The Paleocene-Eocene Temperature Maximum (PETM)

Using a variety of temperature proxies, including the ratio of the different stable isotopes of carbon, ¹³C and ¹²C, where higher temperatures favor the lighter isotope, ¹²C and one would expect to see a negative δ¹³C. Another indicator is the negative δ¹⁸O > 1% present in foraminifera shells that grew both in the surface and deep oceanic waters that occurred during this same time period. Likewise, analyses of the foraminifera Mg/Ca ratio and ratios of particular organic compounds used for TEX₈₆^1,2, a paleothermometer based on the composition of marine picoplankton, Crenarchaeota³. There is clear evidence of a massive injection of ¹³C-depleted carbon at the Paleocene-Eocene transition. First, the previously mentioned negative δ¹³C change in carbon compounds at this time, about 55 million years ago. Second, carbonate dissolution which indicates the acidification of the ocean that occurs when atmospheric CO₂ increases. The source of this carbon dioxide is unknown. Massive volcanic activity might have been to blame, but there is no evidence of sufficiently large volcanic activity such as the ash and lava deposits one would expect. There are volcanic traps in Siberia that were formed about this time, but there that activity alone would not account for the volume necessary to account for the likely CO₂ content in the atmosphere of over 1700 ppm (parts per million) at its peak. This is based on a base value of about 1000 ppm near the end of the Paleocene and an addition of about 3,000 GtC (gigatonnes of carbon). This amount of carbon was determined by taking into account the carbonate compensation depth (CCD), a value determined by the carbonate depletion of shallow ocean bottom cores.⁴ A comet or asteroid impact that caused continent-wide fires was considered and rejected because there is no layer of soot that has been found in ocean bottom cores as would be expected. Nor has a crater been found of the right age to account for this. A third possibility is that the large deposits of methane hydrate that exist on the deep continental shelves were destabilized and released. Methane hydrate is a single molecule of methane, CH₄, enclosed in a "cage" of water molecules, H₂O. This compound is only stable in a narrow range of temperatures and pressures. It would only have taken a small change in temperature or a physical disturbance of the water surrounding the methane hydrate to cause it to become unstable and release the CH₄. Methane is 20X as effective as CO₂ at retaining heat, so with a large release of methane, there would have been an immediate rapid surge in temperature. Methane decays over a period of about ten years to carbon dioxide which would then linger for over one hundred years, heating the atmosphere more slowly for a longer period of time. The total temperature of the ocean water, both shallow and deep was about 9^oF,reaching 77^oF in the surface waters near the poles.  There was virtually no ice anywhere on Earth at this time since the temperature had already been warm prior to the PETM.  The poles warmed more than the rest of the planet because with the lack of snow, the albedo increased, causing a larger temperature excursion.¹

The transition from the Paleocene epoch to the Eocene epoch Is marked by sharp decrease in the percentage of ¹³C, δ¹³C, dissolution of carbonate in all the ocean basins, the extinction of many terrestrial mammals, and foraminifera in the mud on the ocean floor (i. e., benthic).  It was also marked by the origin of several new mammalian orders, including primates, artiodactyls (even-toed ungulates), and perissodactyls (odd-toed ungulates). The δ¹³C and dissolution of carbonate indicate that the ocean experienced a geologically rapid acidification and temperature rise. The acidification strongly implies a rapid rise in the amount of carbon in the atmosphere. This increase occurred over a period of about 20,000 years, a rate that is about one-tenth of the rate of increase of CO₂ that we have experienced during the past 150 years.
Humans are currently adding about 30 GtC annually. At this rate, anthropogenic carbon additions will equal what was released at the P-E boundary in 100 - 200 years, some 100 times faster than occurred 55 million years ago.^1,5 because we have geologic evidence of what the climate was like during this P-E boundary time period, we have an idea of what the climate will be like in our near future if we continue on our current path. Periods of 100^o temperatures in the North American Southwest will last for months around the clock. Drought will be longer and more frequent than now. Flooding will be worse in those areas that commonly flood. All the glaciers will melt, raising the sea level by about 200 feet - it was 220 feet higher at the P-E Boundary than it is now. Since there are vast stores of methane under the permafrost, if the permafrost melts, and that now seems inevitable, the released methane will just exacerbate the problem and hasten the warming. There are also large deposits of methane hydrate on the continental shelves that could be released if the ocean temperature exceeds the threshold.
Only broad features of the climate during the 150,000 year transition from the Paleocene to the Eocene until CO₂ levels returtned to the levels of the late Paleocene after this large carbon dioxide excursion. One can hope that by further study, a more detailed understanding will be gained along with indications of how this scenario might be mitigated

1. National Geographic, October 2011, pp. 90 – 109
2. http://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum
3. http://en.wikipedia.org/wiki/TEX86
4. http://www.realclimate.org/index.php/archives/2009/08/petm-weirdness/
5. http://www.realclimate.org/index.php/archives/2004/12/how-do-we-know-that-recent-cosub2sub-increases-are-due-to-human-activities-updated/ 

Scientist claims that he has created life-like cells based on metal

Lee Cronin at the University of Glasgow claims that he may have developed cell-like structures capable of adapting to changing environments.¹ The materials that he has used to create what he calls iCHELLS (inorganic chemical cells) are known as polyoxometalates. These are compounds made with various metal atoms combined with oxygen (O) and phosphorous (P).  Tungsten (W) is the most common metal used.

One of the iCHELLs.
Image from NewScientist.com.

He creates large negatively charged ions of these metal oxides and creates a salt by mixing these ions with protons (positively charged hydrogen [H⁺]) or sodium (Na⁺).  He next injects a solution of this salt into a solution containing an organic salt with large organic cations (positive ions) and small anions (negative ions).  What results is a salt of the metal oxide anion with the organic cation that precipitates from the solution in the form of a small bubble-like structure.  He is able to manipulate the form of these structures to give them some of the characteristics of organic cell membranes such as selective permeability that will control what chemicals reside within the bubble.  He has created bubbles within bubbles to give the appearance of the internal structure of living cells.  He has attached photosensitive dyes to the iCHELLS which enabled them to mimic rudimentary photosynthesis, including the ability to split H₂⁺ and O plus an electron (e^-), an important step in the process.

It is during his current experiment, scheduled to run for seven months that he has given some indication that he has succeeded in modifying the iCHELLs so that they will adapt to the environment they are in.  The final results are still a few months away and the details have not yet been published.  Last year he also showed that polyoxometallates could serve as templates for self-replication analogous to how DNA and RNA operate.  Taken together, these could be good first steps toward creating artificial life.

Reproduction, self-repair, adaptation, growth, and evolution are all characteristics of single-celled and more complex life as we know it.  If Cronin is able to induce these iCHELLs to perform all three, would this constitute a new form of life?  It would seem to be.  If he is able to accomplish this, and it is not certain that he will, it would revolutionize our understanding of what life forms might be possible on other planets in our solar system and elsewhere in the universe.  It may expand the Goldilocks zone and drastically increase the possibility of finding other life.

1. http://www.newscientist.com/article/dn20906-lifelike-cells-are-made-of-metal.html

Contributions to Global Warming and Climate Change

The Sun and Global Warming

Of the many trends that appear to cause fluctuations in the Sun’s energy, those that last decades to centuries are the most likely to have a measurable impact on the Earth’s climate in the foreseeable future. Many researchers believe the steady rise in sunspots and faculae since the late seventeenth century may be responsible for as much as half of the 0.6^o of global warming over the last 110 years (IPCC, 2001).


The effects of orbital mechanics on global warming - the Milankovic cycle
The variation of insolation due to orbital mechanics was solved by Milankovich in the 1930's.
There are three relevant cycles and four factors that contribute: precession of the orbit, meaning that the location of the perihelion (point of closest approach of the Earth to the Sun) rotates around the Sun; precession of the Earth's spin axis relative to the orbital axis (like a top that is spinning with its axis of rotation at a tilt); change in eccentricity of the orbit between a perfect circle and an ellipse that is slightly different from a circle; and variation of the tilt of the Earth's axis between about 23^o and 24.5^o.
The combination of the variation of the orbit's eccentricity and the Earth's spin-axis precession creates climate change on about a twenty-thousand-year cycle. The oscillation of the spin-axis relative to the orbital plane between 23^o and 24.5^o has a 40,000 year cycle. The eccenticity change by itself causes small variations in the insolation with a cycle of about 100,000 years, but its effect is only about 0.1 % of the others. These factors are known as Milankovich forcing.


These cycles were correlated with the the timing of the ice ages and hypothesized to actually cause them. Currently, these variations should have been cooling the Earth's mean temperature over the past 150 years, but the global mean temperature has in fact been rising.


Relationship between CO2 emissions and rise in temperature
The relationship between CO₂ emissions and rise in temperature, one tonne (one tonne = 1000 kilograms = 2200 lb = one long ton) of added carbon will cause 1.5 x 10^-12 degree rise in temperature, is based on an article in Nature.  In the USA, one tonne of carbon is emitted per person annually. Assuming that worldwide emissions per person are one tenth of a tonne per person, then for just the additional carbon emitted each year and assuming that this rate is steady (It is not, it is increasing), then each year the temperature rise will be 9 x 10^{-4 o}C. However, this also assumes that the temperature has reached equilibrium with the current level of CO₂ in the atmosphere, but it hasn't.


This chart shows the normal lag of CO₂ concentration to temperature rise and that the relationship has reversed in the present, i.e., the CO₂ concentration has continued to rise even as the temperature has been relatively stable. Based on the past record from the ice cores, one would expect that the temperature would be dropping with the CO₂ concentration either stable or decreasing as well:






















When the The Milankovich cycles cause an increase in solar energy striking the Earth, this will initiate a melting of some of the glaciers and at least one of the polar ice caps.(depending on the season). As the article states, 18,000 years ago, this increase in the intensity of the sunlight occurred during the spring in the Southern Hemisphere. This led to the Antarctic ice cap melting more than it had been. This decrease in the area of ice decreased the amount of sunlight reflected and a corresponding increase in the amount of sunlight absorbed. This initiated a positive feedback loop where reduced reflection and ocean warming lead to more temperature rise than would be expected from Milankovitch forcing. Currently, if Milankovitch forcing were the primary factor, global temperature should be falling.


As the temperature of the ocean increases, it can hold less carbon dioxide, so the carbon dioxide level in the atmosphere increases. This increased CO₂ level creates a second positive feedback loop that also causes more warming than can be explained by Milankovitch forcing, oceanic warming, and reduced reflection alone. The lag in CO₂ concentration from temperature rise has normally been about 600 +/- 400 years for the last 450,000 years based on several different sources (primarily ice cores).  For about the last one hundred years, the rate of increase of CO₂ has been leading the rise in temperature.


Another point is that with the melting of the permafrost, the risk of large methane releases increases. It isn't a matter of "if" but "when" if current trends continue. Methane has 25 times the warming effect of carbon dioxide. This is being studied in Alaska where new shallow summer lakes are forming on top of the permafrost and permafrost is meting more deeply than in recent history and increasing amounts of methane are being released. It is uncertain where the threshold is for large releases to occur.


For a more detailed explanation and the history of the theory that links CO₂ to temperature rise, see http://www.aip.org/history/climate/co2.htm.

Maunder Minimum and Climate Change

A Maunder Minimum is a period of low sunspot activity. The period from about 1650 to 1720 was the nominate Maunder Minimum and coincided with a period known as the Little Ice Age. Recently, Space.com posted an article, Sun's Fading Spots, that stated that we may be in the beginning of a new Maunder Minimum. In the following, I attempt to assess the probable influence this will have on the climate.

It is apparently correct that reduced sunspot activity is correlated with reduced solar irradiance. The Maunder Minimum during the latter half of the 17th century did lead to what was known as the Little Ice Age. However, there is also strong evidence that the rise in greenhouse gases has become the dominant agent affecting global temperature as can be seen in this graph:

Courtesy of http://lasp.colorado.edu/images/science/solar_infl/Surface-Temp-w-paleo.jpg

The golden line with diamonds is the measured or reconstructed total solar irradiance. The solid blue line is the reconstructed global surface temperature. The dashed blue line is the measured temperature in the Northern Hemisphere (NH). One can see that solar irradiance and the reconstructed global temperature follow one another fairly closely. The measured NH temperature also tracks total solar irradiance until the last 40 years when it starts to sharply diverge. This graph shows the recent data at higher resolution:

Courtesy of http://www.skepticalscience.com/pics/Solar_vs_Temp_basic.gif

The divergence is even more clear here since total solar irradiance has been declining as global mean temperature has been rising. One can see on the first chart that there is a very close correlation between solar irradiance and temperature. The effect of the three major volcanic eruptions that are noted caused an immediate drop in solar irradiance and a corresponding drop in temperature. So the implication of the second chart is that there must be at least one other factor that is influencing global mean temperature than solar irradiance and that this factor is overriding the drop in solar irradiance.

If we are indeed entering another Maunder Minimum of solar activity, it at most will give us a temporary reprieve and slow the rise in temperature. It will not cause a long term (i.e., greater than 100 years) cooling and it will not reduce the importance of reducing anthropogenic greenhouse gases.

Critique of Junk Science on Climate Change

An acquaintance cited this as a critique of climate science that debunks the “myth” of anthropogenic contributions to climate change:
http://junksciencearchive...reenhouse/What_Watt.html.  My response follows. 

From the beginning of this article, she is minimizing the significance of the role of CO₂ in the value of the mean global temperature.  She is also claiming that mean global temperature is not a significant number.  She writes, “… many excellent researchers who have pointed out that the concept of a globally averaged forcing constant is flawed and they are right. Sensitivity absolutely depends on where the forcing is applied and when. Unfortunately a globally averaged forcing value is applied via climate models and cited in IPCC documents and we are thus stuck with addressing an invalid value in common use.”  However, she doesn’t name these excellent researchers, nor does she explain why globally averaging the value is invalid.  When she states that the sensitivity depends on where and when, she is correct as for local effects.  But because of the convective action of the atmosphere and ocean, these local effects are naturally averaged out over the globe.  If one thinks about heating one’s house in winter, one could just as easily say that since the air coming from the vents when the furnace is running causes convection to occur near the vents and not so much away from the vents, trying to calculate the mean temperature rise in your house based on the total amount of heat coming from the furnace minus the heat that is being lost through the walls and ceiling is invalid.  Her reasoning, at least as stated, is incorrect. 
She next states, “climate models make much of water vapor "feedbacks" -- a multiplier effect due to a small warming from carbon dioxide increasing evaporation and thus adding to the major greenhouse gas, water vapor -- this in turn is supposed to increase the greenhouse effect, leading to more evaporation and yet more warming and so on. The amount of water vapor in the atmosphere is not a simple function of evaporation, however. All of the water vapor that is being continuously evaporated from the Earth's surface must eventually return to the surface as precipitation. The climate system strikes a balance, allowing only so much water vapor to accumulate before it is depleted by either rain or snow."

A fact that she is overlooking is that the amount of water vapor in the atmosphere is dependent on the temperature of the air.  The warmer the air, the more water vapor it can contain and on average will contain.  This is why we talk about relative humidity instead of absolute humidity.  Relative humidity is the amount of water vapor present compared to the amount it can hold.  The dew point is the temperature at which relative humidity equals 100%.  This temperature varies with the amount of water vapor actually present.  As an illustrative example without doing real calculations, if the RH is 70% at 50 F, then the dew point might be 40 F while if the RH is 70% at 70 F, the DP might be 45 F.  One can see this if one has noticed that, in general, dew won’t be present in winter, on those days when temperatures have remained above freezing, until a lower temperature than in summer.  The atmosphere will approach a dynamic equilibrium of the amount of water vapor present based on the global mean temperature.  It will vary from place to place and with the time of day, always changing everywhere, but on average, the vapor content will rise as the temperature rises.  There will be both more precipitation and more evaporation, but the balance will increase with increasing temperature.  See: http://www.giss.nasa.gov/research/briefs/lacis_01/ for a discussion based on recent satellite measurements.
She states, “climate models use λ values of 0.75 ± 0.25 °C per Wm^-2, 5-10 times greater than empirical measures support.”  This is false.  She has chosen the lowest empirical value available.  A value of ~0.7 k/Wm^-2 is empirically derived as shown in this article from Wikipedia: http://en.wikipedia.org/wiki/Climate_sensitivity.  This article includes citations giving a range of values for the climate sensitivity parameter. The rest of her article is similarly skewed.  She consistently cherry picks the data and research to support her point of view.  Consider her referenced to an article by Lyman et al.  It initially claimed that there had been a cooling of the ocean surface temperature in the early 2000s, but they later published a correction that stated that there had been no cooling, but the temperature had been stable during the three year time period of their study.  She includes this information, which is good, but then does not correct her conclusions to account for this.

In her discussion of cloud cover effects, she emphasizes only the negative feedback.  This is unwarranted.  Based on recent studies, it appears that thick clouds have a negative feedback effect (net cooling effect), but thin cloud cover like from cirrus clouds or contrails have a net positive feedback effect (net warming).  The balance between these two is unclear, but it seems to be that there is a net positive feedback based on the most recent satellite measurements.  See: http://sciencetrends.blogspot.com/2011/04/positive-and-negative-feedback-in.html for more detail.
Based on my analysis of her article, she is strongly biased against anthropogenic global warming.  She does not consider all the data that contradicts her position.  If this article is an example of how he analyzes scientific results, “Junk Science” applies more to what she has written than the science that she is trying to debunk.  The good climate scientists, as illustrated in the quoted Wikipedia article, cite a range of results, trying to make it as representative as possible.  There is much uncertainty in the climate models and in some of the data as well as a glaring lack of data in some areas.  However, on balance, the available data do support the contention that the global climate is warming and that it is warming at a rate higher than can be accounted for without considering the effect of anthropogenic CO₂.
Similarly, Bryson, http://drywind.net/blog/science/climatologist-who-discovered-jet-stream-debunks-human-caused-global-warming/75/, has discounted recent data and seems to dismiss climate model projections because he doesn't think they are good enough.  He may be right, but the fact is that the mean value of the results of the computer models twenty years ago underestimated the temperature rise and sea level rise.  Current models are improved because of more accurate and finer grained data.  The results published in the latest IPCC report,  a not perfect summary of the status of climate science, tend toward the conservative end of the projections.  If one actually considers all the data and not just the data that fits one's preconception or bias, the rising temperature trend is clear and the fact that human activity is contributing is clear.  It is not clear exactly how much of the warming is due to human activity, but it appears to be at least 30% of it.
It has also been suggested that higher CO2 content was actually beneficial because some plants were growing faster.  It is true that some plants are growing faster but that is only one effect (and does anyone in Georgia really want kudzu to grow any faster than it already does?).  The resulting warming from the increasing CO2 level also is eliminating the habitats of several species and possibly contributing to the decline of amphibians by enhancing the ability of certain fungal diseases to spread.  The warming is causing the Greenland ice cap and many continental glaciers to melt at an increasing rate, raising the sea level and threatening low-lying coastal areas and islands.  Parts of the Antarctic ice cap are increasing while other parts are decreasing, but overall there is a net decrease in the ice contained there that is also contributing to the sea level rise.  Rising temperatures also are improving the agricultural potential of northern areas such as Greenland and Iceland.  What have historically been considered tropical diseases, such as malaria and dengue fever, are now spreading to mid latitudes.  The ocean is acidifying, threatening the health of the plankton that form the base of the global food chain.  So obviously the effects are varied and complex.  The net effect, though, is deleterious to many species of land animals, including humans.  If the acidification continues, it will negatively impact nearly every species except bacteria.