By the way... just thought you should know that plants seem to be rather enjoying the climate, rather than being poisoned off by it like you seemed to suggest maxi baby.
http://www.sciencema...t/300/5625/1560Climate-Driven Increases in Global Terrestrial Net Primary Production from 1982 to 1999
Ramakrishna R. Nemani,1* Charles D. Keeling,2 Hirofumi Hashimoto,1,3 William M. Jolly,1 Stephen C. Piper,2 Compton J. Tucker,4 Ranga B. Myneni,5 Steven W. Running1
Recent climatic changes have enhanced plant growth in northern mid-latitudes and high latitudes. However, a comprehensive analysis of the impact of global climatic changes on vegetation productivity has not before been expressed in the context of variable limiting factors to plant growth. We present a global investigation of vegetation responses to climatic changes by analyzing 18 years (1982 to 1999) of both climatic data and satellite observations of vegetation activity. Our results indicate that global changes in climate have eased several critical climatic constraints to plant growth, such that net primary production increased 6% (3.4 petagrams of carbon over 18 years) globally. The largest increase was in tropical ecosystems. Amazon rain forests accounted for 42% of the global increase in net primary production, owing mainly to decreased cloud cover and the resulting increase in solar radiation.
1 School of Forestry, University of Montana, Missoula, MT 59801, USA.
2 Scripps Institution of Oceanography, University of California, San Diego, CA 92037, USA.
3 Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyoku, Tokyo 113, Japan.
4 NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA.
5 Department of Geography, Boston University, Boston, MA 02215, USA.
http://www.umt.edu/u...2002/9plant.htmUM SATELLITE STUDY SHOWS
INCREASED PLANT GROWTH
This image from the Terra satellite shows North American plant growth in late fall 2001.
A NASA-funded study directed by UM finds that changing rainfall patterns over much of the United States in the last century have allowed plants to grow more vigorously and absorb more carbon dioxide from the atmosphere.
In the presence of water and sunlight, plants take in carbon dioxide (CO2) during photosynthesis to create fuel, glucose and other sugars, as well as build plant structures. Better understanding of biological and physical processes that contribute to carbon uptake by plants will help scientists predict climate change and future levels of CO2, a heat-trapping gas in the atmosphere.
“The changes in the hydrologic cycle are a mechanism often overlooked in the recent debate over carbon sequestration in the United States,” says Ramakrishna Nemani, a researcher at the UM School of Forestry and lead author of the study, which appeared in an issue of Geophysical Research Letters earlier this year.
Scientists have noticed that the U.S. terrestrial sink, an effect where carbon is drained from the air and stored in the land, has been increasing since the latter part of the 20th century. Previous research has claimed this rise may be due to an observed greening of the United States as a result of forest regrowth, as well as greater concentrations of atmospheric CO2 and warming temperatures.
For the first time, however, this study suggests that changing rainfall patterns may play a bigger role in plant growth and carbon absorption. Computer model results show that on average from 1950 to 1993 higher humidity combined with an 8 percent increase in precipitation has led to a 14 percent increase in plant growth in the United States. Data over that time period also show increases in cloud cover, minimum temperatures, soil moisture and stream flows, all of which are signs of a changing hydrologic cycle.
Whether or not shifting rainfall patterns result in a positive uptake of carbon by land ecosystems depends on complex interactions that include plant physiology and both the magnitude and timing of changes that impact the water cycle.
Between 1950 and 1993, minimum temperatures in the spring generally have become warmer and autumns generally have been wetter, which has combined to lengthen the growing season for plants. A longer growing season means plants pull carbon from the air for a greater period of time. In addition, the magnitude of precipitation on average has gone up in the conterminous United States, except over the Pacific Northwest.
“Most people only think of the idea that more water means more growth, but really plants benefit from more water in a number of ways,” says Steven Running, a UM forestry professor and co-author of the study.
When the air is wetter, plants can open special cells in their leaves without losing much water to the air, increasing CO2 uptake while reducing the amount of water needed to grow. Additionally, wetter soils promote decomposition of dead plant materials, releasing nutrients needed for plant growth. Also, higher humidity in the spring helps maintain higher night temperatures, which makes for more frost-free days and lengthens the growing season.
The authors found that without enhanced rainfall and humidity, CO2 increases and temperature changes have a lesser effect on plant growth.
Greenhouse gases warm the air, and warmer air can hold more water, which impacts the hydrologic cycle. Changes in the cycle may mean more rainfall in some regions and less in other places, affecting plant growth and carbon absorption, which in turn affects future concentrations of greenhouse gases, Nemani says.
The study was funded by the Vegetation Ecosystem Modeling and Analysis Project and the Moderate-resolution Imaging Spectroradiometer science team, which are part of NASA’s Earth Science Enterprise. V
And JoSH is still blogging away and poking holes left and right
http://www.foresight...nanodot/?p=3611Original Sin
By J. Storrs Hall, on December 20th, 2009
Mike Treder has a post at IEET that reads like a catechism of the Gaian religion. Now I’m a firm supporter of freedom of religion and Mike has a perfect right to believe what he does and indeed to preach it to whomever will listen. (And besides, Mike is a friend of mine.) But in this particular article he takes a backhanded swipe at Foresight, linking to us from this paragraph:
Techno-rapturists among our reading audience might be quick to respond with glib answers about miraculous nanotechnology solutions that are just around the corner, or the promise of a superintelligent friendly AI who can take over everything and solve all our troubles just like Daddy would.
So I feel that it would be appropriate to set the record straight on a few points. First and simplest, the Dead Sea is a completely natural phenomenon — it is dead because it has ten times the salinity of the oceans, and the salinity is from exactly the same reason — rivers run into it, bearing dissolved minerals, but water leaves by evaporation, leaving and thus concentrating the solutes. The idea of using a picture of the Dead Sea to illustrate a paragraph about ocean acidification makes me quite skeptical of the scientific reasoning behind the rest of the article.
Let us suppose that, for example, we had been monitoring the oceanic biosphere by satellite for a decade and over that time the levels of life had fallen by 6%. That would be a clear cause for alarm and one would have to worry about acidification and other deleterious human influences. But in fact the results of such studies show that the opposite is the case. Both in the ocean and on land, plant growth, which is what can be measured directly by satellite, has increased, and this appears largely due to increased CO2 and warming. (After all, we build greenhouses for a reason.)
Mike quotes a Green angst blog that quotes a Green angst opinion piece in Nature as follows:
The Earth has nine biophysical thresholds beyond which it cannot be pushed without disastrous consequences.
Ominously, we have already moved past three of these tipping points.
There is really no scientific basis for this kind of statement. James Hansen, one of the authors of the Nature piece in question, has been making this kind of noise about runaway warming feedbacks for years. But the actual physical greenhouse effect is logarithmic. You have to postulate some completely different positive feedback to talk about “tipping points”, and no such thing has been demonstrated in the real climate system (although there is no lack of them in the computer models). In fact the icecore paleothermometry reconstructions show that there have been fairly rapid rises at the beginning of each interglacial, as if there were a positive feedback operating, but that they stop uniformly when they get to temperatures a little warmer than current, as if there were some very strong negative feedback in that part of the phase space.
Furthermore, there’s not much sign of a positive feedback acceleration in the current temperature record, either:
cubic fit to UAH temp record
(This is a simple least-squares cubic fit to the satellite temperature record (UAH global monthly averages) to date.) For there to be a dominant positive feedback (there are plenty of minor ones), it would have to be something that operates on longer timescales than the PDO/ENSO oscillations (and thus longer current GCMs can model accurately). Regarding which this pithy remark in one of the climategate emails:
Without trying to prejudice this work, but also because of what I
almost think I know to be the case, the results of this study will
show that we can probably say a fair bit about <100 year
extra-tropical NH temperature variability (at least as far as we
believe the proxy estimates), but honestly know fuck-all about what
the >100 year variability was like with any certainty (i.e. we know
with certainty that we know fuck-all).
So, what’s the difference between a Gaian take on Sinners in the Hands of an Angry Earth, and a reasoned scientific stance? One main difference is the degree of certainty which is attached to the statements. Another is the moral coloration given to any human influence. The main reason I object to that is the attempted disguise of the coloration as scientific projections of physical effects. It would be perfectly fine to say, as other religions do, that men are born evil and we should all take vows of poverty because it is harder for a camel to go through the eye of a needle than a rich American to enter the kingdom of heaven.
There are, of course, deleterious effects to human operations and expansion over the Earth’s surface. If we pave over the whole planet, it would be a pretty bad thing. The satellite biosphere inventories show that, indeed, life is contracting in some areas while expanding in others. There are limits to virtually every form of human impact, from emitting CO2 to building suburban homes and mowing the grass. But by and large the effects are proportional to the cause: we do more stuff, things get worse in some regard (polluted waters, for example), the effects are noticed, and the causes are backed off from. But there’s very little reason to believe that we’re sitting in a circle of traps where one false step in any direction will result in certain doom.
Would it be nice to save the Earth as a park and wildlife preserve? I personally happen to think so. Indeed, I live in the remote mountains where I can’t see another human habitation from my windows, putting up with considerable inconvenience to do so because I like the natural environment more than cities or suburbs. But the only way that will happen in a realistic projection, is for the substantial mass of humanity and industry to move into space (or cyberspace or the equivalent). And that will require nanotech.
