, including encroaching red fox populations and variation in prey availability. By baiting and periodically photographing the area, the authors found red foxes to be the most important influence on the Arctic fox population in northeast Norway. Not only are red foxes more comfortable in the warming temperatures of the tundra, but there has also been a significant reduction in fox hunting, allowing the red fox population to flourish. Rodent population fluctuations were first documented alongside fox populations as a limiting factor of population growth; however, they had fewer effects than either land cover changes or red fox infiltration. Continue reading

Greenland Warming at Last Deglaciation: the Younger-Dryas Not So Cold

by Emil Morhardt

I’ve been blogging recently about papers that claim the thousand-year cessation of global warming in the midst of the last deglaciation—known as the Younger-Dryas (Y-D)—was triggered by a comet. Buizert et al.’s (2014) paper on Y-D temperature changes doesn’t address the comet question, but another equally interesting one: why did the sudden reversal of temperature 12,800 years ago (whatever it was triggered by) cause the temperature to plunge clear back to what it was before any warming had started? That’s what the relative deuterium and oxygen-18 concentrations from the Greenland Ice Sheet ice cores imply—more about that in a moment. Nevertheless, it seemed unlikely because at the time of the Y-D, a considerable amount of CO2 had accumulated in the atmosphere and Antarctica was warming apace. The answer, according to this paper is that temperatures did not cool down so much after all; things cooled off for sure, and warming was delayed for another thousand years, but at the depth of the Y-D cooling most of Greenland was on the order of 4˚C warmer than it had been 4,000–5,000 years before—but still quite cold. Continue reading