Rising CO2 levels likely to change vegetation locally more so than globally: study

Jun 28, 2012 by Bob Yirka report
Transitions between vegetation states projected for the period 1850-2100. Image (c) Nature (2012) doi:10.1038/nature11238

(Phys.org) -- In all the talk about global warming as a result of human created CO2 emissions, it seems other impacts of higher levels of carbon dioxide on the environment tend to get overlooked. One of those impacts, argue German researchers Steven Higgins and Simon Scheiter, who have been building models showing what impact such levels might have on vegetation, is a likely shift away from deserts and grasslands to more woody areas and forests. The two have written a paper describing their findings which has been published in the journal Nature.

Everyone that’s been to grade school knows that what we breathe out, plants breath in, and vice-versa, thus more of what we breath out, i.e. (though from another source) should mean more for plants to breathe in, which should indicate better plant growth, more plant growth, or the switch from low level breathers to those that thrive on more CO2 in the air. Higgins and Scheiter suggest at least locally, that it’s the last possibility that might create the most change over the coming decades as the Earth’s vegetation slowly responds to finding more CO2 in the air.

The two restricted their area of study to the African continent and found first that because grasses that live in the savannah tend to need less CO2 to thrive than do trees, there are large swaths of the continent that favor savannah, which is demonstrated by the abundance of with the occasional stand of trees. Adding more CO2 to the mix is likely to change that balance they show, to favor tree growth over grasses, leading to more woodland. They also found that increased CO2 levels also tend to favor grasslands over , which for Africa should mean decreasing desert sizes.

Throwing a wrench into the whole works though is water, of course, in the form of rainfall. If there is no rain, a desert will always be desert. But because of changes in topography, rainfall levels can vary dramatically over short distances leading to differences in the impact of rising CO2 levels. In areas with higher CO2 and adequate rainfall, the trend will be from savannah to , whereas in similar areas with less rainfall, tress might not be able to survive even with the addition of more CO2, thus the area would remain savannah.

This all means, the two write, that Africa is likely to see significant change over the next few decades as CO2 levels in the atmosphere continue to rise, causing significant changes to local areas of vegetation growth, depending on rainfall amounts, which will of course impact wildlife and the way the land is used by the people that live there, in ways that are impossible to predict.

Explore further: New study examines undergraduate understanding and misconceptions of climate change

More information: Atmospheric CO2 forces abrupt vegetation shifts locally, but not globally, Nature (2012) doi:10.1038/nature11238

It is possible that anthropogenic climate change will drive the Earth system into a qualitatively different state1. Although different types of uncertainty limit our capacity to assess this risk2, Earth system scientists are particularly concerned about tipping elements, large-scale components of the Earth system that can be switched into qualitatively…

Related Stories

Global warming: New study challenges carbon benchmark

Sep 28, 2011

The ability of forests, plants and soil to suck carbon dioxide (CO2) from the air has been under-estimated, according to a study on Wednesday that challenges a benchmark for calculating the greenhouse-gas ...

US rivers and streams saturated with carbon

Oct 17, 2011

Rivers and streams in the United States are releasing enough carbon into the atmosphere to fuel 3.4 million car trips to the moon, according to Yale researchers in Nature Geoscience. Their findings could ...

Araucarias gauge ancient levels of carbon dioxide

Apr 29, 2011

One way of telling how much carbon dioxide was in the atmosphere in the past is by counting pores (or stomata) in leaves – the tiny openings plants use to absorb CO2 and lose water. It may seem far-f ...

Deforestation reduces rainfall in Africa

Sep 19, 2011

Deforestation in the rainforests of West Africa reduces rainfall over the rest of the forest, according to new University of Leeds research published in Geophysical Research Letters.

Recommended for you

Should we all escape to the country during a heatwave?

15 minutes ago

A University of Birmingham research project has highlighted the potential health impacts of heatwaves in urbanised areas. By modelling the 2003 heatwave the researchers were able to identify areas where city centres were ...

NASA maps beach tar from California oil pipeline spill

1 hour ago

When an on-land pipeline ruptured north of Santa Barbara, California, on May 19—spilling 105,000 barrels of crude oil onto Refugio State Beach and about 21,000 gallons of oil into the Pacific Ocean in the ...

Not all plastics equal

2 hours ago

Ever buy a fish at a pet store that died within days of being put in an aquarium at home?

Carbon capture and storage safety investigated

2 hours ago

A significant step has been made for potential Carbon Capture and Storage (CCS) deployment, with the publication of the results from the world's first experiment into the realistic simulation of potential ...

Australia hails 'tremendous' UN barrier reef decision

6 hours ago

Australia Thursday hailed a United Nations decision to keep the Great Barrier Reef off its in danger list as "tremendous", but activists warned more must be done to improve the marine park's health.

Cities, regions, demand bigger climate say

14 hours ago

Leaders of city and regional governments gathered Wednesday in the French city of Lyon, in the grips of a western European heatwave, to demand a bigger stake in the global push to curb global warming.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.