Satellite observations show global plant growth is not keeping up with CO2 emissions

December 7, 2015, University of Minnesota
Ball-and-stick model of carbon dioxide. Credit: Wikipedia

Because plants need carbon dioxide to grow, scientists have expected rising atmospheric CO2 to substantially enhance plant growth, offsetting a portion of human CO2 emissions and, in turn, slowing climate change. However, new research from the Institute on the Environment published today in Nature Climate Change adds to a growing body of research challenging this expectation.

The study, led by William Kolby Smith, a Luc Hoffman Institute postdoctoral fellow working with IonE's Global Landscapes Initiative and the Natural Capital Project, found that global plant growth has indeed increased over the past 30 years, but not as much as expected given the change in atmospheric CO2 concentrations. Comparing their findings with results of widely used on-the-ground measurements and the best available models of plant responses to increasing CO2, Smith and colleagues concluded that current model estimates of plants' ability to offset growing may be unrealistically optimistic.

"Current Earth system models assume that global plant growth will provide the tremendous benefit of offsetting a significant portion of humanity's CO2 emissions, thus buying us much needed time to curb emissions," says Smith. "Unfortunately, our observation-based estimates of global vegetation growth indicate that plant growth may not buy us as much time as expected, [so] action to curb emissions is all the more urgent."

The authors identify two important factors that could be driving the divergence between satellite-based results and model-based results: availability of water and availability of nutrients. Satellite data indicate that warmer climate conditions resulting from rising atmospheric CO2 may be increasing plant water stress, counteracting any positive effect of CO2. Additionally, limited availability of nitrogen and phosphorus in the environment could also limit the ability of plants to soak up additional CO2 (see also previous work co-authored by Smith).

These findings indicate that current climate models do not accurately predict future plant growth and suggest that allowable emissions targets based on these models may need reevaluation. The authors recommend better integration among model, satellite and on-the-ground measurement approaches to improve our understanding of the effects of rising atmospheric CO2 on .

The work provides an important step forward in the understanding of how plants may respond (or not respond) to rising atmospheric CO2, as well as highlights ways scientists from different specialties can work together to reach a deeper understanding of how ecosystems will respond to global change, says Sasha Reed, a U.S. Geological Survey scientist and co-author of the paper. "We have many scientific tools in our toolbox, and bringing them together is a powerful approach to asking questions and to solving problems."

Explore further: Soil nutrients may limit ability of plants to slow climate change

More information: Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization, DOI: 10.1038/nclimate2879

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cjones1
not rated yet Dec 07, 2015
Time to plant more Tulip poplars. I understand they utilize CO2 at a higher rate than other trees.
antigoracle
1.6 / 5 (13) Dec 07, 2015
So, nature defies the delusional world of the AGW Cult and their failed computer models and what a surprise, their conclusion is their computer models are still right.
jeffensley
1.7 / 5 (11) Dec 07, 2015
Current Earth system models assume that global plant growth will provide the tremendous benefit of offsetting a significant portion of humanity's CO2 emissions, thus buying us much needed time to curb emissions," says Smith. "Unfortunately, our observation-based estimates of global vegetation growth indicate that plant growth may not buy us as much time as expected, [so] action to curb emissions is all the more urgent.


Again, scientists undercut themselves by politicizing their research. This attitude just feeds skepticism. Funny that you never hear mention of plants taking up a lot of extra CO2 in the mainstream until a study comes out and suggests it may not be happening as quickly as they thought.
my2cts
4.3 / 5 (11) Dec 07, 2015
So, nature defies the delusional world of the AGW Cult and their failed computer models and what a surprise, their conclusion is their computer models are still right.

You are one mixed up boy/girl.
leetennant
4.6 / 5 (9) Dec 07, 2015
It's a problem with a news site reporting science, even a science news site like this.

"Because plants need carbon dioxide to grow, scientists have expected rising atmospheric CO2 to substantially enhance plant growth, offsetting a portion of human CO2 emissions..."

Ahh, no, they didn't. They knew plants would take in CO2 but didn't know the extent of CO2 and heat tolerances. The MEDIA and denier sites said that "CO2 was plant food" and so there was nothing to worry about because they'd "offset human emissions". Not scientists.

In fact, those of us who actually read the science have been trying to get people to stop the stupid "CO2 is plant food" movement because initial research was that plants had upper limits of absorption. We just weren't sure what they were so of course the models were using proxies.

But I guess "study supports need to adjust assumptions of plants' CO2 absorption" is not as sexy I guess.
my2cts
4.5 / 5 (8) Dec 07, 2015
So Freeman Dyson is wrong with his "CO2 is good".
Smart people tend to occasionally underestimate their fallibility.
leetennant
4.5 / 5 (8) Dec 07, 2015
If I never hear the name 'Freeman Dyson' again it will be too soon
howhot2
5 / 5 (4) Dec 09, 2015
The dumbass @antigoracle says;
nature defies the delusional world of the AGW Cult and their failed computer models
Typical rightwing fruitcake can't get the truth straight! So here is what the headline says
observations show global plant growth is not keeping up with CO2

That's all you need to know you BS rightwing fruity wingnut @antigoracle. How much do you want to bet that he goes all Trump on us.

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