Unaccounted feedbacks from climate-induced ecosystem changes may increase future climate warming

In addition to the carbon cycle-climate interactions that have been a major focus of modeling work in recent years, other biogeochemistry feedbacks could be at least equally important for future climate change. The authors of the Nature Geoscience article argue that it is important to include these feedbacks in the next generation of Earth system models.

The terrestrial biosphere regulates atmospheric composition, and hence climate. Projections of future climate changes already account for "carbon-climate feedbacks", which means that more CO2 is released from soils in a warming climate than is taken up by plants due to . Climate changes will also lead to increases in the emission of CO2 and methane from wetlands, nitrous oxides from soils, from forests, and trace gases and from fires. All these emissions affect , including the amount of ozone in the lower atmosphere, where it acts as a powerful as well as a pollutant toxic to people and plants.

Although our understanding of other feedbacks associated with climate-induced ecosystem changes is improving, the impact of these changes is not yet accounted for in modelling. An international consortium of scientists, led by Almut Arneth from Lund University, has estimated the importance of these unaccounted "biogeochemical feedbacks" in an article that appears as Advance Online Publication on Nature Geoscience's website on 25 July at 1800 London time. They estimate a total additional radiative forcing by the end of the 21st century that is large enough to offset a significant proportion of the cooling due to carbon uptake by the biosphere as a result of fertilization of .

There are large uncertainties associated in these feedbacks, especially in how changes in one biogeochemical cycle will affect the other cycles, for example how changes in nitrogen cycling will affect carbon uptake. Nevertheless, as the authors point out, palaeo-environmental records show that ecosystems and trace gas emissions have responded to past climate change within decades. Contemporary observations also show that ecosystem processes respond rapidly to changes in climate and the atmospheric environment.

Thus, in addition to the carbon cycle-climate interactions that have been a major focus of modelling work in recent years, other biogeochemistry feedbacks could be at least equally important for future climate change. The authors of the Nature Geoscience article argue that it is important to include these feedbacks in the next generation of Earth system models.


Explore further

Stabilizing climate change more daunting than thought

Provided by University of Helsinki
Citation: Unaccounted feedbacks from climate-induced ecosystem changes may increase future climate warming (2010, July 25) retrieved 14 May 2021 from https://phys.org/news/2010-07-unaccounted-feedbacks-climate-induced-ecosystem-future.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.
0 shares

Feedback to editors

User comments