Citation:

Barnes, P., T. Robson, R. Zepp, J. Bornman, M. Jansen, R. Ossola, Q. Wang, S. Robinson, B. Foereid, K. Andrew, J. Martinez-Abaigar, W. Hou, R. Mackenzie, AND N. Paul. Interactive effects of changes in UV radiation and climate on terrestrial ecosystems, biogeochemical cycles, and feedbacks to the climate system. PHOTOCHEMICAL AND PHOTOBIOLOGICAL SCIENCES. Royal Society of Chemistry, Cambridge, Uk, 22(5):1049-1091, (2023). https://doi.org/10.1007/s43630-023-00376-7

Impact/Purpose:

Terrestrial ecosystems are being exposed to rapidly changing combinations of solar UV radiation and other environmental factors due to ongoing changes in stratospheric ozone and climate.  Stratospheric ozone depletion was a potential driver of increases in UV radiation at the Earth's surface a few decades ago.  But implementation of the Montreal  Protocol has reduced the release of ozone-depleting substances into the atmosphere, thus preventing global-scale increases in damaging solar UV-B radiation.  Now other factors are becoming more important determinants of UV reaching the ground. For example, changes in climate (cloud cover, aerosols, and surface reflectivity) are projected to cause an increase of 3-8% in the UV index over the tropics and mid-latitudes by 2100.  These changes could result in substantial changes in UV-sensitive chemicals that are being used in agriculture and various consumer products.  Among these are various nanocomposites of polymers and carbon-based nanopesticides.   Exposure to solar UV radiation causes fragmentation of the nanocomposites with concurrent release of nanomaterials and nanopesticides. Since risk is a function of the inherent hazards of a substance and the actual potential for exposure, the data on nanomaterial release dynamics from commercially relevant nanocomposites are a valuable starting point for consideration in fate and transport modeling, exposure assessment, and risk assessment frameworks.  The recent advances in nanotechnology have been accompanied by increased use of nano-enabled products, which often include composites of engineered nanomaterials (ENMs) (including carbon nanotubes, graphene) with polymers.  These carbon based products have disinfecting capability.  This increased use of nanocomposites has increased the potential for releases of ENMs and fragments of ENM-containing products (FPs) to the environment.  Current models are not designed to simulate concentrations of ENMs and FPs derived from nanocomposites in aquatic environments.  Consequently, there are no available methods for simulating ecosystem exposures of key aquatic and marine sentinel species to FPs.  This product will address this gap in ENM exposure assessment through providing data and relationships that describe releases and transformations of FPs and ENMs from carbon nanopesticides and consumer products under simulated environmental conditions.  The product further addresses exposure evaluation through the development and application of an FP exposure simulation model in concert with companion studies on exposure of sentinel species to FPs .  ORD will work with OPPT to evaluate Research on carbon-based nanomaterials  that contain engineered nanomaterials (ENMs).  Current studies  have demonstrated that the composition and speciation of ENM may undergo significant alteration during the product lifecycle, and that ENMs that are released from products will often undergo further transformation in the environment. 

Description:

Terrestrial organisms and ecosystems are being exposed to new and rapidly changing combinations of solar UV radiation and other environmental factors because of ongoing changes in stratospheric ozone and climate. In this Quadrennial Assessment, we examine the interactive effects of changes in stratospheric ozone, UV radiation and climate on terrestrial ecosystems and biogeochemical cycles in the context of the Montreal Protocol. We specifically assess effects on terrestrial organisms, agriculture and food supply, biodiversity, ecosystem services and feedbacks to the climate system. Emphasis is placed on the role of extreme climate events in altering the exposure to UV radiation of organisms and ecosystems and the potential effects on biodiversity. We also address the responses of plants to increased temporal variability in solar UV radiation, the interactive effects of UV radiation and other climate change factors (e.g. drought, temperature) on crops, and the role of UV radiation in driving the breakdown of organic matter from dead plant material (i.e. litter) and biocides (pesticides and herbicides). Our assessment indicates that UV radiation and climate interact in various ways to affect the structure and function of terrestrial ecosystems, and that by protecting the ozone layer, the Montreal Protocol continues to play a vital role in maintaining healthy, diverse ecosystems on land that sustain life on Earth. Furthermore, the Montreal Protocol and its Kigali Amendment are mitigating some of the negative environmental consequences of climate change by limiting the emissions of greenhouse gases and protecting the carbon sequestration potential of vegetation and the terrestrial carbon pool.

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