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At least 181 records · Page 10

Quasi-periodic climatic changes on Mars and earth

Evidence of climatic changes on Mars and the earth due to geologic and astronomical variations is discussed. Finely striped ice-free bands in the Martian polar caps have been taken to indicate that long term variations in the orbit and axial tilt of Mars have precipitated these features at the rate of a mm/yr. Photogrammetric and photometric methods have contributed to measurements of the composition and depth of the Martian caps (14-46 m), and observations of higher solar energy absorption in the northern ice cap implies greater dust deposition in that region than on the south cap; however, the transport mechanisms are not well understood. Comparisons of earth and Martian climatic variations data are made, noting a lack of information on the age intervals of marine and nonmarine sediments on the earth. The possibilities of using quantitative data other than layer thickness to constrain climate models are discussed, and the slope or albedo of layers, or the spacing of polar undulations are suggested.

Cutts, J. A.↗

Regional climate change predictions from the Goddard Institute for Space Studies high resolution GCM

Model simulations of global climate change are seen as an essential component of any program aimed at understanding human impact on the global environment. A major weakness of current general circulation models (GCMs), however, is their inability to predict reliably the regional consequences of a global scale change, and it is these regional scale predictions that are necessary for studies of human/environmental response. This research is directed toward the development of a methodology for the validation of the synoptic scale climatology of GCMs. This is developed with regard to the Goddard Institute for Space Studies (GISS) GCM Model 2, with the specific objective of using the synoptic circulation form a doubles CO2 simulation to estimate regional climate change over North America, south of Hudson Bay. This progress report is specifically concerned with validating the synoptic climatology of the GISS GCM, and developing the transfer function to derive grid-point temperatures from the synoptic circulation. Principal Components Analysis is used to characterize the primary modes of the spatial and temporal variability in the observed and simulated climate, and the model validation is based on correlations between component loadings, and power spectral analysis of the component scores. The results show that the high resolution GISS model does an excellent job of simulating the synoptic circulation over the U.S., and that grid-point temperatures can be predicted with reasonable accuracy from the circulation patterns.

Crane, Robert G.↗

Impact of Climate Change on Heat-Related Mortality in Jiangsu Province, China

A warming climate is anticipated to increase the future heat-related total mortality in urban areas. However, little evidence has been reported for cause-specific mortality or nonurban areas. Here we assessed the impact of climate change on heat-related total and cause-specific mortality in both urban and rural counties of Jiangsu Province, China, in the next five decades. To address the potential uncertainty in projecting future heat-related mortality, we applied localized urban- and nonurban-specific exposure response functions, six population projections including a no population change scenario and five Shared Socioeconomic Pathways (SSPs), and 42 temperature projections from 21 global-scale general circulation models and two Representative Concentration Pathways (RCPs). Results showed that projected warmer temperatures in 2016-2040 and 2041-2065 will lead to higher heat-related mortality for total non-accidental, cardiovascular, respiratory, stroke, ischemic heart disease (IHD), and chronic obstructive pulmonary disease (COPD) causes occurring annually during May to September in Jiangsu Province, China. Nonurban residents in Jiangsu will suffer from more excess heat-related cause-specific mortality in 2016-2065 than urban residents. Variations across climate models and RCPs dominated the uncertainty of heat-related mortality estimation whereas population size change only had limited influence. Our findings suggest that targeted climate change mitigation and adaptation measures should be taken in both urban and nonurban areas of Jiangsu Province. Specific public health interventions should be focused on the leading causes of death (stroke, IHD, and COPD), whose health burden will be amplified by a warming climate.

projection↗

Climate Change Observation Accuracy: Requirements and Economic Value

This presentation will summarize a new quantitative approach to determining the required accuracy for climate change observations. Using this metric, most current global satellite observations struggle to meet this accuracy level. CLARREO (Climate Absolute Radiance and Refractivity Observatory) is a new satellite mission designed to resolve this challenge is by achieving advances of a factor of 10 for reflected solar spectra and a factor of 3 to 5 for thermal infrared spectra. The CLARREO spectrometers can serve as SI traceable benchmarks for the Global Satellite Intercalibration System (GSICS) and greatly improve the utility of a wide range of LEO and GEO infrared and reflected solar satellite sensors for climate change observations (e.g. CERES, MODIS, VIIIRS, CrIS, IASI, Landsat, etc). A CLARREO Pathfinder mission for flight on the International Space Station is included in the U.S. Presidentâ€"TM"s fiscal year 2016 budget, with launch in 2019 or 2020. Providing more accurate decadal change trends can in turn lead to more rapid narrowing of key climate science uncertainties such as cloud feedback and climate sensitivity. A new study has been carried out to quantify the economic benefits of such an advance and concludes that the economic value is ~ $9 Trillion U.S. dollars. The new value includes the cost of carbon emissions reductions.

Wielicki, Bruce↗

Ocean Heat and Carbon Uptake in Transient Climate Change: Identifying Model Uncertainty

Global warming on decadal and centennial timescales is mediated and ameliorated by the oceansequestering heat and carbon into its interior. Transient climate change is a function of the efficiency by whichanthropogenic heat and carbon are transported away from the surface into the ocean interior (Hansen et al. 1985).Gregory and Mitchell (1997) and Raper et al. (2002) were the first to identify the importance of the ocean heat uptakeefficiency in transient climate change. Observational estimates (Schwartz 2012) and inferences from coupledatmosphere-ocean general circulation models (AOGCMs; Gregory and Forster 2008; Marotzke et al. 2015), suggest thatocean heat uptake efficiency on decadal timescales lies in the range 0.5-1.5 W/sq m/K and is thus comparable to theclimate feedback parameter (Murphy et al. 2009). Moreover, the ocean not only plays a key role in setting the timing ofwarming but also its regional patterns (Marshall et al. 2014), which is crucial to our understanding of regional climate,carbon and heat uptake, and sea-level change. This short communication is based on a presentation given by A.Romanou at a recent workshop, Oceans Carbon and Heat Uptake: Uncertainties and Metrics, co-hosted by US CLIVARand OCB. As briefly reviewed below, we have incomplete but growing knowledge of how ocean models used in climatechange projections sequester heat and carbon into the interior. To understand and thence reduce errors and biases inthe ocean component of coupled models, as well as elucidate the key mechanisms at work, in the final section we outlinea proposed model intercomparison project named FAFMIP. In FAFMIP, coupled integrations would be carried out withprescribed overrides of wind stress and freshwater and heat fluxes acting at the sea surface.

periodic variations↗

AO/NAO Response to Climate Change: Relative Importance of Low- and High-Latitude Temperature Changes - 2

Using a variety of GCM experiments with various versions of the GISS model, we investigate how different aspects of tropospheric climate changes affect the extratropical Arctic Oscillation (AO)/North Atlantic Oscillation (NAO) circulation indices. The results show that low altitude changes in the extratropical latitudinal temperature gradient can have a strong impact on eddy forcing of the extratropical zonal wind, in the sense that when this latitudinal temperature gradient increases, it helps force a more negative AO/NAO phase. In addition, local conditions at high latitudes can stabilize/destabilize the atmosphere, inducing negative/positive phase changes. To the extent that there is not a large temperature change in the tropical upper troposphere (either through reduced tropical sensitivity at the surface, or limited transport of this change to high levels), the changes in the low level temperature gradient can provide the dominate influence on the extratropical circulation, so that planetary wave meridional refraction and eddy angular momentum transport changes become uncorrelated with potential vorticity transports. In particular, the climate change that produces the most positive NAO phase change would have substantial warming in the tropical upper troposphere over the Pacific Ocean, with high latitude warming in the North Atlantic. An increase in positive phase of these circulation indices is still more likely than not, but it will depend on the degree of tropical and high latitude temperature response and the transport of low level warming into the upper troposphere. These are aspects that currently differ among the models used for predicting the effects of global warning, contributing to the lack of consensus of future changes in the AO/NAO.

Rind, D.↗

Wetting and Drying Trends Under Climate Change

The geography and timing of changes in water availability under climate change are of considerable societal interest. Characterizing these changes in a robust and meaningful manner, however, has not been easy. In the past decade, studies have engaged two provocative hypotheses to explain and predict large-scale trends in water availability. One hypothesis holds that there will be increased contrasts in available water, as wet places become wetter and dry places become drier. Another hypothesis states that there will be global aridification, as widespread increases in evapotranspiration overwhelm changes in precipitation in most terrestrial regions. There is an extensive and sometimes contentious literature on the evidence for each. In some cases, these debates reflect direct disagreement, but the appearance of disagreement is exaggerated by the diversity of methods and terminologies employed in different studies. Herein we examine the applicability and limits of both hypotheses across different frameworks, scales and contexts, yielding insights on hydrologic change and the future of water availability.

Benjamin F. Zaitchik↗

High and Mid-Latitude Wetlands, Climate Change, and Carbon Storage

Pollen and macrofossil stratigraphy from wetlands associated with AMS chronology provides a vegetational and climatic history over thousands of years. From these records we establish a record of climate change which can be compared with independent records of carbon accumulation rates in these same wetlands. In this way, inferences can be made concerning carbon storage during different climatic regimes. One focus of our research has been high-latitude regions such as Alaskan and Siberian tundra, from which we have paleorecords which span the last 10,000 years. We will present records from the Malaspina Glacier region, Alaska and the Pur-Taz region of Western Siberia. A second focus of our research is in mid-latitude eastern North America. We will present paleorecords from wetlands in Vermont, New York, and Virginia showing the relationship between carbon accumulation rates and climatic changes since the late Pleistocene.

Peteet, Dorothy↗

A Cloud Greenhouse Effect on Mars: Significant Climate Change in the Recent Past

The large variations in Mars orbit parameters are known to be significant drivers of climate change on the Red planet. The recent discovery of buried CO2 ice at the South Pole adds another dimension to climate change studies. In this paper we present results from the Ames GCM that show within the past million years it is possible that clouds from a greatly intensified Martian hydrological cycle may have produced a greenhouse effect strong enough to raise global mean surface temperatures by several tens of degrees Kelvin. It is made possible by the ability of the Martian atmosphere to transport water to high altitudes where cold clouds form, reduce the outgoing longwave radiation, and drive up surface temperatures to maintain global energy balance.

Haberle, Robert M.↗

Model Intercomparison of Maize Response to Climate Change in Low-Input Smallholder Cropping Systems

Smallholder farming systems are characterized by poor soil fertility and low agricultural input use; process-based crop growth models can help quantifying the potential impact of climate change on productivity in these systems.With limiting conditions (water and nutrients), crop models need to rigorously account for soil water, nutrient, CO2, and temperature interactions when simulating climate change effects.

Maize↗

Gray Wave of the Great Transformation: A Satellite View of Urbanization, Climate Change, and Food Security

Land cover change driven by human activity is profoundly affecting Earth's natural systems with impacts ranging from a loss of biological diversity to changes in regional and global climate. This change has been so pervasive and progressed so rapidly, compared to natural processes, scientists refer to it as "the great transformation". Urbanization or the 'gray wave' of land transformation is being increasingly recognized as an important process in global climate change. A hallmark of our success as a species, large urban conglomerates do in fact alter the land surface so profoundly that both local climate and the basic ecology of the landscape are affected in ways that have consequences to human health and economic well-being. Fortunately we have incredible new tools for planning and developing urban places that are both enjoyable and sustainable. A suite of Earth observing satellites is making it possible to study the interactions between urbanization, biological processes, and weather and climate. Using these Earth Observatories we are learning how urban heat islands form and potentially ameliorate them, how urbanization can affect rainfall, pollution, and surface water recharge at the local level and climate and food security globally.

Imhoff, Marc Lee↗

Climate Change Impacts on Agriculture: Challenges, Opportunities, and AgMIP Frameworks for Foresight

Agricultural systems are currently undergoing rapid shifts owing to socioeconomic development, technological change, population growth, economic opportunity, evolving demand for commodities, and the need for sustainability amid global environmental change. It is not sufficient to maintain current harvest levels; rather, there is a need to rapidly increase production in light of a population growing to nearly 10 billion by mid-century and to more than 11 billion by 2100 (FAO, 2016; UN, 2016; Popkin et al., 2012). Current and future agricultural systems are additionally burdened by human-caused climate change, the result of accumulating greenhouse gas and aerosol emissions, ecological destruction, and land use changes that have altered the chemical composition of Earth’s atmosphere and trapped energy in the Earth system (IPCC, 2013; Porter et al., 2014). This increased energy has already raised average surface temperatures by approximately 1 degree Centigrade (GISTEMP Team, 2017; Hansen et al., 2010), leading early on to the term “global warming,” but this phenomenon is now more accurately referred to as “climate change” because it also modifies atmospheric circulation, adjusts regional and seasonal precipitation patterns, and shifts the distribution and characteristics of extreme events (Bindoff et al., 2013; Collins et al., 2013). Food and health systems face increasing risk owing to progressive climate change now manifesting itself as more frequent, severe extreme weather events—heat waves, droughts, and floods (IPCC, 2013). Often without warning, weather-related shocks can have catastrophic and reverberating impacts on the increasingly exposed global food system—through production, processing, distribution, retail, disposal, and waste. Simultaneously, malnutrition and ill health are arising from lack of access to nutritious food, exacerbated in crises such as food price spikes or shortages. For some countries, particularly import-dependent low-income countries, weather shocks and price spikes can lead to social unrest, famine, and migration.

Ruane, Alex C.↗

A11I-2104 Evaluation of the NASA GEOS Chemistry-Climate Model Coupled Atmosphere-Ocean Configuration for its Suitability to Simulations of Atmospheric Composition in a Changing Climate

The NASA Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM) is a full tropospheric-stratospheric chemistry enabled configuration of the NASA GEOS Earth system model. Among the objectives for research performed with GEOSCCM is to understand the impacts of climate change on recovery of the stratospheric ozone layer over the twenty-first century. Simulations performed in the past with GEOSCCM did not have an interactive ocean and were driven with projected sea surface temperature and sea ice boundary conditions provided by external models. This method limits the application of GEOSCCM for climate study because it doesn’t allow the feedback of composition changes to ocean. For a full representation of the chemistry-climate feedbacks in the Earth System, we have developed a configuration of GEOSCCM that makes use of the MOM5 ocean general circulation model coupled to the GEOS atmospheric general circulation model. This configuration leverages development of the GEOS Sub-seasonal-to-Seasonal (S2S) prediction system, and includes interactive, radiatively coupled aerosols and two-moment, aerosol-aware cloud microphysics. W e have assessed the baseline model climate sensitivity with an Monday, 11 December 2023 08:30 - 12:50 Poster Hall A-C - South (Exhibition Level, South, MC) experiment performed under pre-industrial (e.g., year 1850) greenhouse gas conditions and a second experiment under 4xCO2 conditions, similar to the typical CMIP protocol. The GEOS model is demonstrated to have a climate sensitivity of a 2.6 K increase in global mean surface temperature for an equivalent doubling of CO2 from pre-industrial conditions, in line with current CMIP models. This configuration of the GEOS model is suitable for application to multidecadal to century-long simulations of climate system response to changing greenhouse gas levels. We report here our evaluation of the climate diagnostics of this configuration and discuss future directions for work with this model configuration, including an ongoing twenty-first century projection experiment based on the Chemistry-Climate Model Intercomparison project protocol.

models↗

Climate Change in the US: Potential Consequences for Human Health

The U.S. National Assessment identified five major areas of consequences of climate change in the United States: temperature-related illnesses and deaths, health effects related to extreme weather events, air pollution-related health effects, water- and food-borne diseases, and insect-, tick-, and rodent-borne diseases. The U.S. National Assessment final conclusions about these potential health effects will be described. In addition, a summary of some of the new tools for studying human health aspects of climate change as well as environment-health linkages through remotely sensed data and observations will be provided.

Maynard, Nancy G.↗

Indicators of Climate Change Impacts on the Water Cycle and Water Management

Managing water is a top social and economic responsibility and is expected to become even more critical as climate change, in addition to other human activities, alters water availability and quality. Robust indicators reflecting the effects of climate change on the U.S. and global water cycles are needed in order to appropriately manage water resources. Here, we describe a suite of seventeen water cycle and management indicators, which are based on synthesis of available datasets. These indicators include: average and heavy precipitation, standardized precipitation index, annual, 7-day low and 3-day high streamflow volume, streamflow timing, snow cover, snow water equivalent, groundwater level, lake water temperature, stream water temperature, dissolved oxygen, salinity, Palmer Drought Severity Index, water withdrawals and water use. We also identify three indicators that could be included in the suite of water cycle and management indicators with some additional, directed work: snowfall, evapotranspiration and soil moisture. Our conceptual framework focuses on known water cycle changes in addition to potential effects on management, and addresses water quantity and quality, as well as water use and related interactions with freshwater ecosystems, societal impacts, and management. Water cycle indicators are organized into three categories: (1) hydrologic processes, (2) water quality processes, and (3) water quality and quantity impacts. Indicators described here are recommended to serve as critical references for periodic climate assessments. As such, these indicators support analyses of the effects of global change on the natural environment, agriculture, energy, and water resources, among other sectors. Additionally, we identify research gaps and needs that can be addressed to advance the development of future indicators.

Christa D Peters-Lidard↗

The effects of global climate change on Southeast Asia: A survey of likely impacts and problems of adaptation

Study results indicate the likelihood of significant net damages from climate change, in particular damages from sea-level rise and higher temperatures that seem unlikely to be offset by favorable shifts in precipitation and carbon dioxide. Also indicated was the importance of better climate models, in particular models that can calculate climate change on a regional scale appropriate to policy-making. In spite of this potential for damage, there seems to be a low level of awareness and concern, probably caused by the higher priority given to economic growth and reinforced by the great uncertainty in the forecasts. The common property nature of global environment systems also leads to a feeling of helplessness on the part of country governments.

Njoto, Sukrisno↗

Using Satellites to Understand Climate and Climate Change

This viewgraph presentation reviews the measurement of climate with the use of satellites. The basic greenhouse effect, Ice-albedo feedback, climate models and observations, aerosol-cloud interactions, and the Antarctic are discussed, along with the human effect on climate change.

remote sensing↗

Impact of Growth Phase, Pigment Adaptation, and Climate Change Conditions on the Cellular Pigment and Carbon Content of Fifty‐One Phytoplankton Isolates

Owing to their importance in aquatic ecosystems, the demand for models that estimate phytoplankton biomass and community composition in the global ocean has increased over the last decade. Moreover, the impacts of climate change, including elevated carbon dioxide (CO2), increased stratification, and warmer sea surface temperatures, will likely shape phytoplankton community composition in the global ocean. Chemotaxonomic methods are useful for modeling phytoplankton community composition from marker pigments normalized to chlorophyll a (Chl a). However, photosynthetic pigments, particularly Chl a, are sensitive to nutrient and light conditions. Cellular carbon is less sensitive, so using carbon biomass instead may provide an alternative approach. To this end, cellular pigment and carbon concentrations were measured in 51 strains of globally relevant, cultured phytoplankton. Pigment-to-Chl a and pigment-to-carbon ratios were computed for each strain. For 25 strains, measurements were taken during two growth phases. While some differences between growth phases were observed, they did not exceed within class differences. Multiple strains of Amphidinium carterae, Ditylum brightwellii and Heterosigma akashiwo were measured to determine whether time in culture influenced pigment and carbon composition. No appreciable trends in cellular pigment or carbon content were observed. Lastly, the potential impact of climate change conditions on the pigment ratios was assessed using a multistressor experiment that included increased mean light, temperature, and elevated pCO2 on three species: Thalassiosira oceanica, Ostreococcus lucimarinus, and Synechococcus. The largest differences were observed in the pigment-to-carbon ratios, while the marker pigments largely covaried with Chl a. The implications of these observations to chemotaxonomic applications are discussed.

Pigments↗