A Hidden Loop In the Carbon Cycle Discovered 310
Googlesaysmysiteisdangerousanditisn't! writes "A recent article in Science says that researchers in China and the US have found massive carbon uptake in the world's deserts. The effects of this are huge. 35% of the Earth's land surface is desert, and the uptake equates to 5.2 billion tons of carbon sequestered each year. This is more than half of the carbon released by humans. In these 'dry oceans,' the grains of sand allow the carbon dioxide to enter and react with alkaline soil to become carbonates. Another scientist suspects that biotic desert crusts, alkaline soils, and increased precipitation may be driving the uptake."
Re:Obviously (Score:4, Informative)
Sure, as long as you don't skimp on the sandworms.
Re:Not the whole story (Score:3, Informative)
Re:Sooo... (Score:5, Informative)
No, the prolific amount of oil in the Middle East is mainly related to organic carbon [wikipedia.org] in source rock [wikipedia.org] deposits that formed in the marine environment. The source rocks in the Middle East are particularly widespread and productive.
The article is talking about carbonate [wikipedia.org] (i.e. minerals with CO3 in their structure), which is completely different and is often referred to as "inorganic carbon". It's as different as algae (organic carbon) and sea shells (carbonate). They both involve carbon and both can have biological origins, but you can't generate oil from carbonate. You need molecules with plenty of H and C for that (i.e. hydrocarbon molecules).
You can, however, find holes in carbonate rocks. In the right setting these can contain oil that has migrated into the porous rock from organic-rich source rocks nearby. Such rocks are known as petroleum reservoirs. Again, the Middle East has some spectacular reservoirs with very high porosity and permeability, allowing for plenty of space to hold the oil and to allow it to flow out. For example, the Ghawar field [wikipedia.org], which is the biggest oil field in Saudi Arabia and the world, has limestone reservoirs with up to 35% porosity by volume -- i.e. 35% of the volume isn't rock, but open spaces filled with fluid (either oil, gas, or water). That's extraordinarily high porosity. It's full of holes like a sponge.
So, if you want the short answer to why there is so much oil in the Middle East: 1) spectacularly prolific and widespread organic-carbon-rich source rocks, 2) highly porous and permeable reservoir rocks (some of which are carbonates, some of which are other rock types), and 3) large "trap" structures, which I haven't discussed, but basically refers to the geometry of the porous reservoir and an impermeable seal that keeps the oil/gas from leaking out.
It has very little to do with the modern deserts that are widespread in that part of the world today. Many of the conditions necessary for the large oil deposits were set up far enough back in geological history that today's climate is mostly irrelevant.
Misleading Summary (Score:5, Informative)
The effect could be huge: About 35% of Earth's land surface, or 5.2 billion hectares, is desert and semiarid ecosystems. If the Mojave readings represent an average CO2 uptake, then deserts and semiarid regions may be absorbing up to 5.2 billion tons of carbon a year.
Also...
For now, some experts doubt that the world's most barren ecosystems are the longsought missing carbon sink. "I'd be hugely surprised if this were the missing sink. If deserts are taking up a lot of carbon, it ought to be obvious," says William Schlesinger, a biogeochemist at the Cary Institute of Ecosystem Studies in Millbrook, New York, who in the 1980s was among the first to examine carbon flux in deserts. Nevertheless, he says, both sets of findings are intriguing and "must be followed up." Scientists have long struggled to balance Earth's carbon books. While atmospheric CO2 levels are rising rapidly, our planet absorbs more CO2 than can be accounted for.
and...
Provided the surprising CO2 sink in the deserts is not a mirage, it may yet prove ephemeral. "We don't want to say that these ecosystems will continue to gain carbon at this rate forever," Wohlfahrt says. The unexpected CO2 absorption may be due to a recent uptick in precipitation in many deserts that has fueled a visible surge in vegetation. If average annual rainfall levels in those deserts were to abate, that could release the stored carbon and lead to a more rapid buildup of atmospheric CO2--and possibly accelerate global warming.
This is not, as some posters are implying, published science that concludes the IPCC predictions are in any way likely to be inaccurate, or that carbon is accumulating in the atmosphere at a rate lower than previously thought.
This is a news article in science detailing some interesting research showing that deserts may be absorbing more carbon than was previously thought, and that this may account for the fact that atmospheric measurements show the earth is absorbing carbon at a higher rate than can be accounted for by currently known sinks. The amount of CO2 in the atmosphere is known from atmospheric measurements, and is higher than at any time in the last 650,000 years.
Re:Not just a joke (Score:4, Informative)
http://www.abc.net.au/science/articles/2008/08/05/2324476.htm [abc.net.au]
Wild untouched forests store three times more carbon dioxide than previously estimated and 60% more than plantation forests, a world-first study of "green carbon" and its role in climate change shows.
The European tax effect (Score:5, Informative)
The problem with CAFE was that it was indeed a boondoggle - the mandated efficiency improvements were actually less than were achieved automatically by European taxation levels, and as you note it was easily evaded with the "light truck" class.
Taxation of fuel is sensible because it is a tax on actual consumption. Most people are able to reduce their consumption by varied means - aggregated journeys, car shares, vacations closer to home, reducing acceleration, using mail order more - without changing their vehicles.
Re:Create more deserts? (Score:3, Informative)
Re:Safari (Score:3, Informative)
If you remove Acrobat Reader and use an alternative viewer, it's even faster.
Preview on OS X (built-in)
Foxit Reader on Windows
Xpdf on Linux and friends
Re:Create more deserts? (Score:3, Informative)
I agree but recognise that the same can be said about any area of scientific enquiry. Science is more than a seemingly contradictory pile of factoids, it's a way of thinking that is never 100% certain about anything, and can never prove anything to anyone. But if it's not the best model of the Universe that we have then may God strike me down before I hit submit.
"unless you count a consensus of scientists as evidence"
A scientific opinion is not evidence, at best it is an "expert witness statement". However consensus [wikipedia.org] is an intergral part of the "republic of science", scientific consensus is implied by the term "scientists say", eg: "Scientists say the Earth orbits the Sun". Have a google and find out what the consensus on GW actualy says and then we can discuss.
Vested interests [ucsusa.org] cut both ways, IMHO the track record of science is much more impressive than the track record of politics and industry. Here are a couple [realclimate.org] of blogs [nature.com] to practice the art of skepticisim on. The first is run by a bunch of climate scientists who contributed to the IPCC, it's founder is M.Mann the guy who came up with the much maligned "hockey stick", the second is from nature.com. Other excellent sites include NASA, NOAA, WMO, MET, CSIRO and countless other (not so excellent) sites from national scientific and meterological institutions across the globe.
Global, right? (Score:3, Informative)
...temperatures from 1961 to 1990...We in the Northwestern hemisphere have experienced 7 of the top 8 warmest years on record since 2001, and all 10 top warmest years since 1995.
So...you know that the Earth as a whole has been cooling since 1998, right?
Re:Fragile Earth or Robust Earth? (Score:3, Informative)
I've afraid you're the one whose bought into a common lie. Human activity releases far, far less carbon dioxide than the planet produces. We are minuscule in the big picture, nothing but ants.
Re:Fragile Earth or Robust Earth? (Score:5, Informative)
Indeed? Then I'd like to see your figures. Because we outdo the volcanoes by a factor of a hundred [wikipedia.org]. Looking into other sources, well: rotting vegetation was mentioned, and I agree it's a far larger quantity than human activity, but is that a source of carbon dioxide? Rotting vegetation can never release more carbon dioxide than the amount it absorbed when it first grew, making it net carbon neutral. Unless there is a net decrease in the planet's biomass, there's no overall extra carbon dioxide in the atmosphere due to plant life. Same goes for respiration by living things: the CO2 I exhale is carbon that was absorbed when my food grew, and will be absorbed again as a future meal grows.
We on the other hand are digging up and releasing vast quantities of carbon dioxide, all year, every year, and unlike the plants we're not taking it back out of the atmosphere. That's producing an ongoing year-on-year net increase in carbon dioxide. Nothing else on earth compares to human industry for increasing atmospheric CO2 concentrations.
Re:Create more deserts? (Score:3, Informative)
Its just a shame there are so many positive feedback systems compared to this one negative feedback.
as temperature rises:
+methane trapped in ice is released
+co2 trapped in oceans is released
+methane trapped under oceans is released
+more water vapour in the air
+ice-caps reflect back less heat
-deserts absorb more carbon
Re:Not just a joke (Score:3, Informative)
There are a few kinds of grass that require less mowing because they grow very slowly. A quick Googling led me to nomowgrass.com [nomowgrass.com]; I've heard of others but can't recall their names.
Re:it's you who is advocating massive change (Score:3, Informative)
Why doesn't anyone want to talk about the known increase in solar radiation over the last 30 years?
Because there isn't one. See here [royalsociety.org]. Solar irradiance has been on average flat since 1960, although there were some ups and down until the mid-1980s, after which it's definitely been quite flat on average. (By flat I mean the trend; there's the usual 11-year solar cycle oscillation too.) If anything there's been a very slight decrease over the last 30 years.
AFAIK, we don't have numbers going back any further, but it seems fairly obvious that if there is more solar radiation entering the earths atmosphere, the climate will change.
We do have numbers going back further, although they're pre-satellite, and if you go even further back they become indirect (inferred from counting sunspots and such).
The fact is, the average amount of solar radiation entering the Earth's atmosphere has changed very little over the last 30 years. Even if you ignore the greenhouse effect, increases in solar irradiance are far too small to produce the observed warming.
Maybe we won't run out of oil because it isn't really made from dead trees and dinosaurs.
Ok, not only is that a totally crackpot theory, but it's also irrelevant. Our estimates of how much oil there is aren't based on adding up how many dead trees and dinosaurs we think there used to be. They're based on going all over the world and digging for oil and seeing how often we find it. How the oil got there doesn't matter to our measurements of how much is there now.
The oil companies have a massive financial interest in how much oil is left. I can assure you, they have studied this question thoroughly from every angle, even more than the scientific community has.
All the problems with non-biogenic oil formation theories aside, it's possible to tell the difference between organic and non-organic carbon sources by looking at isotopic ratios. Oil is made of organic carbon. (That's one of the several lines of evidence which tell us that the excess carbon now in the atmosphere is due to our burning of fossil fuels, by the way.)
I've been meaning to find some numbers, but I have a hard time understanding the amount of decaying organic matter necessary to create the 80+ million barrels/day of oil pumped from the ground in 2005. I know were talking about geologic time scales here, so I'd be interested in seeing some numbers about how many trees and dinos that adds up to.
This overview [manicore.com] has some numbers.
I'd also be interested to find out how trees and dinos ended up 10k+ feet below the surface of the earth. Some of these are 35k+ feet (7+miles) deep.
You can build up a lot of material on top of it over 500 million years. Also, rock is porous. Oil sinks.
I doubt there were many trees or dinosaurs on Hyperion or Titan, 2 of Saturns moons. Yet, they have pools of hydrocarbons,
"Hydrocarbons" aren't always oil; the pools on Titan are things like methane and ethane, which are formed by chemical reactions in Titan's atmosphere. Hydrocarbons exist even in comets and interstellar dust, but they're not oil.
I'm just concerned that global warming is really another scam to take more of my money in the form of taxes to "save the earth".
Sheesh, lay off the conspiracy theories. Scientists don't get together in a back room and decide what scam to cook up next. There is plenty of legitimate scientific evidence, starting from basic atom-light physics and conservation of energy, and working up to our understanding of atmospheric and ocean circulation.
If I remember correctly, when I was a kid, the big fear was we we
Re:Create more deserts? (Score:3, Informative)
Rising water levels in the oceans means more water to dissolve the CO2 (although the temperature of the water is important, too).
Nope, the rise in water levels is due to the density of water decreasing, while the amount of water (moles) is staying the same* and the absorption coefficient of the water is decreasing.
*It may even be decreasing due to the shift in equilibrium causing more water vapour, but i'm not a climatologist so the whole water vapour assumption may have been completely wrong.
More water vapor hopefully means more clouds, and clouds reflect back sunlight, too.
True but i dont think that makes up for the greenhouse effect of the water and due to the shape of water it has a huge absorption spectrum, just in the right/wrong place. Ofc this is all pointless if water vapour doesn't increase.