Wit's End

Wednesday, April 3, 2019

Playing with Fire

These scenes are from the Romanian Orthodox version of Burning Man
Humans love to play with fire.  It yields so many benefits, what's not to like?  Cooked food, heat, light, insanely rapid transportation - and back in the good old days, predator deterrence.

As medical researchers are discovering however, smoke particulates are extremely dangerous to human lungs, and can pass into the bloodstream to wreak havoc in organs throughout the body.  Injury passes through the placenta, and permanently adversely affects the young, who are still developing.  Persistent damage extends all the way from impaired cognitive ability in children to Alzheimer's in the aged.

It seems quite likely that transitioning from open wood and coal fireplaces to modern heaters in homes played a significant role on the increased life expectancy, particularly among infants, that has occurred in developed nations.  

Though it is becoming more widely recognized that pollution underlies premature mortality and widespread chronic disease in humans, there remains almost no interest in what that same pernicious toxicity means for mammal species, insects, birds, amphibians - and forests - despite ubiquitous reports of biodiversity loss and tree decline all over the globe.  These losses are found irrespective of localized weather, temperatures, habitat encroachment or pesticide use.

The World Meteorological Organization has, however, managed to sneak a few hints into its newly released report on the "State of the Global Climate". Since this blog is maintained (sort of) by an unabashed Ozonista, we'll skip everything else to zero in on what they say about ozone, starting on page 36, under the subtitle Air pollution and climate change.  Following are excerpts, with yellow highlighting references to the impact of ozone on "ecosystems" or "the environment" by which they mean damage to trees, plants, and agriculture - and also on their accurate observation that climate change studies rarely take into account the feedback of pollution on temperature, extreme weather, and the production of yet more ozone. The section also points out a longtime complaint, that advocates of biofuels as "green" sources of energy neglect to include their significant increase in ozone precursor formation.

Although climate change and air pollution are closely connected, these two environmental challenges are still viewed as separate issues and dealt with by different science communities and within different policy frameworks. However, it is not possible to separate the anthropogenic emissions into two distinct categories – atmospheric pollutants and climate-active species – as many air pollutants, such as tropospheric ozone or aerosol, have direct or indirect impacts on climate. Air pollution itself has detrimental effects on human health and the environment (see following figure). According to a report by WHO,1 over 90% of the urban population of the world breathes air containing levels of outdoor air pollutants that exceed WHO guidelines. Air pollution inside and outside the home is the second leading cause of death from non-communicable disease worldwide.

Air quality and climate change are not only driven by common constituents, they are also closely interlinked through diverse atmospheric processes. The second figure, below, depicts the complexity of these interactions.

The effects, both direct and indirect, of air quality on climate change are related to the interactions of atmospheric pollutants with solar radiation. The global average radiative forcing of ozone is similar to that of CH4, and about one quarter of that due to CO2. Tropospheric ozone negatively affects ecosystems and reduces their capacity to absorb CO2. Another indirect impact of ozone on radiative forcing has the opposite effect: production of the hydroxyl radical increases with increasing ozone concentration, shortening the lifetime of CH4 in the atmosphere. Particulate matter, which has adverse effects on human health, has both direct and indirect influences on radiative forcing. Depending on its composition, it can scatter or absorb incoming radiation directly, but particles can also act as cloud condensation nuclei and thereby affect radiative forcing and weather patterns indirectly. Deposition of the particles on snow and ice changes their albedo.

Climate change also affects air quality through changes in meteorology (including temperature, precipitations, boundary-layer dynamics, humidity and cloud cover) and through the impact it has on natural emissions. Increasing temperatures lead to increasing emissions of volatile organic compounds that are the precursors of tropospheric ozone and aerosols. Higher temperatures are also favourable for faster ozone formation. As the climate changes, ozone in peak episodes is expected to increase – the so-called “climate penalty”. Climate change is also associated with changing transport patterns and mixing and can lead to more frequent extreme pollution events due to stagnation. Changes in wildfire frequencies could lead to increasing levels of pollution, particularly aerosols. Changing precipitation patterns affect the deposition of pollutants.

Despite a growing recognition of the strong links between the two areas, policies addressing air pollution and those focusing on climate change remain weakly linked. The major challenge is to identify policies that provide “win–win” solutions, as not all climate policies are beneficial for air pollution reductions and vice versa. One example is the use of biofuels that leads to a reduction of CO2 but contributes to increasing levels of tropospheric ozone. An integrated approach is therefore needed to evaluate the air quality and climate policies that take into account the factors outlined above. Such integrated policies are likely to constitute the best environmental policy strategies in terms of both social and economic costs.

Caption for above figure: An overview of the main categories of air quality and climate change interactions, including a depiction of an example interaction or feedback for each category. Depicted emission sources are examples but do not encompass all emission sources relevant to the depicted interaction. The most relevant components are listed in the brackets following the category. PM (particulate matter) indicates all aerosol sources, including OA (organic aerosol), BC (black carbon), and SO2; O3 (ozone) includes O3 and its precursor compounds, NOx, nonmethane volatile organic compounds (NMVOCs), and CO.

Below, enlarged, is the section from the middle right, above, depicting "plant damage" which = "decreased CO2 uptake by plants" AND "crop losses".  How much you want to bet that nobody pays any attention to the existential threat posed by ozone to all life forms which are dependent upon vegetation - including, of course, us??

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