CICERO Research Archive (CICERO Senter for klimaforskning)
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Veikart for utslippsreduksjoner i Trondheim
Get PDFCICERO Senter for klimaforskning og Transportøkonomisk institutt (TØI) har utarbeidet et veikart for utslippsreduksjoner i Trondheim fram mot 2030. Veikartet inneholder en referansebane for klimagassutslippene og beregninger av effekter av mulige tiltak som kan redusere utslippene. Resultatene viser at utslippene i referansebanen forventes å gå noe ned fram mot 2030, men at det vil være behov for omfattende tiltak for å nå Trondheim kommunes mål om å redusere utslippene innenfor kommunens grenser med 80 prosent innen 2030. Det er satt sammen tre pakker med tiltak som kan redusere utslippene, og det er anslått at gjennomføring av alle tre tiltakspakkene kan redusere utslippene i Trondheim kommune med 87 prosent i 2030 sammenliknet med 2009. Rapporten inneholder også en gjennomgang av mulige tiltak som kan øke karbonopptaket i Trondheim kommune fram mot 2030.publishedVersio
The added value of km-scale simulations to describe temperature over complex orography: the CORDEX FPS-Convection multi-model ensemble runs over the Alps
Get PDFThe increase in computational resources has enabled the emergence of multi-model ensembles of convection-permitting regional climate model (CPRCM) simulations at very high horizontal resolutions. An example is the CORDEX Flagship Pilot Study on “Convective phenomena at high resolution over Europe and the Mediterranean”, a set of kilometre-scale simulations over an extended Alpine domain. This first-of-its-kind multi-model ensemble, forced by the ERA-Interim reanalysis, can be considered a benchmark dataset. This study uses a recently proposed metric to determine the added value of all the available Flagship Pilot Study hindcast kilometre-scale simulations for maximum and minimum temperature. The analysis is performed using state-of-the-art gridded and station observations as ground truth. This approach directly assesses the added value between the high-resolution CPRCMs against their driving global simulations and coarser resolution RCM counterparts. Overall, models display some modest gains, but also considerable shortcomings are exhibited. In part, these deficiencies can be attributed to the assimilation of temperature observations into ERA-Interim. Although the gains for the use of kilometre-scale resolution for temperature are limited, the improvement of the spatial representation of local atmospheric circulations and land–atmosphere interactions can ultimately lead to gains, particularly in coastal areas.The added value of km-scale simulations to describe temperature over complex orography: the CORDEX FPS-Convection multi-model ensemble runs over the AlpspublishedVersio
Spatiotemporal Differentiation and Driving Mechanism of Coupling Coordination between New-Type Urbanization and Ecological Environment in China
Get PDFThe coupling coordination between new-type urbanization and ecological environment is important for regional sustainable development in China. This study proposes an evaluation index system of new urbanization and ecological environment, and adopts a coupling coordination degree model and a spatial error model to explore the spatiotemporal evolution characteristics and driving factors of the coupling coordination degrees of new-type urbanization and ecological environment in 31 provinces of China from 2010 to 2019. The results show spatiotemporal differences in the overall coupling coordination degree, which has shifted from a mild disorder stage to a near disorder stage over the study period. The spatial distribution of the coupling coordination degrees by province has shifted over time from a pattern of low in the middle and high in both east and west regions to a pattern of stepwise decreasing from east, middle to west regions. The spatial correlation of the coupling coordination degrees is gradually weakening over time. Regional economic development, social security, technological progress, industrial structure, and education input can all contribute to inject strong impetus to the coupled and coordinated development of the two systems. As the development of impetus is still insufficient, it is suggested to pay attention to local conditions, strengthen inter-regional cooperation, and strengthen the superposition effect of multiple driving forces.publishedVersio
Evaluating global and regional land warming trends in the past decades with both MODIS and ERA5-Land land surface temperature data
Get PDFGlobal surface temperature has been setting new record highs in the recent decades, imposing increasing environmental challenges for societies and ecosystems worldwide. Global warming rates of the 20th century have been documented by a number of studies, nevertheless, the warming rates in the most recent decades in the 21st century are of particular interest for understanding the ongoing climate change. Analyzing temperature trends demands data with high spatial resolution and broad geographical coverage to allow for analyzing trends and changes on a regional scale. Land Surface Temperature data from NASA MODIS with global resolution of 0.05° and Skin Temperature data from European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5-Land reanalysis with global resolution of 0.1° fulfill these demands. In this study, we analyze the remote-sensing-based MODIS data to estimate land surface temperature change rates over the period 2001–2020 in global, continental, and pixel-wise scales with statistical significance indicated. The model-based ERA5-Land data are also analyzed in parallel, extending the period of analysis back to 1981. These two independently-sourced datasets, one from satellites above the atmosphere and one from combining surface modeling and observations, are shown to produce highly consistent results. It is revealed that the trends in the shorter period 2001–2020 are spatially conforming to the trends in the longer period 1981–2020 despite the shorter time length. For the period 2001–2020, we show that the global average land surface temperature rate of change was 0.26 °C-0.34 °C per decade, with substantially different warming rates in different regions. The Arctic, Europe, and Russia show statistically significant warming in both datasets. The Arctic, in particular, warmed at a rate 2.5–2.8 times the global average, and data in the 40-year period 1981–2020 suggest that warming is accelerating in almost all the continents or large regions. Most noticeably, the two independent datasets both indicate that Arctic permafrost regions had the world's highest warming rate at the onset of the 21st century, reaching >2 °C per decade in some areas.publishedVersio
Modeling the Joint Effects of Vegetation Characteristics and Soil Properties on Ecosystem Dynamics in a Panama Tropical Forest
Get PDFoai:pub.cicero.oslo.no:11250/2998522In tropical forests, both vegetation characteristics and soil properties are important not only for controlling energy, water, and gas exchanges directly but also determining the competition among species, successional dynamics, forest structure and composition. However, the joint effects of the two factors have received limited attention in Earth system model development. Here we use a vegetation demographic model, the Functionally Assembled Terrestrial Ecosystem Simulator (FATES) implemented in the Energy Exascale Earth System Model (E3SM) Land Model (ELM), ELM-FATES, to explore how plant traits and soil properties affect tropical forest growth and composition concurrently. A large ensemble of simulations with perturbed vegetation and soil hydrological parameters is conducted at the Barro Colorado Island, Panama. The simulations are compared against observed carbon, energy, and water fluxes. We find that soil hydrological parameters, particularly the scaling exponent of the soil retention curve (Bsw), play crucial roles in controlling forest diversity, with higher Bsw values (>7) favoring late successional species in competition, and lower Bsw values (1 ∼ 7) promoting the coexistence of early and late successional plants. Considering the additional impact of soil properties resolves a systematic bias of FATES in simulating sensible/latent heat partitioning with repercussion on water budget and plant coexistence. A greater fraction of deeper tree roots can help maintain the dry-season soil moisture and plant gas exchange. As soil properties are as important as vegetation parameters in predicting tropical forest dynamics, more efforts are needed to improve parameterizations of soil functions and belowground processes and their interactions with aboveground vegetation dynamics.publishedVersio
Mapping the dependence of black carbon radiative forcing on emission region and season
Get PDFFor short-lived climate forcers such as black carbon (BC), the atmospheric concentrations, radiative
forcing (RF), and, ultimately, the subsequent effects on climate, depend on the location and timing of the emissions. Here, we employ the NorESM1-Happi version of the Norwegian Earth System Model to systematically study how the RF associated with BC emissions depends on the latitude, longitude, and seasonality of the emissions. The model aerosol scheme is run in an offline mode to allow for an essentially noise-free evaluation of the RF associated with even minor changes in emissions. A total of 960 experiments were run to evaluate the BC direct RF (dirRF) and the RF associated with BC in snow/ice (snowRF) for emissions in 192 latitude–longitude boxes covering the globe, both for seasonally uniform emissions and for emissions in each of the four seasons separately. We also calculate a rough estimate of the global temperature response to regional emissions and provide a Fortran-based tool to facilitate the further use of our results.
Overall, the results demonstrate that the BC RFs strongly depend on the latitude, longitude, and season of the emissions. In particular, the global mean dirRF normalized by emissions (direct specific forcing; dirSF) depends much more strongly on the emission location than suggested by previous studies that have considered emissions from continental-/subcontinental-scale regions. Even for seasonally uniform emissions, dirSF varies by more than a factor of 10, depending on the emission location. These variations correlate strongly with BC lifetime, which varies from less than 2 to 11 d. BC dirSF is largest for emissions in tropical convective regions and in subtropical and midlatitude continents in summer, both due to the abundant solar radiation and strong convective transport, which increases BC lifetime and the amount of BC above clouds. The dirSF is also relatively large for emissions in high-albedo, high-latitude regions such as Antarctica and Greenland. The dependence of snow specific forcing (snowSF) on the emission location is even larger. While BC emissions originating from most low-latitude regions result in negligible snowSF, the maxima of snowSF for emissions in polar regions greatly exceed the largest values of dirSF for low-latitude emissions. The large magnitude of snowSF for high-latitude BC emissions suggests that, for a given mass of BC emitted, the climate impacts are also largest for high-latitude emissions.
The additivity of the RFs resulting from BC emissions in different regions and seasons is also investigated. It is found that dirRF is almost additive for current-day emissions, so that summing the RFs computed for individual regions/seasons without considering BC emissions from elsewhere overestimates dirRF by less than 10 %. For snowRF, the overestimate is somewhat larger, at 20 %.publishedVersio
Indoor Air Pollution and Health: Bridging Perspectives from Developing and Developed Countries
Get PDFMuch of the global population spends most of their time indoors; however, air pollution measurement, a proxy of exposure, occurs primarily outdoors. This fundamental disconnect between where the people are and where the measurements are made likely leads to misestimation of the true burden of air pollution on human health, which is already substantial, with exposure leading to approximately 6.7 million deaths yearly. In this review, we describe the two disparate but linked fields commonly referred to as indoor air pollution and household air pollution. Both fields focus on the measurement and characterization of exposures and subsequent health effects that occur primarily in the indoor environment. The former tends to focus on issues in the developed world, whereas the latter focuses on issues in low- and middle-income countries reliant on solid fuels, like wood, dung, coal, and crop residues, for basic household energy needs. Both lead to substantial exposures to air pollutants that are damaging to human health. We describe and contrast both contexts and provide potential topics for conversation between the disciplinespublishedVersio
Changes in IPCC Scenario Assessment Emulators Between SR1.5 and AR6 Unraveled
Get PDFThe IPCC's scientific assessment of the timing of net-zero emissions and 2030 emission reduction targets consistent with limiting warming to 1.5°C or 2°C rests on large scenario databases. Updates to this assessment, such as between the IPCC's Special Report on Global Warming of 1.5°C (SR1.5) of warming and the Sixth Assessment Report (AR6), are the result of intertwined, sometimes opaque, factors. Here we isolate one factor: the Earth System Model emulators used to estimate the global warming implications of scenarios. We show that warming projections using AR6-calibrated emulators are consistent, to within around 0.1°C, with projections made by the emulators used in SR1.5. The consistency is due to two almost compensating changes: the increase in assessed historical warming between SR1.5 (based on AR5) and AR6, and a reduction in projected warming due to improved agreement between the emulators' response to emissions and the assessment to which it is calibrated.publishedVersio
Earlier emergence of a temperature response to mitigation by filtering annual variability
Get PDFThe rate of global surface warming is crucial for tracking progress towards global climate targets, but is strongly influenced by interannual-to-decadal variability, which precludes rapid detection of the temperature response to emission mitigation. Here we use a physics based Green’s function approach to filter out modulations to global mean surface temperature from sea-surface temperature (SST) patterns, and show that it results in an earlier emergence of a response to strong emissions mitigation. For observed temperatures, we find a filtered 2011–2020 surface warming rate of 0.24 °C per decade, consistent with long-term trends. Unfiltered observations show 0.35 °C per decade, partly due to the El Nino of 2015–2016. Pattern filtered warming rates can become a strong tool for the climate community to inform policy makers and stakeholder communities about the ongoing and expected climate responses to emission reductions, provided an effort is made to improve and validate standardized Green’s functions.publishedVersio
The Paris Agreement has the potential to facilitate ambitious climate action: a reply to ‘Why do climate change negotiations stall? Scientific evidence and solutions for some structural problems’ by Ulrich J. Frey and Jazmin Burgess
Get PDFFrey and Burgess (2022) argue that climate change negotiations have stalled because of the global public goods nature of the problem, the consensus decision-making process and the lack of institutions to enforce sanctions. I will argue that this is not the most precise, nor the most fruitful, way to frame the political challenge of limiting climate change, for two reasons. First, the authors of the Paris Agreement were mindful of the limitations of a global accord negotiated under a consensus rule. They created a flexible umbrella for national – and non-governmental – action that can allow climate ambitions to ramp up over time. Second, whereas climate change is a global problem, important elements of it can potentially be solved through climate clubs, where many of the issues that plague global negotiations do not apply.acceptedVersio