At last, a mainstream documentary about “the environment” that looks at real causes instead of just blathering about “climate change”. Now that the deserts are spreading into Europe, maybe we will see some of the tax money going to research that will lead to change, rather than just UN-boosting carbon taxes. But don’t hold your breath; the real changes will be made by local communities acting intelligently.
Plos One has published a study that implies that fungal spores can create rain.
From the Abstract:
Millions of tons of fungal spores are dispersed in the atmosphere every year. These living cells, along with plant spores and pollen grains, may act as nuclei for condensation of water in clouds. Basidiospores released by mushrooms form a significant proportion of these aerosols, particularly above tropical forests. Mushroom spores are discharged from gills by the rapid displacement of a droplet of fluid on the cell surface. This droplet is formed by the condensation of water on the spore surface stimulated by the secretion of mannitol and other hygroscopic sugars. This fluid is carried with the spore during discharge, but evaporates once the spore is airborne.
Despite ‘careful’ phrasing, this article and the research it refers to is very useful support for the notion that we need more forests if we are to survive here for much longer. Big Pharma and its mainstream ‘medicine’ lackeys can make all kinds of definitive claims about their particular brands of snake oil, but when one is challenging the onslaught of progress one has to use careful language:
the deterioration of the rainforest – through logging, fires and land clearance – has resulted in a decrease in forest transpiration and a lengthening of dry seasons. This might be one of the factors of the severe drought affecting south-east Brazil.
In fairness, this and other examples of cowardly deference to corporate masters might (!) be coming from the reporter, not the author of the study. In any case, the article has some interesting insights into how mainstream science has been separated from reality:
…science has become so fragmented. Atmospheric scientists don’t look at forests as much as they should and vice versa,” said Nobre, who wrote the report for a lay audience. [when you look into the abyss…?]
In Trees Make Rain V we saw how trees enable microbes to put just the right kind of particles in the air to make it rain. It turns out that these are the most productive of all three known types of nucleating particles:
Meteor dust particles, which serve as ice nucleators mostly at temperatures colder than -15 degrees Celsius);
Inorganic soil particles (mainly clays), which also serve as ice nucleators mostly at temperatures colder than -15 degrees Celsius; and
Biological particles, which serve as ice nucleators temperatures as warm as, or warmer than, -5 degrees Celsius.
This is shown in detail in a paper called “The Biologic Origin of Snowflakes and Raindrops” by the Suburban Emergency Management Project.
The most active ice nucleators are biological in origin, declare Christner, et al. in their paper recently published in Science (February 29, 2008). (11) “This is important because the formation of ice in clouds is required for snow and most rainfall. Dust and soot particles can serve as ice nuclei, but biological ice nuclei are capable of catalyzing freezing at much warmer temperatures”, the researchers explain. (14) In other words, a mechanism exists whereby snowflakes and other precipitation can form when cloud temperatures in the troposphere are relatively warm.
Like the Marvel Comics superhero Iceman, some bacteria have harnessed frozen water as a weapon. Species such as Pseudomonas syringae have special proteins embedded in their outer membranes that help ice crystals form, and they use them to trigger frost formation at warmer than normal temperatures on plants, later invading through the damaged tissue. When the bacteria die, many of the proteins are wafted up into the atmosphere, where they can alter the weather by seeding clouds and precipitation.
Now scientists from Germany have observed for the first time the step-by-step, microscopic-level action of P. syringae‘s ice-nucleating proteins locking water molecules in place to form ice. More in the full article:
If you cut your forest, the winds will not blow from the ocean and will not bring you rain. Natural forests draw atmospheric moisture inland from the ocean in a positive feedback loop. This builds up precipitation inland, compensating for water lost through river flow and ultimately increasing river runoff due to the sustained low pressure area inland. Forests make rivers.
(2005) Australian scientists say they have found proof that cutting down forests reduces rainfall. The finding, independent of previous anecdotal evidence and computer modelling, uses physics and chemistry to show how the climate changes when forests are lost, by analyzing variations in the molecular structure of rain along the Amazon River.
Not all water, Professor Henderson-Sellers said, was made from the recipe of two atoms of “common” hydrogen and one of “regular” oxygen. About one in every 500 water molecules had its second hydrogen atom replaced by a heavier version called deuterium. And one in every 6500 molecules included a heavy version of the oxygen atom.
Knowing the ratio allowed scientists to trace the Amazon’s water as it flowed into the Atlantic, evaporated, blew back inland with the trade winds to fall again as rain, and finally returned to the river. The study showed that since the 1970s the ratio of the heavy molecules found in rain over the Amazon and the Andes had declined significantly. The only possible explanation was that they were no longer being returned to the atmosphere to fall again as rain because the vegetation was disappearing. “With many trees now gone and the forest degraded, the moisture that reaches the Andes has clearly lost the heavy isotopes that used to be recycled so effectively,” Professor Henderson-Sellers said.
“This is the first demonstration that deforestation has an observable impact on rainfall.”
Isotope studies have shown that almost all oceanic moisture falls as rain within the first 150 miles from any coast. All the rest of the rainfall on land is recycled water, evaporated from the land and the vegetation on it. Bare land such as sand or rock desert can only evaporate a small amount of the water before it runs off back to the sea. Farmland will hold a little, but the best reservoir is a forest.
A single oak tree may have ten to thirty acres of leaf surface, so forests are the best thing for ensuring that inland areas get rain. In fact, to destroy the Amazon forest, all we need to do is to chop down the first 200 miles, and we’re busy doing that now.
Until relatively recently, most scientists thought rain was caused by mineral particles in the air which were just the right size for water (or ice) to condense around them. Research is beginning to show that a major factor in rain creation could be bacteria associated with plants. http://en.wikipedia.org/wiki/Bioprecipitation
If this is true then it is yet another way in which forests create rain. A forest has a far greater plant surface area than farmland or desert.
The image shows two views of the rabbit-proof fence, stretching aobut 2,000 miles across South-Western Australia. It separates off native land from farmland with the idea of keeping rabbits out.
Clouds form a lot more on the native side than the other, showing a correlation between farmland and decreased rainfall. That’s it really, but there are some speculations and other stuff in a NY Times article about it.
There is a research paper by Tom Lyons of Murdoch University, impact_of_clearing (pdf) which goes into detail, and an abstract of another paper: The role of land use change on the development and evolution of the west coast trough, convective clouds, and precipitation in southwest Australia on the JGR site
(And the fence, it doesn’t work, obviously — what kind of idiot would try to build a 2,000 mile long version of something they haven’t invented a one mile version of yet? And more to the point, what kind of idiot would pay them to do it? Oh, hang on, the kind of idiot that would chop all the trees down and expect to just keep on farming without them forever. The fence builders saw them coming didn’t they?!