The Void Between Rhetoric and Reality

Vitis vinfera - ordinary grape leaves, damaged by ozone
Photos of damaged foliage are from the ozoneinjury website, linked below

The UK Guardian featured a story one year ago, reporting on research that indicates climate change is far worse than most scientists, activists and politicians make it out to be.  Since then all indications are that real impacts are advancing ever faster than was imagined even then...tipping points, accelerating amplifying feedbacks, black swans, catastrophe theory and all that.  Perhaps this notion is too unpalatable for the Center for American Progress, because they refused to publish the link with my comment in response to a post about denialist misinformation (Your comment is [*still!*] awaiting moderation. March 6, 2012 at 5:50 pm) which was:

Quercus faginea, Oak leaves - left, in filtered clean air...right, exposed to ozone

Let's hope more scientists will speak up like Kevin Anderson and tell the truths, the absence of which enables deniers such suspicions - it's going to be VERY unpleasant to reduce emissions enough to even begin to avert the worst effects of climate change.  That's what he means when he says it will require:

Viburnum lantana

"...radical changes in behaviour, particularly from those of us with very high energy consumption."

In other words, consumers in rich, industrialized countries are going to have to make real sacrifices in their standard of living (to the extent it is measured by consumption).  That's what deniers realize, even if environmental activists do not.  Here are excerpts from the article:

Frangula alnus

"Too many models use an extrapolation of old data and this gives results that are too optimistic," said Anderson. "When I present my findings I am often pulled apart for taking away people's hope. But what these models are giving us is false hope. Surely that is worse?"

He and his co-author  "...found that several models assumed that fossil-fuel carbon-dioxide emissions from developing nations would exceed those from industrialised nations as late as 2013–2025, despite the actual date being around 2006."

Salix alba

"He believes that this false hope that the output from these models has been spreading is one reason why policymakers and the general public have not engaged with the sweeping changes necessary for industrialised nations to drastically reduce their emissions. 'This requires radical changes in behaviour, particularly from those of us with very high energy consumption," said Anderson. "But as long as the scientists continue to spread the message that we will be ok if we all make a few small changes, then climate change will never be on top of the policy agenda and we will fail to meet our international commitments to avoid a 2°C rise.'"

Vinca difformis

He adds: "All too often, climate change is described as a problem of the future, but climate change is a cumulative problem that needs to be tackled now. And this can only be done if researchers use realistic data and report brutally honest results, no matter how disturbing or depressing."

His presentation from 2011, where he discusses the "void between the rhetoric...and the reality" is titled "Climate Change - Going Beyond Dangerous...brutal numbers and tenuous hope."

Tilia cordata

Exactly the same void between rhetoric and reality is true for damage to plants from pollution, only more so.  Despite the enormous amount of research documenting the problem, going back to the 1950's, not one of the scientists will openly explain just how serious the threat to the ecosystem and agriculture really is.  Does this parsley look anything like what they're selling in the grocery store lately?

Parsley

The New York Times declared excitedly that new research indicates Asian pollution is impacting the western states, which is ridiculous, because it's been known for some time that it is traveling over the ocean - should anybody care to check.  In fact the authors (Lin et al) themselves state in the abstract of their  paper that they are corroborating earlier studies indicating that massive amounts of pollution from Asia are imported to the US.  What IS new is that they say:  "To the best of our knowledge, this is the first time a global high-resolution model with full stratospheric and tropospheric chemistry has been employed to address the problem of trans-Pacific pollution transport."

Broccoli

What's actually important and novel about this paper is that their model and satellite measurements indicate that earlier estimates of how much pollution is being imported were too low.  And it's getting continually worse - their study examines episodes in Spring of 2010, but as this article explains, China just announced it has been unable to meet its own goals in reducing pollution in 2011, especially the ozone precursors:  "Sulphur dioxide emissions fell by 2.2 percent, below the 2.9 percent goal, while nitrogen oxide, which was intended to fall by 1.5 percent, actually rose by 5.7 percent."

Viburnum opulus

Following are excerpts from the Lin et al paper:

"During strong episodes, Asian emissions can contribute 8–15 ppbv ozone in the model on days when observed daily maximum 8-h average ozone (MDA8 O3) exceeds 60 ppbv. We find that in the absence of Asian anthropogenic emissions, 20% of MDA8 O3 exceedances of 60 ppbv in the model would not have occurred in the southwestern USA. For a 75 ppbv threshold, that statistic increases to 53%. Our analysis indicates the potential for Asian emissions to contribute to high-O3 episodes over the high-elevation western USA, with implications for attaining more stringent ozone standards in this region."

"In particular, we quantify the contribution of Asian pollution to surface O3 levels on highly polluted days in both densely populated regions such as the Los Angeles (LA) Basin and in rural areas such as national parks."

Figure 3. Evolution of two midlatitude cyclones and associated flow structures over the Pacific North America on May 17–19, 2010. Shown are (a–c) AM3 6-h mean sea level pressure (contours, hPa) with 300–400 hPa layer average specific humidity (shading, mg/kg) at 21:00 UTC and (d–f) AIRS retrievals of daily mean total column amounts of ozone (shading, DU) with 300 hPa potential vorticity (contours, PVU) computed from GFS Final analysis at 18:00 UTC. Only PV values greater than 2 PVU are contoured and signify air of essentially stratospheric origin. The thick black line along the California coast in Figure 3e indicates the location of vertical cross-section shown in Figure 4.

Figure 6. Spatial patterns of daily maximum 8-h average ozone in western U.S. surface air on June 20– 22, 2010, showing (a) CASTNet (circles) and AQS (squares) observations, (b) results from the surface layer in the GFDL AM3 model, and (c) the enhancements due to Asian anthropogenic emissions, calculated using the same 8-h interval identified for the MDA8 in the base simulation.

Rumex sp.

"The threshold value for the U.S. primary National Ambient Air Quality Standard (NAAQS) for ground-level O3, based on the 4th highest daily maximum 8-h concentration (MDA8) averaged over three years, has been lowered twice since the 1980s, with the current 75 ppbv threshold implemented in May 2008. In 2010, the U.S. EPA proposed to further revise the NAAQS O3 threshold to one in the range of 60–70 ppbv.  If a 60 ppb threshold were to be adopted, the number of violating counties across the USA would double (based on the 2006–2008 monitoring data)."

Lavatera arborea

"The rising Asian contribution to U.S. surface O3 levels poses an additional challenge to meeting more stringent NAAQS for O3. Earlier work indicates that the contribution of Asian emissions to surface O3 in the U.S. reflects mostly an enhancement in background levels, and generally decreases on highly polluted days in summer. However, a few recent studies suggest a correlation between O3 entering the U.S. west coast and local pollution episodes in California."

Oenothera biennis

"At present, quantitative estimates of the specific sources of O3 flowing into the western USA (e.g., recirculation of North American emissions, intercontinental transport, stratosphere-to-troposphere exchange, and other natural sources) are lacking. Advancing our understanding of the contribution from these sources to total surface O3 over the western U.S. is crucial to inform the NAAQS- setting process and to develop effective state implementation plans (SIPs; the process by which states demonstrate their path to achieving compliance with the NAAQS)."

Polygonum lepathifolium

"Observational studies document the frequent transport of Asian dust, sulfate aerosol and mercury to the surface of western North America, and on rare occasions these events can be relatively strong. While these events are common, modeling studies suggest that only a small portion (<10%) of the Asian pollutants reaching the North American free troposphere actually descends into surface air."

Morus alba

"However, these prior estimates, based on global-scale chemical transport models (CTMs) or Lagrangian trajectory models, both driven with meteorological fields typically at 2° 2° horizontal resolution, may be conservative as these coarse-resolution models have limitations in capturing meso-scale processes contributing to the exchange of pollutants between the boundary layer and the free troposphere. The dilution of intense plumes due to numerical diffusion in global-scale models further diminishes the modeled impacts of vigorous episodic transport events."

Tamus communis

Just by coincidence, I happened to revisit a site called ozoneinjury.org.  I'm not sure how long ago I last looked at it, but I don't recall it being nearly the splendid resource it is now.  A joint effort under the auspices of various European agencies, they have been conducting research with controlled fumigation at a site in Spain, assessing foliar damage, both visible and microscopic.  I've reported here at Wit's End many times that studies indicate ozone causes a reduction in crop yields - but even so I found this picture of potatoes absolutely staggering.

The published paper is here

On the left are potatoes grown in filtered (clean) air, the middle group in non-filtered (ambient, 2002 polluted background levels) - and on the right, additional ozone added (30 ppb/8hours/day).  This is from the research abstract:  "In comparison with the filtered treatment, the ozone treatments significantly reduced commercial tuber production, by 53% (NF) and 65% (NF+)".

Potato leaves damaged by ozone

Since this study was conducted in 2002, the background ambient levels have been going up globally about 2 ppb/year (at least).  The purpose of the study was to determine if fertilizing with manure would help ameliorate ozone impacts, which according to their results, it does.  The photo of potatoes above is from the control group in the experiment with no added manure (0 Kg).  Let's keep in mind - we can't possibly add manure to the forests of the world, even assuming that it will be sufficient to mitigate ozone as levels continue to climb in the troposphere.

Scrophularia auriculata, filtered air on left, ambient + added ozone on right

The site also has two pages of photographs, some of which are reproduced here.  One page is for annual agricultural crops and one for forest species, where you can have no end of fun clicking on different species to see photos of what leaves look like when they have been exposed to ozone.  This is going to be quite useful as the spring and summer unfold, because I can guarantee you, every single leaf is going to exhibit symptoms identical to those depicted, by July.  Their handy guide is a manual of how to distinguish ozone symptoms - stippling, chlorosis, premature senescence and other effects.

Tropaeolum majus, nasturtium - this is exactly what they have looked like the past 2 summers

This is from their home page:

"Ozone is one of the most important pollutants in large areas of Europe. There is evidence that the ambient ozone concentrations found in Europe can cause a range of effects to ecosystems and agrosystems, including visible leaf injury, growth, yield reductions, and altered sensitivity to biotic and additional abiotic stresses. Since ozone pollution leaves no elemental residue that can be detected by analytical techniques, visible injury on leaves is the only easily detectable evidence in the field. Even though visible injury does not include all the possible forms of injury natural vegetation (i.e. pre-visible physiological changes, reduction in crop production, growth, etc.), observation of typical symptoms on above ground plant parts in the field has turned out to be a valuable tool for the assessment of the impact of the ambient ozone in sensitive species."

Solanum sodomeum

Another page at the site reproduces microscopic evidence of damage from absorption of ozone in Acer Campestre (common name "field Maple", native to Europe).  This is very important because the internal chemical reactions that occur when plants absorb ozone lead to diminished nutrient value.  The text is and illustrations are as follows:

DESCRIPTION OF VISIBLE INJURY: 

Symptoms produced by ozone in  Acer campestre leaves are initially characterized by an interveinial yellowing in the upper side of the leaves. Later, these symptoms evolve into an interveinial brown-reddish stippling. As it is typical of ozone, injury is mainly observed in the oldest leaves.

DESCRIPTION OF HISTOLOGICAL CHANGES:

In general, there is a decrease in the amount of chloroplasts and chlorophyll content, an increase of calose content in the phloem, intercellular species increase and some stomata become occasionally altered. Senescence is accelerated.

  

Palisade parenchyma of young leaves experiences an increase in tannins and starch content. In more affected leaves, cells become more separated, intercellular speces increasing; chlorophyll and starch content decrease. Effects are also observed in the spongy parenchyma; the middle lamella is altered, cells are deformed and there is a decrease in vacuolar and chlorophyll contents. Calose 

increases in the phloem. 

In older leaves, symptoms are similar to those described for young leaves. Palisade and spongy parenchyma experience a degradation of chloroplasts, intercellular spaces increase, and chlorophyll and starch content decrease. Calose accumulation in the phloem also increases, and some injured stomata are observed.

 Fig. 1:  Leaf with initial ozone symptoms (interveinial yellowing).

 Fig. 2:  Symptomatic leaves with brown-reddish sttipling

 Fig. 3:  Section of a control (filtered air) young leaf (paraffin embedded, stained with safraninfast green). Both the mesophyll and the two epidermises are very compact. Intercellular spaces are almost absent. Parenchyma cells show many chloroplasts in the periphery of the cell, which central part is filled with a vacuole. In the adaxial epidermis, cells are provided with large vacuoles which content shows affinity for safranin. Bar: 20 μm.

 Fig. 4:  Section of a control (filtered air) leaf (semithin section, stained with toluidine blue). Note the inner part of the epidermis, with vacuoles showing polyphenol accumulation, with a high affinity for toluidine. Mesophyll cells show no structural damage. Vascular bundles are perfectly functional. Bar: 20 μm.

 Fig. 5: Micrograph of a control old leaf stained with toluidine blue. Above epidermis, cuticle is thin. A vacuole containing poliphenols is clearly observed in the lower part of epidermal cell. Palisade parenchyma is monostratified. Transition and spongy parenchyma cells show a big central vacuole and chloroplasts that are uniformly distributed in their periphery. Bar: 20 μm.

 Fig. 7.  Micrograph of a young leaf exposed to enhanced ozone levels for a few weeks and stained with toluidine blue. Injury is observed both in palisade and in spongy parenchyma cells. Intercellular spaces increase and cells become slightly deformed due to alterations in the cell wall. Bar: 20 μm.

Fig. 8:  Semithin section of a young fumigated leaf stained with toluidine blue. Upper side of the leaves show characteristic incipient injury. Walls turn sinuous, some palisade parenchyma cells show a more dense vacuolar content, not homogeneous, with granulose areas and strips. Polyphenol content of epidermal-cell vacuoles is more dense and obscure. Chloroplasts are more disorganized and swollen. Bar: 20 μm.

Fig. 9: Semithin section of a young leaf fumigated for several weeks, and stained with toluidine blue. With respect to the previous figure, injury is progressing; alteration of the middle lamella and cellular collapse produces an increase in intercellular spaces. Spongy parenchyma is formed by angulose and deformed cells (characteristic of the injury caused by ozone). Vacuoles lose turgor and some chloroplasts may have a more central position inside cells. Polyphenolic content of epidermal cell vacuoles is extravasated and fills intercellular spaces among palisade parenchyma. Bar: 20 μm.

Fig. 10: Semithin section of an old leaf exposed to ozone during a few weeks. It has been stained with neutral red. Palisade parenchyma shows large intercellular spaces due to cell collapse, and chloroplasts are few and are severely injured. Spongy parenchyma show angular cells which vacuolar content shows a high affinity for neutral red, suggesting an increase in antioxidants. Middle lamella is degraded, vacuole tonoplast is degraded and finally some cells also collapse. Bar: 20 μm.

Fig. 12:  Micrograph of a young fumigated leaf after a few weeks of fumigation. Semithin section stained with Lugol, with a large accumulation of amiloplasts (stained dark bluish  brown). Barra: 20 μm.

And now, we'll have a quick recap, before we finish today's post with a Quiz! (these remaining images are from the brilliant photographer Peter Lippmann, whose work, like the fabulous link to all the other pictures on this post, was originally sent to me by the endlessly resourceful and indefatigable anonymous researcher, known only to the world as Highschooler...THANK YOU!!!).

In an overview already articulating the existential threat of ozone from 2008, we learned this:

"Modern day concentrations of ground level ozone pollution are decreasing the growth of trees in the northern and temperate mid-latitudes, as shown in a paper publishing today in Global Change Biology. Tree growth, measured in biomass, is already 7% less than the late 1800s, and this is set to increase to a 17% reduction by the end of the century."

"Ozone pollution is four times greater now than prior to the Industrial Revolution in the mid-1700s; if modern dependence on fossil fuels continues at the current pace, future ozone concentrations will be at least double current levels by the end of this century with the capacity to further decrease the growth of trees."

"The study is the first statistical summary of individual experimental measurements of how ozone will damage the productivity of trees, including data from 263 peer-reviewed scientific publications.

Ozone is the third strongest greenhouse gas, directly contributing to global warming, and is the air pollutant considered to be the most damaging to plants."

"But more importantly, it has the potential to leave more carbon dioxide, ranked as the first strongest greenhouse gas, in the atmosphere by decreasing carbon assimilation in trees. Ozone pollution occurs when nitrogen oxides have a photochemical reaction with volatile organic compounds."

"'This research quantifies the mean response of trees to ozone pollution measured in terms of total tree biomass, and all component parts such as leaf, root and shoot, lost due to ozone pollution,' said Dr. Victoria Wittig, lead author of the study. 'Looking at how ozone pollution affects trees is important because of the indirect impact on carbon dioxide concentrations in the atmosphere which will further enhance global warming, in addition to ozone's already potent direct impact.'"

"In addition to ozone pollution reducing the strength of trees to hold carbon in the northern temperate mid-latitudes by reducing tree growth, the research also indicates that broad-leaf trees, such as poplars, are more sensitive to ozone pollution than conifers, such as pines, and that root growth is suppressed more than aboveground growth."

"'Beyond the consequences for global warming, the study also infers that in mixed forests conifers will be favored over broad-leaved trees, and that the decrease in root size will increase the vulnerability to storms,' said Wittig."  (full original paper here)

Now to our quiz, choose TRUE or FALSE for each statement:

T or F?  Ozone levels are increasing

T or F?  Ozone levels have been underestimated

T or F?  Ozone travels around the world to even remote rural areas

T or F?  Ozone damages the surface of leaves and needles, disabling protective waxy layers - and also enters plant tissue through stomates when they photosynthesize, where it causes internal injury

T or F?  Ozone causes plants to be more vulnerable to insects, disease and fungus

T or F?  Ozone reduces root systems, causing vegetation to be more vulnerable to drought and wind

T or F?  Ozone reduces annual crop quality

T or F?  Ozone reduces plant biomass, causing yield loss in annual crops

T or F?  Ozone reductions in biomass will lead to a loss of an invaluable carbon sink, exacerbating climate change

T or F?  All over the world, trees are dying

Did you answer True for each one???  Great!  I'm glad that's all settled now.

Of course, I was compelled several years ago to follow up on that study, for all the good it did.  For those inclined towards nostalgia, here is correspondence with some of the authors, from last January and following backwards, referring to the first exchanges about the results:

Folks

I agree with these comments from John, but I would also like to add a positive note concerning the link between the mitigation of climate change and the mitigation of ground-level ozone...

Increases in ozone are known to have an impact on climate as ozone is a greenhouse gas. Also, as pointed out by "Wit's End" and John, near-surface ozone has a detrimental impact on crop yields, and on the net primary productivity and carbon content of natural vegetation. This means that ground-level ozone also has an indirect impact on climate by reducing the amount of CO2 that can be taken-up by the land biosphere. This may double the effect of tropospheric O3 as a climate forcing factor  (Sitch et al., Nature, 2007).

If we were to take a pessimistic view, we might say that this means that increases in tropospheric ozone are really bad news for both climate and food availability.

On the other (more optimistic..;-) hand, you could conclude that reversing the increase in tropospheric ozone is a major opportunity to partially tackle two of the biggest 21st century problems. As John suggests, pollution controls (particularly regarding NOx) have the potential to reverse the rise in O3, particularly if they are coupled to reductions in anthropogenic emissions of CH4. I attach a brief paper (by myself and Hazel Jeffery) that discusses the latter point (building on previous studies from John's group at MIT).

So I agree that potential increases in tropospheric O3 are more important than most climate scientists realize (even for climate), but I don't see this as reason for despair because we can do something about it, and (unlike CO2 emissions reductions) it looks like we will....

Happy New Year

Peter

Prof Peter Cox
Professor of Climate System Dynamics
College of Engineering,  Mathematics and Physical Sciences
University of Exeter
Exeter

________________________________________
From: John M Reilly, MIT
Sent: Thursday, January 06, 2011 11:48 PM
To: Wit's End; executive-editor@nytimes.com; wittig@atmos.uiuc.edu; lisa.ainsworth@ars.usda.gov; kpercy@nrcan.gc.ca;wmanning@microbio.umass.edu; tsharkey@msu.edu; Cox, Peter
Subject: RE: ozone

Ozone clearly has detrimental effects on vegetation but so far the effects on crops are estimated at the 5 to 10% level for large regions with high levels.  We have been examining this issue and publishing work that shows that left unchecked it could become a more severe threat.  Of course ozone also causes damages to human health and we have tried to document these effects on the economy through lost wages, leisure time, and increased hospital care to treat increased asthma and other respiratory problems, which are actually a greater economic threat than its effects on vegetation and crops.  We work closely with, and with funding from the EPA and so I believe we are doing what we can to support formulation of better policies and measures to control ozone levels.  The US and Europe have regulatory processes in place to deal with ozone.  We have also worked to alert policymakers to the potential for hemispheric transport of ozone, making it that much more difficult to control domestic levels with only domestic controls, and are working on the issue in China and elsewhere in the world to help alert countries as to why it is in there interest to control ozone levels.  I’ve discussed some of these aspects of the problem with media when I have had the chance.  We are concerned with many environmental threats—global climate change, mercury, ozone, particulate pollution, etc.—that are all having various deleterious effects on vegetation, and so it is important to understand what is causing what and how these different pollutants interact so that regulatory measures can most effectively reduce the threat.

Problems like these need pushes from many directions, and I feel most comfortable and that my efforts are more effective if I work to conduct careful scientific studies and assessments and bring these to the attention of regulators and policy makers, as opposed to developing a strong advocacy approach to the problem.    Strong advocacy and highly visibly public actions may be needed as well, but that just isn’t my strong suit.

Sincerely,

John M. Reilly
Co-Director,
Joint Program on the Science and Policy of Global Change
& Senior Lecturer,
MIT Sloan
Massachusetts Institute of Technology, E19-429L
77 Massachusetts Ave,
Cambridge, MA 02139

From: Wit's End [mailto:witsendnj@yahoo.com]
Sent: Thursday, January 06, 2011 6:07 PM
To: executive-editor@nytimes.com; wittig@atmos.uiuc.edu; lisa.ainsworth@ars.usda.gov; kpercy@nrcan.gc.ca;wmanning@microbio.umass.edu; tsharkey@msu.edu; John M Reilly; p.m.cox@ex.ac.uk
Subject: ozone

Dear Editor and Professors,

I last wrote you in August of 2009 to inquire about the impacts of ozone on vegetation.  Only Dr. Sharkey was kind enough to reply.

Since then, I wonder if any of you realize that we are in the midst of a mass extinction of perennial vegetation, as well as devastating reductions in annual crops, from ozone - and simply decline to inform the general public?

Or, have you actually not noticed the rapidly accelerating death of trees, perennial shrubs and plants (including ocean phytoplankton), and extremely diminished production of agricultural products from rice to wheat, due to exposure to ozone?

Don't you, as experts and persons of influence, feel some responsibility to inform the citizenry and policy makers that if we don't cease burning massive amounts of fuel on an emergency basis...to conserve and ration, and switch as rapidly as possible to clean sources of energy...we will most certainly starve - because the inexorably rising levels of tropospheric ozone are interfering with the essential ability of vegetation (the base of the food chain) to photosynthesize?

I would very much appreciate any response.  For your information, I have been collecting links to research and documenting the decline here <http://www.witsendnj.blogspot.com/>.

Please understand that if you choose to not even acknowledge this specific correspondence, I will do my utmost to the extent possible to make sure that it is widely recognized that you have the knowledge and have chosen to refudiate (oh no oops, that's Sarah Palin!) repudiate any responsibility for disseminating information which is essential for the survival of the human race, among countless other species.

I welcome any comments or suggestions.

Sincerely,

Gail Zawacki
Oldwick, NJ