| 1. |
- Barnes, Paul W., et al.
(författare)
-
Ozone depletion, ultraviolet radiation, climate change and prospects for a sustainable future
- 2019
-
Ingår i: Nature Sustainability. - : Springer Science and Business Media LLC. - 2398-9629. ; 2:7, s. 569-579
-
Forskningsöversikt (refereegranskat)abstract
- © 2019, Springer Nature Limited. Changes in stratospheric ozone and climate over the past 40-plus years have altered the solar ultraviolet (UV) radiation conditions at the Earth’s surface. Ozone depletion has also contributed to climate change across the Southern Hemisphere. These changes are interacting in complex ways to affect human health, food and water security, and ecosystem services. Many adverse effects of high UV exposure have been avoided thanks to the Montreal Protocol with its Amendments and Adjustments, which have effectively controlled the production and use of ozone-depleting substances. This international treaty has also played an important role in mitigating climate change. Climate change is modifying UV exposure and affecting how people and ecosystems respond to UV; these effects will become more pronounced in the future. The interactions between stratospheric ozone, climate and UV radiation will therefore shift over time; however, the Montreal Protocol will continue to have far-reaching benefits for human well-being and environmental sustainability.
|
|
| 2. |
- Strandberg, Gustav, et al.
(författare)
-
Regional climate model simulations for Europe at 6 and 0.2 k BP : sensitivity to changes in anthropogenic deforestation
- 2014
-
Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 10:2, s. 661-680
-
Tidskriftsartikel (refereegranskat)abstract
- This study aims to evaluate the direct effects of anthropogenic deforestation on simulated climate at two contrasting periods in the Holocene, similar to 6 and similar to 0.2 k BP in Europe. We apply We apply the Rossby Centre regional climate model RCA3, a regional climate model with 50 km spatial resolution, for both time periods, considering three alternative descriptions of the past vegetation: (i) potential natural vegetation (V) simulated by the dynamic vegetation model LPJ-GUESS, (ii) potential vegetation with anthropogenic land use (deforestation) from the HYDE3.1 (History Database of the Global Environment) scenario (V + H3.1), and (iii) potential vegetation with anthropogenic land use from the KK10 scenario (V + KK10). The climate model results show that the simulated effects of deforestation depend on both local/regional climate and vegetation characteristics. At similar to 6 k BP the extent of simulated deforestation in Europe is generally small, but there are areas where deforestation is large enough to produce significant differences in summer temperatures of 0.5-1 degrees C. At similar to 0.2 k BP, extensive deforestation, particularly according to the KK10 model, leads to significant temperature differences in large parts of Europe in both winter and summer. In winter, deforestation leads to lower temperatures because of the differences in albedo between forested and unforested areas, particularly in the snow-covered regions. In summer, deforestation leads to higher temperatures in central and eastern Europe because evapotranspiration from unforested areas is lower than from forests. Summer evaporation is already limited in the southernmost parts of Europe under potential vegetation conditions and, therefore, cannot become much lower. Accordingly, the albedo effect dominates in southern Europe also in summer, which implies that deforestation causes a decrease in temperatures. Differences in summer temperature due to deforestation range from -1 degrees C in south-western Europe to +1 degrees C in eastern Europe. The choice of anthropogenic land-cover scenario has a significant influence on the simulated climate, but uncertainties in palaeoclimate proxy data for the two time periods do not allow for a definitive discrimination among climate model results.
|
|
| 3. |
- Matthes, Heidrun, et al.
(författare)
-
Sensitivity of high-resolution Arctic regional climate model projections to different implementations of land surface processes
- 2012
-
Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 111:2, s. 197-214
-
Tidskriftsartikel (refereegranskat)abstract
- This paper discusses the effects of vegetation cover and soil parameters on the climate change projections of a regional climate model over the Arctic domain. Different setups of the land surface model of the regional climate model HIRHAM were realized to analyze differences in the atmospheric circulation caused by (1) the incorporation of freezing/thawing of soil moisture, (2) the consideration of top organic soil horizons typical for the Arctic and (3) a vegetation shift due to a changing climate. The largest direct thermal effect in 2 m air temperature was found for the vegetation shift, which ranged between −1.5 K and 3 K. The inclusion of a freeze/thaw scheme for soil moisture shows equally large sensitivities in spring over cool areas with high soil moisture content. Although the sensitivity signal in 2 m air temperature for the experiments differs in amplitude, all experiments show changes in mean sea level pressure (mslp) and geopotential height (z) throughout the troposphere of similar magnitude (mslp: −2 hPa to 1.5 hPa, z: −15 gpm to 5 gpm). This points to the importance of dynamical feedbacks within the atmosphere-land system. Land and soil processes have a distinct remote influence on large scale atmospheric circulation patterns in addition to their direct, regional effects. The assessment of induced uncertainties due to the changed implementations of land surface processes discussed in this study demonstrates the need to take all those processes for future Arctic climate projections into account, and demonstrates a clear need to include similar implementations in regional and global climate models.
|
|
| 4. |
- Chen, Deliang, 1961, et al.
(författare)
-
Summary of a workshop on extreme weather events in a warming world organized by the Royal Swedish Academy of Sciences
- 2020
-
Ingår i: Tellus Series B-Chemical and Physical Meteorology. - : Stockholm University Press. - 1600-0889 .- 0280-6509. ; 72:1
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change is not only about changes in means of climatic variables such as temperature, precipitation and wind, but also their extreme values which are of critical importance to human society and ecosystems. To inspire the Swedish climate research community and to promote assessments of international research on past and future changes in extreme weather events against the global climate change background, the Earth Science Class of the Royal Swedish Academy of Sciences organized a workshop entitled 'Extreme weather events in a warming world' in 2019. This article summarizes and synthesizes the key points from the presentations and discussions of the workshop on changes in floods, droughts, heat waves, as well as on tropical cyclones and extratropical storms. In addition to reviewing past achievements in these research fields and identifying research gaps with a focus on Sweden, future challenges and opportunities for the Swedish climate research community are highlighted.
|
|
| 5. |
- Andrady, Anthony, et al.
(författare)
-
Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2016
- 2017
-
Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 16:2, s. 107-145
-
Tidskriftsartikel (refereegranskat)abstract
- The Parties to the Montreal Protocol are informed by three Panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects of UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials. The second focus is on interactions between UV radiation and global climate change and how these may affect humans and the environment. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously believed. As a result of this, human health and environmental issues will be longer-lasting and more regionally variable. Like the other Panels, the EEAPproduces a detailed report every four years; the most recent was published as a series of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1–184). In the years in between, the EEAP produces less detailed and shorter Progress Reports of the relevant scientific findings. The most recent of these was for 2015 (Photochem. Photobiol. Sci., 2016, 15, 141–147). The present Progress Report for 2016 assesses some of the highlights and new insights with regard to the interactive nature of the direct and indirect effects of UV radiation, atmospheric processes, and climate change. The more detailed Quadrennial Assessment will bemade available in 2018.
|
|
| 6. |
- Kerren, Andreas, 1971-, et al.
(författare)
-
Multi-Scale Trend Visualization of Long-Term Temperature Data Sets
- 2014
-
Ingår i: Proceedings of SIGRAD 2014, Visual Computing, June 12-13, 2014, Göteborg, Sweden. - : Linköping University Electronic Press. - 9789175192123 ; , s. 91-94
-
Konferensbidrag (refereegranskat)abstract
- The analysis and presentation of climate observations is a traditional application of various visualization approaches. The available data sets are usually huge and were typically collected over a long period of time. In this paper, we focus on the visualization of a specific aspect of climate data: our visualization tool was primarily developed for providing an overview of temperature measurements for one location over decades or even centuries. In order to support an efficient overview and visual representation of the data, it is based on a region-oriented metaphor that includes various granularity levels and aggregation features.
|
|
| 7. |
- Wolf, Annett, et al.
(författare)
-
Process-based estimates of terrestrial ecosystem isoprene emissions : incorporating the effects of a direct CO2-isoprene interaction
- 2007
-
Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 7:1, s. 31-53
-
Tidskriftsartikel (refereegranskat)abstract
- In recent years evidence has emerged that the amount of isoprene emitted from a leaf is affected by the CO2 growth environment. Many - though not all - laboratory experiments indicate that emissions increase significantly at below-ambient CO2 concentrations and decrease when concentrations are raised to above-ambient. A small number of process-based leaf isoprene emission models can reproduce this CO2 stimulation and inhibition. These models are briefly reviewed, and their performance in standard conditions compared with each other and to an empirical algorithm. One of the models was judged particularly useful for incorporation into a dynamic vegetation model framework, LPJ-GUESS, yielding a tool that allows the interactive effects of climate and increasing CO2 concentration on vegetation distribution, productivity, and leaf and ecosystem isoprene emissions to be explored. The coupled vegetation dynamics-isoprene model is described and used here in a mode particularly suited for the ecosystem scale, but it can be employed at the global level as well. Annual and/or daily isoprene emissions simulated by the model were evaluated against flux measurements ( or model estimates that had previously been evaluated with flux data) from a wide range of environments, and agreement between modelled and simulated values was generally good. By using a dynamic vegetation model, effects of canopy composition, disturbance history, or trends in CO2 concentration can be assessed. We show here for five model test sites that the suggested CO2-inhibition of leaf-isoprene metabolism can be large enough to offset increases in emissions due to CO2-stimulation of vegetation productivity and leaf area growth. When effects of climate change are considered atop the effects of atmospheric composition the interactions between the relevant processes will become even more complex. The CO2-isoprene inhibition may have the potential to significantly dampen the expected steep increase of ecosystem isoprene emission in a future, warmer atmosphere with higher CO2 levels; this effect raises important questions for projections of future atmospheric chemistry, and its connection to the terrestrial vegetation and carbon cycle.
|
|
| 8. |
- Yager, P. L., et al.
(författare)
-
A carbon budget for the Amundsen Sea Polynya, Antarctica: Estimating net community production and export in a highly productive polar ecosystem
- 2016
-
Ingår i: Elementa-Science of the Anthropocene. - : University of California Press. - 2325-1026. ; 4
-
Tidskriftsartikel (refereegranskat)abstract
- Polynyas, or recurring areas of seasonally open water surrounded by sea ice, are foci for energy and material transfer between the atmosphere and the polar ocean. They are also climate sensitive, with both sea ice extent and glacial melt influencing their productivity. The Amundsen Sea Polynya (ASP) is the greenest polynya in the Southern Ocean, with summertime chlorophyll a concentrations exceeding 20 mu g L-1. During the Amundsen Sea Polynya International Research Expedition (ASPIRE) in austral summer 2010-11, we aimed to determine the fate of this high algal productivity. We collected water column profiles for total dissolved inorganic carbon (DIC) and nutrients, particulate and dissolved organic matter, chlorophyll a, mesozoo-plankton, and microbial biomass to make a carbon budget for this ecosystem. We also measured primary and secondary production, community respiration rates, vertical particle flux and fecal pellet production and grazing. With observations arranged along a gradient of increasing integrated dissolved inorganic nitrogen drawdown (Delta DIN; 0.027-0.74 mol N m(-2)), changes in DIC in the upper water column (ranging from 0.2 to 4.7 mol C m(-2)) and gas exchange (0-1.7 mol C m(-2)) were combined to estimate early season net community production (sNCP; 0.2-5.9 mol C m(-2)) and then compared to organic matter inventories to estimate export. From a phytoplankton bloom dominated by Phaeocystis antarctica, a high fraction (up to similar to 60%) of sNCP was exported to sub-euphotic depths. Microbial respiration remineralized much of this export in the mid waters. Comparisons to short-term (2-3 days) drifting traps and a year-long moored sediment trap capturing the downward flux confirmed that a relatively high fraction (3-6%) of the export from similar to 100 m made it through the mid waters to depth. We discuss the climate-sensitive nature of these carbon fluxes, in light of the changing sea ice cover and melting ice sheets in the region.
|
|
| 9. |
- Hultin, Kim, et al.
(författare)
-
Aerosol and bacterial emissions from Baltic Seawater
- 2011
-
Ingår i: Atmospheric research. - : Elsevier BV. - 0169-8095 .- 1873-2895. ; 99:1, s. 1-14
-
Tidskriftsartikel (refereegranskat)abstract
- Factors influencing the production of primary marine aerosol are of great importance to better understand the marine aerosols' impact on our climate. Bubble-bursting from whitecaps is considered the most effective mechanism for sea spray production, and a way of sea-air transfer for some bacterial species. Two coastal sites in the Baltic Sea were used to investigate aerosol and bacterial emissions from the bubble-bursting process by letting a jet of water hit a water surface within an experimental tank, mimicking the actions of breaking waves. The aerosol size distribution spectra from the two sites were similar and conservative in shape where the modes were centered at about 200 nm dry diameter. We found a distinct decrease in bubbled aerosol production with increasing water temperature. A clear diurnal cycle in bubbled aerosol production was observed, anticorrelated with both water temperature and dissolved oxygen, which to our knowledge has never been shown before. A link between decreasing aerosol production in daytime and phytoplankton activity is likely to be an important factor. Colony-forming bacteria were transferred to the atmosphere via the bubble-bursting process, with a linear relationship to their seawater concentration.
|
|
| 10. |
- Martinez-Garcia, Eduardo, et al.
(författare)
-
Overstory dynamics regulate the spatial variability in forest-floor CO2 fluxes across a managed boreal forest landscape
- 2022
-
Ingår i: Agricultural and Forest Meteorology. - : Elsevier. - 0168-1923 .- 1873-2240. ; 318
-
Tidskriftsartikel (refereegranskat)abstract
- The forest-floor represents an important interface for various carbon dioxide (CO2) fluxes, however, our knowledge of their variability and drivers across a managed boreal forest landscape is limited. Here, we used a three-year (2016-2018) data set of biometric- and chamber-based flux measurements to investigate the net forest-floor CO2 exchange (NEff) and its component fluxes across 50 forest stands spanning different soil types, tree species, and age classes within a 68 km2 boreal catchment in Sweden. We found that the forest-floor acted as a net CO2 source with the 10th-90th percentile (used hereafter for describing reported variations) ranging from 149 to 399 g C m- 2 yr-1. Among the key landscape attributes, stand age strongly affected most NEff component fluxes, whereas tree species and soil type effects were weak and absent, respectively. Specifically, forest-floor net CO2 emissions increased with stand age due to declining understory gross and net primary production, ranging between 77-275 and 49-163 g C m- 2 yr- 1, respectively. Furthermore, we observed higher understory production rates in pine than in spruce stands. Across the 50 stands, the total forest-floor respiration ranged between 340 and 549 g C m- 2 yr-1 and its spatial variation was primarily regulated by its autotrophic components, i.e., understory and tree root respiration, which displayed divergent increasing and decreasing age-related trends, respectively. Furthermore, heterotrophic soil respiration remained within a relatively narrow range (154-290 g C m- 2 yr- 1), possibly owing to compensating gradients in forest-floor properties. We further identified tree biomass as the major driver of the landscape-scale variations of CO2 fluxes, likely attributable to modulating effects on forest-floor resource availability and growing conditions. This implies that tree growth responses to forest management and global change will be particularly important for regulating magnitudes and spatial variations of forest-floor CO2 fluxes in boreal forests.
|
|
