Image: MONDOLITHIC STUDIOS
In Brief
- Researchers are altering temperature, carbon dioxide and precipitation levels across plots of forests, grasses and crops to see how plant life responds.
- Warmer temperatures and higher CO2 concentrations generally result in more leaf growth or crop yield, but these factors can also raise insect infestation and weaken plants’ ability to ward off pests and disease.
- Future field experiments that can manipulate all three conditions at once will lead to better models of how long-term climate changes will affect ecosystems worldwide.
Thirty years ago Charles F. Baes, Jr., a chemist at the U.S. Department of Energy’s Oak Ridge National Laboratory, wrote that the earth was undergoing a great “uncontrolled experiment,” one that would soon reveal the global consequences of rising greenhouse gas concentrations. Today scientists know that deforestation, land use and the burning of fossil fuels are warming our planet. We are less certain, however, about how climate change will alter forests and grasslands, as well as the goods and services these ecosystems provide society.
Much of the climate change news in the mass media comes not from experiments but observations. Scientists monitor Arctic sea ice, glaciers and natural events such as the timing of leaf appearance and inform the public when changes fall outside normal expectations. Recording this kind of information over time is important. But rather than waiting to see how an evolving climate slowly alters the biosphere, climate change biologists are conducting field experiments, often at large scales, to see how ecosystems will respond to more or less precipitation, rising concentrations of carbon dioxide (CO2) and warming temperatures. Experimental data are key to determining if and to what extent ecosystems will be affected by climate change in 10, 50 or 100 years and how those changes might feed back to further advance change. The results can help separate fact from fiction in the climate debate, which is charged with emotion.
This article was originally published with the title Climate Change: A Controlled Experiment.
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15 Comments
Add CommentThe money quote : "Future field experiments that can manipulate ALL three conditions at once will lead to better models of how long-term-climate changes will affect ec0-systems worldwide."
Reply | Report Abuse | Link to thisHow can scientists "know" that deforestation, land use, etc. are warming are planet? With all the missing data and the placement of temperature recorders near airports, among other sites, how can you prove it?
Over 32,000 scientists who've signed the petition (www.petitionproject.org) don't agree with you!
Your article is non-science and a serious disappointment.
We are currently running an experiment on our planet. Sadly, it's the only lab model we have so if the results do turn out to be on the negative side, it's not like we can just set up another lab experiment and start over. And as BHG points out, there is little consensus within the scientific community as to exactly what is our influence.
Reply | Report Abuse | Link to thisThe experiment the scientist are conducting is not in a purely closed system, but hopefully it will provide some useful information.
As mentioned in the "Key Concepts" section above, higher CO2 concentration levels in the air tend to increase plant growth. But I thought the atmospheric CO2 levels were the important factor in enhancing the greenhouse effect? How would raising the concentration of CO2 for the plants test how the greenhouse gases act as a warming agent?
Reply | Report Abuse | Link to thissparcboy,
Reply | Report Abuse | Link to this"... And as BHG points out, there is little consensus within the scientific community as to exactly what is our influence ..."
That is incorrect. Not only is there a consensus, but the degree of confidence that AGW is in play is increasing.
http://news.bbc.co.uk/2/hi/science/nature/8550090.stm
"Over 32,000 scientists who've signed the petition (www.petitionproject.org) don't agree with you! "
Reply | Report Abuse | Link to thisThat list strikes me as extremely dubious, as it doesn't list which person on the list has which qualifications - and there is no easy way of finding out.
And apparently, they even let people with a _medical_ degree sign this list - and how does a medical degree qualify anyone for making such an authoritative statement on climatology?
Unless someone can come up with a similar list including only climatologists _and_ their publication lists, I am not impressed.
I signed the list, TWICE, and I am not a scientist.
Reply | Report Abuse | Link to thisSo, did anyone bother to check your qualifications during the process?
Reply | Report Abuse | Link to thisBHG: are you seriously of the opinion then that human pollution is a good thing? Or are you being paid by someone who's interested in maintaining the insane status quo that is running humanity off the cliff? You forgot to mention above what qualifies you to judge something "non-science". My guess is a TV commercial you saw over the weekend paid for by an oil company.
Reply | Report Abuse | Link to thisLast I checked, the proxy temperature data of the last few hundred years was in doubt and no one has yet established a significant connection between rising CO2 levels and warming. So how do we know that "deforestation, land use and the burning of fossil fuels are warming our planet?"
Reply | Report Abuse | Link to thisThough controlled experiments are laudable so we can separate fact from fiction, how do you control all the variables in a large-scale field experiment?
"Last I checked, the proxy temperature data of the last few hundred years was in doubt and no one has yet established a significant connection between rising CO2 levels and warming."
Reply | Report Abuse | Link to thisCould you please list your scientific sources for this? In which journals were the papers claiming this published?
We know that rising CO2 levels and deforestation cause warming because that has been observed in our climate, and is a prediction of the basic physics of interactions between photons and molecules, specifically in the infrared part of the spectrum and molecules of CO2, CH4, etc. The 32,000 scientist thing was debunked long ago, and the "putting thermometers near airports" thing proves that you have done little to no research into the subject, as that statement is a) patently false and b) straight out of Michael Crichton's book "State of Fear", which says on the inside cover to be a work of FICTION. I know this one, it was covered in my Environmental Science class: Crichton asserts that global warming is an illusion caused by the "heat island" effect, where dark surfaces such as asphalt in cities heat up the surrounding area, and that all the thermometers that are showing rising temperatures are just recording this effect. However, that is not that case, hundreds (maybe thousands) of the sensor stations are far from any cities, and even using the ones hand-picked by skeptics to be the most bias-free, the upward trend was essentially identical to the common consensus.
Reply | Report Abuse | Link to this"Today scientists know that deforestation, land use and the burning of fossil fuels are warming our planet."
Reply | Report Abuse | Link to this--------------------------------
BHG: "Over 32,000 scientists who've signed the petition"
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Typical....seems that just as soon as ANY article that has anything to do with global warming or climate change is posted here at SciAm, the religious denialists swarm like flies to dung, and post their already debunked propaganda, while taking the usual swipes at SciAm for being non-scientific!
@Jürgen, start with "Corrections to the Mann et al. (1998) Proxy Data Base and Northern Hemisphere Average Temperature Series" published in 2003 in Energy and Environment. Follow up with Steve McIntyre's careful analysis at climateaudit.org--much more careful than the original study by McMann, et. al. for which, inconveniently, the original data and methods have been lost. To date no one has been able to duplicate the "hockey stick" graph. So much for peer review.
Reply | Report Abuse | Link to thisFor more enlightenment read recent news articles in the NY Times, the Daily Mail (UK), and Wall Street Journal about Climategate. The graphs and proxy data have been questioned for well over a decade but only since the East Anglia and IPCC Himalayan Glacier scandals has the wider public begun to understand how spurious are the data and conclusions underlying the majority of claims (especially McMann et. al.) that the globe has recently warmed and its pace is unprecedented. Drafts of the original IPCC reports showed that the studies which did not show significant warming were removed from the final published reports. The IPCC is now under fire for its methods as well.
@fisixisfun, so far no one has established a significant link between rising CO2 levels and warming; except to note from ice core analysis that CO2 levels appeared to rise after the planet warmed (if the proxy data truly reflects warming), but lagged it by thousands of years. James Hansen's extrapolation of warming on Venus--with an atmosphere that is 97% CO2--to supposed warming on earth (0.0387% atmospheric CO2) has so far been unsubstantiated. The equation for determining heat build-up as CO2 saturation increases is well understood, but it is a logarithmic function, meaning it has a negligible effect; vanishingly small at 0.0387%. A change in humidity by as little as 4% has a more profound effect on warming than that suggested by the CO2 increase of the last 100 years. If you doubt this, ask yourself why CO2 saturation continues to increase but global temperatures (as measured by satellite in the last 3 decades) don't track with CO2; they fluctuate up and down.
Nobody in his right mind would play Russian Roulette. Yet that is what people are doing with Climate...
Reply | Report Abuse | Link to thishttp://templeofmut.wordpress.com/2010/08/05/scientists-challenge-the-fraud-and-emotionalism-behind-cas-captrade-rules/
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