For several days a stray kitty has been lurking around Wit's End. At first I thought it was feral, and merely hungry - poaching the food I leave on the porch for my own cats. But even after it was well fed, it started lunging frantically at the old beveled window pane in the kitchen door.
It had scrabbled up the hydrangea vine growing on a trellis and hung precariously from the mullion.
It kept falling off, and climbing up again.It rubbed its face against the door jamb. Please please let me in! Finally, I relented and have been letting it stay in the warm mudroom where the two (very disgruntled) barn cats overnight in the winter.
I took pity on it, even though its behavior is frighteningly psychotic, because most of the time it is yowling voraciously, like this!A friend who lives on a neighboring farm said she thinks that people can't afford pet food and vet bills anymore, so they are bringing their cats out to the countryside and ditching them, hoping perhaps they can fend for themselves in the wild - she had two show up last month. I suppose that may be the explanation - an even worse story is of horses being abandoned and left to starve, all over the UK.
Montebello, Quebec, Canada |
Forest Service 2007 Tree Mortality Map, Aerial Survey |
Daniel Boone National Forest, Kentucky |
Foret du Day, Africa |
Peroxyacetyl nitrate (PAN) is an organic compound found in photochemical smog. It is a secondary pollutant produced in the atmosphere by the action of sunlight on the air pollutants present in urban areas. It is a highly potent oxidant that is both toxic and irritating. Sources of pollutants that become PAN include vehicle emissions, tobacco smoke and smoke from the burning of petroleum products, such as natural gas and coal.
Foret du Day, Africa |
Ecological Systems
- PAN is formed in urban areas where there are high levels of pollutants from vehicles and industrial sources, and the formation of PAN peaks around midday when sunlight is strongest. Because it is fairly stable, winds can carry it to rural regions and pristine areas where it can have an ecological impact well away from its origin. A 1997 study reported in the Economist found levels of peroxyacetyl nitrate at Cheeka Peak Observatory, Washington, were 100 percent above normal due to pollutants reaching the West Coast from Asia. This means pollution from one region can affect the whole planet.
Foret du Day, Africa, Hookbill |
A new study, which has caused quite a stir, urges smart targeting of pollution sources to save lives and climate. Following is a release from the University of York:
Helena National Forest, Montana |
While all regions of the world would benefit, avoided warming is greatest in central and northern Asia, southern Africa and around the Mediterranean, total numbers of avoided premature deaths are greatest in Asia and Africa and the greatest total tonnage gains in crop production are estimated to occur in China, India and the US, followed by Pakistan and Brazil. Countries in South Asia and the Sahel region of Africa could see considerable reduction in the disruption of rainfall patterns.
China |
The research published this week in the journal Science was led by Drew Shindell of NASA's Goddard Institute for Space Studies in New York City.
Dr Johan Kuylenstierna, the Director of SEI at York, said: "All 14 measures are based on existing technologies and can be implemented immediately, so do not require long development processes. The measures maximize climate benefits but would also have important 'win-win' benefits for human health and agriculture.”
Buenos Aires, Argentina |
Dr Kevin Hicks, at SEI, added: “The motivation for taking action will vary from country to country and region to region. In some, climate change will be the main concern but in others, air quality may well take precedence.”
Black carbon, a product of the incomplete combustion of fossil fuels or biomass such as wood or agricultural crop residues, damages human health by entering the lungs and exacerbating a number of respiratory diseases. It also absorbs radiation from the sun causing the atmosphere to warm and rainfall patterns to shift and reduces the reflectivity of bright surfaces, such as ice and deserts, a process that hastens global warming. Methane is a precursor to ground-level or lower atmosphere ozone, a component of health-sapping smog, and is also a potent greenhouse gas. Ground level ozone at current levels also damages plants and reduces agricultural yields in sensitive areas.
Dr Lisa Emberson, of SEI, said: '’Ground level ozone is a particular problem in areas such as South Asia which is particularly vulnerable to food insecurity and climate change.”
Black carbon, a product of the incomplete combustion of fossil fuels or biomass such as wood or agricultural crop residues, damages human health by entering the lungs and exacerbating a number of respiratory diseases. It also absorbs radiation from the sun causing the atmosphere to warm and rainfall patterns to shift and reduces the reflectivity of bright surfaces, such as ice and deserts, a process that hastens global warming. Methane is a precursor to ground-level or lower atmosphere ozone, a component of health-sapping smog, and is also a potent greenhouse gas. Ground level ozone at current levels also damages plants and reduces agricultural yields in sensitive areas.
Colorado |
Co-author of the study, Professor Martin Williams from the Environmental Research Group at King’s College London, added: "Measures taken now to reduce carbon dioxide emissions will not have any effect on the global climate for another 40-50 years. We have shown that there are things we can do to begin to mitigate the temperature increases already being seen.’’
“The combination of methane and black carbon measures along with substantial carbon dioxide emissions reductions has a high probability of limiting global mean warming to <2ºC during the next 60 years, something which neither set of emissions reductions achieves on its own.”
Professor David Fowler, of the Centre for Ecology and Hydrology, added: “These control measures represent many win – win options with benefits for human health and climate as well as reducing waste, for example with the methane controls.”
Prielom-Rohatka, High Tatras, Carpathians, Slovakia |
Black carbon and methane pollutants come from a wide variety of sources and the 14 measures identified by the study have all been successfully applied in different parts of the world.
For methane, the key strategies the scientists considered in their analysis were capturing gas that would otherwise escape from coal mines and oil rigs, reducing leakage from long-distance gas pipelines, preventing methane emissions in city landfills, updating city wastewater treatment plants, aerating rice paddies more frequently, and limiting emissions on farms from manure.
For black carbon, the strategies analyzed include installing particle filters in diesel vehicles, keeping high-emitting vehicles off the road, upgrading cook stoves and boilers to cleaner burning types, installing more efficient kilns for brick production, upgrading coke ovens and banning agricultural burning.
Northern Rim, Grand Canyon |
The research team used sophisticated emission, air quality and climate models (e.g. IIASA GAINS, NASA GISS and ECHAM) to estimate the impact of emissions reductions. The modelling shows that the benefits from the methane reductions would be widespread because methane is evenly distributed throughout the atmosphere. The methane measures if fully implemented will to large global climate and agriculture benefits and relatively small human health benefits, all with high confidence and worldwide distribution.
The black carbon measures are likely to provide substantial global climate benefits, but uncertainties are much larger. There is more certainty for the black carbon measures concerning the large regional human health benefits as well as reductions in regional rainfall disruptions, ice melting in both the Arctic and the Himalayas and improvements in regional agricultural yields.
Apparently, the Washington Post and perhaps others have seized on this to mean there are some easy fixes to climate change (!) - so I left this comment at The Daily Impact's dissection (which is well worth reading):
Shenandoah National Park |
Regardless of how the Post distorted the Shindell study, my take on the point of it is that the “other” greenhouse gases – ozone, black carbon, etc – while they do not pose the same sort of long term climate change effect as CO2 – are more responsible for the disproportionately faster rate of temperature increase in the Arctic… which is quite extreme compared to lower latitudes. This is leading to very dangerous feedback effects, like methane release. So they are recommending policies to address these other emissions, and make it clear this is not going to solve the CO2 problem. Not that, as you say, we’re going to do anything about any of it. Or the bees, for that matter!
I think what they are saying in a nice science-y way is that we’re kind of in an existential emergency with the albedo effect on ice and the permafrost melt.
Krkonose National Park, Czech Republic |
Dear Dr. Emberson,
I am writing in regards to the impact of ozone on vegetation. I live in New Jersey, USA, and for several years now it has been obvious to me that individual trees and indeed entire forests are universally in decline. There has been an abrupt, dramatic, and alarming deterioration in their health, not only around where I live but many places on this continent I have visited personally, and in fact all around the world from many reports.
It's quite clear that the composition of the atmosphere is at the bottom of what is a global trend towards vegetative die-back...and that all the insects, disease, fungus, and drought from climate change usually blamed, especially by American foresters and agronomists, actually constitute secondary, opportunistic damage to plants and trees that are already fatally compromised by ozone.
Since this would appear to be an existential threat I have been trying with little success to encourage scientific experts to warn government agencies and by extension the public that we have to stop burning fuels for energy before the ecosystem collapses and there is nothing left to eat. Unfortunately the study of ozone and climate change are so fragmented that very few if any researchers are bold enough to put the entire picture together, and mentioning the role ozone plays in diminishing crop yield and quality is practically taboo.
Hunting Island State Park, South Carolina |
Hunting Island State Park, South Carolina |
Second, I wonder if you have any ideas about exactly why all the trees are dying so suddenly and quickly. Although acid rain and other biotic injuries have accrued for many decades, there has definitely been a recent surge in deaths, in a very alarming trend. Not being a scientist I can't really investigate why, but I have considered the following possibilities and would appreciate any insights or additions you may have to this list:
1. We have reached a tipping point where the background level of ozone is intolerable, perhaps in combination with the disruption of the nitrogen cycle;
2. Burning biofuels has significantly contributed to worse and more persistant ozone (from acetaldehyde);
Horseshoe Lake, Mammoth, California |
I am copying Drew Shindell because he is listed as the contact for your research, although I have written him before and never received a reply.
Thank you so much for your attention.
Sincerely,
Gail Zawacki
Oldwick, NJ
Tatra Forest, Slovakia |
I have had no response from Dr. Emberson, but I did find that she had contributed to the ozone portions of this UNEP 2008 Summary, titled "Atmospheric Brown Clouds - Regional Assessment Report with an Emphasis on Asia" which is excerpted below:
In addition, elevated concentrations of ground level ozone have been found to have large effects on crop yields. Experimental evidence suggests that growing season mean ozone concentrations of 30 - 45 ppb could see crop yield losses of 10 - 40 per cent for sensitive varieties of wheat, rice and legumes. A recent study translated such impacts on yield into economic losses estimating that for four key crops (wheat, rice, corn and soybean) annual losses in the region of US$ 5 billion may occur across Japan, the Republic of Korea, and China. These studies used dose-response relationships derived from Europe and North America, recently collated scientific evidence suggests that some important Asian grown crop cultivars may actually be more sensitive to ozone than European or North American varieties. Concern for a worsening situation in the future is highlighted by projections which suggest that the annual surface mean ozone concentrations in parts of South Asia will grow faster than anywhere else in the world and exceed 50 ppb by 2030.
Maligne Lake, Jasper National Park, Alberta, Canada |
1. Ozone concentrations vary across Asia as a result of regional and local scale variations in precursor emissions and atmospheric circulation patterns. Ozone concentrations across Asia appear to follow a well-defined annual profile with two ozone peaks (during spring and autumn, when ozone concentrations commonly reach monthly mean values of 50 and 40 ppb, respectively) and a
mid-summer trough associated with the main monsoon season, when monthly mean ozone concentrations are reduced to approximately 30 ppb. However, these values vary considerably depending on geographical location and proximity to pollutant sources.
Jasper National Park, Alberta, Canada |
Oregon |
without carbon dioxide (CO2) effects.
Aspen, Kenusha Pass, CO |
environmental conditions or pollutant exposure characteristics. However, these data should be interpreted with caution given the heterogeneity in the experimental methods used in the derivation of the Asian data.
Aroostuck County, Maine |
to higher ozone concentrations and therefore be more susceptible to ozone damage. For example, the sensitive grain filling period for wheat occurs during February-March across much of Asia, coinciding with periods of high ozone concentration.
Union Pass, Wyoming |
(wheat, rice, corn and soybean) at US$ 5 billion in Japan, South Korea and China; these economic losses were attributed to percentage yield losses of up to 9 per cent for cereal crops and 23-27 per cent for soybean.
Inside Passage, Alaska |
Seven Lakes, Colorado |
Australia |
Because I'm starting to suspect that the contribution of methane to ozone is underestimated, I googled around and came up with this site, Global Methane Initiative, which says:
Malaysia |
Methane contributes to background tropospheric ozone levels both as an ozone precursor and by contributing to global warming, which raises daytime temperatures. Studies have shown that reducing global methane emissions can lower tropospheric ozone formation and reduce associated mortalities, particularly in equatorial regions. In addition, many of the technologies and practices that reduce methane emissions also reduce associated emissions of volatile organic compounds (VOCs), odors, and other local air pollutants.
According to Scientific Certification Systems, ozone and black carbon are swirling around the globe. They have terrific animated videos from NASA, which I couldn't figure out how to embed, but following are screenshots. What's even scarier is that they are from 2004 - and emissions have increased dramatically since then. It's pretty amazing to see how far pollution travels.
According to Scientific Certification Systems, ozone and black carbon are swirling around the globe. They have terrific animated videos from NASA, which I couldn't figure out how to embed, but following are screenshots. What's even scarier is that they are from 2004 - and emissions have increased dramatically since then. It's pretty amazing to see how far pollution travels.
Lake Arrowhead, CA |
Black Carbon
Biogenic Arctic Methane
Getting back to the first paper by Shindell and Emberson et al, here are excerpts from an earlier iteration, in 2008, called "Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies."
Abstract.
Several short-lived pollutants known to impact Arctic climate may be contributing to the accelerated rates of warming observed in this region relative to the global annually averaged temperature increase. Here, we present a summary of the short-lived pollutants that impact Arctic climate including methane, tropospheric ozone, and tropospheric aerosols. For each pollutant, we provide a description of the major sources and the mechanism of forcing. We also provide the first seasonally averaged forcing and corresponding temperature response estimates focused specifically on the Arctic. The calculations indicate that the forcings due to black carbon, methane, and tropospheric ozone lead to a positive surface temperature response indicating the need to reduce emissions of these species within and outside the Arctic. Additional aerosol species may also lead to surface warming if the aerosol is coincident with thin, low lying clouds. We suggest strategies for reducing the warming based on current knowledge and discuss directions for future research to address the large remaining uncertainties.
Fig. 1. Forcing mechanisms in the Arctic environment resulting from the poleward transport of middle latitude gas and particulate phase pollutants. Season of maximum forcing at the surface (FS) is indicated for each forcing agent. 1T indicates the surface temperature response.
Foret du Day, Tadjoura, Djibouti, East Africa |
But even if swift and deep reductions were made, given the long lifetime of CO2 in the atmosphere, the reductions may not be achieved in time to delay a rapid melting of the Arctic. Hence, the goal of constraining the length of the melt season and, in particular, delaying the onset of spring melt, may best be achieved by targeting shorter-lived climate forcing agents, especially those that impose a surface forcing that may trigger regional scale climate feedbacks pertaining to sea ice melting. Addressing these species has the advantage that emission reductions will be felt immediately.
Marco Island, FL |
Lusen Mountain, Bavaria, Germany (follow this sad couple as they hike to higher elevations) |
With a lifetime of about 9 years, methane is much shorter lived than CO2 but still is globally well-mixed. Methane has contributed the second largest anthropogenic radiative forcing since the pre-industrial after CO2 and, on a per molecule basis, is a more effective Greenhouse Gas (GHG). Radiative forcing by methane results directly from the absorption of longwave radiation and indirectly through chemical reactions that lead to the formation of other radiatively important gases. The latter is dominated by the formation of tropospheric ozone, also a short-lived GHG, through the oxidation of methane by the hydroxyl radical (OH) in the presence of nitrogen oxides (NOx) and sunlight.
Lusen Mountain, Bavaria, Germany |
Both observations and modeling studies provide evidence that tropospheric ozone concentrations, which are controlled primarily by photochemical production and loss processes within the troposphere, have increased since preindustrial times due to increases in emissions of anthropogenic ozone precursors. The rapid increase in ozone concentrations during the latter half of the 20th century has been attributed to increases in economic development at middle and low latitudes. Ozone precursors include NOx, carbon monoxide, methane, and non-methane volatile organic compounds (NMVOC).
Lusen Mountain, Bavaria, Germany |
Lusen Mountain, Bavaria, Germany |
Lusen Mountain, Bavaria, Germany |
Lusen Mountain, Bavaria, Germany |
Lusen Mountain, Bavaria, Germany |
Lusen Mountain, Bavaria, Germany |
Forcing due to tropospheric ozone is at a maximum during spring when transport of ozone is efficient, radiation is abundant, and substantial ozone precursors persist from the winter buildup that occurs under conditions of low photochemical loss. Summertime forcing could also be significant, particularly when agricultural or boreal forest fire emissions increase ozone levels in the Arctic.
Lusen Mountain, Bavaria, Germany |
Ozone and black carbon are not globally well mixed due to their relatively short lifetimes. Hence, specific source regions must be targeted to lessen their impacts in the Arctic. On timescales of days to weeks, northern Eurasia is the strongest source region for Arctic air pollution, especially in the lower troposphere. Therefore, to decrease concentrations of ozone precursors and black carbon in the lower atmosphere, emissions in this region should be reduced. The source regions of short-lived pollutants in the upper Arctic atmosphere include northern Eurasia and also areas in North America and Asia.
Therefore, a substantial reduction of ozone and BC in the upper troposphere will require more widespread emission reductions throughout the Northern Hemisphere. The correspondence between surface temperature response in the Arctic and global and Northern Hemisphere extratropical forcings due to ozone emphasizes the need to reduce ozone on a northern hemisphere and global basis to reduce climate response in the Arctic. Finally, emissions of ozone precursors and BC within the Arctic should be kept at a minimum as these will have a disproportionately large impact on within Arctic concentrations.
Lusen Mountain, Bavaria, Germany |
Reducing methane emissions as outlined above will decrease ozone production. Reductions in NOx also will contribute but, at the same time, will decrease OH which is the major sink for methane. Hence, an ozone reduction strategy using NOx controls that benefits climate will also include methane, NMVOCs, and/or carbon monoxide reductions. Carbon monoxide forms when carbon in fuel does not burn completely. The main source of carbon monoxide is gasoline powered vehicles.
Lusen Mountain, Bavaria, Germany |
Tatra Forest, Slovakia |
This section provides a brief description of the atmospheric chemistry leading to the formation of greenhouse gases from CH4 emissions. CH4 oxidation leads to enhanced formation of ozone
in the troposphere and lower stratosphere through a sequence of reactions involving NOx compounds. The CH3 resulting from reaction (R1) is oxidized and the reaction products are photolyzed in the presence of sunlight:
M is an air molecule (usually N2), participating in a three‐body reaction, and “hn” represents the solar photon flux. Through this cycle ozone is efficiently formed in the presence of NOx, CO and CH4. The end product of the OH and HO2 formation from CH4 is water vapor. As two H2O molecules are formed from each CH4 molecule, water vapor enhancements due to additional CH4 releases can be
important in relative terms in the dry stratosphere. Reaction (R9) yields CO2, constituting another important product from CH4 oxidation. The result of the CH4 oxidation chain is thus the formation of the three greenhouse gases O3, H2O, and CO2, which comes in addition to the enhancement of CH4 concentrations due to direct emissions.
Wielka Sowa (Owl Mountain) Poland |
PART A: OZONE AND PARTICULATE MATTER
Figure 1.4. Pathways of intercontinental pollution transport in the Northern Hemisphere. Shading indicates the location of the total column of a passive anthropogenic CO tracer released over the Northern Hemisphere continents after 8-10 days of transport, and averaged over 15 years. Shown are transport pathways in summer (June, July, August; upper panel), and winter (December, January, February; lower panel). Gray arrows show transport in the lower troposphere (< 3 km) and black arrows show transport in the mid- and upper troposphere (> 3 km).
Figure 1.6. Source attribution of the ozone found at a rural location in southern England during 2006. Europe-regional refers to the ozone advected directly over the local- and regional-scales to the location. North America to that formed over that continent and over the North Atlantic and east Pacific; Asia to that formed over that continent and over the western Pacific; Europe-intercontinental to that advected around latitude circles and back into Europe; Extra-continental refers to that from interhemispheric transport.
New Mexico |
The doubling of tropospheric ozone (O3) in the Northern Hemisphere since the Industrial
Revolution has had significant, negative impacts on crop production, forest productivity and has been shown to cause changes in the species composition of semi-natural systems. Rapid industrialization in the Northern Hemisphere has also resulted in increases in emissions of pollutants such as SO2, NOx and BC that enhance atmospheric PM and can impact ecosystems through acidification, eutrophication and perturbations to the quality of photosynthetically active radiation. Here we make a first attempt to investigate the implications of intercontinental long-range transport (ICT) of these pollutants for ecosystems. The focus of this section is on terrestrial ecosystems, however impacts on oceans are also briefly covered.
Buckeye Knob, Marion, North Carolina |
The regional distribution of experimental evidence for impacts on ecosystems is predominantly driven by the historical identification of impacts related to the regional occurrence of elevated pollutant concentrations and associated deposition. Hence, most evidence has been collected from North America and Europe over the past 30 years. The relatively recent advent of rapid industrialization and associated pollutant emissions in Asia has led to a disconnect between the level of experimental evidence available and the scale of the pollutant problem by world region.
Finland |
The majority of the existing experimental evidence comes from bio-monitoring and Open Top
Chamber studies that have been conducted first in North America and later in Europe under the European Open Top Chamber and UNECE ICP Vegetation Programmes; these have mainly focussed on arable crops. Over the last decade similar studies are now increasingly being conducted in Asia. The Free Air Concentration Enrichment approach has recently been used as an experimental method to assess impacts on crops: soybean in the US; rice in China: forest trees (Aspen, Maple and birch) in Wisconsin, US; mature beech stands in Bavaria, Germany: and grasslands (alpine semi-natural grassland in the Swiss Alps. These methods have advantages of being closer to field conditions but are limited in their ability to define impacts at or below ambient pollutant concentrations and in defining dose-response relationships which are necessary for regional scale risk assessments.
Big Cypress Swamp, Florida |
p. 217 In addition to experimental studies, epidemiologic methods have also been used, initially driven by a need to overcome difficulties in extrapolating experimental studies conducted on young forest tree species in Open Top Chambers to understand effects on mature trees growing under forest stand conditions. Such studies have consistently demonstrated that O3 can negatively influence a variety of forest responses from crown condition to radial growth. More recently, similar spatially relevant studies have been extended to crop loss assessments. These studies have found that the influence of O3 can be detected in regional level production statistics and field trial data although damage estimates have been found to differ from those obtained from risk assessments performed using empirically derived dose-response relationships. This may be due to these methods being most effective in those regions characterized by higher average O3 concentrations where the O3 signal is strong enough to overcome the influence of confounding variables affecting yield.
Rising background concentrations experienced over the last few decades can particularly enhance spring and autumn O3 levels, in effect lengthening the period of elevated O3 concentrations from the existing summer peak O3 exposures; the influence of these new seasonal profiles on ecosystems needs to be understood, this can only be achieved with new experimental investigations. To date, such new investigations have used diurnal fumigation patterns that emphasize chronic rather than peak O3 exposures and investigation of species with growth periods that extend into those times of the year when ICT is a more substantial fraction of the total pollution load i.e. the spring and autumn periods.
Torres del Paine, Chile |
Key impacts for agriculture include visible injury to leafy crop species; declines in arable yields and effects on crop quality (e.g. nitrogen content of grains, tubers etc. and nutritive quality of forage crops). Importantly, impacts have been found to vary substantially according to crop species and cultivars. Prevailing climatic and meteorological conditions and agricultural management practices (e.g. irrigation) will also affect response to O3.
Routt National Forest, Colorado - ironically from a skimobile site. |
For forest trees, O3 has been shown to impact visible foliar injury, accelerate leaf senescence, reduce photosynthesis, alter carbon allocation, and reduce growth and productivity; again, these effects vary by forest tree species and genotype. O3 also appears to weaken tree resilience to a range of biotic (e.g. pest and pathogen attack) and abiotic (e.g. drought, frost hardiness) stresses. The extent to which results obtained from tree seedlings/saplings can be extrapolated to mature trees under real forest condition has been severely challenged and resulted in a study conducted at Kranzberg Forest, Germany on naturally growing and late-successional, adult forest trees. This study found reductions in annual whole-stem volume increments for beech which, when scaled to stand level, supported modelling predictions that claim elevated O3 to cause substantial reduction of C sink strength in trees.
Semi-natural grasslands are genetically highly diverse multi-species communities ranging from low to high productivity depending on site conditions and management. Component species differ strongly in their sensitivity to O3 and thus community response to O3 is likely to be species-driven. However, changes in productivity and species composition in established temperate calcareous or alpine grassland are difficult to detect against a background of considerable natural spatial and temporal variability.
Inner Mongolia |
FINDING: There is evidence that O3 can cause a variety of damage responses to crops, forests and grasslands. The strength of this evidence varies with receptor type and location, with more evidence on crops than forest trees, more on trees than grasslands, and equal evidence in North America and Europe, but less in Asia.
Eastern Norway |
The experimental campaigns conducted in North America and Europe were instrumental in providing experimental data describing yield and growth responses for a range of crop species (and a far more limited number of forest and grassland species) that could be used to define O3 metrics and dose-response relationships. It is important to note that in Europe, the selection of the AOT (accumulated ozone concentration over a threshold over a growing season) cut-off concentration of 40 ppb was actually driven by consideration of the level of background O3 concentrations; AOT30 was as statistically robust in terms of defining crop damage but was considered to have implications for control strategies outside of Europe and hence the 40 ppb cut-off concentration was retained.
Since the background O3 level can vary considerably across different regions, and most importantly with altitude, a single cut-off value may not be suitable for risk assessments in every geographical region with important implications for use of such threshold indices for assessment of ICT.
Pine Barrens, New Jersey |
Pine Barrens, New Jersey |
Walnut trees, David, California |
p. 219 Mechanisms of adverse effects of O3 relevant for ICT
Phenology will play an important role in determining the importance of ICT damage to ecosystems. The timing and duration of growth periods will determine species exposure to ICT. For example, early or late season crops such as oil seed rape and maize may be more at risk, similarly forests and grasslands which have appreciably longer growth periods will be more likely to experience ICT. Within life-cycle and annual growing season variability in sensitivity may also be important. For example, age dependent changes in leaf morphology were related to changes in the defence capacity against oxidative stress, with concentrations of antioxidants increasing with tree age; therefore, early season ICT O3 exposures may occur when antioxidative defence capacities are still establishing. In more remote regions with early springtime peaks in O3, together with conditions favouring high stomatal conductance, the situation may be worse as the advancement of plant development may lead to more frequent co-occurrence of sensitive stages and early-season O3 stress.
Species distribution will also affect vulnerability to ICT. For example, many forests and grassland communities extend to high altitudes where the planetary boundary is more likely to be coupled to the lower layers of the free troposphere and hence more prone to ICT influence. Forests also host understory species, which often have ephemeral growth periods in the spring before closure of the forest canopy restricts growth.
Shingletown Gap, Pennsylvania |
p. 225 FINDING: There is considerable uncertainty as to how much of the damage to ecosystems
caused by O3 is attributable to hemispheric ICT. Provisional results from HTAP model-based risk assessments using AOT40 and Mx indices indicate that emissions from one continent have the potential to influence crop productivity on other continents by affecting O3 concentrations, with the largest influence of ICT found from North American emissions impacting on European crop yields. Based on the HTAP multi-model experiments, ICT may be responsible for about 5 to 35% of the estimated crop yield losses depending on the location, crop, and response function used, subject to large uncertainties. Oh boy, I'll bet the European farmers love hearing that!
Casco Bay Island, Maine |
Sweden |
Sherwood Forest, Edwinstowe, England |
Texas |
In contrast to agriculture, little work has been done to assess the impacts of ground level O3 on important global forest biomes. Work that has been conducted has been confined to studies in Europe and North America. A Scandinavian study estimated timber yield losses due to O3 at 2.2% in Sweden over the period 1993-2003. The resulting economic loss was estimated to be a 2.6% decline, which is equivalent to €56 million based on 2004 prices for timber and pulpwood. Additionally, Muller and Mendelsohn [2009] estimated annual timber yield losses equivalent to $80 million in the U.S.
South Sister, Smith Rock State Park, Oregon |
the Northern Hemisphere, even though heavily forested areas coincide with regionally high O3
concentrations in east and southeast Asia, northern Asia, and boreal North America. Recent studies in
Scandinavia have identified certain aspects of O3 exposure of the more northerly, boreal forest
ecosystems that could particularly enhance vulnerability to ICT. These include the earlier onset of the
growing season as climate changes, the extensive periods of 24 hour daylight that allow more or less
continuous gas exchange leading to a large cumulative O3 dose, and lack of recovery from oxidative
stress during darkness. In terms of tropical forests, Fowler et al. [1999] estimated that O3 concentrations in excess of 60 ppb were experienced by an area of 3 million km in 1990 (almost 20% of total tropical forest cover) with the increase particularly great in southeast Asia. In spite of this rapid increase in exposure, our knowledge of O3 impacts on forest ecosystems of tropical biomes is extremely limited.
I'll Say!
South Sister, Smith Rock State Park, Oregon |
Dying Melaleuca forest, Queensland, Australia |
Highly diverse communities with an important conservation value in regions with a warmer climate may be more vulnerable than perennial grasslands in temperate and montane habitats. This may concern regions where C3 species predominate and where typically high O3 levels are observed, such as the Mediterranean basin in Europe or in coastal parts of southern California. Grasslands dominated by C4 grasses in warmer regions such as India, southeast Asia, southern China and in much of the Southern Hemisphere may be less sensitive to O3 as the C4 photosynthetic pathway (which is capable of providing a near constant and optimum supply of CO2 for photosynthesis with relatively low stomatal conductance) will confer some protection against O3. Similarly, therophytic grasslands in arid and semi-arid regions such as northern China may be less affected with only a few percent simulated reductions in net primary production due to O3 alone.
Dead and dying birch, shore of Lake Superior, Minnesota |
p. 230 5.2.4. Interactions with climate change
Effect of atmospheric composition on plant physiology
Vegetation plays an important role in determining surface O3 levels, via dry deposition of O3 to the interior of leaves through stomata. As atmospheric CO2 levels rise, the stomata will not need to open as widely to allow sufficient CO2 to enter for photosynthesis. This may reduce O3 uptake, decreasing the sensitivity of the plants to O3. Such reductions in stomatal conductance of plants would result in both lower uptake rates and increased O3 concentrations in the boundary layer.
Dead and dying birch, shore of Lake Superior, Minnesota |
You often see this nonsense about ozone flux being reduced thanks to higher levels of CO2 causing stomatal closure. It just seems like a ridiculous Hail Mary pass to me.
Figure 5.14. Global assessment of the key biodiversity areas at high risk from O3 impacts; the figure shows the projected percent decrease in gross primary productivity due to O3 within the Global 200 priority conservation areas.
Hemlocks, DuPont State Forest, North Carolina |
Impact of future atmospheric conditions on ecosystems
Models simulate that global mean precipitation increases with global warming. However, there are substantial spatial and seasonal variations. Increases in the amount of precipitation are very likely in high latitudes, while decreases are likely in most subtropical land region, continuing observed patterns in recent trends in observations. Precipitation is projected to decrease in many areas already suffering from water shortages [e.g., the Mediterranean and parts of Africa], which together with rising temperatures, will increase stress among plants. Reduced stomatal conductance that may occur in response to elevated CO2 may enhance water use efficiency of plants, which may help to partly alleviate the effects of reduced rainfall. The projected increase in temperatures in many parts of the world mean that yields from
crops may also be reduced. Increased water stress in a warmer climate may be expected to decrease sensitivity to O3 via reduced uptake; however O3 induced damage to stomatal functioning might confound this effect. The exact impacts of pollutants on vegetation in the future will be complicated by the differential response of plants to climate change and rising CO2 levels, whereby the latter will increase growth and might offset some of the projected yield losses from crops by the former.
Oregon |
A mechanistic model of plant-O3 interactions was implemented into the Hadley Centre land surface model and run with O3 scenarios from the STOCHEM chemistry transport model driven with SRES A2 emission scenario. Results suggest a large negative impact of near-surface O3 on plant productivity. These model results have been used to identify eco-regions where a significant effect on global primary productivity might be expected to occur. The results in Figure 5.14 are based on the "low sensitivity" simulation which is overlain with the G200 regions and used to assess threats of O3 deposition to biodiversity. This identifies eco-regions of south and east Asia, central Africa and Latin America as being at risk from elevated O3 levels during this century, in addition to areas of North America and Europe where the effects of O3 are better documented. However, there is almost no information available on whether the plant communities in these other regions of the world are as sensitive to O3 as those that have been used to define critical levels, and hence the real significance of these areas of potential risk to biodiversity is completely unknown.
Institute of Community Forest Governance, India |
With all the above warning of reduced crop productivity and quality due to air pollution, I have to say, I got a bit annoyed when I received this ludicrous, delusional email from Lester Brown's Earth Policy Institute:
Bumper 2011 Grain Harvest Fails to Rebuild Global Stocks Janet Larsen www.earth-policy.org/indicators/C54/grain_201 | Earth Policy Release Eco-Economy Indicator: Grain January 11, 2012 | ||
The world’s farmers produced more grain in 2011 than ever before. Estimates from the U.S. Department of Agriculture show the global grain harvest coming in at 2,295 million tons, up 53 million tons from the previous record in 2009. Consumption grew by 90 million tons over the same period to 2,280 million tons. Yet with global grain production actually falling short of consumption in 7 of the past 12 years, stocks remain worryingly low, leaving the world vulnerable to food price shocks.
Nearly half the calories consumed around the world come directly from grain, with grain-fed animal products making up part of the remainder. Three grains dominate the world harvest: wheat and rice, which are primarily eaten directly as food, and corn, which is largely used as a feedgrain for livestock. Wheat was the largest of the world’s grain harvests until the mid-1990s. Then corn production surged ahead in response to growing demand for grain-fed animal products and, more recently, for fuel ethanol. Despite a drop in the important U.S. harvest due mostly to high summer temperatures, global corn production hit 868 million tons in 2011, an all-time high. The harvests of wheat (689 million tons) and rice (461 million tons) were also records. (See data at www.earth-policy.org.) I wrote back to ask: How can you possibly write anything about crop yield decline without mentioning: 1. overpopulation and the need for birth control 2. climate change causing extreme weather, and the need to drastically curtail fuel emissions and 3. the damage done to crop yield and quality by tropospheric ozone, also a result of fuel emissions. |
Here's a video about trees dying in Oregon...and a quote from Martin Luther King, which was reprinted at Our Finite World:
The tide in the affairs of men does not remain at the flood; it ebbs. We may cry out desperately for time to pause in her passage, but time is deaf to every plea and rushes on. Over the bleached bones and jumbled residue of numerous civilizations are written the pathetic words: “Too Late.”
Dr. Martin Luther King, Jr.
Riverside Church
New York City
April 4, 1967
Riverside Church
New York City
April 4, 1967
OMG! How am I going to get my wedding sewing done, if I have to read all this? You are AMAZING!
ReplyDeleteYes, you are amazing.
ReplyDeleteObviously we are well into a self inflicted "crisis" of catastrophic proportions.
Civil government's public health and safety responsibilities are not up to the primary task of preserving and protecting the health of the community.
But more important, us citizens are not demanding this of ourselves.
To borrow from MLK's The World House:
"The large house in which we live demands that we transform this worldwide neighborhood into a worldwide brotherhood. Together we must learn to live as brothers or together we will be forced to perish as fools."
We either demand from ourselves, our neighbors, our community, and our leaders that we back off from the black carbon edge of this final precipice, or we will perish as vain idiots, but more tragic we will have taken with us many, if not all other of Earth's creatures with us. I shudder at the absolute shame of evil this would be.
The present destruction of trees is visible ...in our field of vision... in front of our eyes... yet why is it so far from our hearts? We must scream at the top of our lungs for them.
D Lange 93101
Mossy and Windspirit...I am humbled by the recognition, that I have only recently realized...I'm honestly abjectly, horrified, at how stupid I've been for so long. It's a tough awakening. Thanks, for your understanding and your comments are welcome always.
ReplyDeleteYou bet! We must chorus loudly as well.
ReplyDeleteWow, where did you manage to find this collection of photos? Google image search? Things are looking more and more grim.
ReplyDeleteyep, I just got it into my head to search for "dead forest" and so many came up, I couldn't believe it. Way more than I could use, because I have to do a screen grab, and convert each one to a jpeg, it's very time consuming.
ReplyDeleteEvery caption goes back to the website where it originated - there are some interesting stories there!
There were several dozen of these critters flying over my place today in southeastern PA.
ReplyDeletehttp://www.sovereignindependent.com/?p=33593
Gail, you're wonderful!
ReplyDeleteYou're thorough and hard hitting with words and data that must be heard by all.
I too, find it very easy to find data that backs up the obvious and easily observable tree and plant mortality that surrounds us.
You are a "scientist", in the best sense of the word. And you share your findings with your community.
If you are at your "wit's end", then I, after six years of alarm at the build up of traffic caused pollution, which now, has many trees and plants destroyed forever, I am on about my eighth "wit", and I started with just a half.
And, in those six years, tens of thousands of "scientific" college degrees have "awarded", to arborists, botanists, etc...and now... after blah, blah, blah from them... all the trees are dying, as well as habitat for birds, bees, and insects...so much for having a degree that just encases you with blinders which allow for such observable and preventable destruction.
Gail, you're more capable than any scientist I know, so never back down from being right for the right reasons.
I will keep up the fight here in Coastal Southern California using all the wits I can muster.
Sincerely, David
Thanks David! I'm trying to build a real website that has more organized information. But I'm tempted to set up a special Rogues tab for a Gallery of Shame consisting of of a list of all the professional Liars, Scoundrels, Fabulists and Hopelessly Hopeful Delusionals who have ridiculed me over the years!
ReplyDeleteMy recent post w photos, mine.
ReplyDeletehttp://wind-and-sky-spirit.blogspot.com/
Gail
ReplyDeleteMy recent Facebook post w photos.
http://www.facebook.com/profile.php?id=100002160192677
WitsEnd blog...you might "Follow" WindSpirit, as its photos are, many, real time, verifiable, and show plant and tree conditions in So. Calif. zip 93101 in 2011-2012. Windspirit does "
ReplyDelete