Extreme Temperature Diary- Sunday November 27th, 2022/ Main Topic: Getting to the Root of Another Carbon Problem

The main purpose of this ongoing blog will be to track planetary extreme, or record temperatures related to climate change. Any reports I see of recently reported ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉

Main Topic: Getting to the Root of Another Carbon Problem

Dear Diary. Today’s main subject is a brand-new item never addressed on this blog. Think about this. Plant roots hold a lot of carbon. When land is cleared to grow crops, roots from crops are mostly not as lengthy as those from undisturbed native fauna. Therefore, statistically root systems are getting shorter, holding less carbon. In our transition towards a more sustainable world, farming practices should take this into account.

Here are more details using a short article from Eos:

The World’s Roots Are Getting Shallower – Eos

The World’s Roots Are Getting Shallower

Root-filled soils are hot spots of nutrient cycling and carbon storage. New research finds that the world has lost millions of cubic meters of rooted soil volume—and we’re on track to lose much more.

By Rebecca Dzombak 17 November 2022

Row crops typically have shorter roots than the native plants they replace, such as prairie grasses like the switchgrass shown here, which stretches 4.25 meters in length. As agricultural areas expand globally, millions of cubic meters of rooted soil critical for carbon and water storage, nutrient cycling, and soil formation are being lost, according to a new study. Credit: Steve Renich/Wikimedia CommonsCC BY 3.0

Source: Earth’s Future

Plant roots act as engineers for Earth’s surface, breaking up bedrock, transporting water and nutrients, and stabilizing landscapes. They’re so important that scientists have hypothesized that their evolution, beginning around 415 million years ago, altered landscapes and the course of Earth’s history.

Today the world’s roots are getting shallower on average, a new study finds. Shallower roots mean there’s less rooted soil, which could lead to decreased carbon storage, less efficient nutrient cycling, and less fertile soils.

Hauser et al. provide the first estimate of global changes in the volume of rooted soil resulting from human-driven land use. They examined changes in many types of environments but focused on the balance between two in particular: agricultural land, where row crop roots are shallower than those of native grasses, and forests, where woody plant roots typically reach deep into the soil. Agricultural land is expanding greatly as a direct result of human efforts. Meanwhile, forests are expanding in some places, especially in high-latitude boreal environments, as atmospheric carbon dioxide levels and associated warming increase.

The researchers used root depth data from two newly updated ecological databases, along with knowledge of past and present land cover types, to calculate average rooting depths for different ecosystems globally in the past, present, and future.

They found that rooting depths—considered the depth above which 99% of an ecosystem’s root biomass exists—are about 8 centimeters (or 5% of soil depth) shallower on average than they would be without human alteration. That loss equates to roughly 11.6 million cubic meters of rooted soil. The study predicts, on the basis of Intergovernmental Panel on Climate Change projections of continuing land use change under a high-emissions scenario, that the volume of loss could be as high as 43.5 million cubic meters of rooted soil by 2100, with a global shallowing of about 30 centimeters. Shrublands in North Africa, the Middle East, Asia, and Australia are likely to experience the most shallowing as they transition to herbaceous grasslands or agricultural and pastoral areas.

“The volume loss is especially striking to me,” said Emma Hauser, who led the study. “That represents a lot of belowground space that is no longer performing the same kind of carbon and water storage processes as it was previously.”

There are “myriad feasible consequences” of shallower global rooting depths, the authors write, including slower or less soil formation and decreased nutrient availability. Understanding the extent of potential impacts, they say, will require further study. (Earth’s Futurehttps://doi.org/10.1029/2022EF002897, 2022)

—Rebecca Dzombak, Science Writer

Citation: Dzombak, R. (2022), The world’s roots are getting shallower, Eos, 103, https://doi.org/10.1029/2022EO220534. Published on 17 November 2022.

Here are some “ET’s” recorded from around the planet the last couple of days, their consequences, and some extreme temperature outlooks:

Here is more climate and weather news from Sunday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)

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Guy Walton… “The Climate Guy”

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