The Last Frontier Places First in the U.S. Warming Derby
Anders Carlson in Alaska. Photo courtesy of Anders Carlson
Thoughts of Alaska bring to my mind massive glaciers (the largest glaciers outside of the continental ice sheets), endless frozen ground to the horizon (called permafrost), towering mountains (the highest relief of any mountain on the planet), so much snow and avalanches, dark spruce forests, never-ending days in the boreal summer sun and never-ending winter nights lit by the aurora borealis, lazy brown bears, mad moose cows with their quirky calves, clumsy caribou, cold streams choked with salmon, coastal waters teaming with food, huckleberries, and more lazy brown bears (haven’t seen a polar bear in Alaska, yet…). You know, the last frontier. Oh, I forgot mosquitos. Can’t leave those out, which go with the permafrost that makes wetlands in the summer months as the upper frozen layer seasonally melts (called the “active layer”).
What you don’t see in my icy memories and cold impressions is another of Alaska’s superlatives:
the fastest warming state in the nation.[1] Since 1950, Alaska has warmed at about 0.6°F per decade while the lower 48 warmed at around 0.33°F per decade. For comparison, the globe has warmed at about 0.27°F per decade over the same time period. At a more granular level, Alaska’s mountains are some of the fastest warming mountain ranges on the planet at rates of 0.7-1.0°F per decade.[2] While it seems counterintuitive that the U.S.’s coldest state is warming the fastest, this is actually expected due to feedback processes collectively called arctic amplification[3] (a similar process also applies to mountains, called alpine amplification[4]). Namely, all that snow and then frozen surrounding ocean (sea ice) is highly reflective and reflects much of the Sun’s radiation. However, with a little warming, a little snow/sea-ice loss is replaced by darker, radiation-absorbing ground/open water. This warmer land/water releases its absorbed heat, warming the surroundings, driving more snow/ice melting, and we are off to the races with Alaska in the lead.
Hubbard Glacier, Alaska, USA. Photo by Peter Hansen
Kind of in opposition to Bob Dylan’s “when you ain’t got nothing, you got nothing to lose,”
Alaska’s got much and much to lose. And it is losing it right now due to this warming mainly caused by the use of fossil fuels. The biggest loss that Alaska has experienced, so far, is from Columbia Glacier in Prince William Sound (see Figure). From 1980 up to now, this glacier collapsed[5], constituting the largest contribution to sea-level rise of any ice body outside of the Greenland and Antarctic ice sheets.[6] In 2017, colleagues and I were able to show that this collapse was unprecedented in more than 900 years and was triggered by climate warming due to human greenhouse gas emissions.[7] In the 21stcentury, Alaska is still the largest contributor to sea-level rise outside of the continental ice sheets, constituting 25% of global glacier mass loss from 2000 to 2019.[8] Again, this glacier mass loss is all due to human caused global warming[9] mainly from using fossil fuels. Indeed, even at the Paris Agreement 1.5°C level of global warming, half of Alaska’s glacier mass is projected to disappear this century.[10]
Figure. Columbia Glacier location and collapse.[11] (A) Location of Prince William Sound. (B) Location of Columbia Glacier (CG) in the Sound. (C) Ice-margin retreat history of Columbia Glacier where white lines are margins in a given year (1980 up to 2012) while red dots are tree ring ages on prior ice advance (1010 up to 1808). Note the 5 km (3.1 miles) scale bar to give context to how much this glacier retreated in >32 years.
Human-caused global warming is also driving melting and loss of Alaska’s permafrost[12], the permanently frozen ground that underlies about 85% of the state[13]. A quarter of a century ago, I personally experienced what such thawing feels like when I fell into a mud volcano, or pingo, that was beginning to slowly melt due to warming.
Global warming can still be icy cold!
Across the state around the latitude of Fairbanks, the permafrost is melting so much it is forming permanent areas of unfrozen ground, called taliks, with this projected to cover 70% of the region by 2030.[14]Indeed, summer temperatures around this latitude in Alaska and the Yukon are now unprecedented in more than 13,600 years.[15] Permafrost melting also weakens Alaskan shorelines, making them erode faster[16] and causing whole villages to face relocation[17].
In addition, Alaska has more than 1000 contaminated industrial sites within its permafrost region that risk having their toxic substances mobilized and released as permafrost thaws.[18] In an act of revenge, frozen debris lobes (permafrost that flows downhill like a very slow dirt glacier) are moving faster as their ice warms and melts, threatening the Dalton Highway[19] that resupplies oil extraction on the North Slope (they’ve already moved the road once[20]) and the Alaska Pipeline that itself is a cause of the warming! On top of that, melting permafrost releases carbon that had been sequestered for millennia, driving further global warming[21]. This means we need to cool the climate from today’s level to avoid triggering a climate tipping point of more rapid global warming.[22]
Permafrost melting in the summer of 1999. Photo courtesy of Anders Carlson
The warming climate is also expanding Alaska’s boreal forest where spruce trees are now invading the tundra.[23]Trees are darker than the tundra, absorbing more solar radiation and causing more warming[24] in another amplifying feedback. Likewise, fires are increasing in Alaska’s forests since the 1980s.[25] Now, you could think that these fires are the forests own fault as these are called “drunken forests” due to the trees tipping every-which-way in response to freeze-thaw melting of the active permafrost layer (this is a seasonal cycle, with nothing to do with human-caused climate change). But these trees are sober and it’s the fossil fuel industry’s fault. Between 1979 and 2019, the Alaskan fire season increased in length by about 70% while the number of days with extreme fire weather (hot, dry, windy) rose by about 60%.[26] As another global warming feedback, these fires release carbon into the atmosphere[27] with 2021 having an unprecedented fire summer where North American and Eurasian forests both had a water deficit leading to unprecedented burning and carbon release[28]. In addition to emitting carbon dioxide, these fires release fine particulates that are highly harmful to youth.[29] Just stay indoors, right (ignoring how this violates these youths’ rights)? Wrong.
In adjacent British Columbia, air quality detectors found that within 60 minutes about 90% of the outside fine particulates penetrated to inside childcare facilities during periods of fire smoke.[30] And the exposure of children to fire smoke lowers their test scores![31] In the current climate, interior Alaska already experiences high-levels of fire particulate exposure well above World Health Organization guidelines.[32] Folks, we can’t simply “suck it up” and close the windows and lock the doors on this one, because sucking it up will cause all sorts of health problems including death.
Lastly, this warming is impacting Alaskan wildlife, particularly fisheries.[33] Chinook and Chum salmon populations in the Yukon River plummeted to nearly zero in 2020 and 2021, forcing closure of the fishery.[34] This crash in salmon populations has been linked to both warming ocean water in the Bering Sea and warmer water in the Yukon River.[35]Prior to this fishery failure, we had the Blob in the Northeast Pacific, the largest marine heatwave ever recorded on the planet that lasted from 2013 to 2016[36]. The Blob fundamentally altered marine ecosystems[37] and led to widespread salmon loss and massive die-offs of seabirds, seals and sea lions due to lack of food[38]. Then another Blob hit in 2019-2021.[39] These marine heatwaves in the Northeast Pacific are almost entirely (>99%) due to human greenhouse gas emissions[40]; that is, they would not occur in the absence of our fossil fuel emissions. If we reach the Paris Agreement level of 1.5°C of global warming, these marine heatwaves will have a reoccurrence interval of about 10 years versus the current roughly 40 years (it’s just random chance that two occurred back-to-back recently = gamblers roll back-to-back snake eyes sometimes).[41]
I know that what I’ve just laid out is mind-numbingly depressing and demoralizing. We can, and should, be full of rage in how we got here. But as any good therapist will tell you, that rage and five bucks will only buy you a cup of coffee. Any result requires action; even winning the lottery requires buying the ticket. So, take a deep breath and relax. I find it far more helpful (and hopeful) to ask the question of what type of world do we want and then work for it. If you want a world that aligns with my Alaskan memories, then I’ve got good news! We already know how to get there!
The solution is mind-boggling simple.
One: stop using fossil fuels, period, full stop. This will take a little time, like a decade or two, but the good news is we can meet all our energy needs from non-emitting clean and renewable sources.[42] No magical thinking required. Two: when we quit emitting carbon dioxide from fossil fuels, then we quit saturating the Earth’s traditional carbon dioxide sinks of oceans, trees, plants, bogs, soils, and chemical weathering of silica-rich rocks (the ultimate sink). Once not soaked in our yearly new emissions, then these sinks can start to address our past emissions with the best climate models that include a carbon cycle simulating falls in atmospheric carbon dioxide of 75 to 115 ppm in a century.[43] Upon our ceasing of carbon dioxide emissions, the warming stops[44] and the planet begins to experience cooling within decades due to declining atmospheric carbon dioxide concentrations[45]. The real question then is just how much more warming do we allow before we start the solution.
[1] All rates of warming are taken from U.S. NOAA Climate at a Glance: https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/.
[2] Wei-Ping Chan et al., Climate Velocities and Species Tracking in Global Mountain Regions, 629 Nature 114 (2024).
[3] https://climate.nasa.gov/news/927/arctic-amplification/.
[4] Mountain Research Initiative EDW Working Group, Elevation-Dependent Warming in Mountain Regions of the World, 5 Nature Climate Change 424 (2015).
[5] R. W. McNabb, R. Hock, Alaska Tidewater Glacier Terminus Positions, 1948-2012, 119 J. Geophysical Rsch. 2013JF002915 (2014).
[6] E. Berthier et al., Contribution of Alaskan Glaciers to Sea-Level Rise Derived from Satellite Imagery, 3 Nature Geoscience 92 (2010).
[7] Anders E. Carlson et al., Recent Retreat of Columbia Glacier, Alaska: Millennial Context, 45 Geology 547 (2017).
[8] Romain Hugonnet et al., Accelerated Global Glacier Mass Loss in the Early Twenty-First Century, 592 Nature 726 (2021).
[9] Ben Marzeion et al., Attribution of Global Glacier Mass Loss to Anthropogenic and Natural Causes, 345 Science 919 (2014); Gerard H. Roe et al., On the Attribution of Industrial-Era Glacier Mass Loss to Anthropogenic Climate Change, 15 Cryosphere 1889 (2021).
[10] David R. Rounce et al., Global Glacier Change in the 21st Century: Every Increase in Temperature Matters, 379 Science 78 (2023).
[11] Anders E. Carlson et al., Recent Retreat of Columbia Glacier, Alaska: Millennial Context, 45 Geology 547 (2017).
[12] Sharon L. Smith et al., The Changing Thermal State of Permafrost, 3 Nature Reviews Earth Env’t 10 (2022).
[13] https://www.adfg.alaska.gov/index.cfm?adfg=ecosystems.permafrost.
[14] Louise M. Farquharson et al., Sub-Aerial Talik Formation Observed Across the Discontinuous Permafrost Zone of Alaska, 15 Nature Geoscience 475 (2022).
[15] Trevor J. Porter et al., Recent Summer Warming in Northwestern Canada Exceeds the Holocene Thermal Maximum, 10 Nature Communications 1631 (2019).
[16] David Marcolino Nielsen et al., Increase in Arctic Coastal Erosion and Its Sensitivity to Warming in the Twenty-First Century, 12 Nature Climate Change 263 (2022).
[17] https://toolkit.climate.gov/case-studies/relocating-kivalina.
[18] Moritz Langer et al., Thawing Permafrost Poses Environmental Threat to Thousands of Sites with Legacy Industrial Contamination, 14 Nature Communications 1721 (2023).
[19] Margaret M. Darrow et al., Frozen Debris Lobe Morphology and Movement: An Overview of Eight Dynamic Features, Southern Brooks Range, Alaska, 10 Cryosphere 977 (2016).
[20] https://www.adn.com/alaska-news/science/2018/09/06/state-reroutes-dalton-highway-to-protect-motorists-from-migrating-blob/.
[21] E. A. G. Schuur et al., Climate Change and the Permafrost Carbon Feedback, 520 Nature 171 (2015).
[22] David I. Armstrong McKay et al., Exceeding 1.5°C Global Warming Could Trigger Multiple Climate Tipping Points, 377 Science eabn7950 (2022).
[23] Roman J. Dial et al., Sufficient Conditions for Rapid Range Expansion of a Boreal Conifer, 608 Nature 546 (2022).
[24] Natalia Hasler et al., Accounting for Albedo Change to Identify Climate-Positive Tree Cover Restoration, 15 Nature Communications 2275 (2024).
[25] M. Roxana Sierra-Hernández et al., Increased Fire Activity in Alaska Since the 1980s: Evidence from an Ice Core-Derived Black Carbon Record, 127 J. Geophysical Rsch. 2021JD035668 (2022).
[26] Matthew W. Jones et al., Global and Regional Trends and Drivers of Fire Under Climate Change, 60 Reviews Geophysics e2020RG000726 (2022).
[27] Carly A. Phillips et al., Escalating Carbon Emissions from North American Boreal Forest Wildfires and the Climate Mitigation Potential of Fire Management, 8 Science Advances eabl7161 (2022).
[28] Bo Zheng et al., Record-High CO2 Emissions from Boreal Fires in 2021, 379 Science 912 (2023).
[29] https://www.epa.gov/system/files/documents/2023-04/CLiME_Final%20Report.pdf.
[30] Michael Joseph Lee et al., Using Low-Cost Air Quality Sensors to Estimate Wildfire Smoke Infiltration into Childcare Facilities in British Columbia, Canada, 2 Env’t Rsch. Health 025002 (2024).
[31] Jeff Wen, Marshall Burke, Lower Test Scores from Wildfire Smoke Exposure, 5 Nature Sustainability 947 (2022).
[32] Seung Hyun Lucia Woo et al., Air Pollution from Wildfires and Human Health Vulnerability in Alaskan Communities Under Climate Change, 15 Env’t Rsch. Letters 094019 (2020).
[33] https://nca2023.globalchange.gov/downloads/NCA5_Ch29_Alaska.pdf.
[34] https://climateadaptation.ucdavis.edu/dwindling-salmon-populations-yukon.
[35] https://uaf-iarc.org/wp-content/uploads/2022/06/Bering-Science_spring-2022_WEB.pdf; Vanessa R. von Biela et al., Premature Mortality Observations Among Alaska’s Pacific Salmon during Record Heat and Drought in 2019, 47 Fisheries Magazine 157 (2022).
[36] Charlotte Laufkötter et al., High-Impact Marine Heatwaves Attributable to Human-Induced Global Warming, 369 Science 1621 (2020).
[37] Dylan G. E. Gomes et al., Marine Heatwaves Disrupt Ecosystem Structure and Function Via Altered Food Webs and Energy Flux, 15 Nature Communications 1988 (2024).
[38] Letícia M. Cavole et al., Biological Impacts of the 2013-2015 Warm-Water Anomaly in the Northeast Pacific, 29 Oceanography 273 (2016).
[39] Armineh Barkhordarian et al., Recent Marine Heatwaves in the North Pacific Warm Pool Can Be Attributed to Rising Atmospheric Levels of Greenhouse Gases, 3 Communications Earth Env’t 131 (2022).
[40] Charlotte Laufkötter et al., High-Impact Marine Heatwaves Attributable to Human-Induced Global Warming, 369 Science 1621 (2020); Armineh Barkhordarian et al., Recent Marine Heatwaves in the North Pacific Warm Pool Can Be Attributed to Rising Atmospheric Levels of Greenhouse Gases, 3 Communications Earth Env’t 131 (2022).
[41] Charlotte Laufkötter et al., High-Impact Marine Heatwaves Attributable to Human-Induced Global Warming, 369 Science 1621 (2020).
[42] James H. Williams et al., Carbon-Neutral Pathways for the United States, 2 AGU Advances e2020AV000284 (2021); Christian Breyer et al., On the History and Future of 100% Renewable Energy Systems Research, 10 IEEE Access 78176 (2022); Mark Z. Jacobson et al., Low-Cost Solutions to Global Warming, Air Pollution, and Energy Insecurity for 145 Countries, Mark Z. Jacobson et al., Zero Air Pollution and Zero Carbon from All Energy at Low Cost and Without Blackouts in Variable Weather Throughout the U.S. with 100% Wind-Water-Solar and Storage, 184 Renewable Energy 430 (2022).
[43] Andrew H. MacDougall et al., Is There Warming in the Pipeline? A Multi-Model Analysis of the Zero Emissions Commitment from CO2, 17 Biogeosciences 2987 (2020).
[44] Sofia Palazzo Corner et al., The Zero Emissions Commitment and Climate Stabilization, 1 Frontiers Science 1170744 (2023).
[45] Alex Borowiak et al., Projected Global Temperature Changes After Net Zero Are Small but Significant, 51 Geophysical Rsch. Letters e2024GL108654 (2024).