Green Week Air quality & ecosystems status update

Transcription

1 Green Week Air quality & ecosystems status update

2 Ozone pollution: Impacts on ecosystem services and biodiversity Harry Harmens 1, Gina Mills 1, Lisa Emberson 2, Patrick Büker 2 1 ICP Vegetation Programme Coordination Centre, CEH Bangor, UK 2 Stockholm Environment Institute, University of York, York, UK

3 ICP Vegetation International Cooperative Programme (ICP) that reports on the impacts of air pollution on (semi-)natural vegetation and crops It reports to the Working Group on Effects (WGE) of the UNECE Long-range Transboundary Air Pollution (LRTAP) Convention Over 200 scientists in over 40 countries contribute (also outside ECE region) Develop risk assessment methodologies for ozone impacts on vegetation Review ozone impacts on vegetation in thematic reports Monitor heavy metal and nitrogen deposition to mosses every five years

4 Ozone risk assessment Ozone concentration (AOT40) EU Ozone flux or Phytotoxic Ozone Dose (PODy) LRTAP Convention Emberson et al. (2000) Env. Pollution 109: AOT40 forests in 2000 Calculated from hourly mean: Ozone concentration Light intensity Temperature Humidity (VPD) Soil moisture Ozone flux forests in 2000(POD 1 ) Different spatial pattern of risk of impact

5 Widespread plant damage O 3 concentration O 3 flux (crops) Hayes et al. (2007) Mills et al. (2011) Global Change Biology 17: Field-based evidence: Surveys Ad hoc observations ICP Vegetation biomonitoring with clover Air filtration experiments

6 ES, biodiversity & human well-being Millennium Ecosystem Assessment Ecosystem services: Supporting ( underpinning role ) (e.g. biomass production, soil formation, nutrient and water cycling) Provisioning (e.g. food, fresh water, fuel, wood) Regulating (e.g. water purification, water and climate regulation, pollination) Cultural (e.g. education, recreation, aesthetic) LIFE ON EARTH - BIODIVERSITY Biodiversity enhances the ability of ecosystems to maintain multiple functions (Maestre et al. (2012) Science 335: ) Species-richness has positive impacts on ecosystem services (Gamfeldt et al. (2013) Nature Communication 4: 1340) HUMAN WELL-BEING

7 Ozone impacts on ES & biodiversity Supporting services (ecological processes): - Primary production (and C cycling) - Nutrient cycling - Stomatal functioning (and water cycling) Provisioning services: - Crop production - Timber production Regulating services: - C sequestration and global warming - Air quality (via effects on vegetation) - Methane emissions - Water cycling - Flowering, pollination, insect signalling Cultural services (leisure, recreation, amenity) Biodiversity (including case-study Mediterranean) Mills, Wagg, Harmens (2013) Valuing ozone impacts on ecosystem services

8 Relative yield ( ) y = * POD6 r 2 = 0.84 p < BE FI IT SE POD6, mmol m Ozone flux (POD -2 6 ) Wheat Wheat Food security Relative yield Tomato y = * POD 6 r 2 = 0.49 p < Tomato IT SP POD 6, mmol m -2 Ozone flux (POD 6 ) In 2000, ozone pollution reduced wheat yield by 14%, a loss of 3.2 billion in EU27+CH+NO Ozone damage to leaves of salad crops reduces their market value Mills & Harmens (2011) Ozone pollution: A hidden threat to food security. In 2000, ozone pollution reduced tomato yield by 9%, a loss of 1.0 billion in EU27+CH+NO

9 C sequestration, air & climate regulation Harmens & Mills (2012) Ozone pollution: Impacts on C sequestration in Europe. Ozone is also the third most important greenhouse gas Ozone pollution reduces the sink capacity for carbon dioxide and ozone, enhancing their atmospheric concentrations (positive feedback) and affecting the global water cycle Sitch et al. (2007) Nature 448: In 2000, ozone pollution reduced potential carbon sequestration in tree biomass by 14% in Europe. Forest production in Sweden was reduced by 38 million Indirect global warming effect ozone might of similar magnitude as the direct effect Sitch et al. (2007) Nature 448: Include ozone impacts in global climate modelling

10 Water cycling at catchment scale SE USA, Appalachian region Measured flow O 3 + climate (R 2 = 0.78) Climate only (R 2 = 0.51) Sun et al. (2012) Global Change Biology 18: Ozone contributes to variation in late season streamflow by as much as 23% Ozone at near ambient concentration reduces control of leaf pore closing Consequences: Increase plant water use & transpiration, reduced stream flow Loss of stomatal sensitivity will increase drought frequency and severity, affecting ecosystem hydrology and productivity, and has implications for flow-dependent aquatic biota

11 Plant species sensitivity and balance Number of species species Plant species and communities vary in ozone sensitivity (Hayes et al. (2007) Env Pollut 146: ; Mills et al. (2007) Env Pollut 146: ) < Relative sensitivity range > R 2 = 0.84 Area covered Leontodon Dactylis R 2 = Ozone can affect species balance in communities as shown in controlled ozone exposure studies Ozone, season mean, ppb

12 Flowering and seed production 4 th July 9 th June Julian day of peak flowers 185 Lotus corniculatus Ozone exposure (POD 1, mmol m -2 ) Ozone can promote early flowering, affecting the synchronisation of pollinators and flowers Meta-analysis Leisner & Ainsworth (2012) Global Change Biology 18: : Current ambient ozone decreases seed number (-16%), fruit number (-9%) and fruit weight (-22%), but trend towards increased flower number and weight. Enhanced ozone, compared to current ambient ozone, decreases seed yield by 27%.

13 Plant diversity Ozone impact are less clear in field-based studies with long established communities or from field surveys (ozone signal difficult to unravel) Very preliminary results gradient studies UK: dose-response relationships vary per habitat More field-based research needed, particularly in biodiversity hotspots that experience high ozone concentrations such as the Mediterranean Species richness P Value: Heath P Bog Value: Fen P Value: Ozone exposure (24 hr mean)

14 Research recommendations A systematic review and data mining exercise for ecosystem services and plant biodiversity to derive generic response functions for quantifying ozone effects Based on this review, identify services for which there is insufficient experimental data to derive response functions: e.g. impacts of ozone on C sequestration in roots and soils ozone impacts in a future climate (warmer, higher CO 2 ) large-scale field experiments on intact ecosystems epidemiological analysis of field measurements to detect spatial patterns and temporal trends Further research on economic evaluation methods to aid cost-benefit analysis for future scenarios, where possible and appropriate

15 Policy recommendations Ozone risk assessment methodologies should be flux-based, a biologically more relevant metric than ozone concentrations in the air Policy negotiations need to take into account the benefits of air pollution control for ecosystem services and biodiversity, affecting human well-being, in addition to the direct benefits for human health The full benefits of air pollution abatement for ecosystem services and biodiversity have to be assessed and weighed up against the costs of more stringent air pollution controls An effects-based, integrated assessment of policies is required to evaluate impacts of air pollution on ecosystems in a future climate

16 Acknowledgements & further info Department for Environment, Food and Rural Affairs (Defra), UK United Nations Economic Commission for Europe (UNECE) Natural Environment Research Council (NERC) UK Participants of the ICP Vegetation Thank you very much for your attention!