Global and regional temperature-change potentials for near-term climate forcers

We examine the climate effects of the emissions of near-term climate forcers (NTCFs) from 4 continental regions (East Asia, Europe, North America and South Asia) using radiative forcing from the task force on hemispheric transport of air pollution source-receptor global chemical transport model simulations. These simulations model the transport of 3 aerosol species (sulphate, particulate organic matter and black carbon) and 4 ozone precursors (methane, nitric oxides (NOx), volatile organic compounds and carbon monoxide). From the equilibrium radiative forcing results we calculate global climate metrics, global warming potentials (GWPs) and global temperature change potentials (GTPs) and show how these depend on emission region, and can vary as functions of time. For the aerosol species, the GWP(100) values are −37±12, −46±20, and 350±200 for SO2, POM and BC respectively for the direct effects only. The corresponding GTP(100) values are −5.2±2.4, −6.5±3.5, and 50±33. This analysis is further extended by examining the temperature-change impacts in 4 latitude bands. This shows that the latitudinal pattern of the temperature response to emissions of the NTCFs does not directly follow the pattern of the diagnosed radiative forcing. For instance temperatures in the Arctic latitudes are particularly sensitive to NTCF emissions in the northern mid-latitudes. At the 100-yr time horizon the ARTPs show NOx emissions can have a warming effect in the northern mid and high latitudes, but cooling in the tropics and Southern Hemisphere. The northern mid-latitude temperature response to northern mid-latitude emissions of most NTCFs is approximately twice as large as would be implied by the global average.

The global atmospheric water cycle

Water vapour plays a key role in the Earth's energy balance. Almost 50% of the absorbed solar radiation at the surface is used to cool the surface, through evaporation, and warm the atmosphere, through release of latent heat. Latent heat is the single largest factor in warming the atmosphere and in transporting heat from low to high latitudes. Water vapour is also the dominant greenhouse gas and contributes to a warming of the climate system by some 24°C (Kondratev 1972). However, water vapour is a passive component in the troposphere as it is uniquely determined by temperature and should therefore be seen as a part of the climate feedback system. In this short overview, we will first describe the water on planet Earth and the role of the hydrological cycle: the way water vapour is transported between oceans and continents and the return of water via rivers to the oceans. Generally water vapour is well observed and analysed; however, there are considerable obstacles to observing precipitation, in particular over the oceans. The response of the hydrological cycle to global warming is far reaching. Because different physical processes control the change in water vapour and evaporation/precipitation, this leads to a more extreme distribution of precipitation making, in general, wet areas wetter and dry areas dryer. Another consequence is a transition towards more intense precipitation. It is to be expected that the changes in the hydrological cycle as a consequence of climate warming may be more severe that the temperature changes.

Nonlinear regional warming with increasing CO₂ concentration

When considering adaptation measures and global climate mitigation goals, stakeholders need regional-scale climate projections, including the range of plausible warming rates. To assist these stakeholders, it is important to understand whether some locations may see disproportionately high or low warming from additional forcing above targets such as 2 K (ref. 1). There is a need to narrow uncertainty2 in this nonlinear warming, which requires understanding how climate changes as forcings increase from medium to high levels. However, quantifying and understanding regional nonlinear processes is challenging. Here we show that regional-scale warming can be strongly superlinear to successive CO2 doublings, using five different climate models. Ensemble-mean warming is superlinear over most land locations. Further, the inter-model spread tends to be amplified at higher forcing levels, as nonlinearities grow—especially when considering changes per kelvin of global warming. Regional nonlinearities in surface warming arise from nonlinearities in global-mean radiative balance, the Atlantic meridional overturning circulation, surface snow/ice cover and evapotranspiration. For robust adaptation and mitigation advice, therefore, potentially avoidable climate change (the difference between business-as-usual and mitigation scenarios) and unavoidable climate change (change under strong mitigation scenarios) may need different analysis methods.

Metrics for linking emissions of gases and aerosols to global precipitation changes

Recent advances in understanding have made it possible to relate global precipitation changes directly to emissions of particular gases and aerosols that influence climate. Using these advances, new indices are developed here called the Global Precipitation-change Potential for pulse (GPP_P) and sustained (GPP_S) emissions, which measure the precipitation change per unit mass of emissions. The GPP can be used as a metric to compare the effects of different emissions. This is akin to the global warming potential (GWP) and the global temperature-change potential (GTP) which are used to place emissions on a common scale. Hence the GPP provides an additional perspective of the relative or absolute effects of emissions. It is however recognised that precipitation changes are predicted to be highly variable in size and sign between different regions and this limits the usefulness of a purely global metric. The GPP_P and GPP_S formulation consists of two terms, one dependent on the surface temperature change and the other dependent on the atmospheric component of the radiative forcing. For some forcing agents, and notably for CO2, these two terms oppose each other – as the forcing and temperature perturbations have different timescales, even the sign of the absolute GPP_P and GPP_S varies with time, and the opposing terms can make values sensitive to uncertainties in input parameters. This makes the choice of CO2 as a reference gas problematic, especially for the GPP_S at time horizons less than about 60 years. In addition, few studies have presented results for the surface/atmosphere partitioning of different forcings, leading to more uncertainty in quantifying the GPP than the GWP or GTP. Values of the GPP_P and GPP_S for five long- and short-lived forcing agents (CO2, CH4, N2O, sulphate and black carbon – BC) are presented, using illustrative values of required parameters. The resulting precipitation changes are given as the change at a specific time horizon (and hence they are end-point metrics) but it is noted that the GPPS can also be interpreted as the time-integrated effect of a pulse emission. Using CO2 as a references gas, the GPP_P and GPP_S for the non-CO2 species are larger than the corresponding GTP values. For BC emissions, the atmospheric forcing is sufficiently strong that the GPP_S is opposite in sign to the GTP_S. The sensitivity of these values to a number of input parameters is explored. The GPP can also be used to evaluate the contribution of different emissions to precipitation change during or after a period of emissions. As an illustration, the precipitation changes resulting from emissions in 2008 (using the GPP_P) and emissions sustained at 2008 levels (using the GPP_S) are presented. These indicate that for periods of 20 years (after the 2008 emissions) and 50 years (for sustained emissions at 2008 levels) methane is the dominant driver of positive precipitation changes due to those emissions. For sustained emissions, the sum of the effect of the five species included here does not become positive until after 50 years, by which time the global surface temperature increase exceeds 1 K.

Representing the Arctic in global surface temperature time series of recent climate change

The Arctic is an important region in the study of climate change, but monitoring surface temperatures in this region is challenging, particularly in areas covered by sea ice. Here in situ, satellite and reanalysis data were utilised to investigate whether global warming over recent decades could be better estimated by changing the way the Arctic is treated in calculating global mean temperature. The degree of difference arising from using five different techniques, based on existing temperature anomaly dataset techniques, to estimate Arctic SAT anomalies over land and sea ice were investigated using reanalysis data as a testbed. Techniques which interpolated anomalies were found to result in smaller errors than non-interpolating techniques. Kriging techniques provided the smallest errors in anomaly estimates. Similar accuracies were found for anomalies estimated from in situ meteorological station SAT records using a kriging technique. Whether additional data sources, which are not currently utilised in temperature anomaly datasets, would improve estimates of Arctic surface air temperature anomalies was investigated within the reanalysis testbed and using in situ data. For the reanalysis study, the additional input anomalies were reanalysis data sampled at certain supplementary data source locations over Arctic land and sea ice areas. For the in situ data study, the additional input anomalies over sea ice were surface temperature anomalies derived from the Advanced Very High Resolution Radiometer satellite instruments. The use of additional data sources, particularly those located in the Arctic Ocean over sea ice or on islands in sparsely observed regions, can lead to substantial improvements in the accuracy of estimated anomalies. Decreases in Root Mean Square Error can be up to 0.2K for Arctic-average anomalies and more than 1K for spatially resolved anomalies. Further improvements in accuracy may be accomplished through the use of other data sources.

Making sense of the early-2000s warming slowdown

It has been claimed that the early-2000s global warming slowdown or hiatus, characterized by a reduced rate of global surface warming, has been overstated, lacks sound scientific basis, or is unsupported by observations. The evidence presented here contradicts these claims.

Aquecimento global e acidificação oceãnica: efeitos da temperatura, salinidade e dióxido de carbono no desenvolvimento larval do caranguejo intertidal Eriphia gonagra (Crustacea, Decapoda, Eriphiidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mudanças climáticas: o discurso da mídia sobre o aquecimento global

This research is aimed at discussing the ways in which social agents influence global warming, analyzing the discourse of social actors involved in the debate on climate change, since there is a wide divergence in the scientific community about how man is able to modify the climate on a global scale. In fact the debate that permeates the issues beyond the limits of science and enter into a political-economic framework that takes extraordinary proportions. This emphasis can be very unscientific in the fundamental design concepts, or even creating a trivialization of the media. The main way to convey these concepts is to disclose them in the media, but the media has enormous power to transform the concepts and often manipulate the news by creating a common sense goes against the interests of the scientific community. Thus was conducted extensive research in major newspapers and magazines that move in the country. We surveyed the first two papers which were: “Folha de S. Paulo” and “O Estado de S. Paulo”, during the period from January 2000 to December 2008, totaling 3285 units for the newspaper Folha and 2555 for the newspaper Estadão. Subsequently a survey was made of data published in two journals that move at the national level, and these are the magazines VEJA and ÉPOCA for the same period. By performing these steps, it was concluded that several factors involving the media and climate change, such as topic relevance, types of approaches, perspectives of analysis, the staff development, supplies, among other factors of utmost importance for building news. As a result we can say that the media in fulfilling its role of mediator scientific, disclosing only a vision that permeates the scientific debate. The newspaper media, especially newspapers, has an informative and instantaneous. Often this preoccupation...(Complete abstract, click electronic access below)

Modelos de circulación global y procesos de mezcla en el océano

La difusividad diapicna en el océano es uno de los parámetros más desconocidos en los modelos climáticos actuales. Su importancia radica en que es uno de los principales factores de transporte de calor hacia capas más profundas del océano. Las medidas de esta difusividad son variables e insuficientes para confeccionar un mapa global con estos valores. A través de una amplia revisión bibliográfica hasta el año 2009 del tema se encontró que el sistema climático es extremadamente sensible a la difusividad diapicna, donde el escalado del Océano Pacífico Sur, con una potencia de su coeficiente de difusividad o kv de 0.63, resultó ser más sensible a los cambios en el coeficiente de difusividad diapicna que el Océano Atlántico con una potencia de kv de 0.44 , se pone de manifiesto así la necesidad de esclarecer los esquemas de mezcla, esquemas de clausura y sus parametrizaciones a través de Modelos de Circulación Global (GCMs) y Modelos de Complejidad Intermedia del Sistema Terrestre (EMICs), dentro del marco de un posible cambio climático y un calentamiento global debido al aumento de las emisiones de gases de efecto invernadero. Así, el objetivo principal de este trabajo es comprender la sensibilidad del sistema climático a la difusividad diapicna en el océano a través de los GCMs y los EMICs. Para esto es necesario el análisis de los posibles esquemas de mezcla diapicna con el objetivo final de encontrar el modelo óptimo que permita predecir la evolución del sistema climático, el estudio de todas las variables que influyen en el mismo, y la correcta simulación en largos periodos de tiempo. The diapycnal diffusivity in the ocean is one of the least known parameters in current climate models. Measurements of this diffusivity are sparse and insufficient for compiling a global map. Through a lengthy review of the literature through 2009 found that the climate system is extremely sensitive to the diapycnal diffusivity, where in the South Pacific scales with the 0.63 power of the diapycnal diffusion, in contrasts to the scales with the 0.44 power of the diapycnal diffusion of North Atlantic. Therefore, the South Pacific is more sensitive than the North Atlantic. All this evidenced the need to clarify the schemes of mixing and its parameterisations through Global Circulation Models (GCMs) and Earth Models of Intermediate Complexity (EMICs) within a context of possible climate change and global warming due to increased of emissions of greenhouse gases. Thus, the main objective of this work understands the sensitivity of the climate system to diapycnal diffusivity in the ocean through the GCMs and EMICs. This requires the analysis of possible schemes of diapycnal mixing with the ultimate goal of finding the optimal model to predict the evolution of the climate system, the study of all variables that affect it and the correct simulation over long periods of time.

Mesocosm experiment on warming and acidification effects in 2012: Zooplankton data

Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts

The Global Carbon Pricing Policy Solution to Climate Change

While the topic of climate change is controversial, the world needs to take a precautionary approach to reduce carbon dioxide emissions. With growing populations and increasing energy demands, solutions to cleaner energy need to be developed and implemented. In order to successfully reduce carbon dioxide emissions, a global carbon pricing policy needs to be developed that includes all countries and allows each region to utilize the best clean energy technology options along with economic incentives that will be the most effective. The research conducted in this project validates the hypothesis that placing a monetary price on carbon will allow natural, technological, and financial resources to come together to implement a feasible energy solution that will reduce global carbon dioxide emissions.

Can a global climate risk pool help the most vulnerable countries? Bruegel Policy Brief 2015/04 December 2015

Extreme climate events related to global warming will happen somewhat randomly and could have a huge cost for the most vulnerable countries. A global climate risk pool, with contributions from all countries, could help these vulnerable countries to recover from such events and might thus smooth the way towards a broader climate deal.

Global change information packet.

Mode of access: Internet.