London to feel as hot as Milan by 2050, New York like DC

In less than 30 years climate change will force us to re-evaluate how we live and work in our urban environments. If emissions remain unchecked, temperatures and humidity will quickly rise, leaving many major cities facing more frequent and severe heatwaves. Forward-thinking major organisations and governments will have to start building these issues into their planning, as heat stress, which can trigger confusion, dizziness, fatigue, nausea and even death, will become an increasingly important factor for highly exposed populations.

By 2050, extreme heat stress is projected to impact 350 million people in the world’s megacities. The burden is likely to be significant: healthcare facilities will become stressed, transport and power grids will face disruption, and GDP will reduce as productivity and outputs fall.

So, what will the future look like? We’ve handpicked major cities in North America and Europe to show how rising heat stress will change northern urban environments. Tracking two journeys south using our Current and Future Heat Stress indices, we show how major metropolitan areas will transform under future heat stress by revealing the cities that they will most resemble by 2050.

4 degrees of separation

Intensifying levels of heat stress over the next 30 years will make Glasgow as warm as London. While Glaswegians may welcome the change from iron grey skies and rain, those familiar with London’s stifling underground system will not relish the thought of heat in the UK capital feeling more like Milan does today.

Milan’s July average high temperature comes in around 30°C, 11 degrees warmer than London’s current average, elevating the frequency and length of rail delays as more days climb over 24°C. Yet London’s transition into a climate like Milan’s equates to more than just a sweaty commute. As heatwaves like London’s 2019 and 2020 events become the summer norm by 2050, the city could see losses upwards of USD2.8 billion in productivity – from increased labour inefficiency, illness and workplace injuries and delays due to impacts on transport – despite its workforce being largely staffed by people in climate-controlled offices.

The next city pairing on our journey is Milan to Rome. Milan will be mostly buffered from the severest impacts of heat stress due to its economic focus on financials and services, but Rome’s transition will be harsher as it moves into a climate more like that of Agadir, Morocco. Italy’s capital is no stranger to the effects of heat stress, but this will be amplified by 2050 when it will experience an additional 41 heat stress days, which occur when temperature and humidity exceed 25˚C on a measure known as the Wet Bulb Globe Temperature (WBGT). The 2017 heatwave saw the Italian capital, renowned for its aqueducts and water fountains, threatening to ration water for over a million residents.

Pressures on power and water supplies, excess mortalities and labour capacity losses are already shared across Southern European cities like Lisbon, Bologna and Athens. But they will, on average, transition into feeling more like Middle Eastern and North African cities over 400 miles to their south, where fatalities related to heat stress are most concentrated. It is going to be an uncomfortable journey and one operators, investors, and city officials need to start preparing for now.

US cities coming in hot by 2050

Across the Atlantic, the situation is similarly worrying. The summer of 2020 saw US cities reaching record monthly temperatures and humidity, but this will feel like the new norm by mid-century. The increase in heat stress will pose particular risks for the US’s nearly 8 million construction workers and 13 million manufacturing employees.

City dwellers will be increasingly familiar with heat stress days. New York City will experience an additional 30 heat stress days by midcentury, leaving the Big Apple feeling more like muggy Washington DC, and presenting the city with a growing set of health and infrastructure challenges.

In a 2018 climate lawsuit against fossil fuel companies, NYC stated that hotter summers even by 2020 could result in an additional 260 heatrelated deaths each year and that it is spending over USD100 million on a program to protect vulnerable communities from extreme heat. These expenditures will grow hugely over the coming decades, with the costs of heat resilience strategies and fluctuating energy demands being passed on to real asset owners and businesses.

The journey southward sees DC’s heat profile transitioning into today’s Houston which, in turn, will feel more like Culiacán, Mexico over 800 miles southwest by 2050. Around 7.4 million barrels of crude oil are produced per day in Texas and the Gulf of Mexico, but Houston faces large labour capacity losses as its heat stress days increase by 50% annually to nearly 150 by mid-century. This could translate into price rises for importers if production costs climb or product availability falls.

The jumps between major US cities today and those they will resemble in 30 years is consistently large. By 2050, Chicago will be more like Las Vegas; hot and humid Miami will be more reflective of Venezuelan cities; Los Angeles will resemble sweltering New Orleans; and water-stressed Denver will feel like Hollywood, California. The high exposure of cities in the US Sunbelt and the negative impacts on its main economic sectors, such as agriculture, tourism and the growing manufacturing sector, is a significant concern to real asset managers and investors, as well as governments.

Slowing the burn by building climate resilience

Cities like London and NYC will have to face up to rising health crises as heat waves become commonplace. Asset owners, especially those involved in real estate, will see operational and retrofitting costs soar as cooling demands increase and buildings require better heat resilience. And corporate supply chains should expect commodity price increases, falling labour productivity and growing labour risks in warmer months.

The key word for cities, asset owners, and corporates alike is resilience

The key word for cities, asset owners and corporates alike is resilience. Heat stress will have to be front of mind in their climate strategies and their investment decisions from today. Failing to adapt to heat stress will not only be deadly but also devastating – it will scorch economies, inflate inequalities, drive migration, and amplify natural hazard risks already damaging key urban economies.