Assessing the costs of ozone pollution in India for wheat producers, consumers, and government food welfare policies.

We assess wheat yield losses occurring due to ozone pollution in India and its economic burden on producers, consumers, and the government. Applying an ozone flux-based risk assessment, we show that ambient ozone levels caused a mean 14.18% reduction in wheat yields during 2008 to 2012.

Quantifying the impact of ozone on crops in Sub-Saharan Africa demonstrates regional and local hotspots of production loss.

Tropospheric ozone can have a detrimental effect on vegetation, including reducing the quantity of crop yield. This study uses modelled ozone flux values (PODIAM; phytotoxic ozone dose above 3 nmol m s, parameterised for integrated assessment modelling) for 2015, together with species-specific flux-effect relationships, spatial data on production and growing season dates to quantify the impact of ozone on the production of common wheat (Triticum aestivum) and common beans (Phaseolus vulgaris) across Sub-Saharan Africa (SSA). A case study for South Africa was also done using detailed data per province.

Reduced photosynthetic thermal acclimation capacity under elevated ozone in poplar (Populus tremula) saplings.

The sensitivity of photosynthesis to temperature has been identified as a key uncertainty for projecting the magnitude of the terrestrial carbon cycle response to future climate change. Although thermal acclimation of photosynthesis under rising temperature has been reported in many tree species, whether tropospheric ozone (O ) affects the acclimation capacity remains unknown. In this study, temperature responses of photosynthesis (light-saturated rate of photosynthesis (A ), maximum rates of RuBP carboxylation (V ), and electron transport (J ) and dark respiration (R ) of Populus tremula exposed to ambient O (AO , maximum of 30 ppb) or elevated O (EO , maximum of 110 ppb) and ambient or elevated temperature (ambient +5°C) were investigated in solardomes.

Ozone-induced effects on leaves in African crop species.

Tropospheric (ground-level) ozone is a harmful phytotoxic pollutant, and can have a negative impact on crop yield and quality in sensitive species. Ozone can also induce visible symptoms on leaves, appearing as tiny spots (stipples) between the veins on the upper leaf surface. There is little measured data on ozone concentrations in Africa and it can be labour-intensive and expensive to determine the direct impact of ozone on crop yield in the field.

Can Reduced Irrigation Mitigate Ozone Impacts on an Ozone-Sensitive African Wheat Variety?

Ground-level ozone (O) pollution is known to adversely affect the production of O-sensitive crops such as wheat. The magnitude of impact is dependent on the accumulated stomatal flux of O into the leaves. In well-irrigated plants, the leaf pores (stomata) tend to be wide open, which stimulates the stomatal flux and therefore the adverse impact of O on yield.

Nitrogen availability does not affect ozone flux-effect relationships for biomass in birch (Betula pendula) saplings.

To investigate whether nitrogen (N) load affects the ozone (O) stomatal flux-effect relationship for birch biomass, three-year old birch saplings were exposed to seven different O profiles (24 h mean of 35-66 ppb) and four different N loads (10, 30, 50 and 70 kg ha yr) in precision-controlled hemispherical glasshouses (solardomes) in 2012 and 2013. Stomatal conductance (g) under optimal growth conditions was stimulated by enhanced N supply but was not significantly affected by enhanced O exposure. Birch root, woody (stem + branches) and total biomass (root + woody) were not affected by the Phytotoxic Ozone Dose (PODSPEC) after two seasons of O exposure, and enhanced N supply stimulated biomass production independent of PODSPEC (i.

Closing the global ozone yield gap: Quantification and cobenefits for multistress tolerance.

Increasing both crop productivity and the tolerance of crops to abiotic and biotic stresses is a major challenge for global food security in our rapidly changing climate. For the first time, we show how the spatial variation and severity of tropospheric ozone effects on yield compare with effects of other stresses on a global scale, and discuss mitigating actions against the negative effects of ozone. We show that the sensitivity to ozone declines in the order soybean > wheat > maize > rice, with genotypic variation in response being most pronounced for soybean and rice.

Ozone pollution will compromise efforts to increase global wheat production.

Introduction of high-performing crop cultivars and crop/soil water management practices that increase the stomatal uptake of carbon dioxide and photosynthesis will be instrumental in realizing the United Nations Sustainable Development Goal (SDG) of achieving food security. To date, however, global assessments of how to increase crop yield have failed to consider the negative effects of tropospheric ozone, a gaseous pollutant that enters the leaf stomatal pores of plants along with carbon dioxide, and is increasing in concentration globally, particularly in rapidly developing countries. Earlier studies have simply estimated that the largest effects are in the areas with the highest ozone concentrations.

Leaf traits and photosynthetic responses of Betula pendula saplings to a range of ground-level ozone concentrations at a range of nitrogen loads.

Ground-level ozone (O) concentrations and atmospheric nitrogen (N) deposition rates have increased strongly since the 1950s. Rising ground-level O concentrations and atmospheric N deposition both affect plant physiology and growth, however, impacts have often been studied in isolation rather than in combination. In addition, studies are often limited to a control treatment and one or two elevated levels of ozone and/or nitrogen supply.

Comparing strengths and weaknesses of three ecosystem services modelling tools in a diverse UK river catchment.

Ecosystem services modelling tools can help land managers and policy makers evaluate the impacts of alternative management options or changes in land use on the delivery of ecosystem services. As the variety and complexity of these tools increases, there is a need for comparative studies across a range of settings, allowing users to make an informed choice. Using examples of provisioning and regulating services (water supply, carbon storage and nutrient retention), we compare three spatially explicit tools - LUCI (Land Utilisation and Capability Indicator), ARIES (Artificial Intelligence for Ecosystem Services) and InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs).

Current and future ozone risks to global terrestrial biodiversity and ecosystem processes.

Risks associated with exposure of individual plant species to ozone (O) are well documented, but implications for terrestrial biodiversity and ecosystem processes have received insufficient attention. This is an important gap because feedbacks to the atmosphere may change as future O levels increase or decrease, depending on air quality and climate policies. Global simulation of O using the Community Earth System Model (CESM) revealed that in 2000, about 40% of the Global 200 terrestrial ecoregions (ER) were exposed to O above thresholds for ecological risks, with highest exposures in North America and Southern Europe, where there is field evidence of adverse effects of O, and in central Asia.

Ozone impacts on vegetation in a nitrogen enriched and changing climate.

This paper provides a process-oriented perspective on the combined effects of ozone (O3), climate change and/or nitrogen (N) on vegetation. Whereas increasing CO2 in controlled environments or open-top chambers often ameliorates effects of O3 on leaf physiology, growth and C allocation, this is less likely in the field. Combined responses to elevated temperature and O3 have rarely been studied even though some critical growth stages such as seed initiation are sensitive to both.