Degree Of Warming Research Articles

Meteorological Comfort Indices to Assess Extreme Warmness in Southwest, Nigeria

2015, 2016 and 2017 have been confirmed the three warmest years on record and the degree of warming during these three years has been exceptional. Extremes of heat and cold environmental conditions have been known to be very detrimental to the health and comfort of humans. The severity of these adverse effects is often local and varies from one place to another though they are happening on a global scale therefore Temperature variation, Heat Index (HI) temperature and Dew Point Temperature (DPT) ( Meteorological comfort indices) were used to assess the effect of this condition in southwest, Nigeria. Air temperature and Humidity data were collected from meteorological stations situated in the southwestern states selected for study and was processed using the rule of Thumb for DPT calculations and Steadman (1979) formula simplified by Rothfusz’ model (1990) for HI temperature. The data analysis was done using Microsoft Excel Package and Statistical Package for the Social Sciences (SPSS), the following results were obtained: Elevation may affect temperature yet during extreme warmness other factors can have a greater influence on temperature and meteorological comfort indices used to assess extreme warmness in southwest Nigeria from this study showed greater impacts thus: Heat Index Temperature has highest values in Lagos State, while Dew Point Temperature have highest values in Ogun state. None of these extreme warmness measuring variables seem to be solely in favour of state Location in terms of coordinates and elevation; this suggests more anthropogenic influence forming the characteristics of the states to geographic locations of the states however, between the start year of extreme warmness (2015) and 2017, HI temperature showed a significant increase while average DPT did not really change during the period of extreme warmness.

Meteorological Comfort Indices to Assess Extreme Warmness in Southwest, Nigeria

2015, 2016 and 2017 have been confirmed the three warmest years on record and the degree of warming during these three years has been exceptional. Extremes of heat and cold environmental conditions have been known to be very detrimental to the health and comfort of humans. The severity of these adverse effects is often local and varies from one place to another though they are happening on a global scale therefore Temperature variation, Heat Index (HI) temperature and Dew Point Temperature (DPT) ( Meteorological comfort indices) were used to assess the effect of this condition in southwest, Nigeria. Air temperature and Humidity data were collected from meteorological stations situated in the southwestern states selected for study and was processed using the rule of Thumb for DPT calculations and Steadman (1979) formula simplified by Rothfusz’ model (1990) for HI temperature. The data analysis was done using Microsoft Excel Package and Statistical Package for the Social Sciences (SPSS), the following results were obtained: Elevation may affect temperature yet during extreme warmness other factors can have a greater influence on temperature and meteorological comfort indices used to assess extreme warmness in southwest Nigeria from this study showed greater impacts thus: Heat Index Temperature has highest values in Lagos State, while Dew Point Temperature have highest values in Ogun state. None of these extreme warmness measuring variables seem to be solely in favour of state Location in terms of coordinates and elevation; this suggests more anthropogenic influence forming the characteristics of the states to geographic locations of the states however, between the start year of extreme warmness (2015) and 2017, HI temperature showed a significant increase while average DPT did not really change during the period of extreme warmness.

Thermodynamic versus Dynamic Controls on Extreme Precipitation in a Warming Climate from the Community Earth System Model Large Ensemble

The moisture budget is evaluated as a function of the probability distribution of precipitation for the end of the twentieth century and projected end of the twenty-first century in the Community Earth System Model Large Ensemble. For a given precipitation percentile, a conditional moisture budget equation relates precipitation minus evaporation ( P − E) to vertical moisture transport, horizontal moisture advection, and moisture storage. At high percentiles, moisture advection and moisture storage cancel and evaporation is negligible, so that precipitation is approximately equal to vertical moisture transport, and likewise for projected changes. Therefore, projected changes to extreme precipitation are approximately equal to the sum of thermodynamic and dynamic tendencies, representing changes to the vertical profiles of moisture content and mass convergence, respectively. The thermodynamic tendency is uniform across percentiles and regions as an intensification of the hydrological cycle, but the dynamic tendency is more complex. For extreme events, per degree of warming, in the mid-to-high latitudes the dynamic tendency is small, so that precipitation approximately scales by the Clausius–Clapeyron 7% K−1 increase. In the subtropics, a drying tendency originating from dynamics offsets the thermodynamic wetting tendency, with the net effect on precipitation varying among regions. The effect of this dynamic drying decreases with increasing percentile. In the deep tropics, a positive dynamic tendency occurs with magnitude similar to or greater than the positive thermodynamic tendency, resulting in generally a 10%–15% K−1 precipitation increase, and with a >25% K−1 increase over the tropical east Pacific. This reinforcing dynamical tendency increases rapidly for high percentiles.

Does global warming amplify interannual climate variability?

Based on the outputs of 30 models from Coupled Model Intercomparison Project Phase 5 (CMIP5), the fractional changes in the amplitude interannual variability (σ) for precipitation (P′) and vertical velocity (ω′) are assessed, and simple theoretical models are constructed to quantitatively understand the changes in σ(P′) and σ(ω′). Both RCP8.5 and RCP4.5 scenarios show similar results in term of the fractional change per degree of warming, with slightly lower inter-model uncertainty under RCP8.5. Based on the multi-model median, σ(P′) generally increases but σ(ω′) generally decreases under global warming but both are characterized by non-uniform spatial patterns. The σ(P′) decrease over subtropical subsidence regions but increase elsewhere, with a regional averaged value of 1.4% K− 1 over 20°S–50°N under RCP8.5. Diagnoses show that the mechanisms for the change in σ(P′) are different for climatological ascending and descending regions. Over ascending regions, the increase of mean state specific humidity contributes to a general increase of σ(P′) but the change of σ(ω′) dominates its spatial pattern and inter-model uncertainty. But over descending regions, the change of σ(P′) and its inter-model uncertainty are constrained by the change of mean state precipitation. The σ(ω′) is projected to be weakened almost everywhere except over equatorial Pacific, with a regional averaged fractional change of − 3.4% K− 1 at 500 hPa. The overall reduction of σ(ω′) results from the increased mean state static stability, while the substantially increased σ(ω′) at the mid-upper troposphere over equatorial Pacific and the inter-model uncertainty of the changes in σ(ω′) are dominated by the change in the interannual variability of diabatic heating.

Global Energy Consumption in a Warming Climate

We combine econometric analysis of the response of energy demand to temperature and humidity exposure with future scenarios of climate change and socioeconomic development to quantify the impacts of future climate warming on final energy consumption across the world. Globally, changes in climate circa 2050 have a moderate impact on energy consumption of 7–17%, depending on the degree of warming. Impacts vary in sign and magnitude across regions, fuels, and sectors. Climatically-induced changes in energy use are larger in tropical regions. Almost all continents experience increases in energy demand, driven by the commercial and industrial sectors. In Europe declines in energy use by residences drive an overall reduction in aggregate final energy. Energy use increases in almost all G20 economies located in the tropics, while outside of Europe G20 countries in temperate regions experience both increasing and declining total energy use, depending on the incidence of changes in the frequency of hot and cold days. The effect of climate change is regressive, with the incidence of increased energy demand overwhelmingly falling on low- and middle-income countries, raising the question whether climate change could exacerbate energy poverty.

Freshwater vulnerability under high end climate change. A pan-European assessment

As freshwater availability is crucial for securing a sustainable, lower‑carbon future, there is a critical connection between water management and climate policies. Under a rapidly changing climate, it is more important than ever to estimate the degree of future water security. This is a challenging task as it depends on many different variables: the degree of warming and its consequent effects on hydrological resources, the water demand by different sectors, and the possible ameliorations or deteriorations of the effects due to climate change adaptation and mitigation strategies. A simple and transparent conceptual framework has been developed to assess the European vulnerability to freshwater stress under the present hydro-climatic and socioeconomic conditions, in comparison to projections of future vulnerability for different degrees of global warming (1.5°C, 2°C and 4°C), under the high-rate warming scenario (RCP8.5). Different levels of adaptation to climate change are considered in the framework, by employing various relevant pathways of socioeconomic development. A spatially detailed pan-European map of vulnerability to freshwater shortage has been developed at the local administrative level, making this approach extremely useful for supporting regional level policymaking and implementation and strategic planning against future freshwater stress.

Impacts of climate change on European hydrology at 1.5, 2 and 3 degrees mean global warming above preindustrial level

Impacts of climate change at 1.5, 2 and 3 °C mean global warming above preindustrial level are investigated and compared for runoff, discharge and snowpack in Europe. Ensembles of climate projections representing each of the warming levels were assembled to describe the hydro-meteorological climate at 1.5, 2 and 3 °C. These ensembles were then used to force an ensemble of five hydrological models and changes to hydrological indicators were calculated. It is seen that there are clear changes in local impacts on evapotranspiration, mean, low and high runoff and snow water equivalent between a 1.5, 2 and 3 °C degree warmer world. In a warmer world, the hydrological impacts of climate change are more intense and spatially more extensive. Robust increases in runoff affect the Scandinavian mountains at 1.5 °C, but at 3 °C extend over most of Norway, Sweden and northern Poland. At 3 °C, Norway is affected by robust changes in all indicators. Decreases in mean annual runoff are seen only in Portugal at 1.5 °C warming, but at 3 °C warming, decreases to runoff are seen around the entire Iberian coast, the Balkan Coast and parts of the French coast. In affected parts of Europe, there is a distinct increase in the changes to mean, low and high runoff at 2 °C compared to 1.5 °C, strengthening the case for mitigation to lower levels of global warming. Between 2 and 3 °C, the changes in low and high runoff levels continue to increase, but the changes to mean runoff are less clear. Changes to discharge in Europe’s larger rivers are less distinct due to the lack of homogenous and robust changes across larger river catchments, with the exception of Scandinavia where discharges increase with warming level.

Quantifying global soil carbon losses in response to warming.

The majority of the Earth's terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30 ± 30 petagrams of carbon to 203 ± 161 petagrams of carbon under one degree of warming, depending on the rate at which the effects of warming are realized. Under the conservative assumption that the response of soil carbon to warming occurs within a year, a business-as-usual climate scenario would drive the loss of 55 ± 50 petagrams of carbon from the upper soil horizons by 2050. This value is around 12-17 per cent of the expected anthropogenic emissions over this period. Despite the considerable uncertainty in our estimates, the direction of the global soil carbon response is consistent across all scenarios. This provides strong empirical support for the idea that rising temperatures will stimulate the net loss of soil carbon to the atmosphere, driving a positive land carbon-climate feedback that could accelerate climate change.

A 133-Year Record of Climate Change and Variability from Sheffield, England

A 133-year length (1883–2015) daily climate record from Sheffield, England (53.38°N, 1.49°W) is analysed. Across the entire length of the record, there are significant warming trends annually and for all seasons, whereas precipitation shows a significant annual increase but the seasonal trends, whilst all positive, are not significant. Trends in extreme indices mirror the mean long-term warming and wetting signal. Record hot and cold daily temperatures and precipitation amounts are associated with summer anticyclonic conditions, an anomalous easterly winter jet stream and summer cyclonic activity, respectively. Whilst there are large uncertainties surrounding the calculation of return periods for the daily maximum, minimum and precipitation records from a single record, our best estimates suggest that in the current climate (2015), the existing records have return periods of 38, 529 and 252 years, respectively. The influence of several climate indices on mean and extreme indices are considered on seasonal scales, with the North Atlantic Oscillation displaying the strongest relationship. Future mean maximum temperature and precipitation alongside extreme indices representing the warmest and wettest day of the year are analysed from two downscaled climate model output archives under analysis periods of a 1.5 and 2 degree warmer world and the 2080–2099 end of 21st century period. For this mid-latitude location, there is minimal difference in model projections between a 1.5 and 2 degree world, but a significant difference between the 1.5/2 degree world and the end of century 2080–2099 period under the most severe climate warming scenarios.

The effect of the pathway to a two degrees warmer world on the regional temperature change of Europe

The purpose of this study is to investigate if the pathway to reach a 2 degree warmer world influences the regional climate in Europe at the time of 2 degrees of global warming above the pre-industrial level. We have investigated this using climate change data from ensembles of both Global Climate Models and Regional Climate Models. We compare the change of regional temperature in Europe to the global temperature change for different emission scenarios, following the IPCC Representative Concentration Pathways (RCP), to see if the pathway has any influence. We find that there is a small but significant difference in the regional temperature change, but the effect is small compared to internal variability on the timescales involved in reaching +2 degrees for the investigated emission scenarios. From an adaptation point of view, reaching +2 degrees as slowly as possible will obviously allow for a longer time period to implement adaptation measures to mitigate the effect of climate change.

Global Energy Demand in a Warming Climate

This paper combines an econometric analysis of the response of energy demand to temperature and humidity exposure with future scenarios of climate change and socioeconomic development to characterize climate impacts on energy demand at different spatial scales. Globally, future climate change is expected to have a moderate impact on energy demand, in the order of 6-11%, depending on the degree of warming, because of compensating effects across regions, fuels, and sectors. Climate-induced changes in energy demand are disproportionally larger in tropical regions. South America, Asia, and Africa, increase energy demand across all sectors and climate scenarios, while Europe, North America and Oceania exhibit mixed responses, but with consistent reductions in the residential sector. Even so, only Europe and Oceania in the moderate warming scenario experience aggregate reductions in energy use, as commercial electricity use increases significantly. We find that climate change has a regressive impact on energy demand, with the incidence of increased energy demand overwhelmingly falling on low- and middle-income countries, raising the question whether climate change could exacerbate energy poverty.

Snow albedo feedback

Over the past decade, substantial progress has been made in improving our understanding of surface albedo feedbacks, where changes in surface albedo from warming (cooling) can cause increases (decreases) in absorbed solar radiation, amplifying the initial warming (cooling). The goal of this review is to synthesize and assess recent research into the feedback caused by changing continental snow cover, or snow albedo feedback (SAF). Four main topics are evaluated: (i) the importance of SAF to the global energy budget, (ii) estimates of SAF from various data sources, (iii) factors influencing the spread in SAF, and (iv) outstanding issues related to our understanding of the physical processes that control SAF (and their uncertainties). SAF is found to exert a small influence on a global scale, with amplitude of ∼ 0.1 Wm−2K−1, roughly 7% of the strength of water vapor feedback. However, SAF is an important driver of regional climate change over Northern Hemisphere (NH) extratropical land, where observation-based estimates show a peak feedback of around 1% decrease in surface albedo per degree of warming during spring. Viewed collectively, the current generation of climate models represent this process accurately, but several models still use outdated parameterizations of snow and surface albedo that contribute to biases that impact the simulation of SAF. This discussion serves to synthesize and evaluate previously published literature, while highlighting promising directions being taken at the forefront of research such as high resolution modeling and the use of large ensembles.

An Improved Open-Top Chamber with Solar-Heated Double Funnels That Can Adapt to All Wind Directions for Simulating Future Global Warming Conditions in Rice Paddy Fields

An Open-Top Chamber with Solar-heated Double Funnels (OTC-SDF2) that uses solar energy as a heating source was developed in this study. Two air entry/exit funnels were connected to the OTC via flat tunnels through which air was warmed by solar radiation. The new apparatus increased the air temperature by approximately 1°C throughout the chamber when more than half the energy of full sunlight was supplied. Although air flow occurs in only two directions, a nearly constant temperature increase was observed for each wind direction. This increase in temperature was stable for 1 mˉs to 4 mˉs wind speeds in every direction. This degree of warming may be adequate for screening high-temperature tolerant plants from medium to weak cultivars. The OTC-SDF2 has the potential to provide moderately high-temperature treatments for screening various cultivars/strains and may be used to evaluate easy, low-cost cropping methods associated with high-temperature stresses.

C₃ and C₄ plant responses to increased temperatures and altered monsoonal precipitation in a cool desert on the Colorado Plateau, USA.

Dryland ecosystems represent >40% of the terrestrial landscape and support over two billion people; consequently, it is vital to understand how drylands will respond to climatic change. However, while arid and semiarid ecosystems commonly experience extremely hot and dry conditions, our understanding of how further temperature increases or altered precipitation will affect dryland plant communities remains poor. To address this question, we assessed plant physiology and growth at a long-term (7-year) climate experiment on the Colorado Plateau, USA, where the community is a mix of shallow-rooted C3 and C4 grasses and deep-rooted C4 shrubs. The experiment maintained elevated-temperature treatments (+2 or +4 °C) in combination with altered summer monsoonal precipitation (+small frequent precipitation events or +large infrequent events). Increased temperature negatively affected photosynthesis and growth of the C3 and C4 grasses, but effects varied in their timing: +4 °C treatments negatively affected the C3 grass early in the growing season of both years, while the negative effects of temperature on the C4 grass were seen in the +2 and +4 °C treatments, but only during the late growing season of the drier year. Increased summer precipitation did not affect photosynthesis or biomass for any species, either in the year the precipitation was applied or the following year. Although previous research suggests dryland plants, and C4 grasses in particular, may respond positively to elevated temperature, our findings from a cool desert show marked declines in C3 and C4 photosynthesis and growth, with temperature effects dependent on the degree of warming and growing-season precipitation.

Poleward shift in Indian summer monsoon low level jetstream under global warming

The low level jetstream (LLJ) transports moisture from the surrounding Oceans to Indian land mass and hence an important component of the Indian summer monsoon (ISM). Widening of tropical belt and poleward shifts in mid-latitude jetstreams have been identified as major impacts of global warming on large-scale atmospheric dynamics. A general northward shift in ISM circulation has been suggested recently, based on the Coupled Model Inter-comparison Project (CMIP5) simulations. Here, we investigate the current and projected future changes in LLJ in observations as well as the coupled model (CMIP3/CMIP5) simulations. A poleward shift in the monsoon LLJ has been detected both in the observations and coupled model simulations. The poleward shift is also reflected in the future projections in a warming scenario, with the magnitude of shift depending on the degree of warming. Consistent with the LLJ shift, a drying (wet) trend in the southern (northern) part of the western coast of India is also observed in the last three decades. Further analysis reveals that enhanced land-sea contrast resulted in a strengthening of the cross-equatorial sea level pressure gradient over Indian Ocean, which in turn resulted in the northward shift of the zero absolute vorticity contour from its climatological position. The poleward shift in zero absolute vorticity contour is consistent with that of LLJ core (location of maximum low-level zonal winds). Possible uncertainties in the results are discussed in the context of known model biases and ensemble sample sizes. These results assume significance in the context of the concerns over ecologically fragile Western Ghats region in a warming scenario.

Broken tropical thermostats

During the early Pliocene epoch, tropical sea surface temperatures were thought to be similar to those of today, even though global mean temperatures were several degrees warmer. Temperature reconstructions now suggest that the Pliocene tropical warm pools were about two degrees warmer than those at present.

Statistical study of surface temperature and rainfall over four stations in north Bengal

This article presents the study of recent trends of surface temperature and rainfall over some selected stations of North Bengal based on 30 years' data (1979-2008). The study revealed that the degree of warming are more pronounced over two most rapidly developing towns of Jalpaiguri and Malda which may be attributed to rapid urbanization and infrastructure development taking place in the districts; the degree of warming observed over Malda being more pronounced than that over Jalpaiguri and it is the least over Balurghat. Also, the intensity of seasonal as well as annual cumulative rainfall over Balurghat is increasing more significantly; the increase in intensity being most significant during the pre-monsoon and monsoon seasons; the geographical location and orography of Balurghat, the least developed town, may be attributed to such an increase.

Global flood risk under climate change

Flood risk is expected to increase as the climate warms. This study, for the first time, uses several climate models to estimate the global risk of flooding at the end of the century. Projections show a large increase in flood frequency in some areas, whereas other regions can expect a decrease. Vulnerability is dependent on the degree of warming and the interannual variability in precipitation.

Large volumes of anatectic melt retained in granulite facies migmatites: An injection complex in northern Quebec

The Opinaca Subprovince in the Superior Province of northern Québec is a metasedimentary belt characterized by metagreywacke rocks that record a late Archean granulite facies metamorphism and contains abundant thin veins of leucogranite. Regional-scale study of this subprovince provides insight to the net budget of anatectic melt (loss versus accumulation) in the lower middle continental crust during anatexis.A petrological study indicates that the metagreywackes partially melted at ~820°C and ~7kbar and generated <10% melt with orthopyroxene±garnet as peritectic phases. The metagreywackes contain various amounts of leucogranite in thin veins, sills and dykes injected sub-parallel to the subvertical E–W striking main foliation. Study of more than 1070 outcrops indicates that the “typical outcrop” contains ~63% of leucogranite; far more than the maximum 10% of melt produced in-situ from the host rocks. Crystallization ages obtained by U–Pb SHRIMP analysis of zircons from both the migmatites and the leucogranite veins indicate that the granulite facies metamorphism and the injection of veins were contemporary and occurred during slow cooling (6°CMy−1) from the metamorphic peak at 2666Ma to the granite solidus at 2636Ma.The large discrepancy (about 50%) between the volume of anatectic melt produced locally (in situ) and the observed volume of leucogranite in the terrain indicates that anatectic melt accumulated in the Opinaca Subprovince; it is an injection complex. This finding that granulite facies terranes can be enriched in melt contrasts with the general view that granulite terranes are melt-depleted.The presence of an injection complex in the deep crust has several broad implications for the continental crust. 1) H2O released as the injected melt crystallized rehydrated the adjacent granulite facies rocks which is evident from orthopyroxene replaced by amphibole and biotite. Consequently, these deep rocks would be more fertile in a subsequent anatectic event than non-rehydrated residuum. 2) The retention of voluminous leucogranite in the injection complex has thermal consequences for the crust. First, the bulk composition of the crust containing the injection complex is necessarily more felsic, thus the budget of heat-producing elements (Th, U and K) is locally enhanced and radiogenic heat production is higher. Secondly, latent heat of crystallization is released at a deeper level where the leucogranite solidifies. The combined effect of both maintains the lower crust several tens of degrees warmer for longer period of time.

Present and future water resources in India: Insights from satellite remote sensing and a dynamic global vegetation model

India is a country of particular interest with regard to its future water resources, as it is expected to undergo continued rapid population growth while also being especially sensitive to climate change. The Land-surface Processes and eXchanges Dynamic Global Vegetation Model (LPX-DGVM) is used here to simulate present and future runoff in India using ClimGen pattern-scaled scenarios of 1°, 2° and 4°C temperature increase (scaled to 2050) forced by six general circulation models (GCMs). As is the case with many DGVMs, groundwater storage is not simulated by LPX, so in order to form a more comprehensive understanding of water resources, Gravity Recovery and Climate Experiment (GRACE) satellite estimates for north-west India are incorporated into this study and compared to LPX runoff simulations. Runoff is simulated to have increased slightly (1.5 mm/year) in this region during 2002–2006, while groundwater extractions appear to have been made at rates of 40 ± 10 mm/year. North-west India is simulated to experience considerable increases in runoff by 2070–2099, with a mean change of 189 mm/year for 2°C climate change (although the range of model results, 247 mm/year, demonstrates high uncertainty among GCMs). Precipitation is shown to have an important bearing on runoff generation, while the degree of warming is shown to affect the magnitude of future runoff. This may subsequently influence the longevity of the local groundwater resource. However, at recent rates of depletion and in view of expected population growth, the long-term sustainability of groundwater reserves in north-west India is in doubt.