This year’s annual Palm Beach Jewelry, Art & Antique Show was held over President’s Day weekend, and as the weather was particularly fine (as it is ordained to be!), I decided to walk across the drawbridge over Lake Worth to the Convention Center. There I expected to wallow in cognitive dissonance, suspended between overt ecosystem collapse and the outrageous, glittering opulence of a community founded by Standard Oil, and I was not disappointed.
Before I set out, I checked by phone to see whether photography was allowed - because I didn’t want to haul my heavy camera over there for nothing - and I was informed pictures were permitted only with permission from each individual vendor. This was an annoying but not impossible impediment for my purposes, so I carried it along, and was pleasantly surprised to be greeted by this sign:WELL, that certainly looked like photography was not only unrestricted but encouraged, and so I wove my way merrily though the exhibits, taking pictures of paintings depicting the life of leisure, the grimacing statues of Tang Dynasty Chinese warriors, plus piles of strands of impossibly fat pearls, and absurdly intricate Russian cloisonné, not to mention must-have 50 million year old Eocene fossils from Wyoming, that can be used as decorative shower tiles...oh and elaborately veneered furniture...
Whenever I could sneak one in without being too obvious, I took pictures of the patrons...which was my main interest in going, actually. Those all came out blurry, because it would have been awkward to use a flash - as it was, I scooted hastily out when I started hearing murmurs from people wondering what I was doing, and the ladies popularly known as Boca Blonds began to glare at me indignantly.
Ever hear of the famous facebook page, which eventually resulted in the eponymous book, Humans of New York? I recently discovered it - and it’s full of adorable, quirky, idiosyncratic, charming portraits of humans young and old, rich and poor, fat and slim, gay and straight, all races and classes replete in glorious human vulnerability and warmth...and the very adorableness of it, for us misanthropes, is unbearably rank with Polyanna cheer. By way of an antidote, I have been anxious since arriving in this area of Florida (which in contrast has only two sorts of people, the wealthy and their
I know I am being mean, but this is for all my anarchist friends who like to blame greedy capitalists for the woes of the world...here they are - go get ’em! - for zombies is exactly what these walking cadavers resemble. Not one female (other than me) under the roof of the cavernous convention center had naturally colored hair, and every one past the age of, say, forty, had a surgically enhanced face.
The Zombies of Palm Beach have for the most part escaped the American epidemic of obesity and instead their inclination is a pronounced tendency towards the grotesquely anorexic. My theory is that they saw those Occupy signs that read “Eat the Rich" on the tv, and decided to make themselves as unappetizing as possible.
Here is a mother determined to look as young as her daughter.
The zombies are as fake as the overpruned, oversprayed hedges that conceal their seaside compounds, plants that are kept barely alive, propped up with extreme chemical treatments to ward off opportunistic and crippling attacks from insects.
I am left with the ongoing dilemma of trying to decide which is more creepy...the plastic manicured trees, or the plastic manicured people.
Anyway, I found plenty of poignant reminders at the exposition of the ironies that plague our modern existence. There were walls covered with botanical prints of birds and shells and flowers that evoke the lush biodiversity that is being fast annihilated in myriad ways.
Yet meanwhile the party continues unabated - in certain locales, that is. In this venue, unrepentant self-congratulation celebrated our so-called progress, such as this Norman Rockwell image titled Couple’s 25th Wedding Anniversary, a 1925 advertisement for the Dodge Brothers Motor Cars. See how happy and victorious they are? Triumphant, even!
In the lower left the newlyweds are depicted in their former state of deprivation:
An 1883 oil painting by William Morgan, titled Young Soldiers, presents their parade with trite affection.
Although, the detail in the lower left depicts a glimpse of ugly bullying.
This collection of pictures revealing the frenzy of acquisition at the show is going to serve as the backdrop for a long-delayed post about ozone, and what it is doing to the environment, especially trees.
There is of course no lack of new research and articles on this topic, but given the rapidity with which the climate is spinning out of control, it’s questionable whether there is anything to be gained by writing more on the subject. It’s far too late to even slow the dash to catastrophe...so no, LOVE is not the answer, Professor Einstein - at least, it won’t do a thing to avert the ecopocalypse.
I am bemused when I hear from people (a few, now and then) who express appreciation for what they have learned from the research that is posted here at Wit’s End - and then go on to express all sorts of hopeful expectations for how we will surmount the intractable dilemmas that are listed here. I have to wonder - do they even actually read what is written? What part of extinction did they miss?
Do they understand that pure vanity is what drives us? The Greeks warned of hubris long ago and yet it still defines our behavior.
Nature just IS - it never “meant” anything to be cosmic or sacred or eternal or spiritually connected (other than the delicious fantasies we invent in our minds) and it never will.
Oops...I digress...One of these days maybe I will write something about the lack of free will, and how we evolved to recognize patterns even where none exist, and how this helped us survive for a long time but has now ensured our extinction...
but for now, back on-topic, we will review a momentous report written by the Working Group on Effects of the Convention on Long-range Transboundary Air Pollution for the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops.
I know it is boring, as in many ways this summation is a repetition of the ISA (Independent Science Advisory) board’s assessment to the EPA on “secondary impacts” (to plants and animals, as opposed to human health), which was the basis for former Administrator Lisa Jackson’s failed attempt to strengthen regulations in the US. But, despite its dry analysis and recommendations, this document offers a chilling portrait of the great unraveling of the natural world, if you pay close attention to the implications of its prognosis.
The
ICP Vegetation Annual Report for 2012/2013 is couched in the typically tepid
bureaucratic language that characterizes government agency publications, even
those that are chronicling the great demise of life on earth. Published by the
Centre for Ecology & Hydrology, the document, titled simply “Air Pollution
and Vegetation” predictably calls for more research, even though it is plain
enough in its pages that for any practical purpose, NO more research is required - because it’s
quite obvious that air pollution is killing the very plantlife we and every
other species require for food, habitat, ample rainfall and clean air to
breathe. It is equally obvious what should have been done about it years ago, and wasn’t, and won’t be, and can’t have ever been.
In
a desperate attempt to salvage some of Earth’s wild biosphere, scientists are
following a trend of placing monetary value (to humans) of ecosystem “services”.
It’s annoying - although perhaps well
intentioned - but nonetheless, for the purposes of unveiling the extent to which Earth’s life
support systems are being mauled, it can be an instructive method, because this approach reveals just how
seriously forests, and by extention the entire biosphere, are being degraded by pollution.
What is astonishing is the vast extent of the
knock-off effects that are chronicled, from plants on to pollinators
and soil microbes and precipitation, and well beyond…nothing less than what, as we shall soon see is deemed, “global toxification”.
This
is a fact which is generally denied when phrased straightforwardly, but which
can be discerned in the backwards presentation of what could be
“saved” were ozone to be reduced - as opposed to what has already been lost (quite likely permanently, so advanced is the damage)...and what inevitably will be lost, since no governments are going to adopt the regulations proposed, contrary to the fervent wishes of environmentalists.
The concept is spelled out in section 3.1, “Ecosystem services”. Everything that follows, unless otherwise indicated, is excerpted from the aforementioned
report. I will not comment, because it seems eminently clear from the extent of impacts revealed, and the level of concern demonstrated by the vast number of countries involved, just how how grave the destruction from ozone has become.
Global
toxification (including air pollution) is one of the “savage sextet” (Aguirre,
2009) of direct drivers of ecosystem degradation, with the others being
over-exploitation of species, introduction of novel exotic species, land use
changes (principally habitat destruction, fragmentation and degradation),
pathogen pollution and global warming (Mantyka-Pringle et al., 2012).
Indirect
drivers of ecosystem change are associated with demographic, economic,
socio-political and cultural or religious changes, and advancements in science
and technology. Stressed or degraded
ecosystems do not have the resilience or re-bound capacity of
pristine/unstressed systems (Rapport and Maffi, 2009).
Furthermore,
there is often a substantial time-lag between a change in a driver and the time
taken to realize the full consequences of that change in any given system. Even
more worrying is that once a threshold is crossed, a system may alter to a
distinctly changed and sometimes irreversible new state.
Careful
management of our ecosystems and the benefits and services we derive from them
are therefore vital for future prosperity and general human well-being.
Human
influence extends into even the remotest landscapes and more often than not has
a pervasive influence on the ecosystems they support, frequently irreversibly
changing biodiversity. Whilst extinction rates of species are now estimated to
be 1,000 times greater than historical background levels (Millennium Ecosystem
Assessment, 2005; Mantyka-Pringle et al., 2012), recent studies have identified
linkages between changes in biodiversity and ecosystem functioning, highlighting
the importance of adopting a multi-sectoral approach to policy and decision
making (e.g. Maestre et al.,
2012;
Mace et al., 2012). Such an approach fully evaluates changes in ecosystem
services and their impacts on humans and examines the supply and condition of
each ecosystem service, as well as the
interactions
among them. Society needs to make difficult decisions regarding its use of
biological resources and environmental valuation techniques provide useful
evidence to support polices by quantifying both the monetary and non-monetary
value associated with the protection of resources.
To
support this drive, the Intergovernmental Platform on Biodiversity and
Ecosystem Services (IPBES) was established in April 2012 by 90 governments and
acts as a global mechanism for gathering, analyzing and synthesizing
information to advise decision-making on biodiversity and ecosystem services
(Redford et al., 2012).
As
shown in Figure 3.1, ecosystem services can be classified into provisioning,
regulating, supporting and cultural services. When considering impacts of one
driver of change (in this case ozone pollution), it immediately becomes clear
that impacts on one service are linked to several and sometimes all of the
other services.
For example, negative effects of ozone on root growth would impact on provisioning services (crop foods, wood production, water uptake), regulating services (climate and water regulation), supporting services (nutrient cycling, primary production, water cycling) and possibly cultural services by impacting on the aesthetics of a natural ecosystem.
For example, negative effects of ozone on root growth would impact on provisioning services (crop foods, wood production, water uptake), regulating services (climate and water regulation), supporting services (nutrient cycling, primary production, water cycling) and possibly cultural services by impacting on the aesthetics of a natural ecosystem.
Because
of such complexities and the growing desire to add an economic value to
ecosystem services, the final ecosystem services that provide goods of value to
humans can be considered to be linked by “stocks and flows” to the underpinning
ecological processes (Mace et al., 2012). For example, ozone reduces primary
productivity in forest trees (i.e. impacts on an ecological process),
influencing the final ecosystem service of tree production which can be used
for a variety of goods such as timber, fuel, carbon sequestration and
recreational value. The final value of these goods is dependent on the inputs
to the forest system such as management costs, fertilizer etc. all of which may
be influenced by the negative effects of ozone on productivity.
3.3
Impacts of ozone on
ecological processes and supporting services
Until
recently, much of the research on ozone impacts has focused on quantifying
effects on ecological processes rather than considering the implications for
ecosystem services. This report, for the first time, places current
process-based knowledge within the context of ecosystem services and thus
reports on the potential for impacts of ozone on ecosystem services and
biodiversity. Ozone pollution impacts directly or indirectly on many of the
fundamentally important ecological processes and supporting services that
underpin almost all ecosystem services, these include:
Primary
productivity and carbon cycling
Ozone
reduces whole plant photosynthesis by directly impacting on the photosynthetic
machinery (Rubisco and chlorophyll content), reducing leaf area by promoting
early senescence and leaf abscission, diverting carbon (C) use into
detoxification and/or repair metabolism, changing stomatal conductance (both
increases and decreases have been noted, see below) and altering C allocation
in favour of the above ground parts rather than below ground parts. Carbon flux
to and from the soil is also altered by changes in leaf litter quality, altered
rhizodeposition of C, changes in soil microbial community composition, and
altered soil processes.
Nutrient
cycling
Tropospheric
ozone has the capacity to impact on nutrient cycling by both direct and
indirect mechanisms: by altering the chemical composition of plant tissue and
the quantity (and quality) of litter fall, impacting on below-ground plant
biomass and root exudates, indirectly altering microbial community
composition(s) and functioning, and soil processes and the chemical properties.
All
of these have the capacity either, independently or in concert, to ultimately
reduce the long-term sustainability of ecosystems (Lindroth et al., 2001).
Pre-Colombiam Tomb Warrior, Sicanese, ca. 100-1400 AD
|
Stomatal
functioning and water cycling
Tropospheric
ozone is known to alter stomatal responses to environmental stimuli and in the
short term (at higher concentrations) can cause stomata (leaf pores) to close,
however, under prolonged chronic exposure (at lower concentrations) many
reports document ozone-induced stomatal opening or loss of stomatal sensitivity
to closing stimuli, such as drought, light and humidity.
In
a review of 49 papers covering 68 species conducted for the full report, 22% of
species showed no change in stomatal conductance, 10% showed a slowed
(sluggish) stomatal response to elevated ozone, 23.5% showed an increased
stomatal opening under elevated ozone and 44% displayed stomatal closure in
response to ozone (Mills et al., 2013).
No clear patterns emerged for the ozone
concentration range for the different responses, except perhaps a tendency for
stomatal opening to occur at lower concentrations than stomatal closure. For
consequence in water cycling, see Section 3.5.
3.4
Impacts of ozone on
provisioning services
Examples
of impacts of ozone on provisioning services include impacts on:
Crop
production
Effects
of ozone on primary productivity are especially relevant for crop plants. With
the world population predicted to increase to 9 billion by 2050, security of
food supplies is one of the most important challenges for this century. Ozone
damages crop plants by, for example, reducing
photosynthesis,
causing a yellowing of leaves and premature leaf loss, decreased seed
production and reduced root growth, in turn resulting in reduced yield quantity
and/or quality and reduced resilience to other stress such as drought.
As a
consequence, the key components of the food system that ozone interferes with
are the productivity of crops, the nutritional value and the stability of food
supplies as ozone concentrations and therefore impacts vary from year to year.
Some of the world’s most important staple food crops are sensitive (wheat,
soybean and other pulses) or moderately sensitive (maize, rice, potato) to
ozone and effects on the yield of these crops are of global significance.
A
recent state of knowledge report by the ICP Vegetation (Mills and Harmens,
2011), for the first time, quantified ozone impacts on wheat yield in Europe
using the stomatal flux-based methodology and predicted that losses would
remain at 9% in 2020 amounting to €2 billion in EU27 (+ Norway and
Switzerland). Current ambient ozone levels in South Asia are also considered to
be reducing crop yield and quality for a range of important crops in the
region, commonly within the range of 10 to 20% (See Emberson et al., in Mills
and Harmens, 2011).
Timber
production
A
recent meta-analysis has suggested that the increase in ozone since the
industrial revolution has been responsible for a reduction in photosynthesis of
approximately 11% in trees (Wittig et al., 2007), which may have reduced tree
productivity by approximately 7% (Wittig et al, 2009). In general, deciduous
trees tend to be more sensitive to ozone than coniferous trees, with ozone
sensitive species present across most of Europe (Wittig et al., 2009).
Using
National forest age class statistics, ozone response relationships for
different species and ages, a model of stem increment growth and national mean
AOT402 values, it was estimated that losses in C stocks averaged 10% across 10
northern European countries, with the highest losses predicted for the Czech
Republic, Germany and Poland (see Karlsson, in Harmens and Mills, 2012; see
also Section 3.5).
3.5
Impacts of ozone on
regulating services
By
impacting on carbon sequestration, nutrient cycling, land-atmosphere exchanges
and biodiversity, ozone impacts on many beneficial regulatory functions of
ecosystems, including:
C
sequestration and global warming
If
ozone concentrations are high enough to reduce photosynthesis (i.e. CO2
fixation) and/or above-ground plant growth, then less CO2 and ozone will be
absorbed by the leaves of vegetation, leading to a positive feedback to
atmospheric CO2 and ozone concentrations and therefore more global warming
(Sitch et al., 2007). The ICP Vegetation recently conducted the first
flux-based assessment of effects of ozone on C sequestration in the living
biomass of trees in Europe focussing on 2000 and 2040 effects (Harmens and
Mills, 2012). This study showed that applying the flux-based methodology using
a climate-region specific parameterisation for 2000 revealed C reductions of
14% in the living biomass of trees. Predictions for 2040 indicated that the
reduction of C storage is expected to decrease considerably compared to the
reduction in 2000, mainly as a result of a predicted reduction in atmospheric
ozone concentrations across Europe. [note - ozone can not be reduced unless the economy crashes.]
Air
quality
Globally,
it has been estimated that ozone deposition to vegetation (by reaction with plant
surfaces and uptake through the stomata) reduces tropospheric ozone
concentrations by as much 20% (Royal Society, 2008). This is an especially
significant function of vegetation given that ozone is the third most important
greenhouse gas causing global warming (IPCC, 2007).
Under drought conditions,
however, plants close stomata to conserve water and stomatal uptake of ozone is
substantially reduced, with one study indicating that the European summer
heatwave in August, 2013 led to 20 – 30 ppb increase in ozone concentration
(Vienno et al., 2010). This has important implications for exposure of humans
to ozone and the impacts on human health (WHO, 2008).
A
further level of complexity involves ozone-induced emission of biogenic
volatile organic compound (BVOCs) from plants - these can either react with
ozone to reduce concentrations or lead to ozone formation.
Methane
emissions
There
is evidence that ozone may influence emissions of the greenhouse gas, methane,
from wetlands although the results are less conclusive than for CO2 effects.
Global estimates of carbon sequestration in peatlands are in the region of
20-30 gC m-2 yr-1 (Wieder et al., 2001), and thus any effects of increasing
ozone are of global significance for climate regulation.
Results
from experiments are rather mixed, with some studies indicating methane
increases (Williamson, 2009; Niemi et al., 2002) whilst others show a decrease
(Toet et al., 2011). The inconsistencies in these effects are most probably due
to differences in species present and concentration and duration of ozone
exposure.
Water
cycling
As
described above, there are two main stomatal responses to ozone, each
potentially having an opposite effect on the water cycle: ozone-induced
stomatal closure will preserve water within soils whilst ozone-induced stomatal
opening will increase water loss from vegetation and soils.
Global
climate modellers have until recently assumed the former mechanism is dominant,
but very recently the implications of increased water loss as a result of
chronic ozone exposure are beginning to be considered within such models.
Extensive measurements of a Southern
Appalachian forest in the USA have indicated an almost linear increase in
average daily sap flows and enhancement of the amplitude of the daily
water-loss form native trees with increasing ambient ozone exposure, suggesting
an ozone-induce disruption to the whole-tree water balance, not only as a
result of increased day-time transpiration but also due to increased night-time
stomatal conductance (McLaughlin et al., 2007 a, f; Sun et al., 2012).
Sun et al. (2012) suggest that loss of
stomatal sensitivity will not only increase drought frequency and severity in the
region, thus affecting ecosystem hydrology and productivity, but it will also
have negative implications for flow
dependent aquatic biota.
Flowering, pollination and insect signalling
Reported ozone-induced changes in the number and
timing of flowering will play an important role in the reproductive success of
plants, particularly for species in which flowering is closely synchronized
with pollinating species (Black et al., 2000; Hayes et al., 2012). However, the
impact of ozone on the timing of flowering varies markedly between species
(Rämö et al., 2007; Hayes et al., 2012).
A recent meta-analysis of ozone effects on plant
reproductive growth and development indicated that current ambient ozone
concentrations significantly reduced seed number, fruit number and fruit
weight, while there was a trend towards increasing flower number and flower
weight at elevated ozone (Leisner & Ainsworth, 2012).
Floral scent trails, important in pollinator attraction and plant defenses against herbivorous insects, have also been shown to be destroyed or transformed by ozone (McFrederick et al, 2008). These ozone-induced changes in flowering timing and signaling could have large ecological impacts, affecting plant pollination, the food supply of nectar feeding insects or defense against herbivorous insects.
Floral scent trails, important in pollinator attraction and plant defenses against herbivorous insects, have also been shown to be destroyed or transformed by ozone (McFrederick et al, 2008). These ozone-induced changes in flowering timing and signaling could have large ecological impacts, affecting plant pollination, the food supply of nectar feeding insects or defense against herbivorous insects.
3.6
Impacts of ozone on
cultural services
The
potential for impacts of ozone on cultural services has attracted very little
attention so far even though ozone can have both subtle and profound influences
over some, if not all, aspects of cultural services by impacting on the visual
appearance and quality of the natural environment, including potentially
impacting on the tourist industry.
Ozone impacts on leaf colour may be the most
visually noticeable effect, as ozone induces early senescence in leaves and
visible injury such as stippling and bronzing on sensitive species.
Approximately 80 species of (semi-)natural vegetation have been recorded with
symptoms attributed to ozone in Europe over the period 1990 – 2006, with
records of injury being widespread across Europe and found in 16 countries
(Hayes et al., 2007; Mills et al., 2011). Furthermore changes in the species
balance of natural ecosystems (see Section 3.8) might make some natural areas
less visually attractive.
3.7
Valuing ozone
impacts on ecosystem services
There
is an explosion of interest globally in placing an economic value on ecosystem
services. This is seen as a useful way to communicate the benefits provided by
the natural environment to policy makers, and to capture in a systematic way
many of the unintended consequences of policy actions
or
management decisions. It also facilitates comparisons of effects of different
drivers of change.
Examples
of approaches are discussed in the full report (Mills et al., 2013), including:
estimating the impact of ozone on a product or service compared with assumed
zero impact under no or low ozone; scenario analysis, estimating marginal cost
of a change in a level of ozone and cost-benefit analysis.
3.8
Impacts of ozone on
(plant) biodiversity and species balance
Typical
effects of ozone on sensitive species include: accelerated aging (early
scenescence) and changes in biomass, resource allocation and/or seed
production. Each of these can impact on the vitality of component species of
plant communities, potentially altering plant biodiversity as well as that of
the animals, fungi, bacteria and insects that live in close association with
plants or in nearby soils. In so doing, ozone-induced changes in species
diversity or shifts in species balance will impact on many ecological processes,
thereby impacting on ecosystem services, flows, goods and values.
Effects
on species balance have been widely reported from controlled exposure
experiments, but a less clear picture emerges from field-based studies with
long established communities and from field surveys. Although more studies are
needed, it is clear that impacts of ozone are of particular concern for global
biodiversity hotspots such as the Mediterranean basin. Current knowledge on
direct ozone effects on biodiversity in Mediterranean European countries is
still too limited for quantification and to draw firm conclusions (see
González-Fernández et al., in Mills et al., 2013).
Importantly, field
validation of effects observed under experimental conditions is still lacking
for many species and plant communities. Also indirect effects remain mostly
unknown, despite the fact that they are probably of great importance in terms
of assessing ozone effects on ecosystem biodiversity.
3.9
Research
recommendations
Whereas
there is a wealth of information on ozone impacts on natural- and
agri-ecosystems, almost all studies were not originally conducted in the
context of ecosystem services, and a comprehensive quantitative assessment of
ozone effects on ecosystem services, including an economic valuation, is not
currently possible for most services. We therefore recommend that the following
further research is conducted:
A systematic review and data mining exercise for each ecosystem service to
derive generic response functions for calculation of effects.
Use this review to identify those services for which there is insufficient
experimental information available for derivation of response functions and
make recommendations for further experimental work. Examples of experimental
research would include:
o
Further quantification of below-ground impacts of ozone on carbon sequestration
in roots and soils;
o
Further studies of the effects of ozone on stomatal conductance and the
potential uncoupling from photosynthesis;
o
Experimental studies on the responses of vegetation to ozone in representative
future climates and CO2 concentrations
o
Large-scale field ozone exposure experiments on intact ecosystems;
o
Epidemiological analysis of field measurements to detect spatial and temporal
trends in ecosystem processes and functions;
o
In association with proof of concept ozone exposure experiments, surveys to
show the extent of occurrence of visible injury, early senescence and changes
in expression of autumn colour.
o
Identification of appropriate spatial data, including land-use, ozone, species
distribution, ecosystem functions and products (for example, carbon stocks and
yield), to facilitate a spatial analysis of impacts on ecosystem services.
o
Further research on economic valuation methods, especially for those ecosystem
services provided by natural ecosystems that are difficult to value without
large uncertainty.
o
Using the above, conduct a comprehensive quantitative assessment of past,
current and predicted future effects of ozone on ecosystem services, and where
possible a cost-benefit analysis for future scenarios.
A related summary report to the United Nations Economic Commission for Europe September
2013 session was referenced within, and although largely redundant, it emphasizes a
few salient points, and adds some illustrative charts. It also (if you want to read it) presents a rosy scenario for nitrogen reduction, while noting that: “effects of excessive nitrogen deposition on the structure and functioning of ecosystems and its biodiversity may not occur instantly, it may take several decades over which the resilience of soils and vegetation is weakened and impacts become apparent.”
B.
Impacts of ozone on plant diversity
6.
Typical effects of ozone on sensitive plant species include: accelerated aging;
reduction in biomass; and changes in resource allocation and/or seed
production. Each of these effects can impact on the vitality of component
species of plant communities, potentially altering species balance and plant
diversity (see ECE/EB.AIR/WG.1/2007/9), as well as that of the animals, fungi,
bacteria and insects that live in close association with plants or in nearby
soils.
In so doing, ozone-induced changes in species diversity or shifts in
species balance will impact on many ecological processes, thereby impacting on
ecosystem services, flows, goods and values. Effects on species balance have
been widely reported from controlled exposure experiments, but a less clear
picture emerges from field-based studies with long established communities and
from field surveys.
The
first results from field surveys in the United Kingdom of Great Britain and
Northern Ireland suggest that the impact of ozone on plant species richness is
habitat dependent. Although more studies are needed, it is clear that impacts
of ozone are of particular concern for global biodiversity hotspots such as the
Mediterranean basin.
B.
Benefits of reduction of ground-level ozone for food security, carbon
sequestration and other ecosystem services
10.
Globally important staple food crops are among the most ozone sensitive,
including wheat, soybeans and rice. Other important European crops such as
potatoes, sugar beets and oilseed rape are moderately sensitive to ozone (see
ECE/EB.AIR/WG.1/2011/3 and ECE/EB.AIR/WG.1/2011/8). In addition, ozone damages
the leaves of salad crops, reducing their market value (or even making them
unmarketable after a severe ozone episode).
Economic losses due to ozone
effects on wheat and tomato yield were estimated to be 3.20 and €1.07 billion
respectively in the 27 member states of the European Union plus Norway and
Switzerland in 2000. Wheat yield losses due to ozone were highest in Western
and Central Europe, where high ozone uptake by vegetation coincided with large
areas of wheat cultivation (figure 6 (a)).
Implementation of current legislation will reduce yield losses due to ozone by 2020; however, substantial reductions in ozone precursor emissions would be needed to achieve zero crop losses.
Implementation of current legislation will reduce yield losses due to ozone by 2020; however, substantial reductions in ozone precursor emissions would be needed to achieve zero crop losses.
11.
Ozone is also the third most important greenhouse gas. Negative impacts on
vegetation reduce the sink capacity for carbon dioxide and ozone, enhancing
their atmospheric concentration (positive feedback), while also affecting the
global water cycle.
The
indirect stimulating contribution of ozone to global warming via ozone effects
on vegetation can be as important as the direct effect of ozone as a greenhouse
gas. Hence, it is important to include the impacts of ozone on vegetation in
global climate change models.
In 2000, ambient ground-level ozone was estimated
to reduce carbon sequestration in the living biomass of trees by 12 to 14 per
cent (see ECE/EB.AIR/WG.1/2012/3 and ECE/EB.AIR/WG.1/2012/8). The forested
areas with the highest reductions in carbon sequestration were Central Europe
and parts of Northern Europe, with total effects per grid square dependent on
the density and age class of ozone-sensitive species as well as accumulated
ozone flux (figure 6 (b)). Caption for the figure below: Estimated reduction in carbon sequestration in the living tree biomass due to
ozone in Europe in 2000. Abreviation: C = carbon, Mt = megatons
12.
Reported ozone-induced changes in the quantity of flowers and timing of
flowering will play an important role in the reproductive success of plants,
particularly for species in which flowering is closely synchronized with
pollinating species. A recent meta-analysis of ozone effects on plant
reproductive growth and development indicated that current ambient ozone
concentrations significantly reduce seed number (16 per cent), fruit number (9
per cent) and fruit weight (22 per cent), while there was a trend towards
increasing flower number and weight. Floral scent trails, important in
pollinator attraction and plant defences against herbivorous insects, have also
been shown to be destroyed or transformed by ozone. These ozone-induced changes
in flowering timing and signaling could have major ecological impacts.
13.
Ground-level ozone will also affect other ecosystem services such as carbon,
nutrient and water cycling, timber production and methane emission (see
ECE/EB.AIR/WG.1/2013/8 for further details).
“My informed opinion is that we, here in the USA, will continue to use less and less logic and common sense to address our manifold problems and dilemmas. Rather we will respond more and more with inchoate rage in the fading light of the Enlightenment. We will fail to see what reasonable choices we have as we pause from an evidence based world view into a magical thinking zeitgeist. As Euripides wrote in 880, She is mounted on her chariot, the queen of sorrow and sighing, and is goading on her steeds, as if for outrage, the Gorgon child of Night, with a hundred hissing serpent-heads, Madness of the flashing eyes. Cause and effect will be discarded as manias, panics, furies, and uniformed passions haunt our daylight world and Nemesis intrudes (pouring fetid nightmares and terrors) on our nearly sleepless nighttime journeys.” ~ Larry Shultz