Contributors: Camila Bauer and Chantelle Morrissette

As part of Bechtel’s commitment to contribute 100 ideas to support the United Nations 2030 Sustainable Development Goals (SDGs), we examine the climate impacts and implications of extreme heat on cities and its citizens.

SDG 9: Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation

SDG 10: Reduce inequality within and among countries

SDG 11: Make cities and human settlements inclusive, safe, resilient and sustainable

SDG 13: Take urgent action to combat climate change and its impacts

Heat waves are silently killing more Americans than any other weather hazard and inflicting a disproportionate toll in the developing world. And climate change is making them hotter, more frequent and longer lasting. Left unmitigated, extreme heat will impact every aspect of human life - from where and how we live to the food we put on our tables and the structure of our economies. 

Raising public awareness about the severity of heat waves by recording them in the same way we do hurricanes, is one of the global initiatives that cities, non-profits, scientists, government agencies, and companies – including Bechtel – are proposing.

This year, Bechtel was honoured to be invited to join the Atlantic Council Extreme Heat Resilience Alliance as the sole engineering, procurement and construction partner. The Alliance’s mission is to support urban preparedness against heat waves around the world.

Its membership counts 30 global cities impacted by extreme heat, from Melbourne to Mexico City, as well as disaster relief charities and experts in the fields of public health, climate change risk and disaster management. Its goal, funded generously by the Rockefeller Foundation – one of the largest climate donors in the States – is to reach out to one billion people with climate resilience solutions.

The criticality of heat waves is supported by research published in July 2020 by Oxford University, showing that there is a lack of official record-keeping to document extreme and worsening heat events in sub-Saharan Africa. This inaction is putting populations at risk. However, it has been suggested that better attention (including from the media) would be paid if heatwaves – like hurricanes – were given names.   

A name is important, but it’s just the start. As part of the Alliance, Bechtel will be advising on engineering and construction solutions to protect people from the perils of extreme heat. Bechtel’s recommendations  include the design of resilience standards; guidelines supporting climate-proof construction standards; cost-benefit analysis of innovations that can make infrastructure more resilient; and collaborating with regional institutions to make existing infrastructure more robust and efficient.

There are two sides to preparing public infrastructure for extreme heat - mitigation and adaptation. Mitigation would entail considering heat from early in the project’s development thus avoiding introducing or exacerbating the problem in the first place. Whereas adapting and retrofitting existing infrastructure will help to make it more heat resilient. Many of our customers are also opting for environmentally-sound design criteria, that would not only protect final users, but also cut down operational costs. Here’s some examples:

  • Orientating building to limit sun exposure and thus higher temperatures.
  • Using appropriate solar radiation index (SRI) values for roofing and paving.
  • Incorporating enough shade as a design criterion.
  • Limiting the demand for air conditioning by taking advantage of natural ventilation.
  • Incorporating smart cooling systems that only cool occupied areas and delivers cool air in proportion to the level of occupancy.
  • Designing appropriate ceiling heights, considering perhaps an extreme heat-related factor of safety.
  • Using high performing glass that allows daylight to enter the building while limiting the heat transfer.
  • Designing underground rail systems to help maintain cooler temperatures within stations, and lower energy demand for cooling. Also, considering potential and kinetic energies when designing routes as these and gravity could reduce the energy required for trains to start and stop.
  • Implementing grey water reuse measures.
  • Thoroughly reviewing flood maps prior to the design.

Building better

At a macro level, many Bechtel customers including in Saudi Arabia, are master planning for a modern society by designing cities and spaces that positively influence behaviour, enabling citizens to make carbon-friendly decisions, such as opting for public transport or switching to electric vehicles. They are also implementing systemic interventions, including planting trees to create shade, replacing heat-absorbing pavement with green spaces and using reflective surfaces. Linear parks and green corridors incorporated into urban design, helps to enhance ventilation and cools cities by enabling the release of trapped heat into the sky.

Extreme heat puts considerable strain on electricity grids as demand for air conditioning increases, meaning energy security is more important than ever before. Our customers are also increasingly wishing to boost their renewables portfolios on the path to a cleaner planet. Among many projects, this drive has seen us build Ivanpah, the largest solar farm of its time, which continues to reduce carbon emissions by more than 400,000 tons per year; and the 695-megawatt Keeyask Generating System which, when completed, will provide clean, renewable, and reliable energy to 400,000 homes.

Understanding the need for reliable low-carbon energy, we have also been supporting the shift from coal to low-carbon energy from the Hummel and Cricket Valley Energy Center in New York State with a highly efficient, environmentally responsible process of converting clean-burning natural gas to electricity. Unlike older combined-cycle power plants, these facilities are equipped with state-of-the-art emission-control technology that significantly reduces emissions.

Carbon capture significantly contributes to extreme heat mitigation by preventing carbon being release into the atmosphere. Bechtel has been implementing carbon capture for over 40-years, beginning at LNG gas fields and spanning Norway, Australia, Canada, Mexico, and the U.S. This lengthy experience in capture technologies and our expertise to retrofit carbon capture systems to power plants is helping our customers magnify their switch to cleaner energy paths.

Adapting and retrofitting existing infrastructure to make it cleaner, must be of high priority on city agendas such as of London, New York and Los Angeles, where leaders are focusing on renewing their ageing assets and reducing their operational energy demand. There is an aim to prevent emissions by electrifying transportation systems and improving energy efficiencies or reducing emissions by decarbonizing existing infrastructure through capture carbon systems and/or modernizing buildings to suit such purpose.

Covering building roofs or walls with a layer of vegetation shades building materials, which would otherwise absorb heat, can help reduce temperatures as well as air pollution and acoustics. Cities including Toronto are providing grants for both green and cool roofs to homes and businesses. In Ahmedabad, India, there is a program to add a white lime wash to roofs is providing a simple and cost-effective solution.

Urban centers and less developed countries are most at risk

A long-standing challenge facing the Alliance stems from the fact that soaring temperatures are not felt equally and those most likely to be adversely affected are the least equipped to take action. Urban jungles and countries with less developed infrastructure will be hit especially hard and vulnerable people including the ill, the elderly, low-income earners, and the homeless, will suffer most as lacking access to air-conditioning is a particularly high-risk factor.

Many cities are taking steps to combat the rising mercury. Baltimore is growing its urban forest by more than 5,000 new trees per year and hopes to increase its tree canopy to 40 percent by 2037. In Athens, city officials have created one of the largest water fountains in Europe, with water creating a cool micro-climate for several blocks.

But extreme heat impacts more than public health, it will affect food security and potentially impact entire economies, continuing to exacerbate wealth inequality among the world’s rich and poor. Millions work in outdoor jobs including agriculture and construction, or indoors where they have little control over the temperatures. A report by the International Labour Organization reveals that by 2030, heat stress – defined as “heat received in excess of that which the body can tolerate without physiological impairment” – is projected to cause 2% of total working hours worldwide lost every year, with up to 5% in regions such as South Asia and West Africa. By 2030, the accumulated financial loss due to heat stress is expected to exceed over US$2 Trillion.

The snowballing impact of extreme heat makes clear that we must act now, and we’re proud that Bechtel will be playing such an important role in tackling this global challenge - there’s no time to waste. 

Average number of extremely hot days (>95°F) expected per year between 2030-2039, under a moderate emissions scenario.
Source: Climate Impact Lab