Subscribe free to our newsletters via your
. Earth Science News .




Subscribe free to our newsletters via your




















CLIMATE SCIENCE
What the ancient CO2 record may mean for future climate change
by Staff Writers
Davis CA (SPX) Oct 27, 2016


Scientists used fossilized plants, like this seed fern, to reconstruct the ancient atmospheric CO2 record from more than 300 million years ago. Image courtesy William DiMichele/Smithsonian Institution. For a larger version of this image please go here.

The last time Earth experienced both ice sheets and carbon dioxide levels within the range predicted for this century was a period of major sea level rise, melting ice sheets and upheaval of tropical forests.

The repeated restructuring of tropical forests at the time played a major role in driving climate cycles between cooler and warmer periods, according to a study led by the University of California, Davis and published in the journal Nature Geoscience.

Using fossilized leaves and soil-formed minerals, the international team of researchers reconstructed the ancient atmospheric carbon dioxide record from 330 to 260 million years ago, when ice last covered Earth's polar regions and large rainforests expanded throughout the tropics, leaving as their signature the world's coal resources.

The team's deep-time reconstruction reveals previously unknown fluctuations of atmospheric carbon dioxide at levels projected for the 21st century and highlights the potential impact the loss of tropical forests can have on climate.

Climate Change Feeding Off Itself
"We show that climate change not only impacts plants but that plants' responses to climate can in turn impact climate change itself, making for amplified and in many cases unpredictable outcomes," said lead author Isabel Montanez, a Chancellor's Leadership Professor with UC Davis Department of Earth and Planetary Science.

"Most of our estimates for future carbon dioxide levels and climate do not fully take into consideration the various feedbacks involving forests, so current projections likely underestimate the magnitude of carbon dioxide flux to the atmosphere."

Similarly to how oceans have served as the primary carbon sink in the recent past, tropical forests 300 million years ago stored massive amounts of carbon dioxide during these ancient glacial periods.

The study indicates that repeated shifts in tropical forests in response to climate change were enough to account for the 100 to 300 parts per million changes in carbon dioxide estimated during the climate cycles of the period.

While plant biologists have been studying how different trees and crops respond to increasing carbon dioxide levels, this study is one of the first to show that when plants change the way they function as CO2 rises or falls, it can have major impact, even to the point of extinction.

"We see great resilience in vegetation to climatic changes, millions of years of stable composition and structure despite glacial-interglacial cycles," said co-author William DiMichele, a paleobiologist with the Smithsonian Institution. "But we've come to understand that there are thresholds that, when crossed, can be accompanied by rapid and irreversible biological change."

Co-leading author Jenny McElwain, professor of paleobiology at University College in Dublin, Ireland, said the study indicates that shifts in atmospheric carbon dioxide impacted plant groups differently.

"The forest giants of the period were hit particularly hard because they were the most inefficient of all the plants around at the time, likely losing water like open hose pipes" McElwain said. "Their forest competitors, like tree ferns, were able to outcompete them as the climate dried."

Unprecedented Rise of CO2
Over the past million years, atmospheric carbon dioxide has been generally low and fluctuated predictably within a window of 200 to 300 ppm. This, the researchers explain, has sustained the current icehouse - a time marked by continental ice at the polar regions - under which humans have evolved.

This trend has been abruptly interrupted by the pronounced rise of carbon dioxide over the past 100 years to the current level of 401 ppm - one not seen on Earth for at least the past 3.5 million years.

The current unprecedented rate of rising atmospheric CO2 raises concerns about melting ice sheets, rising sea level, major climate change, and biodiversity loss - all of which were evident more than 300 million years, the only other time in Earth's history when high CO2 accompanied ice at the polar regions.

.


Related Links
University of California - Davis
Climate Science News - Modeling, Mitigation Adaptation






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
CLIMATE SCIENCE
Atom-by-atom growth chart for shells helps decode past climate
Davis CA (SPX) Oct 27, 2016
For the first time scientists can see how the shells of tiny marine organisms grow atom-by-atom, a new study reports. The advance provides new insights into the mechanisms of biomineralization and will improve our understanding of environmental change in Earth's past. Led by researchers from the University of California, Davis and the University of Washington, with key support from the U.S ... read more


CLIMATE SCIENCE
What happens when people are treated like pollution

Fire at Iraq sulphur plant out: officials

Colombia landslide kills at least six

Canada parliament votes to take in Yazidi refugees

CLIMATE SCIENCE
With new model, buildings may 'sense' internal damage

Fluorescent holography: Upending the world of biological imaging

Pushing the boundaries of magnet design

The smart wheelchair

CLIMATE SCIENCE
Species speed up adaptation to beat effects of warmer oceans

Search suspended for star Chinese sailor lost in mid-Pacific

Major environmental changes seen for Mediterranean: study

Midwater ocean creatures use nanotech camouflage

CLIMATE SCIENCE
Why does our planet experience an ice age every 100,000 years?

Arctic found to play unexpectedly large role in removing nitrogen

UCI and NASA document accelerated glacier melting in West Antarctica

Ice shelf vibrations cause unusual waves in Antarctic atmosphere

CLIMATE SCIENCE
Australia's richest woman ups bid for cattle empire

High levels of algae toxins in San Francisco Bay shellfish

How food affects political regimes

Researchers root for more cassava research

CLIMATE SCIENCE
Italy in 'miraculous' earthquake escape

Strong twin quakes rock central Italy

Enormous dome in central Andes driven by huge magma body beneath it

Japan court orders damages for pupils' tsunami deaths

CLIMATE SCIENCE
Mediator talks with Mozambique opposition leader cancelled

Shabaab takes Somali town after Ethiopia troop pullout

Arms deals with Europe, Israel fuel South Sudan war: UN

Mozambique peace talks resume after negotiator's murder

CLIMATE SCIENCE
Ancient human history more complex than previously thought

Europeans and Africans have different immune systems, and neanderthals are partly to thank

Study finds earliest evidence in fossil record for right-handedness

Extensive heat treatment in Middle Stone Age silcrete tool production in South Africa




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement