Copper demand,supply, and associated energy use to 2050

To a set of well-regarded international scenarios (UNEP’s GEO-4), we have added consideration of the demand, supply, and energy implications related to copper production and use over the period 2010–2050. To our knowledge, these are the first comprehensive metal supply and demand scenarios to be developed. We find that copper demand increases by between 275 and 350% by 2050, depending on the scenario. The scenario with the highest prospective demand is not Market First (a “business as usual” vision), but Equitability First, a scenario of transition to a world of more equitable values and institutions. These copper demands exceed projected copper mineral resources by mid-century and thereafter. Energy demand for copper production also demonstrates strong increases, rising to as much as 2.4% of projected 2050 overall global energy demand. We investigate possible policy responses to these results, concluding that improving the efficiency of the copper cycle and encouraging the development of copper-free energy distribution on the demand side, and improving copper recycling rates on the supply side are the most promising of the possible options. Improving energy efficiency in primary copper production would lead to a reduction in the energy demand by 0.5% of projected 2050 overall global energy demand. In addition, encouraging the shift towards renewable technologies is important to minimize the impacts associated with copper production.     

Exploring future copper demand,recycling and associated greenhouse gas emissions in the EU-28

Copper is widely used in modern technology, but declining ore grades and depletion of natural deposits have raised concerns regarding sustainable demand-supply balance in the long term. The vulnerability to primary copper supply restrictions amplifies for countries dependant on imports, notably many EU Member States. Recycling of post-consumer scrap can provide a valuable source of essential material to the European industry. However, a considerable fraction of collected and processed copper old scrap is exported, while the remaining fraction is either not recovered or lost due to nonfunctional recycling undermining the implementation of a circular economy. In this work, material flow analysis, regression analysis, and life cycle assessment are combined to explore the possible evolution of four scenarios of copper demand in Europe to year 2050 and the potentials for greenhouse gas emissions reduction under material circularity conditions.The results show that for three of the four scenarios, secondary production would not comply with the carbon dioxide emissions reduction target of 50% below 2000 levels neither in case of combined aggressive recycling, moderate decarbonization of electricity, and energy efficiency improvements. In particular, for the scenario that describes a “business as usual” approach, the modelled future domestic demand can only be met by increasing primary inputs and, despite strong efforts to improve recycling at end-of-life, the fraction of old scrap in total metal demand seems likely to achieve 65% at best. Should that scenario ensue, the GHG emissions embodied in EU copper demand might result in an emissions gap of more than 15 TgCO₂eq or about +260% the carbon dioxide reduction target. In contrast, the lowest environmental impacts are associated with a scenario emphasizing green technology and more equitable lifestyles. In that scenario, the secondary copper flows will gradually approach the expected demand, laying the foundation for achieving a circular economy with considerable potential for preserving natural capital and mitigating climate change. This possible future, however, requires dramatic changes in the current pattern of material production and consumption, as we discuss.     

城镇化背景下中国长期低碳转型路径研究

在中国经济步入新常态之际,为了研究城镇化背景下的长期碳排放趋势,构建了人口变动与能源系统互动的综合分析框架与社会经济-能源系统模型。结果显示,从2014年至2050年,预计有3亿人口从农村流向城市,并呈现从中小型城市逐步向大型和特大型城市汇集的趋势。人口流动趋势与人民生活质量改善结合,推动中国基础设施建设、工业产品生产和能源服务需求增长。基准情景下,2050年中国一次能源消费总量达到84亿tce,能源相关CO₂排放达到176亿t,比2013年增长83%;而在低碳转型情景下,通过技术创新,2050年中国一次能源消费需求可以控制在61亿tce左右,CO₂排放在2020—2025年间达峰,2050年比基准情景降低78%。低碳转型过程中,非化石能源电力和能效技术的减排潜力最大,工业和电力部门率先在2020年达峰,建筑和交通 ^①（①按照国际通行的能源系统部门划分标准和能耗概念,工业、建筑、交通均属于终端能源消费部门,其中建筑部门能耗指建筑运行能耗,而非建筑建造过程中的能耗;交通部门能耗指所有交通活动能耗,既包括交通运输业营运类运输工具的交通能耗,也包括私人、公务非营运类运输工具的交通能耗 ^[1]。）将在2030年左右达峰。实现低碳转型所需新增固定投资占GDP的1.5%,不会给国民经济带来重大负担。中国实施新型城镇化战略具有技术和经济可行性。     

Book review

In 2007 the US Congress began considering a set of bills to implement a cap-and-trade system to limit the nation's greenhouse gas (GHG) emissions. The MIT Integrated Global System Model (IGSM)—and its economic component, the Emissions Prediction and Policy Analysis (EPPA) model—were used to assess these proposals. In the absence of policy, the EPPA model projects a doubling of US greenhouse gas emissions by 2050. Global emissions, driven by growth in developing countries, are projected to increase even more. Unrestrained, these emissions would lead to an increase in global CO₂ concentration from a current level of 380 ppmv to about 550 ppmv by 2050 and to near 900 ppmv by 2100, resulting in a year 2100 global temperature 3.5–4.5°C above the current level. The more ambitious of the Congressional proposals could limit this increase to around 2°C, but only if other nations, including developing countries, also strongly controlled greenhouse gas emissions. With these more aggressive reductions, the economic cost measured in terms of changes in total welfare in the United States could range from 1.5% to almost 2% by the 2040–2050 period, with 2015 CO₂-equivalent prices between $30 and $55, rising to between $120 and $210 by 2050. This level of cost would not seriously affect US GDP growth but would imply large-scale changes in its energy system.     

中国交通部门中长期低碳发展路径研究

交通部门在中长期具有很高的碳排放增长潜力,对我国低碳转型有重要影响。构建自下而上的能源系统模型PECE-LIU2017及其交通模块,设置未来交通发展的基准、NDC和低碳3个情景,深入分析交通需求背后的驱动因子及发展趋势,制定交通部门中长期低碳发展路径。结果显示,随着经济发展和人均收入水平提高,未来我国交通需求将持续增长。NDC情景下,交通部门有望在2038年左右达峰。在低碳情景下,我国交通部门2050年CO₂排放将从基准情景30亿t降低为6亿t,并在2030年左右达峰,为我国中长期低碳发展目标贡献17.5%的累计减排量。2016—2050年低碳交通固定投资需求为15.7万亿元人民币,占我国中长期低碳投资总需求的53%。通过提高燃油经济性、推广新能源汽车以及发挥城市公共出行最大潜力,交通部门能够以技术可行的方式实现低碳转型,并对我国长期低碳发展战略做出重要贡献。     

EU corporate action as a driver for global emissions abatement: A structural analysis of EU international supply chain carbon dioxide emissions

Global greenhouse gas emissions driven by European consumption increasingly occur outside European borders. These non-European sources of emissions remain linked to Europe via the international supply chains of European companies. Leading companies are now measuring their supply chain emissions and taking tentative steps to reduce them. If such activities were to become widespread, then an opportunity may exist for European industry to drive significant emissions abatement beyond European borders. This paper provides the first analysis into the maximum potential influence European industry has over its non-European supply chain emissions. The analysis is performed at the level of aggregate industry sectors using a global Multi-Regional Input–Output model. The Total Consumption Attribution method is used to estimate the potential influence of different European industries with detailed decompositions carried out using Structural Path Analysis techniques. The potential influence of European industry over non-European supply chain emissions is found to be greater than one gigatonne of carbon dioxide. The European manufacturing sector is found to have the greatest potential influence over non-European emissions via relatively short supply chains that entail few international border crossings. The results presented in this paper provide initial evidence in support of the development of European climate policies aimed at stimulating supply chain emissions reductions activities within European companies     

Growing stocks of buildings,infrastructures and machinery as key challenge for compliance with climate targets

Drastic reductions of greenhouse-gas (GHG) emissions are required to meet the goal of the 2015 Paris climate accord to limit global warming to 1.5–2.0 °C over pre-industrial levels. We introduce the material stock-flow framework as a novel way to develop scenarios for future GHG emissions using methods from social metabolism research. The basic assumption behind our exploratory scenario approach is that nearly all final energy is required to either expand and maintain stocks of buildings, infrastructures and machinery or to provide services by using them. Distinguishing three country groups, we develop GDP- and population-driven scenarios for the development of these material stocks and the corresponding energy requirements based on historically calibrated model parameters. We analyze the results assuming different future pathways of CO₂ emissions per unit of primary energy. The resulting cumulative carbon emissions from 2018 to 2050 range from 361 Gt C in the lower GDP-driven to 568 GtC in the higher population-driven scenario. The findings from the population-driven scenarios point towards the huge implications of a hypothetical convergence of per-capita levels of material stocks assuming current trajectories of technological improvements. Results indicate that providing essential services with a considerably lower level of material stocks could contribute to large reductions in global resource demand and GHG emissions. A comparison of different stock levels in 2050 demonstrates that complying with ambitious climate targets requires much faster declines of CO₂ emissions per unit of primary energy if growth of material stocks is not limited.     

Steel stocks and flows of global merchant fleets as material base of international trade from 1980 to 2050

Exploring the dynamic changes of steel from the ships is critical for developing sustainable strategies for waste management of shipping industry. However, the information of stocks and flows of ships and related steel is currently unavailable, hindering the sustainable development of shipping industry. By collecting dispersed information on production, use, material composition, and end-of-life management of five types ships, we first estimated the historical steel stocks and flows respect to global ships from 1980 to 2019, and further projected the amount of steel scraps from shipbreaking by 2050. The steel stocks of ships increased by 2.6 times from 208.4 Mt in 1980 to 542.9 Mt in 2019. The top 2 regional contributors, Asia and Latin America & the Caribbean, were together responsible for about half of the total increase. A transition from oil tankers to container ships and bulk carriers reduced the in-use steel stock due to the lower steel intensity of the latter. The rapid increase of ship stocks after year 1980 led to significant increase of steel scrap in the 2010 s, reaching 10.1 Mt/year in 2019. Our projections showed that the steel from scrapped ships worldwide will increase by around 4-fold to 40.4–47.3 Mt/year by 2050, which imposed a great challenge on coordination of recycling ship-related steel and require long-term planning on ship recycling facility development. By identifying the stocks and flows of ships and related steel, this study provides insights for the steel waste and recycling management of end-of-life ships worldwide.     

China’s future emission reduction challenge and implications for global climate policy

In December 2015, China joined 190 plus nations at Paris in committing to the goal of limiting the rise in global average temperature to ‘well below’ 2°C. Carbon budget analysis indicates that goal will require not only that the European Union and US reduce their emissions by greater than 80% by 2050, but that China at least comes close to doing so as well, if any budget is to be left over for the rest of the world (RoW). Given that RoW emissions are, and will come from, low-income and emerging nations, China’s emission reduction potential is of no small consequence. In this paper, we use the Kaya identity to back out changes in the drivers of CO₂ emissions, including gross domestic product (GDP), energy intensity (E/GDP) and the carbon content of energy (C/E), the latter two calculated to be consistent with China’s long-term GDP growth rate forecasts and specified 2050 CO₂ emission reduction targets. Our results suggest that even achieving China’s highly optimistic renewable energy targets will be very far from sufficient to reduce China’s CO₂ emissions from 9.1?Gt it emitted in 2015 to much below 3?Gt by 2050. Even reducing its emissions to 5?Gt will be challenging, yet this falls far short of what is needed if the world is to meet its ‘well below’ 2°C commitment.

Key policy insights

• Under the Paris Agreement there is great pressure on China to very substantially reduce its emissions by 2050.

• While China has attached great importance to renewables and nuclear energy development, even achieving the most optimistic targets would not be sufficient to reduce China’s emissions from 9.1?Gt in 2015 to much below 3?Gt by 2050.

• China’s emission reduction potential falls far short of what is needed if the world is to meet its Paris ‘well below’ 2°C commitment, even if the EU and US reduce their emissions to zero by 2050.

• Emission cuts consistent with the Paris Agreement will require that China and the world give much greater weight to advancing research and development of scalable low-, zero- and negative-carbon sources and technologies.

     

Bioenergy in energy transformation and climate management

This study explores the importance of bioenergy to potential future energy transformation and climate change management. Using a large inter-model comparison of 15 models, we comprehensively characterize and analyze future dependence on, and the value of, bioenergy in achieving potential long-run climate objectives. Model scenarios project, by 2050, bioenergy growth of 1 to 10 % per annum reaching 1 to 35 % of global primary energy, and by 2100, bioenergy becoming 10 to 50 % of global primary energy. Non-OECD regions are projected to be the dominant suppliers of biomass, as well as consumers, with up to 35 % of regional electricity from biopower by 2050, and up to 70 % of regional liquid fuels from biofuels by 2050. Bioenergy is found to be valuable to many models with significant implications for mitigation and macroeconomic costs of climate policies. The availability of bioenergy, in particular biomass with carbon dioxide capture and storage (BECCS), notably affects the cost-effective global emissions trajectory for climate management by accommodating prolonged near-term use of fossil fuels, but with potential implications for climate outcomes. Finally, we find that models cost-effectively trade-off land carbon and nitrous oxide emissions for the long-run climate change management benefits of bioenergy. The results suggest opportunities, but also imply challenges. Overall, further evaluation of the viability of large-scale global bioenergy is merited.     

Projected climate change impacts on skiing and snowmobiling: A case study of the United States

We use a physically-based water and energy balance model to simulate natural snow accumulation at 247 winter recreation locations across the continental United States. We combine this model with projections of snowmaking conditions to determine downhill skiing, cross-country skiing, and snowmobiling season lengths under baseline and future climates, using data from five climate models and two emissions scenarios. Projected season lengths are combined with baseline estimates of winter recreation activity, entrance fee information, and potential changes in population to monetize impacts to the selected winter recreation activity categories for the years 2050 and 2090. Our results identify changes in winter recreation season lengths across the United States that vary by location, recreational activity type, and climate scenario. However, virtually all locations are projected to see reductions in winter recreation season lengths, exceeding 50% by 2050 and 80% in 2090 for some downhill skiing locations. We estimate these season length changes could result in millions to tens of millions of foregone recreational visits annually by 2050, with an annual monetized impact of hundreds of millions of dollars. Comparing results from the alternative emissions scenarios shows that limiting global greenhouse gas emissions could both delay and substantially reduce adverse impacts to the winter recreation industry.     

The global environmental paw print of pet food

Global pet ownership, especially of cats and dogs, is rising with income growth, and so too are the environmental impacts associated with their food. The global extent of these impacts has not been quantified, and existing national assessments are potentially biased due to the way in which they account for the relative impacts of constituent animal by-products (ABPs). ABPs typically have lower value than other animal products (i.e. meat, milk and eggs), but are nevertheless associated with non-negligible environmental impacts. Here we present the first global environmental impact assessment of pet food. The approach is novel in applying an economic value allocation approach to the impact of ABPs and other animal products to represent better the environmental burden. We find annual global dry pet food production is associated with 56–151 Mt CO₂ equivalent emissions (1.1%−2.9% of global agricultural emissions), 41–58 Mha agricultural land-use (0.8–1.2% of global agricultural land use) and 5–11 km³ freshwater use (0.2–0.4% of water extraction of agriculture). These impacts are equivalent to an environmental footprint of around twicethe UK land area, and would make greenhouse gas emission from pet food around the 60th highest emitting country, or equivalent to total emissions from countries such as Mozambique or the Philippines. These results indicate that rising pet food demand should be included in the broader global debate about food system sustainability.     

Climate impact of transportation A model comparison

Transportation contributes to a significant and rising share of global energy use and GHG emissions. Therefore modeling future travel demand, its fuel use, and resulting CO₂ emission is highly relevant for climate change mitigation. In this study we compare the baseline projections for global service demand (passenger-kilometers, ton-kilometers), fuel use, and CO₂ emissions of five different global transport models using harmonized input assumptions on income and population. For four models we also evaluate the impact of a carbon tax. All models project a steep increase in service demand over the century. Technology change is important for limiting energy consumption and CO₂ emissions, the study also shows that in order to stabilise or even decrease emissions radical changes would be required. While all models project liquid fossil fuels dominating up to 2050, they differ regarding the use of alternative fuels (natural gas, hydrogen, biofuels, and electricity), because of different fuel price projections. The carbon tax of 200 USD/tCO₂ in 2050 stabilizes or reverses global emission growth in all models. Besides common findings many differences in the model assumptions and projections indicate room for further understanding long-term trends and uncertainty in future transport systems.     

Electricity generation and cooling water use: UK pathways to 2050

Thermoelectric generation contributes to 80% of global electricity production. Cooling of thermoelectric plants is often achieved by water abstractions from the natural environment. In England and Wales, the electricity sector is responsible for approximately half of all water abstractions and 40% of non-tidal surface water abstractions. We present a model that quantifies current water use of the UK electricity sector and use it to test six decarbonisation pathways to 2050. The pathways consist of a variety of generation technologies, with associated cooling methods, water use factors and cooling water sources. We find that up to 2030, water use across the six pathways is fairly consistent and all achieve significant reductions in both carbon and water intensity, based upon a transition to closed loop and hybrid cooling systems. From 2030 to 2050 our results diverge. Pathways with high levels of carbon capture and storage result in freshwater consumption that exceeds current levels (37–107%), and a consumptive intensity that is 30–69% higher. Risks to the aquatic environment will be intensified if generation with carbon capture and storage is clustered. Pathways of high nuclear capacity result in tidal and coastal abstraction that exceed current levels by 148–399%. Whilst reducing freshwater abstractions, the marine environment will be impacted if a shortage of coastal sites leads to clustering of nuclear reactors and concentration of heated water discharges. The pathway with the highest level of renewables has both lowest abstraction and consumption of water. Freshwater consumption can also be minimised through use of hybrid cooling, which despite marginally higher costs and emissions, would reduce dependence on scarce water resources thus increase security of supply.     

Integrated assessment of biomass supply and demand in climate change mitigation scenarios

Biomass is often seen as a key component of future energy systems as it can be used for heat and electricity production, as a transport fuel, and a feedstock for chemicals. Furthermore, it can be used in combination with carbon capture and storage to provide so-called “negative emissions”. At the same time, however, its production will require land, possibly impacting food security, land-based carbon stocks, and other environmental services. Thus, the strategies adopted in the supply, conversion, and use of biomass have a significant impact on its effectiveness as a climate change mitigation measure. We use the IMAGE 3.0 integrated assessment model to project three different global, long term scenarios spanning different socioeconomic futures with varying rates of population growth, economic growth, and technological change, and investigate the role of biomass in meeting strict climate targets. Using these scenarios we highlight different possibilities for biomass supply and demand, and provide insights on the requirements and challenges for the effective use of this resource as a climate change mitigation measure. The results show that in scenarios meeting the 1.5 °C target, biomass could exceed 20% of final energy consumption, or 115–180 EJ_Prim/yr in 2050. Such a supply of bioenergy can only be achieved without extreme levels land use change if agricultural yields improve significantly and effective land zoning is implemented. Furthermore, the results highlight that strict mitigation targets are contingent on the availability of advanced technologies such as lignocellulosic fuels and carbon capture and storage.     

The scale and drivers of carbon footprints in households,cities and regions across India

The carbon footprint (CF) has emerged as an important yardstick to understand the total contribution of countries, sectors and individuals to climate change. In contrast to conventional emissions accounting which captures only territorial or local production activities, the CF includes the emissions imposed by consumption across global supply chains for goods and services. Recent interest has grown in the application of CF assessment for municipalities owing to their large contribution to global carbon emissions and the limited coverage of existing data to monitor their climate pledges. By linking household-level consumer surveys to a global supply chain database, spatially-explicit CF assessment is possible at a district and household scale. To date, such technique has exposed otherwise unforeseen differences in consumer carbon footprints in developed countries. Within this study we calculate and compare the household carbon footprints 623 districts in India, based on micro consumption data from 203,313 households and explain their variation by economic, cultural and demographic factors. We show the eradication of extreme poverty does not conflict with ambitious climate change mitigation in India. However, our analysis suggests CF reduction policies within India need to target high-expenditure households which are responsible for nearly seven times the carbon emissions than low-expenditure households (living on $1.9 consumption a day). These vast disparities between the carbon footprint of citizens in India highlights the need to differentiate individual responsibilities for climate change in national and global climate policy.     

What future for primary aluminium production in a decarbonizing economy?

Aluminium is an energy intensive material with an environmental footprint strongly dependent on the electricity mix consumed by the smelting process. This study models prospective environmental impacts of primary aluminium production according to different integrated assessment modeling scenarios building on Shared Socioeconomic Pathways and their climate change mitigation scenarios. Results project a global average carbon intensity ranging between 8.6 and 18.0 kg CO₂ eq/kg in 2100, compared to 18.3 kg CO₂ eq/kg at present, that could be further reduced under mitigation scenarios. Co-benefits with other environmental indicators are observed. Scaling aluminium production impacts to the global demand shows total emission between 1250 and 1590 Gt CO₂ eq for baseline scenarios by 2050 while absolute decoupling is only achievable with stringent climate policy changing drastically the electricity mix. Achieving larger emission reductions will require circular strategies that go beyond primary material production itself and involve other stakeholders along the aluminium value chain.     

Assessing decarbonization pathways and their implications for energy security policies in Japan

For countries without sufficient fossil fuel resources such as Japan, climate policies in the mid- to long term need to satisfy requirements not only for decarbonisation but also for energy security in the context of limitations on renewable energies and nuclear power. This study assesses the feasibility of decarbonization pathways to 2050 and their effects on energy security, considering the latest energy and climate policies in Japan using the AIM/Enduse model. The analysis illustrates that deep decarbonization by 2050 is technically feasible even without nuclear power based on three elements: energy efficiency improvements, low-carbon electricity and electrification in end-use sectors. These decarbonization pathways, in the long term, could also contribute to enhanced energy security, reducing import dependency to less than a half of the total primary energy and reducing import bills for fossil fuels by around 70% compared with the current level. Notably, renewable energies could play a strategically significant role in satisfying both climate and energy security requirements. In the mid-term (to 2030), however, although GHG emissions are reduced by 14–20% from 1990 levels, import dependency is relatively stable at today's levels, particularly without the restart of nuclear power. Given the limited potential for renewable energies in the mid-term, it is suggested that the availability of nuclear power will have negative impacts on carbon intensity and energy security, and policies to enhance the security of fossil fuels, including diversification of fuel sources and supply routes, will be required for the foreseeable future.

Policy relevance

Considering the scarcity of indigenous fossil fuel resources and the uncertain availability of nuclear power in Japan, renewable energy could play a strategically significant role in replacing unabated fossil fuels, which would contribute to satisfying both climate and energy security requirements in the long term. However, the renewable energy potential is insufficient to eliminate the requirement for fossil fuels by 2030; therefore the unavailability of nuclear power would affect energy security considerably. Thus, policies in the mid-term would still require enhancement of the energy security of fossil fuels, including the diversification of fuel sources and supply routes, as well as alleviation of the impacts of price volatility.     

The Consequences of CO2 Stabilisation for the Impacts of Climate Change

This paper reports the main results of an assessment of the global-scale implications of the stabilisation of atmospheric CO₂ concentrations at 750 ppm (by 2250) and 550 ppm (by 2150), in relationto a scenario of unmitigated emissions. The climate change scenarios were derived from simulation experiments conducted with the HadCM2 global climate model and forced with the IPCC IS92a, S750 and S550 emissions scenarios. The simulated changes in climate were applied to an observed global baseline climatology, and applied with impacts models to estimate impacts on natural vegetation, water resources, coastal flood risk and wetland loss, crop yield and food security, and malaria. The studies used a single set of population and socio-economic scenarios about the future that are similar to those adopted in the IS92a emissions scenario.An emissions pathway which stabilises CO₂ concentrations at 750 ppmby the 2230s delays the 2050 temperature increase under unmitigated emissions by around 50 years. The loss of tropical forest and grassland which occurs by the 2050s under unmitigated emissions is delayed to the 22nd century, and the switch from carbon sink to carbon source is delayed from the 2050s to the 2170s. Coastal wetland loss is slowed. Stabilisation at 750 ppm generally has relatively little effect on the impacts of climate change on water resource stress, and populations at risk of hunger or falciparum malaria until the 2080s.A pathway which stabilises CO₂ concentrations at 550 ppm by the 2170s delays the 2050 temperature increase under unmitigated emissions by around 100 years. There is no substantial loss of tropical forest or grassland, even by the 2230s, although the terrestrial carbon store ceases to act as a net carbon sink by around 2170 (this time because the vegetation has reached a new equilibrium with the atmosphere). Coastal wetland loss is slowed considerably, and the increase in coastal flood risk is considerably lower than under unmitigated emissions. CO₂ stabilisation at 550 ppm reduces substantially water resource stress, relative to unmitigated emissions, but has relatively little impact on populations at risk of falciparum malaria, and may even cause more people to be at risk of hunger. While this study shows that mitigation avoids many impacts, particularly in the longer-term (beyond the 2080s), stabilisation at 550 ppm appears to be necessary to avoid or significantly reduce most of the projected impacts in the unmitigated case.     

Recent climatic change,greenhouse gas emissions and future climate: The implications for India

Summary In this paper, we discuss past climatic trends over India, greenhouse gas emissions due to energy consumption, forest and land-use changes, climate change scenarios for the year 2050, potential consequences for agriculture and cyclone activity and the possibility that India might limit the increasing trend in its emissions.India's mean surface air temperature has increased significantly by about 0.4°C over the past ccntury. Neither monsoon nor annual rainfall shows any significant trend. On average, there has been a rise in sea levels around India over recent decades, though considerable uncertainties exist in the accuracy and interpretation of the available data.Carbon emissions from the energy sector amount to 71 MT a year, equivalent to all other sectors combined. From land-use data, a marginal net sequestration of 5.25 million tonnes of carbon occurred during 1986. Following the IPCC guidelines, methane emissions from rice and livestock are estimated at 17.4 and 12.8 Tg/year, respectively.According to recent climate model projections, India may experience a further rise in temperature of 1 °C by the year 2050, about four times the rate of warming experienced over the past 100 years. A modest increase in precipitation amounts might occur. Cereals production is estimated to decrease and the nutrition security of the population-rich but land-hungry region of India might be hampered. An increase in local tropical cyclone activity may occur over thc next century, posing added problems as large areas in the coastal regions have a dense population.About 70% of the electricity generation in India is from coal-based power stations. Altering this dependence significantly to reduce emissions would imply a substantial change in the present energy policy of India. There is great potential for improving energy efficiency and conservation. The adoption of cleaner coal-technologies should be considered, as must the development of renewable, non-conventional energy sources. In all cases, serious institulional barriers and resource limitations need to be addressed. The scope for carbon sequestration is limiled by land availabilily and other factors. It is argued that any response to global warming must be located firmly in the framework of sustainable development.With 5 Figures