Saturday, February 2nd 2013, 2:30 PM EST
THE world’s great forests have long been recognised as the lungs of the earth, but the science establishment has been rocked by claims that trees may also be the heart of its climate. Not only do trees fix carbon and produce oxygen; a new and controversial paper says they collectively unleash forces powerful enough to drive global wind patterns and are a core feature in the circulation of the climate system.
If the theory proves correct, the peer-reviewed international paper co-authored by Australian scientist Douglas Sheil will overturn two centuries of conventional wisdom about what makes wind. And it will undermine key principles of every model on which climate predictions are based.
The paper, Where do winds come from? A new theory on how water vapour condensation influences atmospheric pressure and dynamics, is not designed to challenge the orthodox view on climate science. But Sheil, a professor of forest ecology and conservation at Southern Cross University’s School of Environment, Science and Engineering, says he is not surprised that is how the paper has been received internationally.
Boiled down, he says, bad science is protecting shoddy climate models.
The paper, lead authored by Anastasia Makarieva, sparked a long-running and furious debate about whether it should be published at all. At the end of a bruising assessment process the editorial panel of the prestigious journal Atmospheric Chemistry and Physics chose to publish and be damned.
In an accompanying statement the journal editorial board said: “The paper is highly controversial, proposing a fundamentally new view that seems to be in contradiction to common textbook knowledge. The majority of reviewers and experts in the field seem to disagree, whereas some colleagues provide support, and the handling editor (and the executive committee) are not convinced that the new view presented in the controversial paper is wrong.
“The handling editor (and the executive committee) concluded to allow final publication of the manuscript in ACP in order to facilitate further development of the presented arguments, which may lead to disproof or validation by the scientific community.”
Sheil says the key finding is that atmospheric pressure changes from moisture condensation are orders of magnitude greater than previously recognised. The paper concludes “condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics”.
“Climate scientists generally believe that they already understand the main principles determining how the world’s climate works,” says Sheil. “However, if our hypothesis is true then the way winds are driven and the way rain falls has been misunderstood. What our theory suggests is that forests are the heart of the earth, driving atmospheric pressure, pumping wind and moving rain.”
In a blistering assessment of the paper, international climate scientist Isaac Held of the National Oceanic and Atmospheric Administration recommended that publication be rejected.
“The authors make an extraordinary claim that a term that is traditionally considered to be small, to the point that it is sometimes neglected in atmospheric models and, even when not neglected, rarely commented on, is in fact dominant in driving atmospheric circulations,” Held said. “A claim of this sort naturally has to pass a high bar to be publishable, given the accumulated evidence, implicit as well as explicit, that argues against it. I am afraid that this paper does not approach the level required.
“I have done my best to keep an open mind, but do not see any cogent arguments that overturn the conventional wisdom.”
In reply, the authors claimed Held’s logic was bad for science.
“A higher bar for unconventional ideas automatically implies a lower bar for conventional ones,” they said. “Introducing a positive feedback – relating the height of the higher bar to the number of studies that have passed the lower bar – in time, if this continues, a once-vibrating scientific community can be trapped in dogma.”
Shiel says he is not surprised at the resistance from within the climate science establishment. “These guys are under a barrage of claims every day and we are just another one,” he says. “But we are serious scientists, we have serious reasons for looking at this and if you can show us where our analysis is wrong, that’s fine, that’s how science works.
“Accepting our theory would basically mean the climate models are wrong. It wouldn’t mean that theories about carbon dioxide and greenhouse gasses are wrong.
“The basic physical issues are still there. Winds are still caused to some degree by temperature differences, global warming will still be potentially caused by greenhouse gasses. But what we are saying is one of the major reasons that air moves around the surface of the globe, and one of the main reasons that rain falls where it does, is to do with these patterns of moisture evaporation and condensation.”
For Sheil, who returned last year from working at the Institute of Tropical Forest Conservation based in the Bwindi Impenetrable National Park in Uganda, the significance of the findings goes way beyond climate-change politics.
It could have dramatic consequences for how vegetation is considered and managed. And it could have ramifications for securing future rainfall for some of the world’s most impoverished regions.
“Our theory also explains how declines in both rainfall and rainfall reliability can result from forest loss elsewhere,” Sheil says. “Such patterns have been observed in various parts of the world and are clearly of major importance for many people – for example, those who are suffering from the increasingly irregular monsoon rains in West Africa.
“I would have said Australia is a desert because of the global climate cycles, but if you do the calculations, a forest across the surface of Australia would produce forces strong enough to water it and you wouldn’t need to irrigate.
“When we look at the Amazon and ask, is the forest there because there is a lot of rain, we are saying, no, it is the other way around: the rain is there because there is a lot of forest.
“It may sound strange – forests causing wind, forests causing rain – but the physics is quite convincing.”
Climate scientists, however, still say the significance is not as great as has been claimed.
“It has now gone from a discussion about mechanism to a discussion about magnitude,” Sheil says, adding that a key objective of his work is to make climate models more reliable.
“At present the models are incorrect,” he says, “because they are missing one the key mechanisms of how the global climate works. I know it does sound amazing to say this, but once you look at these models they are not as detailed and not as smart as you would think.
“A lot of it is, they are calibrated to fit. There is a little bit of people hiding the problems, and that is bad science.”
Read also: Do forests drive wind and bring rain? Is there a major man-made climate driver the models miss?