Ear To The Ground

Solar cycle is abating impact of GHG emissions, Part 2

A recent posting noted that because the Sun is at a solar minimum, the impact of GHG increases in the atmosphere have been less than would otherwise be anticipated.  Now, a new report suggests that the Sun is entering an unanticipated, a potentially prolonged period of solar minimum.  Some will take a "what, me worry?" attitude in light of this potential "blessing"; others will see it as an opportunity to take corrective action without suffering the full consequences for past activities.

To say that understanding what drives the so-called "eleven year" solar cycle has a ways to go is a statement of the obvious.  What we do know is that a weaker solar cycle is accompanied by a slightly dimmer sun, which changes the average temperature on Earth.  As noted in the prior post, solar cycles are a variable lot, with consistency not being their strong point.  For example, the sun’s brightness did not hit an all-time low during the past solar minimum, even though the sun was unusually quiet.

Nonetheless, the decline in solar brightness from 2002 to 2008 as solar activity dwindled probably countered the warming on Earth that would otherwise have occurred due to GHG increases over that period.  When the Sun does pick up, we can expect that the impact of GHG emissions will be more severe than it now appears to be.

An interesting thesis on what drive's solar cycles can be found at http://www.nature.com/nature/journal/v471/n7336/full/nature09786.html.  However, it should be noted that it is controversial, with critics noting that the speed of the meridional flow, a key factor in the theory, being exactly the opposite to that required by the thesis.

 

Human impacts on the climate preceded the dawn of the petroleum age

Prior posts, occasionally with tongue planted firmly in cheek, have noted that human impact on carbon loading in the atmosphere goes back to well before the industrial era.

A recent assessment has calculated that over the eight millennia before 1850, clearing land (for both hunting and for farming) removed trees that had stored or would store CO2, adding approximately 350 billion metric tons (1 mt = 1,000 kg or 2204.62 lbs) of carbon into the atmosphere by 1850. For purposes of comparison, it should be noted that it has been estimated that humans have added 440 billion metric tons of carbon since 1850, mostly from burning fossil fuels.

As population grew over the 8 millennia before 1850, the Earth's forests were converted to other uses. However, it is not a linear relationship. With irrigation, fertilizer, multicropping, and new tools, crop yields increased and the per capita rate of land use fell.

This new estimate (350 billion metric tons) is much larger than several other estimates published within the last year, and reflects assumptions regarding how carbon is stored in the soil when forests are replaced by grasslands. Critics have noted that the chemical composition of carbon dioxide bubbles in ice cores do not reflect changes that might be expected if forests were removed as hypothecated. In response, researchers have stated that rapidly expanding peatlands could counter-balance some of the impacts.

Other researchers have undertaken more regional studies, and have found that land use often varies significantly. For example, the use of wet-grown rice systems in China required fewer acres to feed people than the cereal grains grown in Mesopotamia. Because of population distribution across the globe, preindustrial emissions goes up for countries like India and China, which emitted a lot of carbon millennia ago. In contrast, North America remained relatively pristine forests until the last couple of hundred years. Thus, the balance between pre-1850 emissions and post-1850 emissions is more complex and nuanced.

The study can be found at http://hol.sagepub.com/content/early/2010/12/24/0959683610386983.short?rss=1&ssource=mfr.

How does one assess the amount of carbon stored in a forest? Lidar

Calibrating measurements from study teams on the ground with the results of a readouts from "light detection and ranging" instrumentation (LIDAR), Arbonaut, a Finnish natural resources management firm, has created the technology to product 3-dimensional images of the trees in a forest, which can be used to estimate the amount of carbon stored.  The information can then be used to verify commitments to prevent forest degradation and also for carbon-trading schemes.  A nice overview of the technique can be found at http://www.economist.com/node/18741402?story_id=18741402.

An articulate end-of-the-world-as-we-know-it view from Thomas Friedman

I am certainly old enough to remember a variety of doomsday scenarios, usually built around decreases in agriculture productivity or population growth (or both).  There have also been some modern scholarly papers that posit that things are going to get very very difficult indeed really soon.  See, for example, http://www.cnr.uidaho.edu/sei_501/pdf%20files/MA%20Stocking_2003.pdf, http://www.springerlink.com/content/j684651843716477/, and http://www.springerlink.com/content/u1l8x71325166654/.

Advocating that we are facing an unusual coalescence of factors is a recent column by Thomas Friedman.  It makes for an interesting read, even if you find his thesis of questionable merit.  See http://www.nytimes.com/2011/06/08/opinion/08friedman.html?_r=1&partner=rssnyt&emc=rss.

I have to admit that when I read such columns, I cannot help but to recall one of my favorite ditties from ages gone by.  See http://www.youtube.com/watch?v=L8-BI89mb9A. 

Arctic salt clouds are reducting the impact of Global Climate Change on the Arctic region

Prior posts have noted both the various impacts of Global Climate Change ("GCC") on various aspects of the Earth and its atmospheric systems, as well as the failure of many/most models to include such impacts within their parameters.  For example, a recent post noted that the solar cycle has probably resulted in GCC having less impact on temperatures than would otherwise be anticipated because the Sun is at a minimum in terms of its "11-year" cycle.  Another such impact has been recently identified -- the impact of Arctic salt clouds.

Earth's warming in recent years has had an exaggerated impact in the Arctic, consistent with most predictions.  There, temperatures have soared relative to temperate areas, resulting in an increased summer melting of sea ice.  But new research indicates that the local warming would be even more dramatic if it were not for salt sprays kicked up by whitecaps from the Arctic's increasingly open waters.  Snow and sea ice reflect much of the Sun's rays back into space.  As an increasing share of the Arctic Ocean's year-round cover of sea ice has disappeared, the sea surface has darkened (reduced its albedo), absorbing more solar energy.  In contrast, clouds deflect incoming solar rays; researchers have noted that some of the salt from sea spray could enter the lower atmosphere, forming diffuse filtering clouds of tiny particles.  The question, thus, has been how effectively these clouds might offset warming due to the Arctic Ocean's diminishing summer albedo.

The majority of sea-salt particles emitted into the air are well under a micrometer in diameter.  These tiny particles (aerosols) can persist in the atmosphere for days or even weeks, and apparently can rise to altitudes of a kilometer or more.  Calculations suggest that the effect is roughly 10% of the albedo warming impact from reduced ice and snow; thus, the impact is small, but not insignificant. 

The report on this study can be found at http://www.atmos-chem-phys.net/11/3459/2011/acp-11-3459-2011.html.

Study warns of potential increase in global mercury emissions, which would impact animals in Arctic region

An assessment by a scientific body set up by the eight Arctic rim countries has projected that global mercury emissions could grow by 25% by 2020 if no action is taken to control such emissions, posing a threat to polar bears, whales, and seals and the Arctic communities who hunt those animals for food.  The assessment also warns that climate change may worsen the problem by releasing mercury stored for thousands of years in permafrost or promoting chemical processes that transform mercury into a more toxic form (methylmercury [see http://toxics.usgs.gov/definitions/methylmercury.html]).

Polar bears, beluga whales, and seals are among the species that have shown heightened levels of mercury in parts of Arctic Canada and Greenland, the researchers report.  They note that it is of particular concern that mercury levels are continuing to rise in some Arctic species in large areas of the Arctic despite emissions reductions in nearby regions like Europe, North America, and Russia.  Emissions have increased in other parts of the world, primarily in China, which is now the No. 1 mercury polluter, accounting for nearly half of total emissions, the researchers noted.  [Information on human activities that cause mercury emissions can be found at http://www.epa.gov/hg/control_emissions/global.htm.]

Information regarding the study and its conclusions can be found at http://www.amap.no/.  The report can be downloaded from the "assessment results" portion of the web site.

D.C. Circuit upholds California's GHG law against challenge, finding that the U.S. Chamber and NADA both lacked standing

Prior posts have followed the development of California's greenhouse gas law. 

The U.S. Chamber of Commerce challenged EPA's 2009 waiver which allowed California to regulate GHG emissions. In Chamber of Commerce of the United States et al v. EPA et al, 2011 U.S. App. LEXIS 8685 (D.C. Cir.: 4/29/11), neither the Chamber nor the Auto Dealers Association claimed standing in its own right; rather, both claimed standing to sue on behalf of their members, particularly their members who were automobile dealers.

The Court, however, found that the Chamber had not identified a single member who was or would be injured by EPA's waiver decision; as such, the Chamber lacked standing to raise that challenge.  The NADA had identified allegedly injured members; however, it did not assert that its dealer members had suffered an actual injury at the time the petition for review was filed.  The Court also found that California's emissions standards did not regulate automobile dealers, but rather automobile manufacturers--third parties that had declined to participate in the present challenge.  The affidavits from the Chamber and the NADA were thus insufficient to show the substantial probability of injury required to establish their standing.

The Court also noted that beginning in Model Year 2012, automobile manufacturers had to comply with the national standards whether the court vacated the waiver decision or not.  Manufacturers selling to dealers outside of California and the 42 U.S.C. Section 7505 states would be subject to the same standards as those selling to dealers within them.

The suit was thus dismissed.

The solar cycle is decreasing the impact of GHG emissions, but probably only for the near-term

The sun’s activity waxes and wanes on a cycle that averages roughly 11 years, though cycles as short as nine years and as long as 14 years have been observed.  Chinese astronomers were already tracking the sun’s activity using sunspots more than 2,000 years ago; the modern record of solar output starts in 1755, with cycle 1, and runs through cycle 24, which began in late 2008. Generated by intense magnetic fields, sunspots have proven one reliable indicator of the sun’s overall output and its production of solar storms.

However, the current cycle (with its relative quite period) is "weak".  Sunspots are predicted to be their lowest in 200 years.  Thus, to the extent that solar activity influences Earth's climate, the impact is at a minimum.  A weaker solar cycle is accompanied by a slightly dimmer sun, which changes the average temperature on Earth.  That generality being said, the sun’s brightness did not hit an all-time low during the past solar minimum, even though the sun was unusually quiet.  So, although it can be said that the influence of Earth's climate will be less than when a solar maximum is reached, it cannot be stated with certainty the full extent to which a solar minimum will mean a truly dimmer sun.

Nonetheless, the decline in solar brightness from 2002 to 2008 as solar activity dwindled probably countered the warming on Earth that would otherwise have occurred due to greenhouse gases over that period.  Thus, as solar activity now increases, it can be expected that this mitigating effect will diminish or cease. 

All this implies that the relationship between GHG concentrations and temperature that have been the focus of so much chatter the last decade is probably skewed toward the low side of temperature response.  As solar activity grows in the next cycle this "relationship" will be seen to be inaccurate and too conservative. 

The assessment of the solar cycle can be found at http://www.nature.com/nature/journal/v471/n7336/full/nature09786.html

Trees damaged by bark beetles slow their uptake of CO2 for up to a century

As noted in prior posts, bark beetles damage large forest areas, often killing or causing the death of 50% to 80% of mature trees.  As these trees decompose, they release CO2, adding to the atmospheric burden of GHG's.  New research has identified additional climate repercussions from beetle outbreaks.  Even after a forest has ostensibly recovered from a beetle infestation, the forest continues to suffer a long-term drop in the rate at which growing trees remove carbon dioxide from the air.  The result makes the forest less efficient at removing carbon dioxide emitted by the burning of fossil fuels.

Researchers have asserted in a report that a forest may regain its previous biomass in 7 to 25 years, but the rate at which the forest removes carbon dioxide may remain diminished for much longer — in some cases well over a century.  However, the issue is more nuanced. 

All forested lands do not suffer equally from beetle invasions.  Those with the highest proportion of old pines, which are the most vulnerable to attack, initially suffer the most damage.  However, young survivors are exposed to more light and have access to more of the available nutrients as the old trees die off.  As a result, the growth of the young trees help increase carbon storage.  Thus, because trees grow more slowly as they age, those stands where beetle "victims" had been oldest and the survivors youngest will pose the most limited risk to climate change.

It is therefore important to distinguish the type of forest that is attacked by the beetles in order to assess the longterm impact of the infestation on carbon storage.  No beetle attack is good, but the nature of the impacted forest determines the longterm impact on carbon storage.

Relevant studies on this issue can be found at http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2010.02226.x/abstract and http://www.nature.com/nature/journal/v452/n7190/abs/nature06777.html. 

Arctic ozone deficiency gets severe and moves beyond the Arctic region

If you thought that limitations on CFC production and usage would solve the ozone "hole" problem, unfortunately you were mistaken.  A number of factors play a role.  First, as noted in prior posts, some of the replacement chemicals turn out to not be ozone neutral, one might say, but attack ozone in a manner akin to CFC's.  Second, a lot of CFC piracy is still going on.  It is produced, used, and released into the atmosphere in many parts of the world.  Third, as shown by this year's events, temperatures and weather patterns can exaccerbate the problem.

The spring thinning of Arctic ozone commences in February and has been far less severe than the hole that begins developing over the Antarctic each October, owing to a host of factors that affect ground-level weather in and around the poles.  This year, however, conditions aligned to make the Arctic stratosphere especially cold (below -78°C), a key requirement for heavy ozone losses.  In some parts of the polar stratosphere, temperatures plummeted to below -85°C.  Researchers speculate that global warming, ironically, may be playing a role.  When greenhouse gases trap heat near Earth's surface that energy does not rise to warm the stratosphere.  Additional factors may act to keep that heat from rising, such as a paucity of winds and active atmospheric waves that could reach into the stratosphere and destabilize the polar vortex.

A key factor that causes ozone depletion to differ from one year to the next is temperature; this year, the polar vortex was very stable and its temperature especially frigid.  When this happens, chlorine is converted from a benign form (known as "reservoir species") to a very reactive form ("radicals").  2011 saw very high levels of radicals in the polar vortex, triggering lots of ozone depletion because when the vortex is cold and stable, polar stratospheric clouds of ice crystals can form.  These cloud particles serve as the platform on which radicals instigate unusual reactions that break apart ozone.  This year proved a good year for cloud formation.  Unfortunately, even after the vortex breaks apart, it might take weeks for the radicals to dissipate, eventually shutting down ozone destruction.

Unfortunately, this Arctic ozone thinning is not without human impacts.  Ozone-depleted Arctic air masses did not remain over the polar region alone; they recently drifted over southern Finland.  Predictions were that the ozone-depleted stratospheric air masses might move over parts of Russia and perhaps extend to the Russian-Chinese border.  Portions of Central Europe might also be affected, including regions as far south as the Mediterranean.  Wherever these air masses moved, exposure on the ground to ultraviolet radiation increased with its attendant increase in skin cancer risk.

The science of ozone depletion has shown, once again, that it is not simple.  The problem has unfortunately not been solved. 

Further information can be found at http://europa.agu.org/?view=article&uri=/journals/gl/gl0404/2003GL018844/2003GL018844.xml&t=2004,rex, http://europa.agu.org/?view=article&uri=/journals/gl/gl0623/2006GL026731/2006GL026731.xml&t=2006,rex, http://books.google.com/books?id=52zXIwAUVa8C&pg=PA154&lpg=PA154&dq=ozone+depletion+arctic+cause+factors+weather&source=bl&ots=Tmfzbh9yDm&sig=BAukw-EWAXvJDJXj9PviHPKYuM4&hl=en&ei=SnqmTcL2LYuisAPDnoX5DA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CB8Q6AEwAQ#v=onepage&q&f=false,  http://www.sciencedaily.com/releases/2011/04/110405102202.htm, and http://cordis.europa.eu/fetch?CALLER=EN_NEWS&ACTION=D&RCN=33189.