Forests under (mega)fire in the Pacific Northwest

Accompaniment to the Third Pod from the Sun Episode

Featured Image: “Forests under fire” original artwork by Jace Steiner. Used with permission.

Paper: Cascadia Burning: The historic, but not historically unprecedented, 2020 wildfires in the Pacific Northwest, USA

Authors: Matthew Reilly, Aaron Zuspan, Joshua Halofsky, Crystal Raymond, Andy McEvoy, Alex Dye, Daniel Donato, John Kim, Brian Potter, Nathan Walker, Raymond Davis, Christopher Dunn, David Bell, Matthew Gregory, James Johnston, Brian Harvey, Jessica Halofsky, Becky Kerns

The natural legacy of fire in the Pacific Northwest (PNW) is complex.  The variable geography of the wet, westside temperate rain forests, to the dry, high elevation forests beyond the Cascade crest make it difficult to find a “catch-all” description of PNW forest fires.  For instance, drier forests of ponderosa pines in eastern Washington experience more frequent, low-severity fires while the temperate rain forests of western Oregon rarely see fires.  However, scientists can reconstruct historical fire regimes and identify centuries-long patterns of burning related to precipitation, temperature, and ignition frequency to define what are historical patterns and what is modern climate change.  In 2020, multiple megafires (a wildfire that burnt more than 100,000 acres of land) broke out in the typically wet parts of Oregon and Washington, burning more than 700,000 acres combined.  This event is called the 2020 Labor Day Fires, and Matthew Reilly and colleagues have revealed these fires were likely part of historical regimes and not a product of accelerated climate change.

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How Machine Learning Helps in the Fight Against Climate Change

Featured Image: Machine Learning has proven itself to be an effective tool in interdisciplinary research, but how can it be useful in understanding climate change? CC BY-NC 4.0, via. Dean Long

Paper: Tackling Climate Change with Machine Learning (Chapter 8)

Authors: David Rolnick et al.

Machine Learning (ML) gives researchers extremely valuable ways of revealing patterns within enormous datasets, and making predictions. Climate change research is one of many fields that is beginning to explore ML approaches. There are three major areas of interest: (1) climate prediction/modeling, (2) assessing impacts, and (3) exploring solutions as we attempt to decarbonize energy production. Rolnick and his coworkers explored the merit of machine learning in climate research and where it can support scientists best. The authors also call for greater collaboration between researchers of different backgrounds to advance our understanding of such a complex issue.

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Greenhouse gasses, ice cover, and the deep ocean shape Earth’s paleoclimate in unexpected ways

Featured Image: Line-scan image of sediment core from the Bay of Bengal. Image from the International Ocean Discovery Program. A. Volcanic ash associated with the Toba eruption. B. Pyrite-, foraminifer-, and shell fragment–rich sandy patch in foraminifer-rich clay with biosilica. C. Scaphopod in nannofossil-rich clay with foraminifers. D. Wood fragments in clay. E. Large dark gray burrow filled with the overlying sediment. F. Core disturbance (cracks) due to gas release when core liner was drilled on the catwalk. G. Minor core disturbance due to mud and water flow-in along the edges of the liner (~1 cm thickness).

Paper: Increased interglacial atmospheric CO2 levels followed the mid-Pleistocene Transition

Authors: Masanobu Yamamoto, Steven C. Clemens, Osamu Seki, Yuko Tsuchiya, Yongsong Huang, Ryouta O’ishi, Ayako Abe-Ouchi

Mention of the ice age may conjure up images of giant mastodons, ferocious saber-tooth tigers, or of a prehistoric squirrel trying so desperately to secure his acorn—all taking place on the vast amount of ice that covered portions of the globe. We know that periods of ice cover followed by stretches of warm weather was a standard pattern in our Earth’s history*, but there was something special about the last ice age (during the Pleistocene) and how long it hung around. 

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How to connect methane in atmosphere to a planets geology and biology

Featuring image: Titan’s atmosphere is rich in organic molecules, but we still don’t know if there is life on Saturn’s icy moon. With JWST and the coming generation of telescopes, we will be able to observe the atmospheres of exoplanets. Is there a way to search for life on these distant worlds? NASA/JPL, public domain (CC0).

Paper: The case and context for atmospheric methane as an exoplanet biosignature

Authors: M. A. Thompson, J. Krissansen-Totton, N. Wogan, M. Telus and J. J. Fortney

Visiting and exploring exoplanets for extraterrestrial life still belong to the realm of science fiction. However, the coming generation of telescopes will enable us to look into the atmospheres of exoplanets and search for possible biosignatures, chemical compounds that could indicate the presence of life.

Searching for life on a planet is not a trivial task. Since the first Mars landing in 1976, scientists still search for recent or ancient traces of life. It becomes even more difficult on planets that we cannot directly visit. The next telescope generation will enable us to observe the atmosphere of distant planets remotely. Are there ways to find evidence of life in a planet’s atmosphere? A new study suggests that the freshly launched James Webb Space Telescope (JWST) could help us to search for life on other worlds.

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The surprising effects rivers have on our atmosphere

Featured Image: Rio Bermejo meeting up with the Paraguay River, on the boarder of Formosa and Chaco Provinces.  Image by Mapio. Used with permision.

Paper: Fluvial organic carbon cycling regulated by sediment transit time and mineral protection

Authors: Marisa Repasch, Joel S. Scheingross, Niels Hovius, Maarten Lupker, Hella Wittmann, Negar Haghipour, Darren R. Gröcke, Oscar Orfeo, Timothy I. Eglinton, and Dirk Sachse

In our current era of rapid climate change, it is critical we understand how every aspect of the Earth system affects carbon cycling.  New work by Marisa Repasch and colleagues shows that rivers, under the right conditions, might be able to sequester more carbon in the sediments than released into the atmosphere. However, these findings may reveal how human impacts to rivers will likely increase the amount of carbon released to the atmosphere.

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Metal-Eating Microbes Who Breathe Methane

Featured Image: Murky pond in Alaska with “rusty” iron-filled sediments. Image courtesy Jessica Buser. Used with permission.

Paper:  Sulfate- and iron-dependent anaerobic methane oxidation occurring side-by-side in freshwater lake sediment

Authors: Alina Mostovaya, Michael Wind-Hansen, Paul Rousteau, Laura A. Bristow, Bo Thamdrup

The table has been set and the food is all prepared. But this is no ordinary dinner party, it’s a microbe party! The guests sit down and proceed to dig into the main course; sulfur, rusty iron, and methane. Curiously, the guests are feeding each other, not themselves! This image seems pretty weird to us humans, but it’s a delight to these microbes. This collaborative method of eating occurs in pond and lake mud all around the world. In a new study, Mostovaya and colleagues describe one such feast in Danish Lake Ørn, that is not only collaborative but may mitigate climate change.

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How did giant impacts influence our atmosphere?

Featuring image: Oxygen was not always present in Earth’s atmosphere, but stated to accumulate only around 3.5 billion years ago. Pixabay, Public Domain (CC0)

Paper: Delayed and variable late Archaean atmospheric oxidation due to high collision rates on Earth

Authors: S. Marchi, N. Drabon, T. Schulz, L. Schaefer, D. Nesvorny, W. F. Bottke, C. Koeberl and T. Lyons

Take a deep breath. Your lungs fill with air and vital oxygen. Not only you, but all higher life depends on oxygen. In the Archean aeon, which lasted from 4 to 2.5 billion years before present, Earth’s atmosphere contained no oxygen. How did oxygen accumulate in the atmosphere? A team of researchers discovered that the evolution of our atmosphere was strongly influenced by impacts of large meteorites when our planet was still young.

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The Charney Report vs IPCC6: What’s changed in climate science in the last 40 years?

NASA satellite image of Earth from space, showing California wildfire smoke visible in the atmosphere.

Papers: Carbon Dioxide and Climate, a Scientific Assessment by Charney et. al (1979);
Climate Change 2021: The Physical Science Basis by the IPCC (2021)

Right now in Glasgow, Scotland, representatives of world governments and other parties are currently gathering yet again to negotiate political solutions to climate change at COP26. This is the 26th semi-annual Conference of the Parties on climate change, but the history of our understanding of the problem — and attempts to deal with it — goes back even further than that. Speaking strictly of the science of global warming and its effects, what do we know now that the participants of the first COP did not?

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Ancient trees tell the story of modern climate change

Featured Image: Larch trees.  Image courtesy North Cascades National Park, used with permission.

Paper: Spring arctic oscillation as a trigger of summer drought in Siberian subarctic over the past 1494 years

Authors: Olga V. Churakova Sidorova, Rolf T. W. Siegwolf, Marina V. Fonti, Eugene A. Vaganov, Matthias Saurer

Seemingly straight out of a fairytale, ancient trees are able to convey details about Earth’s complex history to the scientists willing and able to listen.  Deep in the Siberian Arctic lie the secrets of past weather events, ocean currents, and droughts that occurred thousands of years ago, locked away in petrified wood and in the oldest living larch trees.  We often hear in the news how the Siberian forest is victim to extreme drought and fire—something that is new as of the recent century.  But how “new” are these events, and what exactly is perpetuating this new cycle? 

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How does smoke from wildfires in the western U.S. change the regional climate?

Feature image from Pixabay

Article: Biomass Burning Smoke and Its Influence on Clouds Over the Western U. S.

Authors: C. H. Twohy, D. W. Toohey, E. J. T. Levin, P. J. DeMott, B. Rainwater, … & E. V. Fischer

The area burned by wildfires has been increasing in the western U.S. in recent years and is expected to continue to increase due to climate change. In fact, a large wildfire is currently burning in Sequoia National Park in California, threatening to impact some of the largest and oldest living trees in the world. While wildfires directly impact people, wildlife, and the environment in many ways, a lesser-known impact, involving clouds, can influence the regional weather and climate.

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