## Material Requirements For Infrastructure Development

Mr Son Quang Pham and Dr Michael Burrow University of Birmingham February 2018 

## About This Report

The K4D Emerging Issues report series highlights research and emerging evidence to policy-makers to help inform policies that are more resilient to the future. K4D staff researchers work with thematic experts and DFID to identify where new or emerging research can inform and influence policy. K4D services are provided by a consortium of leading organisations working in international development, led by the Institute of Development Studies (IDS), with Education Development Trust, Itad, University of Leeds Nuffield Centre for International Health and Development, Liverpool School of Tropical Medicine (LSTM), University of Birmingham International Development Department (IDD) and the University of Manchester Humanitarian and Conflict Response Institute (HCRI). For any enquiries, please contact helpdesk@k4d.info. 

## Suggested Citation

Pham, Son Quang, and Burrow, Michael (2018) Material Requirements for Infrastructure Development. K4D Emerging issues Report. Brighton, UK: Institute of Development Studies. 

## Copyright

This report was prepared for the UK Government's Department for International Development (DFID) and its partners in support of pro-poor programmes. It is licensed for non-commercial purposes only. K4D cannot be held responsible for errors or any consequences arising from the use of information contained in this report. Any views and opinions expressed do not necessarily reflect those of DFID, K4D or any other contributing organisation. © DFID - Crown copyright 2018. 


## Contents

1 
Overview .................................................................................................................................. 1 
2 
Methodology 
............................................................................................................................ 2 
3 
Financial requirements .......................................................................................................... 4 
4 
Aluminium ............................................................................................................................... 6 
5 
Cement 
..................................................................................................................................... 9 
6 
Steel........................................................................................................................................ 11 
7 
Wood ...................................................................................................................................... 12 
8 
Human resource requirements ........................................................................................... 14 
9 
References 
............................................................................................................................. 16 
 

## 1 Overview

This literature review aims to identify published studies providing projections of the global demand for, and remaining stock of, materials important for construction that could be constraints to the development of infrastructure worldwide. Our review found very little evidence and few projections addressing this issue. Although a wide variety of materials could potentially constrain infrastructure development, in our research we were only able to identify good quality projections for four materials: aluminium, cement, steel, and wood.  Estimates of the energy needs, water requirements and likely carbon emissions of mining and processing these resources are also provided. 

Demand for all of the materials we were able to study is projected to increase exponentially, along with related trends such as population and economic growth.  Although this suggests the possibility of exhausting the available reserves of raw materials, it is highly likely that substitution of alternative materials, changes in construction techniques, and scarcity enabling the exploitation of formerly uneconomic reserves may help prolong reserves of commodities.  We did not identify any commodities that appear to be in near-term short supply on a global aggregate basis, although local shortages of individual materials are quite possible. We also found several studies projecting the financial investment needed to meet the demand for infrastructure, so we have presented a summary of this information as well. We also attempted to estimate the skilled labour requirements in terms of the number of additional qualified consulting engineers which would be required to design and construct the additional road infrastructure required; we were unable to make similar estimates for other types of infrastructure due to limited information being available. 

Our key findings are:  

- 
The global infrastructure investment requirement for the period 2015-2030 is approximately $63 trillion (i.e. $3.9 trillion per year). This is an increase of about 56% of the current global infrastructure spend.  
- 
Global production of aluminium is growing exponentially at a rate of 4.1% per year (Menzie et al. 2010).  Assuming no changes in techniques, this suggests that known bauxite reserves could be exhausted by 2055.  
- 
Global production of cement has been projected by the IEA (2009) to grow exponentially at a rate of 0.8% to 1.2% per year, but actual production has already far exceeded this projection due to high growth in emerging markets and developing countries. 
- 
Global production of steel is projected to grow exponentially at a rate of 1.4% per year (Accenture 2017).  Assuming no changes in techniques, known iron ore reserves could be exhausted by 2070. 
- 
Global production of wood is projected to grow exponentially at a rate of 1.9% per year (Turner et al. 2006).  Although wood is in principle a renewable resources, water stress appears likely to be an important constraint, as one source suggests that future wood production could require as much water as 29% of total current global water consumption (World Water Exchange 2016). 

| Materials             | Cumulative    | Energy     | Water     | CO      |
|-----------------------|---------------|------------|-----------|---------|
| 2                     |               |            |           |         |
|                       | Energy        |            |           |         |
|                       |               |            |           |         |
| Water                 |               |            |           |         |
|                       |               |            |           |         |
| CO                    |               |            |           |         |
| 2                     |               |            |           |         |
|                       |               |            |           |         |
| per tonne of material | In total      |            |           |         |
| material              |               |            |           |         |
| demand                |               |            |           |         |
| (billion              | (kWh/t)       | (Litres)   | (kgCO     |         |
| 2                     |               |            |           |         |
| )                     | (TWh)         | (Million   | (Mt CO    |         |
| 2                     |               |            |           |         |
| )                     |               |            |           |         |
| tonnes)               | m             |            |           |         |
| 3                     |               |            |           |         |
| )                     |               |            |           |         |
| Cement                |               |            |           |         |
| 50.1                  |               |            |           |         |
| (1)                   |               |            |           |         |
|                       | 110           | 307        | 914       | 5,518   |
| Steel                 |               |            |           |         |
| 26.7                  |               |            |           |         |
| (2)                   |               |            |           |         |
|                       | 5,700         | 28,500     | 2,000     | 152,147 |
| Aluminium             |               |            |           |         |
| 1.7                   |               |            |           |         |
| (3)                   |               |            |           |         |
|                       | 72,000        | 88,000     | 20,900    | 120,967 |
|                       |               |            |           |         |
| Total                 |               |            |           |         |
|                       |               |            |           |         |
|                       | 278,632       | 923,982    | 134,349   |         |

Source: (1) adapted from IEA, 2010; (2) adapted from Accenture, 2017; (3) adapted from Menzie et al., 2010.  
It should be emphasised that all of these projections have a high degree of uncertainty associated with them. 

## 2 Methodology

The review question lends itself to an unbiased aggregation approach where the aim of the study is to identify a sufficient number of studies that provide relevant forecasts. With sufficient resources, such an approach would ideally seek to identify all relevant literature, but in keeping with the resource constraints of this particular study, careful consideration was given to locating a sample of studies most pertinent to addressing the research question. This was achieved by carrying out a key word search of titles and abstracts of studies via internet based search engines and via accessing databases and the websites of specific organisations. Following the initial screening process the full text of pertinent studies were retrieved for further scrutiny.  
To be included in the scope, identified studies had to satisfy the following criteria: 

i. 
Resources: raw and processed physical materials and human resources used in the investment, design, construction and maintenance of physical infrastructure (airports, bridges, commercial and residential buildings, dams, energy extraction/generation 
facilities, freshwater, storm water and sewage infrastructure, ports, power stations, railways, roads and telecommunications) 

ii. 
Study design: Projections which determine the current and future resource requirements associated with planning, financing, building and maintaining infrastructure  
iii. 
Language: English language only. 
The review focused on identifying good quality studies which projected global demands, rather than those which focused on individual countries or groups of countries. The primary raw materials used for the construction of physical infrastructure include clays, gravels, rock, sands and wood.  Processed materials primarily used for physical infrastructure include asphalt / bitumen (processed from petroleum but also found naturally), bricks (made from clays), cement (i.e. clay, limestone or calcium silicate), ceramics (primarily from clays), concrete (i.e. cement plus sands and gravels of various sizes and water), foam (synthetic polystyrene or polyurethane), glass (melted sand and silicates), metals (primarily aluminium from bauxite; iron and steel from iron ore), paper (from wood) and plastics. In our research, however, we were only able to identify good quality projections of the availability of four materials: aluminium, cement, steel and wood.  Secondary sources of information were used to project the associated raw material requirements: bauxite for aluminium, limestone and clay for cement, and iron ore for steel. Estimates associated with the energy and water requirements and likely carbon emissions associated with mining and using these resources are also provided. The study utilised the following databases, websites and search engines:  

- 
Scopus 
- 
Web of Science 
- 
Google Scholar 
- 
Google 
- 
World Bank 
- 
Asian Development Bank 
- 
African Development Bank  
- 
OECD 
- 
New Climate Economy 
- 
FindIT.bham.ac.uk.  

## 3 Financial Requirements

The review of the literature found estimates of the total global infrastructure investment requirement for the period 2015-2030 at 2015 prices ranging between $21.8 trillion and $96.6 trillion.  The average across all of the studies was $63 trillion, equivalent to an annual investment of about $3.9 trillion per year which is 50% more than current annual infrastructure spending of $2.5 trillion per year (McKinsey & Company, 2016). Figure 1 shows the global cumulative projected investment in infrastructure by different authors.  All estimates have been converted to 2015 prices and adapted for the period 2015-2030; the red line shows the average investment value of the projections.  
Our review found six studies which estimated the investment needed for global infrastructure development (see Table 2). The studies apply a wide range of methodologies, estimate periods, definition of infrastructure, assumptions and scenarios. This results in significant differences in the projected infrastructure demand as well as the required investment to meet such demand. 

| Source              | Global            |
|---------------------|-------------------|
| Infrastructure      |                   |
| requirement         |                   |
| (annual)            |                   |
| Global              |                   |
| Infrastructure      |                   |
| requirement         |                   |
| (total)             |                   |
| GCEC, 2014          |                   |
| $ 6 trillion/year   |                   |
| $96.5 trillion by   |                   |
| 2030                |                   |
|                     |                   |
| $ 5 trillion/year   | $80.5 trillion by |
| 2030                |                   |
| Bhattacharya        |                   |
| et al., 2016        |                   |
|                     |                   |
| $ 1.2 trillion/year | $8.1 trillion by  |
| 2020                |                   |
| Ruiz-Nuñez. &       |                   |
| Wei , 2015          |                   |
|                     |                   |
| $ 3.2 trillion/year |                   |
| $19.2 trillion by   |                   |
| 2020                |                   |
| Kennedy,&           |                   |
| Morlot ,2013        |                   |
|                     |                   |
| $3.5 trillion/year  | $62.1 trillion by |
| 2030                |                   |
| McKinsey &          |                   |
| Company,            |                   |
| 2013                |                   |
|                     |                   |
| Dulac, 2013         |                   |
| $ 3.2 trillion/year |                   |
| $128.6 trillion by  |                   |
| 2050                |                   |
|                     |                   |

A study by The Global Commission on the Economy and Climate (GCEC) (2014) projects that the world will need to invest about $88.6 trillion in infrastructure by 2030 (i.e. $ 5.5 trillion per year). The study is based on a business-as-usual (BAU) scenario and assumes that there will be no new policy actions to address additional infrastructure which might be required to tackle the effects of climate change and the requirements for additional energy security. The projections were calculated at 2010 prices and derived from sectoral estimates provide by OECD (2006 and 2012), the International Energy Agency - IEA (2012), and the analysis by Climate Policy Initiative (The Global Commission on the Economy and Climate, 2014). The projection includes the investment for replacement, maintenance and construction for transport (road, rail, airport, and port), water supply and waste (for both human and agricultural use), energy (power generation, electricity transmission and distribution, fossil fuel supply chain, and energy end-use sectors) and 

| What is included      |
|-----------------------|
| period                |
| 2015-                 |
| 2030                  |
| New construction &    |
| maintenance for       |
| Transport, Water &    |
| waste, Energy &       |
| Telecoms              |
| 2015-                 |
| 2030                  |
| New construction &    |
| maintenance for       |
| Transport, Water      |
| supply & sanitation,  |
| Energy, & Telecoms    |
| 2014-                 |
| 2020                  |
| New construction &    |
| maintenance for       |
| Transport, Water      |
| supply & waste,       |
| Energy, & Telecoms    |
| 2015-                 |
| 2020                  |
| New construction &    |
| maintenance for       |
| Transport, Water,     |
| Energy, & Telecoms    |
| 2013-                 |
| 2030                  |
| New construction &    |
| maintenance for       |
| Transport, Water      |
| supply & waste,       |
| Energy, & Telecoms    |
| 2010-                 |
| 2050                  |
| New construction &    |
| maintenance for road, |
| railway and parking   |
| place                 |

telecommunications infrastructure (fixed-line telephony and data, mobile telephony and data, broadband mobile communications). Bhattacharya et al (2016) estimate that between $75 trillion and $86 trillion (at 2015 prices) of investment is needed for new construction and maintenance of core infrastructure (including energy, transport, water supply & sanitation, and telecommunication) for the period 2015 to 2030. They made the calculation based on the average infrastructure investment spending in 2015 and assumptions of GDP growth and investment rates. The uncertainties in these assumptions are the major limitation of the report. Ruiz-Nuñez and Wei (2015) estimate that the required resource to satisfy new infrastructure demand while still maintaining existing global infrastructure will amount to $1.1 trillion (US$ 2011) or 2.2 percent of current world GDP per year over the period 2014 and 2020.  To estimate the infrastructure investment demand Ruiz-Nuñez and Wei (2015) adopted Fay's (2000) model and Yepes (2008) methodology to develop a model in which infrastructure investment requirement is estimated to satisfy the customer and producer demand for services given an expected GDP growth rate. The GDP growth rates between 2014 and 2020 were predicted from the average GDP growth rates of the previous five years. McKinsey and Company (2013) projects global infrastructure needs through combining independent estimates of future needs by sector, including those of the OECD, IEA, and Global Water Intelligence (GWI). The report forecasts that $57 trillion, at 2010 prices, in global infrastructure investment will be required between 2013 and 2030. This figure includes the investment for transport, power, water and telecommunications infrastructure, with roads and power accounting for almost half of the demand. Similar to the above studies, McKinsey and Company's report suggest that the infrastructure investment requirement up until 2030 is greater than the estimated value of today's infrastructure worldwide.  
Similar studies were also conducted by Kennedy & Morlot (2013) and Dulac, (2013). While Kennedy & Morlot (2013) focus on a wide range of infrastructure categories (transport, energy generation, transmission and distribution, water, and telecommunication), Dulac, (2013) only calculates the needs for roads, railways and parking demands. As a whole, Kennedy, & Morlot 
(2013) forecast that the world will need an investment of $18.7 trillion for infrastructure by 2020. For the transport sector, Dulac (2013) estimates an investment of $120 trillion (US$ 2010) is required by 2050.   

## 4 Aluminium

Aluminium's strength to weight properties and its resistance to corrosion make it an important material for the construction infrastructure and transport (trains and aircraft).  Due to its light weight and electrical conductivity, aluminium is also widely in electricity transmission. Approximately 26% of aluminium production is used for the construction sector in 2016 (Statista.com, 2018). The demand for aluminium is expected to continue to increase to match with the exponential growth in global population, the increasing trend in globalization and urbanization. Menzie et al. (2010) project that aluminium consumption by 2025 is likely to reach 120 million tonnes per year, representing a compound growth rate of 4.1 % per year. The growth rate is expected to relatively slow in high-income countries, but remain rapid in low and middle income countries. At this growth rate, aluminium production will double after 15 years and triple after about 23 years. Figure 2 shows actual and predicted aluminium production from 1994 to 2025. 

Utizling the Menzie et al. (2010) projection for the period 2015 to 2025 and extrapolating to 2030 
the resulting accumulated aluminium demand is given in Figure 3.  To meet this projected demand, the world will need to produce about 1.7 billion tonnes of aluminium by 2030.   
Typically four tonnes of bauxite is required to produce a tonne of aluminium (Ashraf, 2014; Australianbauxite.com, 2017). This means to produce 1.7 billion tonnes of aluminium by 2030, the world will need about 6.8 billion tonnes of bauxite.  The total global bauxite reserves are estimated to be about 27.8 billion tonnes (The Bauxite Index, 2017). If the aluminium demand keeps growing at 4.1% per year, there are no significant changes in aluminium production technologies and no new bauxite reserves are found, current known world reserves of bauxite are likely to be exhausted by 2055. This projection is based on current trends continuing unchanged, but substitution, changes in construction techniques, and exploitation of formerly uneconomic reserves are likely to prolong reserves of bauxite.   
The production of a tonne of aluminium requires 72,000 kWh of energy (Rankin, 2012; Low-tech Magazine, 2014), 88 m3 water (Zygmunt, 2007) and results in 21 tonnes of CO2 (Rankin, 2012; Carbon Trust, 2011). To produce 1.7 billion tonnes of aluminium requires approximately 121,000 TWh of energy, 148 billion m3 water and result in about 35 billion tonnes of CO2. The annual average amount of energy required for aluminium production to 2030 is 5% of the entire global energy consumption in 2015 (Ritchie and Roser, 2017).  The carbon emission resulting from aluminium production is about 2.2 billion tonnes per year to 2030, which is equivalent to about 6% of the global carbon emissions in 2015.  

## 5 Cement

Cement is an essential component of concrete, a fundamental material used in buildings, bridges, dams and roads. IEA (2009) suggests a cement production road map up to 2050 with two scenarios in which global cement demand may increase on average by 0.8% to 1.2% per year between 2006 and 2050, reaching between 3.7 and 4.4 billion tonnes per year in 2050.  At the high demand growth rate, cement production would increase by 50% after about 30 years and double after 56 years. Figure 4 shows the actual and predicted global cement production between 1994 and 2050.  The blue line presents actual cement production between 1994 and 2016 derived from USGS's database; the red and green lines show the range of cement demand projected by IEA (2010) between 2006 and 2050. Demand has in fact greatly exceeded IEA projections, possibly because IEA underestimated the growth of the cement market in emerging markets and developing countries. For instance, the projection suggests that China's cement production will peak in 2015 at nearly 1.7 billion tonnes per year, whereas USGS (2017) reported that actual cement production in China was approximately 2.4 billion tonnes in 2015 (i.e. 40% higher than the forecast). Unfortunately, we were unable to find other projections of global cement requirements.  
 
Adjusting IEA's estimate in the high-demand scenario for the period 2015 and 2030, the accumulated cement demand is calculated and shown in Figure 5.  By 2030 the world is predicted to require the production of about 50 billion tonnes of cement. 

Typically about 1.65 tonnes of limestone and 0.4 tonnes of clay are quarried for each tonne of cement produced (British Geological Survey, 2005). This means to produce 50 billion tonnes of cement by 2030, there will be a need for about 83 billion tonnes of limestone and 20 billion tonnes of clay (see table 3).  

| Clay required       |          | Accumulated    |
|---------------------|----------|----------------|
| cement demand       |          |                |
| Limestone per tonne |          |                |
| of cement (*)       |          |                |
| Clay per tonne      |          |                |
| of cement (*)       |          |                |
| Limestone           |          |                |
| required            |          |                |
| (billion tonnes)    | (tonnes) | (tonnes)       |
| 50.16               | 1.65     | 0.40           |

To produce a tonne of cement requires about 110 kWh of energy (GNCS, 2017; IEA-ETSAP, 2010) and 307 litres of water (Lafarge, 2011; World Steel Association, 2015), and 914 kg CO2 
are produced (GNCS, 2017; NRMCA, 2012). This means to meet the projected cement demand of 50 billion tonnes by 2030 about 5,518 TWh of energy, 15 billion m3 of water will be required, and 46 billion tonnes CO2 will be produced. Thus the annual average amount of energy required for cement production up until 2030 is 0.24% of the entire global energy consumption in 2015 i.e. 146,000 TWh, (Ritchie and Roser, 2017). 

As a result, between 2015 and 2030, the cement industry will create 2.9 billion tonnes of CO2 per year on average which is equivalent to 8.1% of the current global carbon emissions of 36 billion tonnes per year (Edgar, 2017). This share of carbon emission is similar to that reported by Andrew (2017) of 8% of global CO2 emissions per year.  

## 6 Steel

The world's steel consumption has more than doubled in the past twenty years, from 0.7 billion tonnes per year in 1994 to 1.6 billion tonnes per year in 2015 (USGS, 1996 & 2017). Steel demand is expected to grow at 1.4% per year, reaching about 2.0 billion tonnes per year by 2035 (Accenture, 2017). Construction is the largest steel-consuming sector, accounting for approximately 50% of global steel consumption (Lee and Dai, 2016). 

Error! Reference source not found. shows global actual steel production from 1994-2015 (blue line) and predicted steel production to 2035 (red line) according to a study by Accenture (2017).  
 
By 2030 the world will need a total of about 27 billion tonnes of new steel produced (Error! Reference source not found.). 

Producing 1 tonne of crude steel typically requires about 1.4 tonnes of iron ore (World Steel Association, 2016). To produce 27 billion tonnes of crude steel will require 37.4 billion tonnes of iron ore by 2030. According to The Statistics Portal (2017), world reserves of iron ore as of 2016 are approximately 170 billion tonnes.  Therefore if steel demand keeps increasing at a rate of 1.4%, there are no significant changes in steel production technologies, and no new iron ore reserves are found, current known world reserves of iron ore may be exhausted by 2070. This projection is based on current trends continuing unchanged, but substitution, changes in construction techniques and exploitation of formerly uneconomic reserves are likely to prolong reserves of iron ore.  
Typically in order to produce a tonne of steel requires about 5,700 kWh of energy (Horvath, 2013; Rankin, 2012) and 28.5 m3 water (World Steel Association, 2015; Colla et al., 2017), and produces about 2 tonnes CO2 (Horvath, 2013; Rankin, 2012). Thus, producing 27 billion tonnes of steel requires about 152,000 TWh of energy, 761 billion m3 water, and results in about 53 billion tonnes of CO2. The annual average amount of energy required for steel production to 2030 is about 7% of the entire global energy consumption, 146,000 TWh, in 2015 (Ritchie and Roser, 2017), and the  annual carbon emissions from steel production to the year 2030 may amount to about 3.3 billion tonnes per year, which is equivalent to about 9% of the global carbon emissions of 36 billion tonnes per year in 2015  (Edgar, 2017). 

## 7 Wood

The studies identified which project the requirement of wood do so in terms of the value of wood harvested or consumed, rather than the mass of wood.  This measure has therefore been used in the report. The amount of energy required and carbon emissions produced as a result of wood production are not provided because of a lack of good quality studies, but the amount of water required to produce wood is estimated. Turner et al. (2006) report that global wood consumption value increased from US$348 billion per year in 1958 to US$597 billion per year in 2002. They also project that the wood consumption will continue to increase at 1.9% per annum, reaching US$1,023 billion per year in 2030. With this growth rate, global wood production value will double by 2038 (see Error! Reference source not found.). The construction sector accounts for about 25% of the global wood consumption 
(Ebohon and Rwelamila, 2001). 

 
Source: Turner et al., 2006 
According to Turner et al. (2006), between 2015 and 2030 at total the world will need about 39.7 billion m3 of round wood; 7.9 billion m3 of sawn wood; 1.8 billion m3 of veneer/plywood; 2.5 billion m3 of particle board; and 1.5 billion m3 of fibrewood. 

To grow and process such an amount of wood, about 21.2 trillion m3 of water is required (see table 4). The annual average requirement for this is 29% of the global water consumption in 2015 
of approximately 4.5 trillion m3 (World Water Exchange, 2016). 

| Type of Wood    | Water required per    | Product demand    |
|-----------------|-----------------------|-------------------|
| m               |                       |                   |
| 3   (*)         |                       |                   |
|                 |                       |                   |
| (m              |                       |                   |
| 3               |                       |                   |
| )               | x 1000 m              |                   |
| 3               |                       |                   |
|                 | Billion m             |                   |
| 3               |                       |                   |
|                 |                       |                   |
| Round wood      |                       |                   |
| 293             | 39,733,053            | 11,642            |
| Sawn wood       |                       |                   |
| 580             | 7,921,641             | 4,595             |
| veneer/ plywood |                       |                   |
| 652             | 1,848,440             | 1,205             |
| particleboard   |                       |                   |
| 847             | 2,524,682             | 2,138             |
| Fiberwood       |                       |                   |
| 1093            | 1,494,787             | 1,634             |
| Total           |                       |                   |
|                 |                       |                   |
| 21,214          |                       |                   |

Source: (*) Schyns et al. (2017) 

## 8 Human Resource Requirements

As requested, we attempted to estimate the human resource requirements (considering in this case only skilled engineers, rather than all labour requirements) to meet road construction needs until 2030.  The assumptions made are presented in Table 3.  We were unable to provide similar estimates for other infrastructure types due to a lack of reliable data. Based on figures provided by Dulac (2013), by 2030 the world will need to construct an additional of 14 million paved road lane‐km at a cost of $18.2 trillion.  This will require about 17 million manyears of qualified engineer design input, or roughly 1.2 million person-years per year.  This is about four times the total number of civil engineering jobs in the US in 2016 (which was 303,500; US Department of Labour, 2016)5 

Additional Road (lane-km) 
14,000,000 
Average construction cost / km ($ million)1 
1.30 
Total capital costs ($ million) 
18,200,000 
Planning and Design Cost2 
10% 
Avg. salary ($/year) 3 
43000 
Overhead cost /labour cost 4 
150% 
Total person-years (2015-2030) 
17,438,140 
Annual person-years 
1,162,543 

1. 
Dulac, 2013 Grant (2017) reports that the average salary for engineering graduates, by country, ranges from $6,379 to $79,243 per year.  The average of this range, i.e. .approximately $43,000 per year, has been used here. 
4. 
Assuming that overhead costs, including support staff, are about 150% of the salary of a fee earning engineer (http://web.mit.edu/e-club/hadzima/how-much-does-an-employee-cost.html 
5. 
Here, civil engineers is defined as people who perform engineering duties in planning, designing, and overseeing construction and maintenance of building structures, and facilities, such as roads, railroads, airports, bridges, ports, channels, dams, irrigation projects, pipelines, power plants, and water and sewage systems.  

## 9 References

Accenture (2017). Steel demand beyond 2030. In: 83rd Session of the Steel Committee, Paris, 28-29 September 2017. Paris: OECD. Available at: http://www.oecd.org/sti/ind/83rd-session-ofthe-steel-committee.htm [Accessed 11 Dec. 2017] 
Andrew R. M. (2017). Global CO2 *emissions from cement production*. Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2017-77 Ashraf A. (2014). *Aluminum Production and Consumption Energy*. Nijmegen, Netherlands: Surinam Industrial Engineering. Australianbauxite.com (2017). *Introduction to Bauxite.* [online] Available at: http://www.australianbauxite.com.au/Introduction-to-Bauxite.htm [Accessed 23 Jan. 2018] 
Bhattacharya A., et al. (2016). Delivering on sustainable infrastructure for better development and better climate. Brookings Institution and Global Commission on the Economy and Climate. British Geological Survey (2005). Mineral Profile: Cement Raw Material *Material*. British Geological Survey, Natural Environment Research Council. Available at: http://www.bgs.ac.uk/mineralsuk/statistics/mineralProfiles.html [ Accessed 2 Jan. 2018] Carbon Trust (2011). *Aluminium. International Carbon Flows* [online] Available at: https://www.carbontrust.com/resources/reports/advice/international-carbon-flows/ [Accessed 2 Jan. 2018] Colla V. et al (2017). Efficient Use of Water Resources in the Steel Industry. *Water 2017,*   9(11), 874; doi:10.3390/w9110874 Dulac, J. (2013). Global Land Transport Infrastructure Requirements: Estimating road and railway infrastructure capacity and costs to 2050. Paris: International Energy Agency Ebohon, O. J. and Rwelamila P. M. D. (2001). Sustainable Construction in Sub‐Saharan Africa: 
Relevance, Rhetoric, and the Reality. Rotterdam, Netherlands: in-house publishing [online] Available at: https://www.irb.fraunhofer.de/CIBlibrary/search-quick-resultlist.jsp?A&idSuche=CIB+DC660 [Accessed 22 Jan. 2018].) Edgar (2017). CO2 *time series 1990-2015 per region/country*. [online] Available at http://edgar.jrc.ec.europa.eu/overview.php?v=CO2ts1990-2015 [Accessed 11 Dec. 2017] GNCS (2017). *The GNCS Factsheets: Mitigating Emissions from Cement*. The Global Network for Climate Solutions. Available at: http://climate.columbia.edu/resources/gncs-factsheets/ [Accessed 25 Dec. 2017] Grant, K., B. (2017). The best and worst countries for paying engineering grads. *CNBC,* [online]. CNBC. Available at:  https://www.cnbc.com/2017/01/12/the-best-and-worst-countries-for-payingengineering-grads.html [Accessed 12 Dec. 2017] Hollar, D.A. (2011). *"Predicting Preliminary Engineering Costs for Highway Projects.*" PhD. North Carolina State University. 

Horvath L. (2013). *Energy use in steel industry*. World Steel Association. Available at: http://ieaghg.org/docs/General_Docs/Iron%20and%20Steel%202%20Secured%20presentations/ 1620%20Ladislav%20Horvath.pdf [Accessed 20 Dec. 2017] IEA (2009). *Energy Technology Transitions for Industry*. International Energy Agency. Available at:https://www.iea.org/publications/freepublications/publication/industry2009.pdf [Accessed 20 Dec. 2017] IEA (2012). *Energy Technology Perspectives 2012: Pathways to a Clean Energy System*. Paris: International Energy Agency. IEA-ETSAP (2010). *Technology Brief I03: Cement production.* International Energy Agency. Available at https://iea-etsap.org/E-TechDS/PDF/I03_cement_June_2010_GS-gct.pdf [Accessed 11 Dec. 2017] 
Kennedy, C. and Morlot J. (2013). Past performance and future needs for low carbon climate resilient infrastructure - An investment perspective. *Energy Policy,* 59, pp.773–783 Lafarge (2011). *Sustainable report: Water footprint.* [online]  Available at: http://www.lafarge.com/05182012-publication_sustainable_development- Sustainable_report_2011-water-uk.pdf [Accessed 20 Dec. 2017] Lee, E. Y. and Dai, A. (2016). Oversupply in the global steel sector: challenges and opportunities. DBS Group Research.  
Low-tech Magazine (2014). How much energy does it take (on average) to produce 1 kilogram of the following materials? [online] Available at: http://www.lowtechmagazine.com/what-is-theembodied-energy-of-materials.html [Accessed 12 Dec. 2017] 
Mansour, M. (2015). Develop A Strategic Forecast of Silica Sand Based on Supply. International Journal of Engineering (IJE), 9 (1), pp.9-27 McKinsey & Company (2013). *Infrastructure productivity: How to save $1 trillion a year*. 

McKinsey Global Institute McKinsey & Company (2016). *Bbridging global infrastructure gaps*. McKinsey Global Institute. 

Menzie W.D. et al. (2010). *The Global Flow of Aluminum from 2006 through 2025. .* Open-File Report 2010–1256. US Geological Survey. Available at: 
https://pubs.usgs.gov/of/2010/1256/pdf/ofr2010-1256..pdf [Accessed 12 Dec. 2017] NCE Global Commission on the Economic and Climate (2014). New Climate Economy Technical Note: Infrastructure investment needs of a low-carbon scenario. The New Climate Economy. NRMCA (2012). Concrete CO2 *Fact Sheet*. Silver Spring: National Ready Mixed Concrete Association. Available at: 
https://www.nrmca.org/sustainability/CONCRETE%20CO2%20FACT%20SHEET%20FEB%2020 12.pdf [Accessed 20 Dec. 2017] OECD (2006). *Infrastructure to 2030: Telecom, Land transport, Water and Electricity*. Paris: 
OECD 
OECD (2012). *Strategic Transport Infrastructure Needs to 2030*. International Futures Programme. Paris: OECD. Oxford Economics (2017). Global Infrastructure Outlook: Infrastructure Investment Needs, 50 Countries, 7 sectors to 2040. Oxford Economics and Global Infrastructure Hub. [online] Available at: https://www.oxfordeconomics.com/publication/open/283970 [Accessed Dec. 2017] Rankin J. (2012). *Energy use in metal production*. Swinburne University of Technology Ritchie, H. and Roser, M. (2017). Energy Production & Changing Energy Sources. Our world in data. Available at: https://ourworldindata.org/energy-production-and-changing-energy-sources/ [Accessed 11 Dec.  2017] Ruiz-Nuñez, F. and Wei Z. (2015). Infrastructure Investment Demands in Emerging Markets and Developing Economies. World Bank Policy Research Working Paper 7414. Washington, DC Schyns et al J. F. (2017). The water footprint of wood for lumber, pulp, paper, fuel and firewood. Advances in Water Resources,  107 (2017), pp. 490–501 Statista.com, (2018). *Global demand for semi-finished aluminum products in 2016, by sector* [online] Available at: https://www.statista.com/statistics/280983/share-of-aluminum-consumptionby-sector/ [Accessed 22 Jan. 2018]. The Bauxite Index (2017). *Bauxite Reserves*. [online] Available at: https://thebauxiteindex.com/en/cbix/industry-101/bauxite-101/bauxite-reserves [Accessed 12 Dec. 2017] The Global Commission on the Economic and Climate (2014).  Technical Note: Infrastructure Investment Needs for a Low-Carbon scenario. The New Climate Economy. The Global Commission on the Economic and Climate (2016). The Sustainable Infrastructure Imperative: Financing for Better Growth and Development. The New Climate Economy.  
The Statistics Portal (2017). *World reserves of iron ore as of 2016*. [online] Available at: https://www.statista.com/statistics/267381/world-reserves-of-iron-ore-by-country/ [Accessed 11 
Dec. 2017] 
Turner J. A.  et al. (2006). *World Wood Industries Outlook: 2005-2030*. New Zealand: Scion & University of Wisconsin US Department of Labour (2016). *Occupational Outlook Handbook* [online] Available at:  
https://www.bls.gov/ooh/architecture-and-engineering/civil-engineers.htm [Accessed 12 Dec. 

2017] USGS (1996). Mineral Commodity Summaries, 1996. U.S. Geological Survey. USGS (2004). Mineral Commodity Summaries, 2004. U.S. Geological Survey. USGS (2006). Mineral Commodity Summaries, 2006. U.S. Geological Survey. USGS (2017). Mineral Commodity Summaries, 2017. U.S. Geological Survey. WB (2017). *Global Economic Perspectives: A Fragile Recovery*. Washington, DC: World Bank.  
World Steel Association (2015). *Water Management in the Steel Industry, Position Paper*. Available at: https://www.worldsteel.org/publications/position-papers/water-management.html [Accessed 20 Dec. 2017] World Water Exchange (2016). Water: Expectation of Demand Outstripping Supply and Increasing Volatility *World water consumption* [online]. Available at: http://worldwaterexchange.com/about-us/ [Accessed 12 Dec. 2017] Yepes, Tito. (2008)*. Investment Needs for Infrastructure in Developing Countries 2008-15.* World Bank. Zygmunt, J. (2007). Hidden water: We consume a lot more water than we can even imagine, and our water footprints extend far beyond our own nation's boundary.  London: Water wise. Available at: http://waterfootprint.org/media/downloads/Zygmunt_2007.pdf [Accessed 12 Dec. 

2017]