Global Changes - Spring 2019 Newsletter

Apr 18, 2019
Global Changes - Spring 2019 Newsletter
Insights, news, projects, publications and other developments at the MIT Joint Program

Growing demands on natural resources underscore need for risk assessment and response

T he world’s natural resource base— water, arable land, minerals and energy—also underpins its economic prosperity. It’s possible to have a prosperous economy with few of these resources—think Hong Kong or Singapore—as well as the exact opposite situation, as is the case in parts of the African continent. So how a nation uses and manages natural resources is as important as how much of them it possesses. And the success of countries with limited resources often depends on trade. Over the course of this century, as the world’s population and economies expand to unprecedented levels, many analysts anticipate multiple, global crises involving natural resources: water shortages, ecosystem disruption from land expansion, and excessive pollution from fossil fuel use. Others are more optimistic that technological change, improved yields, increased energy efficiency and better management of clean water resources will save the day. The bottom line is that global demands for energy, food and water are expected to heighten risks to these interrelated natural resources—and the economies that depend on them—in the coming decades. Our latest projections for each of these sectors, published in the 2018 Food, Water, Energy and Climate Outlook and in peer-reviewed journals, indicate a growing need for risk assessment and response. Here we summarize these projections through midcentury, and highlight how our researchers are assessing risk and identifying opportunities to mitigate that risk. Our energy, agriculture and water projections In the Outlook we project that, between 2015 and 2050, the population will increase to about 9.8 billion and the world GDP annual growth rate will remain at about 2.6%. These trends in population and GDP increase pressure on natural resources including energy, land and water. As noted above, this pressure is offset in part by technological change that increases yields and reduces energy use per unit of production activity, and other broad-scale efficiency improvements. Also playing a key role in driving global change are energy and land-use policies, and water management, which could significantly modify the effects of population and economic growth.  We estimate that global primary energy use rises to about 730 exajoules (EJ) by 2050, up from about 550 EJ in 2015. And without significant new policies beyond current Paris pledges, the share of fossil energy (coal, oil, gas) only drops from about 84% in 2015 to 78% by 2050. As a result carbon dioxide (CO2) and other pollutant emissions continue to increase, contributing further to climate change and to gaseous (e.g. ozone) and particulate (e.g. black carbon) air pollution, which, in turn, affect human health and crop productivity. The agriculture and water sectors will be shaped not only by increasing demands from population and economic growth but also by the changing global environment. Climate change is likely to add to water stress and reduce agricultural productivity in many regions, but adaptation and agricultural development offer opportunities to overcome these challenges. Incorporating recent econometric evidence on the relationship between population, income and food demand, our projections show that, at the global level between 2015 and 2050, the value of overall food production increases by about 130%, crop production increases by 75% and livestock production by 120%. While final demand for crops grows only about as fast as population growth, a projected shift to more meat consumption creates additional demand for crops for livestock feed. Our projections suggest that this can be achieved with a relatively modest increase in land devoted to crops and livestock. This depends, however, on continued availability of water for irrigation, continued technological progress that improves crop and livestock productivity and transforms the global food sector, and absence of policies restricting livestock. One concern here is that continuing conversion of land for livestock production contributes to CO2 emissions from land-use change, and growing ruminant numbers add to methane emissions. Our earlier work on the future of global water resources found that by 2050, economic growth and population change alone can lead to an additional 1.8 billion people living under at least moderate water stress, with 80% of these located in developing countries (Schlosser et al., 2014). The combined effects of socioeconomic growth and uncertain climate change lead to a 1.0–1.3 billion increase of the world’s 2050 projected population living with overly exploited water conditions, where total potential water requirements will consistently exceed surface water supply. An essay in the 2018 Outlook by Joint Program Deputy Director C. Adam Schlosser highlights a more imminent risk. “Assuming [current trends in population and economic growth], and no global efforts to adopt more efficient water use, over the next decade the world will no longer have the capacity to sustain every human at modern living standards,” the essay adds. “By these measures, this constitutes an unprecedented global threat.” Risk assessment and response Joint Program researchers are actively assessing changing demands and potential technology advances in the use of energy, agriculture and water resources to point toward possible hot spots where crises may develop, and evaluating options for managing these resources sustainably. On the energy front, we continue to investigate different technology options and costs, including nuclear, carbon capture and storage (CCS) and renewables. The costs of renewables are falling, but we still need to account for intermittency—the fact that the daily and seasonal patterns of supply from these resources do not closely match the patterns of demand. So while the base cost of a wind turbine or solar photovoltaic system may make them competitive with other generation technologies, the added cost of ancillary services makes high reliance on these sources within an electricity grid more costly. In agriculture we’re looking at how food demand may grow with increased income. More meat-intensive diets will increase water and land demands. Can land-use policy intensify production on available land, and at what cost? How much water will agriculture need, and will limits on water availability increase food costs? Another concern is that expanding agriculture will be a significant contributor to climate change due to greenhouse gas emissions and surface reflectivity (albedo) changes. Finally, increased risks of water shortages are likely to emerge if we don’t change how we use water. But we see many options to reduce water use while maintaining water-using sectors of the economy. The main problem is that water resources are often poorly managed. There is overuse in some sectors and under-recovery of the full cost of investments in water infrastructure, and hence difficulty in maintaining these systems. Work in this area needs to focus not only on physical risk of water shortages, but also on institutional guidelines and mechanisms for managing these resources. In our 2018 Outlook, the goal was to identify not only the most likely future but also the potential high-risk outcomes. We used our models to demonstrate how advanced technology or different management approaches and policies can potentially limit bad outcomes. In so doing, we hope to have provided greater confidence that proactive, prediction-based risk-reduction measures that have the greatest likelihood of success can be identified. Multi-sectoral modeling efforts are beginning to provide the much needed risk-based prognoses necessary to explore solutions across a range of possible outcomes that take account of how these natural resource issues are not independent, but highly intertwined. —Ronald Prinn and John Reilly, Co-Directors REFERENCES Reilly, J., R. Prinn, H. Chen, A. Sokolov, X. Gao, C.A. Schlosser, J. Morris and S. Paltsev (2018): Food, Water, Energy and Climate Outlook. MIT Joint Program on the Science and Policy of Global Change. Schlosser, C.A., K. Strzepek, X. Gao, C. Fant, É. Blanc, S. Paltsev, H. Jacoby, J. Reilly and A. Gueneau (2014): The future of global water stress: An integrated assessment. Earth’s Future, 2(8): 341–361 (doi:10.1002/2014EF000238).