climate change – Geobites

October 16, 2020October 16, 2020

What’s in the Water?

Paper: Contemporary limnology of the rapidly changing glacierized
watershed of the world’s largest
High Arctic lake

Authors: K. A. St. Pierre, V. L. St. Louis, I. Lehnherr, S. L. Schiff, D. C. G. Muir , A. J. Poulain, J. P. Smol, C. Talbot, M. Ma, D. L. Findlay, W. J. Findlay, S. E . Arnott, Alex S . Gardner

As glaciers recede in the arctic, the increase in meltwater may significantly impact downstream ecosystems. Glacial ice can hold thousands of years’ worth of dust, nutrients, and other materials that are released during melting. As the rate of melt increases with a warming climate, the release has the potential to increase nutrient flows and sediment loads, alter pH, and impact other physical, chemical, and biological aspects of downstream watersheds. These changes could negatively impact water clarity and ecosystem function in lakes, rivers, and the ocean.

October 6, 2020October 6, 2020

Strong Atmospheric Updrafts Increase the Danger Associated with Wildfires

Featured Image: Picture of a wildfire by skeeze on Pixabay

Paper: Extreme Pyroconvective Updrafts During a Megafire
Authors: B. Rodriguez, N. P. Lareau, D. E. Kingsmill, and C. B. Clements

Atmospheric updrafts, or columns of air moving quickly upward, are typically associated with severe thunderstorms and tornadoes and have been studied using radar and airplane data for decades. The extreme heat from large, intense fires can also cause updrafts, but this type of updraft has barely been studied by atmospheric science researchers. Understanding the formation and structure of fire-generated updrafts is important because they can be hazardous to aircraft, can loft embers far distances and spark new fires, and can even initiate fire-generated thunderstorms. A recent study has revealed just how powerful these updrafts above large fires can be.

September 2, 2020September 4, 2020

Warmer climate could mean corals thrive in the southern Great Barrier Reef

Featured image: Jeremy Bishop on Pexels

Paper: Re-evaluating mid-Holocene reef “turn-off” on the inshore Southern Great Barrier Reef
Authors: Leonard, N.D., Lepore, M.L., Zhao, J.X., Rodriguez-Ramirez, A., Butler, I.R., Clark, T.R., Roff, G., McCook, L., Nguyen, A.D., Feng, Y. and Pandolfi, J.M.

A new study has reconstructed the complex growth history of coral communities in the Keppel Islands, southern Great Barrier Reef, revealing that the area might provide a safe-haven for coral under climate change.

August 18, 2020August 18, 2020

North Atlantic Ice Melt May Increase the Storminess of the Northern Hemisphere

Featured image of sea ice from Free-Photos on Pixabay

Paper: Rapid Cooling and Increased Storminess Triggered by Freshwater in the North Atlantic
Authors: M. Oltmanns, J. Karstensen, G. W. K. Moore, and S. A. Josey

Way up north in the Arctic Circle, sea ice and glaciers are rapidly melting and sending a massive amount of cold, fresh water into the North Atlantic Ocean. At first this influx of cold water may seem beneficial to offset the warming from climate change, but new research suggests that this meltwater from Greenland and the Arctic increases the number of winter storms that occur in the Northern Hemisphere.

July 23, 2020July 23, 2020

Cave formations show link between ice ages and the tilt of Earth’s axis

Paper: Persistent influence of obliquity on ice age terminations since the Middle Pleistocene transition

Featured image: Stalagmites captured by mareke on Pixabay

Authors: Petra Bajo, Russell N. Drysdale, Jon D. Woodhead, John C. Hellstrom, David Hodell, Patrizia Ferretti, Antje H.L. Voelker, Giovanni Zanchetta, Teresa Rodrigues, Eric Wolff, Jonathan Tyler, Silvia Frisia, Christoph Spötl, Anthony E. Fallick

Our planet has been circling and spinning in a wobbly dance around the Sun for billions of years. The exact motions of this dance- governed by Earth’s near-circular orbit (eccentricity), the tilt of its axis, and the orientation of the tilted axis in space (precession) fluctuate predictably. Variations in this planetary dance have changed the amount and distribution of sunlight reaching Earth’s surface through time, and have determined when the planet experienced long periods of cold temperatures and growth of massive ice caps on the continents (ice ages). However, scientists have not been so sure about which planetary motion is the most important for the timing of ice ages. New research uses climate information stored in caves to precisely link these motions to ice ages, showing that axis tilt may be the most important position in the dance when it comes to pulling Earth’s climate out of those frigid times.

July 21, 2020July 21, 2020

We’re Not in Kansas Anymore: Documenting Historical Tornadoes in Northern Eurasia

Feature image: “Tornado Alley” by Nikolas Noonan on unsplash.com (https://unsplash.com/photos/n_3kdpSkrJo)

Paper: Tornadoes in Northern Eurasia: From the Middle Age to the Information Era
Authors: A. Chernokulsky, M. Kurgansky, I. Mokhov, A. Shikhov, I. Azhigov, E. Selezneva, D. Zakharchenko, B. Antonescu, and T. Kühne

When most people are asked to picture a tornado in their mind, they probably imagine the violent column of swirling wind and debris tearing through an open field in rural Kansas, as depicted in the classic 1939 film The Wizard of Oz. However, while the United States Midwest, so-called “Tornado Alley”, is the most well-known tornado hot-spot in the world, tornadoes touch down on every continent except Antarctica. A recent study by Chernokulsky and his team has established a comprehensive history of tornadoes that have occurred in an area commonly neglected in tornado research: northern Eurasia.

July 17, 2020July 17, 2020

Great Success with Mixed Perennial Grasses for Bioenergy Crops

Paper: Climate Benefits of Increasing Plant Diversity in Perennial Bioenergy Crops
Authors: Yi Yang, Evelyn C. Reilly, Jacob M. Jungers, Jihui Chen, Timothy M. Smith

An Advanced Bioenergy plant.
*Source: Ammodramus / CC BY-SA via Wikimedia Commons.*

Climate change, primarily caused by fossil-fuel-based CO₂ emissions, could trigger disastrous consequences, including extreme weather and mass species extinctions. Bioenergy (a renewable energy derived from plants) can reduce greenhouse gas emissions by replacing fossil fuel with biomass. Atmospheric carbon is consumed via photosynthesis by bioenergy crops, such as wood, grain crops, and perennial grasses. Perennial grasses are good candidates for bioenergy crops because they can be directly combusted or converted to ethanol.

July 17, 2020July 17, 2020

Thickets and patches: woody plants are changing water availability in dry landscapes

Featured Image: Sparse woody plant encroachment, known as xerification, occurs here in the Chihuahuan Desert north of Coyame, in Chihuahua, Mexico. Source: Ricraider / CC BY-SA via Wikimedia Commons.

Paper: Woody Plant Encroachment has a Larger Impact than Climate Change on Dryland Water Budgets

Authors: A.P. Schreiner-McGraw, E.R. Vivoni, H. Ajami, O.E. Sala, H.L. Throop, and D.P.C. Peters

Almost half of the land on Earth is arid, with little precipitation. Arid lands are home to roughly 20% of the world’s human population, and to much of the world’s livestock as well. Arid lands are changing rapidly, both with respect to land cover and water availability. While the effects of climate change on arid places have attracted a lot of attention, the encroachment of woody plants into grasslands is also rapidly transforming arid landscapes. New research shows that the effects of woody plant encroachment are even more important than climate change for the water budget of arid ecosystems.

June 3, 2020June 4, 2020

Humans most likely drove Madagascar’s megafaunal extinction

Featured image: Deforestation in Madagascar, image credit: Gregoire Dubois, CC BY-NC-SA 2.0, on Flickr.

Paper: Relationships between climate change, human environmental impact, and megafaunal extinction inferred from a 4000-year multi-proxy record from a stalagmite from northwestern Madagascar
Authors: L. B. Railsback, L. A. Dupont, F. Liang, G. A. Brook, D. A. Burney, H. Cheng., and R. L. Edwards

Madagascar is so large and ecologically unique that it has been dubbed a continent in its own right. It wasn’t occupied by humans until 3,000 years ago and the island’s megafauna died out comparatively recently. Just 1000 years ago sloth lemurs the size of pandas, 10-foot tall elephant birds, and a puma-like predator called the giant fossa roamed the island.

May 30, 2020May 30, 2020

Climate records written on the seafloor

Featured image: A perspective view of the seafloor at the East Pacific Rise, 9N. Made with GeoMapApp (www.geomapapp.org, CC-BY), and GMRT topography data (Ryan et al. 2009, CC-BY).

Paper: Do sea level variations influence mid-ocean ridge magma supply? A test using crustal thickness and bathymetry data from the East Pacific Rise
Authors: B. Boulahanis, S. M. Carbotte, P. J. Huybers, M. R. Nedimovic, O. Aghaei, J. P. Canales, and C. H. Langmuir

Many of our records of past sea level come from local measurements from coastal towns logged over decades or centuries, or are estimated from ice or sediment cores spanning the last few thousand years, but new research suggests that much longer records can be found in an unlikely place: imprinted deep underground in the oceanic crust.