History I 15
Understanding climate change Meet the scientists looking backward to help predict the future
In 2020, the analysis of the North Pacific core samples is finally reaching completion in the form of a detailed string of scientific papers. Dr. Alan C. Mix, a climate and ocean researcher at Oregon State University and member of the expedition team, explains, “Each paper builds on the previous one, such that the puzzle picture is starting to emerge, and it appears to be pretty important as one of the ‘missing links’ in global climate evolution.” PHOTO BY SHUTTERSTOCK
One of the first pieces of the puzzle was published in 2015 by Dr. Summer n 2014,a former the United Nations Praetorius, student of Mix. on TheIntergovernmental paper made headlinesPanel announcing Climate Change, the world’s a link between abrupt ocean warming leading expansive voice on the oxygen-deficient matter, released and its latest coined assessment delivering regions, “deadreport, zones” because stunning of the potential of their predictions inhospitableness to life. consequences of human-driven Praetorius postulated that hotterclimate water, changecannot in the 21st Atdissolved the same which holdcentury. as much time thatas the U.N. water, panel accelerates in Geneva oxygen cooler prepared theprocesses report for release, by an the chemical undertaken international team of climate and small marine lifeforms, like plankton. ocean processes scientists further left portremove — headed for These oxygen Alaska. hoped to uncoveritone of from theThey water by packaging with the greatest missing pieces in organic material, creating a scientists’ runaway understanding past climate change: feedback loop inofwhich a small amount what hadwarming happened the North of ocean inin a region canPacific cause after depletion the last iceofage from 9,000 adirectly significant oxygen. The
I
“
It appears to be pretty important as one of the ‘missing links’ in global climate evolution.”
to 19,000 years The expedition paper warns thatago. ocean temperatures lasted two months, which in this century are likely during to increase at a the team traveled to five sites toindrill rate beyond anything measured the sediment which act asfor geological past, and cores, the consequences marine timeas capsules, storing information life, well as human fisheries, could in catastrophic. their chemical make-up. Climate be expert and Northeastern professor Dr. Daniel Douglass elaborates, Another former student of Mix,“The Dr. transitionDu, oututilized of the last ice age is a Jianghui the expedition’s goodtochance to study data add another piecehow to thechanges puzzle occur.” Furthermore, comparing these in a 2018 paper, linking the release of results against climate models, carbon dioxidecurrent into the atmosphere Douglass says, “isofthe best way to find to the strength ocean circulation. and correct any mistakes that may Through computer modeling and exist in the Du models and gives usocean more simulation, determined that confidence in the their currents pulled fromaccuracy a massiveofcarbon predictions going sitting forward.” dioxide reservoir at the bottom of the Pacific and circulated it to the
surface, releasing the carbon dioxide into the atmosphere. The model also In 2020,melting the analysis the as North showed glacier of water the Pacificculprit core samples is finally reaching likely of increased circulation, completioninin the of a detailed resulting yet form another climate string of scientific papers. Dr. Alan C. feedback loop where melting glaciers Mix,to a aclimate ocean dioxide researcher at lead releaseand of carbon from Oregon State University the ocean, further warmingand the member planet. of the expedition team explains, “Each paper builds on the previous one, such Since the expedition in 2013, an that the puzzle startingthe to astounding 500 picture papers is detailing emerge, and it past appears be pretty mechanics of the NorthtoPacific have important as one of the ‘missing links’ been published based on the expedition’s in global climate evolution.” data. Nearly a decade of work has culminated in two groundbreaking One ofrecently the firstpublished pieces ofbythe papers thepuzzle team, was published in 2015 by Summer finally piecing together the Dr. story of the Praetorius, a They former student that of Mix. North Pacific. determined the The paper made headlines melting of the Cordilleran Iceannouncing Sheet over a link between ocean warming western Canada abrupt and Alaska had caused and expansive oxygen-deficient multiple feedback loops in the Pacific regions,triggering coined “dead zones” because Ocean, a global climate shift. of their to life. The meltinginhospitableness had created a cascading Praetorius postulated that hottermarine water, climate effect that devastated which cannot hold the as much dissolved ecosystems through creation of dead oxygen warmed as cooler accelerates zones, the water, Antarctic region, the chemicaltoprocesses undertaken by contributed the melting of eastern small American marine lifeforms, like plankton. North ice sheets, and led to a These processes further remove carbon. oxygen global increase of atmospheric frompapers the water by packaging with The solidified the North itPacific organic material, creating runaway as a key player in both past aand future feedback loop events. in which a small amount global climate of ocean warming in a region can cause a significant of oxygen. The The insight depletion these findings provide papermodern warns that ocean temperatures into anthropogenic climate in this century are likely to increase at a change is indispensable. Discussing rate beyond anything measured in the this significance, Mix says, “The past, and the consequences for marine projected scales of [human-driven] life, as well as human fisheries,are could change, estimated by models, far be catastrophic. beyond the range of changes observed in our history... and we now know that Another student involved of Mix, Dr. the Pacificformer is intimately in Jianghui Du, changes.” utilized the rapid global Asexpedition’s the planet data to add piece to the continues to another warm, Mix hopes to puzzle return in a 2018 paper, linking the release of to the North Pacific to study the marine carbon dioxide atmosphere geologic record into fromthe periods even to the strength of we’re oceanheaded. circulation. warmer than where DESIGN BY KATIE GREEN, BIOENGINEERING, 2022
Science (2020). DOI: 10.1126/science.aba7096 Deep Sea Research (2020). DOI: 10.1016/j.dsr.2020.103341
I
n 2014, the United Nations Intergovernmental Panel on Climate Change, the world’s leading voice on the matter, released its latest assessment report, delivering stunning predictions of the potential consequences of human-driven climate change in the 21st century. At the same time that the U.N. panel in Geneva prepared the report for release, an international team of climate and ocean scientists left port — headed for Alaska. They hoped to uncover one of the greatest missing pieces in scientists’ understanding of past climate change: what had happened in the North Pacific directly after the last ice age from 9,000 to 19,000 years ago. The expedition lasted two months, during which the team traveled to five sites to drill sediment cores, which act as geological time capsules, storing information in their chemical make-up. Climate expert and Northeastern professor Dr. Daniel Douglass elaborates, “The transition out of the last ice age is a good chance to study how changes occur.” Furthermore, comparing these results against current climate models, Douglass says, “is the best way to find and correct any mistakes that may exist in the models and gives us more confidence in the accuracy of their predictions going forward.”
Nature (2015). DOI: 10.1038/nature15753 Nature Geoscience (2018). DOI: 10.1038/s41561-018-0205-6
BY NOAH HAGGERTY, APPLIED PHYSICS, 2024
