Dynamics of energy sector and GHG emissions in Saudi Arabia

The energy sector is the main contributor to GHG emissions in Saudi Arabia. The tremendous growth of GHG emissions poses serious challenges for the Kingdom in terms of their reduction targets, and also the mitigation of the associated climate changes. The rising trend of population and urbanization affects the energy demand, which results in a faster rate of increase in GHG emissions. The major energy sector sources that contribute to GHG emissions include the electricity generation, road transport, desalination plants, petroleum refining, petrochemical, cement, iron and steel, and fertilizer industries. In recent years, the energy sector has become the major source, accounting for more than 90% of national CO₂ emissions. Although a substantial amount of research has been conducted on renewable energy resources, a sustainable shift from petroleum resources is yet to be achieved. Public awareness, access to energy-efficient technology, and the development and implementation of a legislative framework, energy pricing policies, and renewable and alternative energy policies are not mature enough to ensure a significant reduction in GHG emissions from the energy sector. An innovative and integrated solution that best serves the Kingdom's long-term needs and exploits potential indigenous, renewable, and alternative energy resources while maintaining its sustainable development stride is essential.

Policy relevance

The main contributor to GHG emissions in Saudi Arabia is the energy sector that accounts for more than 90% of the national CO₂ emissions. Tremendous growth of GHG emissions poses serious challenges for the Kingdom in their reduction and mitigating the associated climate changes. This study examines the changing patterns of different activities associated with energy sector, the pertinent challenges, and the opportunities that promise reduction of GHG emissions while providing national energy and economic security. The importance of achieving timely, sustained, and increasing reductions in GHG emissions means that a combination of policies may be needed. This study points to the long-term importance of making near- and medium-term policy choices on a well-informed, strategic basis. This analytical paper is expected to provide useful information to the national policy makers and other decision makers. It may also contribute to the GHG emission inventories and the climate change negotiations.     

Uncertainty of forest carbon stock changes – implications to the total uncertainty of GHG inventory of Finland

Uncertainty analysis facilitates identification of the most important categories affecting greenhouse gas (GHG) inventory uncertainty and helps in prioritisation of the efforts needed for development of the inventory. This paper presents an uncertainty analysis of GHG emissions of all Kyoto sectors and gases for Finland consolidated with estimates of emissions/removals from LULUCF categories. In Finland, net GHG emissions in 2003 were around 69 Tg (±15 Tg) CO₂ equivalents. The uncertainties in forest carbon sink estimates in 2003 were larger than in most other emission categories, but of the same order of magnitude as in carbon stock change estimates in other land use, land-use change and forestry (LULUCF) categories, and in N₂O emissions from agricultural soils. Uncertainties in sink estimates of 1990 were lower, due to better availability of data. Results of this study indicate that inclusion of the forest carbon sink to GHG inventories reported to the UNFCCC increases uncertainties in net emissions notably. However, the decrease in precision is accompanied by an increase in the accuracy of the overall net GHG emissions due to improved completeness of the inventory. The results of this study can be utilised when planning future GHG mitigation protocols and emission trading schemes and when analysing environmental benefits of climate conventions.     

The global warming potential of two healthy Nordic diets compared with the average Danish diet

The potential greenhouse gas (GHG) emissions from the production of food for three different diets are compared using consequential Life Cycle Assessment. Diet 1 is an Average Danish Diet (ADD); diet 2 is based on the Nordic Nutritional Recommendations (NNR), whilst diet 3 is a New Nordic Diet (NND) developed by the OPUS project. The NND contains locally produced Nordic foods where more than 75 % is organically produced. NNR and NND include less meat and more fruit and vegetables than the ADD. All diets were adjusted to contain a similar energy and protein content. The GHG emissions from the provision of NNR and NND were lower than for ADD, 8 % and 7 % respectively. If GHG emissions from transport (locally produced versus imported food) are also taken into account, the difference in GHG emissions between NND and ADD increases to 12 %. If the production method (organic versus conventional) is taken into account so that the ADD contains the actual ratio of organically produced food (6.6 %) and the NND contains 80 %, the GHG emissions for the NND are only 6 % less than for the ADD. When the NND was optimised to be more climate friendly, the global warming potential of the NND was 27 % lower than it was for the ADD. This was achieved by including less beef, and only including organic produce if the GHG emissions are lower than for the conventional version, or by substituting all meat with legumes, dairy products and eggs.     

Analysis of change in relative uncertainty in GHG emissions from stationary sources for the EU 15

Total uncertainty in greenhouse gas (GHG) emissions changes over time due to “learning” and structural changes in GHG emissions. Understanding the uncertainty in GHG emissions over time is very important to better communicate uncertainty and to improve the setting of emission targets in the future. This is a diagnostic study divided into two parts. The first part analyses the historical change in the total uncertainty of CO₂ emissions from stationary sources that the member states estimate annually in their national inventory reports. The second part presents examples of changes in total uncertainty due to structural changes in GHG emissions considering the GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) emissions scenarios that are consistent with the EU’s “20-20-20” targets. The estimates of total uncertainty for the year 2020 are made under assumptions that relative uncertainties of GHG emissions by sector do not change in time, and with possible future uncertainty reductions for non-CO₂ emissions, which are characterized by high relative uncertainty. This diagnostic exercise shows that a driving factor of change in total uncertainty is increased knowledge of inventory processes in the past and prospective future. However, for individual countries and longer periods, structural changes in emissions could significantly influence the total uncertainty in relative terms.     

Spatial GHG inventory at the regional level: accounting for uncertainty

Methodology and geo-information technology for spatial analysis of processes of greenhouse gas (GHG) emissions from mobile and stationary sources of the energy sector at the level of elementary plots are developed. The methodology, which takes into account the territorial specificity of point, line, and area sources of emissions, is based on official statistical data surveys. The spatial distribution of emissions and their structure for the main sectors of the energy sector in the territory of the Lviv region of Ukraine are analyzed. The relative uncertainties of emission estimates obtained are calculated using knowledge of the spatial location of emission sources and following the Tier 1 and Tier 2 approaches of IPCC methodologies. The sensitivity of total relative uncertainty to change of uncertainties in input data uncertainties is studied for the biggest emission point sources. A few scenarios of passing to the alternative energy generation are considered and respective structural changes in the structure of greenhouse gas emissions are analyzed. An influence of these structural changes on the total uncertainty of greenhouse gas inventory results is studied.     

Regional spatial inventories (cadastres) of GHG emissions in the Energy sector: Accounting for uncertainty

An improvement of methods for the inventory of greenhouse gas (GHG) emissions is necessary to ensure effective control of commitments to emission reduction. The national inventory reports play an important role, but do not reflect specifics of regional processes of GHG emission and absorption for large-area countries. In this article, a GIS approach for the spatial inventory of GHG emissions in the energy sector, based on IPCC guidelines, official statistics on fuel consumption, and digital maps of the region under investigation, is presented. We include mathematical background for the spatial emission inventory of point, line and area sources, caused by fossil-fuel use for power and heat production, the residential sector, industrial and agricultural sectors, and transport. Methods for the spatial estimation of emissions from stationary and mobile sources, taking into account the specifics of fuel used and technological processes, are described. Using the developed GIS technology, the territorial distribution of GHG emissions, at the level of elementary grid cells 2 km?×?2 km for the territory of Western Ukraine, is obtained. Results of the spatial analysis are presented in the form of a geo-referenced database of emissions, and visualized as layers of digital maps. Uncertainty of inventory results is calculated using the Monte Carlo approach, and the sensitivity analysis results are described. The results achieved demonstrated that the relative uncertainties of emission estimates, for CO₂ and for total emissions (in CO₂ equivalent), depend largely on uncertainty in the statistical data and on uncertainty in fuels’ calorific values. The uncertainty of total emissions stays almost constant with the change of uncertainty of N₂O emission coefficients, and correlates strongly with an improvement in knowledge about CH₄ emission processes. The presented approach provides an opportunity to create a spatial cadastre of emissions, and to use this additional knowledge for the analysis and reduction of uncertainty. It enables us to identify territories with the highest emissions, and estimate an influence of uncertainty of the large emission sources on the uncertainty of total emissions. Ascribing emissions to the places where they actually occur helps to improve the inventory process and to reduce the overall uncertainty.     

Role of the Tibetan plateau glaciers in the Asian summer monsoon

The expected growth in the demand for passenger and freight services exacerbates the challenges of reducing transport GHG emissions, especially as commercial low-carbon alternatives to petroleum fuels are limited for shipping, air and long-distance road travel. Biofuels can offer a pathway to significantly reduce emissions from these sectors, as they can easily substitute for conventional liquid fuels in internal combustion engines. In this paper, we assess the potential of bioenergy to reduce transport GHG emissions through an analysis leveraging various integrated assessment models and scenarios, as part of the 33rd Energy Modeling Forum study (EMF-33). We find that bioenergy can contribute a significant, albeit not dominant, proportion of energy supply to the future transport sector: in scenarios aiming to keep the temperature increase below 2 °C by the end of the twenty-first century, models project that in 2100 bioenergy can provide on average 42 EJ/yr (ranging from 5 to 85 EJ/yr) for transport (compared to 3.7 EJ in 2018), mainly through lignocellulosic fuels. This makes up 9–62% of final transport energy use. Only a small amount of bioenergy is projected to be used in transport through electricity and hydrogen pathways, with a larger role for biofuels in road passenger transport than in freight. The association of carbon capture and storage (CCS) with bioenergy technologies (BECCS) is a key determinant in the role of biofuels in transport, because of the competition for biomass feedstock to provide other final energy carriers along with carbon removal. Among models that consider CCS in the biofuel conversion process the average market share of biofuels is 21% in 2100 (ranging from 2 to 44%), compared to 10% (0–30%) for models that do not. Cumulative direct emissions from the transport sector account for half of the emission budget (from 306 to 776 out of 1,000 GtCO₂). However, the carbon intensity of transport decreases as much as other energy sectors in 2100 when accounting for process emissions, including carbon removal from BECCS. Lignocellulosic fuels become more attractive for transport decarbonization if BECCS is not feasible for any energy sectors. Since global transport service demand increases and biomass supply is limited, its allocation to and within the transport sector is uncertain and sensitive to assumptions about political as well as technological and socioeconomic factors.

     

Greenhouse gas emissions from global cities under SSP/RCP scenarios, 1990 to 2100

Projections of greenhouse gas (GHG) emissions are critical to enable a better understanding and anticipation of future climate change under different socio-economic conditions and mitigation strategies. The climate projections and scenarios assessed by the Intergovernmental Panel on Climate Change, following the Shared Socioeconomic Pathway (SSP)-Representative Concentration Pathway (RCP) framework, have provided a rich understanding of the constraints and opportunities for policy action. However, the current emissions scenarios lack an explicit treatment of urban emissions within the global context. Given the pace and scale of urbanization, with global urban populations expected to increase from about 4.4 billion today to about 7 billion by 2050, there is an urgent need to fill this knowledge gap. Here, we estimate the share of global GHG emissions driven by urban areas from 1990 to 2100 based on the SSP-RCP framework. The urban consumption-based GHG emissions are presented in five regional aggregates and based on a combination of the urban population share, 2015 urban per capita CO₂eq carbon footprint, SSP-based national CO₂eq emissions, and recent analysis of urban per capita CO₂eq trends. We find that urban areas account for the majority of global GHG emissions in 2015 (61.8%). Moreover, the urban share of global GHG emissions progressively increases into the future, exceeding 80% in some scenarios by the end of the century. The combined urban areas in Asia and Developing Pacific, and Developed Countries account for 65.0% to 73.3% of cumulative urban consumption-based emissions between 2020 and 2100 across the scenarios. Given these dominant roles, we describe the implications for potential urban mitigation in each of the scenario narratives in order to meet the goal of climate neutrality within this century.     

基于各国NDC/INDC目标的全球减排不确定性研究

基于各国提交的165份国家自主贡献文件,以其中提出的减排目标为基准,尽可能充分地考虑了减排目标的范围不确定性、不同经济情景带来的碳强度减排目标不确定性、减排气体种类边界差异、碳排放达峰约束等因素,并通过蒙特卡洛模拟的方法对全球、各区域和主要经济体的温室气体排放总量、不确定度及其来源进行了定量分析.结果表明,到2030年...     

Understanding public complacency about climate change: adults’ mental models of climate change violate conservation of matter

Public attitudes about climate change reveal a contradiction. Surveys show most Americans believe climate change poses serious risks but also that reductions in greenhouse gas (GHG) emissions sufficient to stabilize atmospheric GHG concentrations can be deferred until there is greater evidence that climate change is harmful. US policymakers likewise argue it is prudent to wait and see whether climate change will cause substantial economic harm before undertaking policies to reduce emissions. Such wait-and-see policies erroneously presume climate change can be reversed quickly should harm become evident, underestimating substantial delays in the climate’s response to anthropogenic forcing. We report experiments with highly educated adults – graduate students at MIT – showing widespread misunderstanding of the fundamental stock and flow relationships, including mass balance principles, that lead to long response delays. GHG emissions are now about twice the rate of GHG removal from the atmosphere. GHG concentrations will therefore continue to rise even if emissions fall, stabilizing only when emissions equal removal. In contrast, most subjects believe atmospheric GHG concentrations can be stabilized while emissions into the atmosphere continuously exceed the removal of GHGs from it. These beliefs – analogous to arguing a bathtub filled faster than it drains will never overflow – support wait-and-see policies but violate conservation of matter. Low public support for mitigation policies may arise from misconceptions of climate dynamics rather than high discount rates or uncertainty about the impact of climate change. Implications for education and communication between scientists and nonscientists (the public and policymakers) are discussed.     

Influence of soil C, N2O and fuel use on GHG mitigation with no-till adoption

Previous research has demonstrated that soil carbon sequestration through adoption of conservation tillage can be economically profitable depending on the value of a carbon offset in a greenhouse gas (GHG) emissions market. However adoption of conservation tillage also influences two other potentially important factors, changes in soil N₂O emissions and CO₂ emissions attributed to changes in fuel use. In this article we evaluate the supply of GHG offsets associated with conservation tillage adoption for corn-soy-hay and wheat-pasture systems of the central United States, taking into account not only the amount of carbon sequestration but also the changes in soil N₂O emission and CO₂ emissions from fuel use in tillage operations. The changes in N₂O emissions are derived from a meta-analysis of published studies, and changes in fuel use are based on USDA data. These are used to estimate changes in global warming potential (GWP) associated with adoption of no-till practices, and the changes in GWP are then used in an economic analysis of the potential supply of GHG offsets from the region. Simulation results demonstrate that taking N₂O emissions into account could result in substantial underestimation of the potential for GHG mitigation in the central U.S. wheat pasture systems, and large over-estimation in the corn-soy-hay systems. Fuel use also has quantitatively important effects, although generally smaller than N₂O. These findings suggest that it is important to incorporate these two effects in estimates of GHG offset potential from agricultural lands, as well as in the design of GHG offset contracts for more complete accounting of the effect that no-till adoption will have on greenhouse gas emissions.     

Dietary greenhouse gas emissions of meat-eaters,fish-eaters,vegetarians and vegans in the UK

The production of animal-based foods is associated with higher greenhouse gas (GHG) emissions than plant-based foods. The objective of this study was to estimate the difference in dietary GHG emissions between self-selected meat-eaters, fish-eaters, vegetarians and vegans in the UK. Subjects were participants in the EPIC-Oxford cohort study. The diets of 2,041 vegans, 15,751 vegetarians, 8,123 fish-eaters and 29,589 meat-eaters aged 20–79 were assessed using a validated food frequency questionnaire. Comparable GHG emissions parameters were developed for the underlying food codes using a dataset of GHG emissions for 94 food commodities in the UK, with a weighting for the global warming potential of each component gas. The average GHG emissions associated with a standard 2,000 kcal diet were estimated for all subjects. ANOVA was used to estimate average dietary GHG emissions by diet group adjusted for sex and age. The age-and-sex-adjusted mean (95 % confidence interval) GHG emissions in kilograms of carbon dioxide equivalents per day (kgCO₂e/day) were 7.19 (7.16, 7.22) for high meat-eaters (?>?=?100 g/d), 5.63 (5.61, 5.65) for medium meat-eaters (50-99 g/d), 4.67 (4.65, 4.70) for low meat-eaters (?<?50 g/d), 3.91 (3.88, 3.94) for fish-eaters, 3.81 (3.79, 3.83) for vegetarians and 2.89 (2.83, 2.94) for vegans. In conclusion, dietary GHG emissions in self-selected meat-eaters are approximately twice as high as those in vegans. It is likely that reductions in meat consumption would lead to reductions in dietary GHG emissions.     

Carbon prices and greenhouse gases abatement from agriculture,forestry and land use in Nepal

The Agriculture, forestry and other land use (AFOLU) sector as a whole accounts for more than 80% of the total greenhouse gas (GHG) emission in Nepal. This study estimates the GHG emissions from the AFOLU sector in the business as usual (BAU) case during 2010–2050 and identifies the economically attractive countermeasures to abate GHG emissions from the sector at different carbon prices. It also estimates the carbon price elasticity of GHG abatement from the sector. The study finds that enteric fermentation processes in the livestock and emissions from agricultural soils are the two major contributors of GHG emission in AFOLU sector. It identifies no-regret abatement options in the AFOLU sector that could mitigate about 41.5% of the total GHG emission during 2016–2050 in the BAU scenario. There would be a net cumulative carbon sequestration of 16 million tonnes of carbon dioxide equivalent (MtCO₂e) at $10 per tonne of carbon dioxide equivalent (tCO₂e) during the period. Carbon price above $75/tCO₂e is not found to be much effective in achieving significant additional reduction in GHG emissions from the AFOLU sector.     

Post-Kyoto energy strategy of the Russian Federation,outlooks and prerequisites of the Kyoto mechanisms implementation in the country

Abstract

Energy sector emissions from Russia have declined by about 33% from 1990 levels. We estimate that some 60–70% of the reduction is due to economic decline, and about 8–12% of it is due to reforms in the energy sector; the remainder being due to the wider use of natural gas and structural changes in the economy. Vigorous institutional and technological measures to promote energy efficiency could lead to savings of over 100 million t.c.e. per year by 2010, and keep CO₂ emissions fairly close to current levels over the decade. In our view, international emissions trading should not lead to global emissions growth, but should facilitate the best energy saving and efficiency. Consequently, we propose that the available assigned amount should be divided into two components. That part arising from ‘type 1’ reductions, produced by special projects and measures relating to GHG reduction taken since 1990, should be freely traded; whereas the remaining ‘type 2’ surplus, without a clear link to real emission reduction activity, should only be traded if the revenues are recycled into special projects resulting in emissions reduction equal to or more than the amount of emissions sold.     

Post-Kyoto energy strategy of the Russian Federation,outlooks and prerequisites of the Kyoto mechanisms implementation in the country

Energy sector emissions from Russia have declined by about 33% from 1990 levels. We estimate that some 60–70% of the reduction is due to economic decline, and about 8–12% of it is due to reforms in the energy sector; the remainder being due to the wider use of natural gas and structural changes in the economy. Vigorous institutional and technological measures to promote energy efficiency could lead to savings of over 100 million t.c.e. per year by 2010, and keep CO₂ emissions fairly close to current levels over the decade. In our view, international emissions trading should not lead to global emissions growth, but should facilitate the best energy saving and efficiency. Consequently, we propose that the available assigned amount should be divided into two components. That part arising from ‘type 1’ reductions, produced by special projects and measures relating to GHG reduction taken since 1990, should be freely traded; whereas the remaining ‘type 2’ surplus, without a clear link to real emission reduction activity, should only be traded if the revenues are recycled into special projects resulting in emissions reduction equal to or more than the amount of emissions sold.     

Sensitivity of the southern annular mode to greenhouse gas emission scenarios

The leading mode of southern hemisphere (SH) climatic variability, the southern annular mode (SAM), has recently seen a shift towards its positive phase due to stratospheric ozone depletion and increasing greenhouse gas (GHG) concentrations. Here we examine how sensitive the SAM (defined as the leading empirical orthogonal function of SH sea level pressure anomalies) is to future GHG concentrations. We determine its likely evolution for three intergovernmental panel on climate change (IPCC) special report on emission scenarios (SRES) for austral summer and winter, using a multi-model ensemble of IPCC fourth assessment report models which resolve stratospheric ozone recovery. During the period of summer ozone recovery (2000–2050), the SAM index exhibits weakly negative, statistically insignificant trends due to stratospheric ozone recovery which offsets the positive forcing imposed by increasing GHG concentrations. Thereafter, positive SAM index trends occur with magnitudes that show sensitivity to the SRES scenario utilised, and thus future GHG emissions. Trends are determined to be strongest for SRES A2, followed by A1B and B1, respectively. The winter SAM maintains a similar dependency upon GHG as summer, but over the entire twenty-first century and to a greater extent. We also examine the influence of ozone recovery by comparing results to models that exclude stratospheric ozone recovery. Projections are shown to be statistically different from the aforementioned results, highlighting the importance of ozone recovery in governing SAM-evolution. We therefore demonstrate that the future SAM will depend both upon GHG emissions and stratospheric ozone recovery.     

Greenhouse gas emissions from the usage of typical e-products by households: a case study of China

The number of electric and electronic products (e-products) owned by Chinese households has multiplied in the past decade. In this study, we analyz the GHG emissions from e-products in Chinese households in order to understand and determine how to mitigate their effects on climate change. The results show that the usage stage of e-products has become an important source of GHG emissions in China, with total GHG emissions of these household e-products reaching about 663 million tons CO₂ eq., accounting for about 8.85 % of all Chinese GHG emissions in 2012. The average GHG emission per household per year in China was 1538 kg CO₂ eq. in 2012, a little higher than that of Norwegian households (1200 kg CO₂ eq.). The electricity mix plays a very important role in GHG emissions, and the 78 % coal-fired power consumption accounted for 99.69 % of the total GHG emissions. Our research also supports the view that GHG emissions from household e-products increased with economic level. To reduce the GHG emissions of household e-products, the development of energy-saving e-products and changes to the electricity mix would be very effective measures.     

Food consumption,diet shifts and associated non-CO2 greenhouse gases from agricultural production

Today, the agricultural sector accounts for approximately 15% of total global anthropogenic emissions, mainly methane and nitrous oxide. Projecting the future development of agricultural non-CO₂ greenhouse gas (GHG) emissions is important to assess their impacts on the climate system but poses many problems as future demand of agricultural products is highly uncertain. We developed a global land use model (MAgPIE) that is suited to assess future anthropogenic agricultural non-CO₂ GHG emissions from various agricultural activities by combining socio-economic information on population, income, food demand, and production costs with spatially explicit environmental data on potential crop yields. In this article we describe how agricultural non-CO₂ GHG emissions are implemented within MAgPIE and compare our simulation results with other studies. Furthermore, we apply the model up to 2055 to assess the impact of future changes in food consumption and diet shifts, but also of technological mitigation options on agricultural non-CO₂ GHG emissions. As a result, we found that global agricultural non-CO₂ emissions increase significantly until 2055 if food energy consumption and diet preferences remain constant at the level of 1995. Non-CO₂ GHG emissions will rise even more if increasing food energy consumption and changing dietary preferences towards higher value foods, like meat and milk, with increasing income are taken into account. In contrast, under a scenario of reduced meat consumption, non-CO₂ GHG emissions would decrease even compared to 1995. Technological mitigation options in the agricultural sector have also the capability of decreasing non-CO₂ GHG emissions significantly. However, these technological mitigation options are not as effective as changes in food consumption. Highest reduction potentials will be achieved by a combination of both approaches.     

2003—2009年中国污水处理部门温室气体排放研究

基于《中国环境统计年报》等的统计数据,采用IPCC提供的方法估算了2003—2009年我国源自污水处理部门的温室气体排放量,并对污水处理部门人均温室气体排放量进行分析。结果表明,2003—2009年污水处理部门温室气体排放呈增加趋势,源自生活污水的N2O排放是主要排放源,生活污水CH4排放增速最快;工业行业中造纸业废水的CH4排放是主要排放源;人均温室气体排放量呈现递增趋势。     

A GCM study of future climate response to aerosol pollution reductions

We use the global atmospheric GCM aerosol model ECHAM5-HAM to asses possible impacts of future air pollution mitigation strategies on climate. Air quality control strategies focus on the reduction of aerosol emissions. Here we investigate the extreme case of a maximum feasible end-of-pipe abatement of aerosols in the near term future (2030) in combination with increasing greenhouse gas (GHG) concentrations. The temperature response of increasing GHG concentrations and reduced aerosol emissions leads to a global annual mean equilibrium temperature response of 2.18 K. When aerosols are maximally abated only in the Industry and Powerplant sector, while other sectors stay with currently enforced regulations, the temperature response is 1.89 K. A maximum feasible abatement applied in the Domestic and Transport sector, while other sectors remain with the current legislation, leads to a temperature response of 1.39 K. Increasing GHG concentrations alone lead to a temperature response of 1.20 K. We also simulate 2–5% increases in global mean precipitation among all scenarios considered, and the hydrological sensitivity is found to be significantly higher for aerosols than for GHGs. Our study, thus highlights the huge potential impact of future air pollution mitigation strategies on climate and supports the need for urgent GHG emission reductions. GHG and aerosol forcings are not independent as both affect and are influenced by changes in the hydrological cycle. However, within the given range of changes in aerosol emissions and GHG concentrations considered in this study, the climate response towards increasing GHG concentrations and decreasing aerosols emissions is additive.