Follow the wind. Plants' records from the past show the true story of global temperatures, according to research by a climate scientist at Washington University.
According to new model simulations published in Science Advances, warmer temperatures brought plants and then came even warmer temperatures.
Alexander Thompson updated simulations from an important climate model to reflect the role of changing vegetation as a key driver of global temperatures over the last 10,000 years.
Thompson was troubled by a problem with models of Earth's atmospheric temperatures. Over time, many of the simulations showed temperatures warming.
Climate proxy records tell a different story. There was a marked peak in global temperatures between 6,000 and 9000 years ago.
Thompson thought the models could be overlooking the role of changes in vegetation in favor of impacts from atmospheric carbon dioxide concentrations or ice cover.
Pollen records suggest a large expansion of vegetation.
He said that previous models only showed a limited amount of vegetation growth.
The changes to vegetative cover were significant.
The Sahara Desert in Africa was more of a grassland in the early days of the geological epoch. The coniferous and deciduous forests in the mid-latitudes and theArctic thrived.
The Community Earth System Model (CESM), one of the best-regarded models in a wide-ranging class of such models, was the subject of a set of experiments designed by Thompson. He ran simulations to account for changes in vegetation that had not been considered before.
Thompson said that expanded vegetation warmed the globe by as much as 1.5 degrees. It is exciting that we can point to Northern Hemisphere vegetation as a potential factor that could allow us to resolve the controversial temperature dilemma.
Understanding the scale and timing of temperature change is important because it is a period of recent history. The rise of human agriculture and civilization occurred during this time, so many scientists and historians are interested in understanding how early and mid-Holocene climate differed from the present day.
Thompson was a graduate student at the University of Michigan. He is working in the laboratory of a climate scientist.
Thompson said that the study emphasizes that accounting for vegetation change is critical.
More information: Alexander J. Thompson, Northern Hemisphere vegetation change drives a Holocene thermal maximum, Science Advances (2022). DOI: 10.1126/sciadv.abj6535. www.science.org/doi/10.1126/sciadv.abj6535 Journal information: Science Advances Citation: Changes in vegetation shaped global temperatures over last 10,000 years (2022, April 15) retrieved 15 April 2022 from https://phys.org/news/2022-04-vegetation-global-temperatures-years.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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