Paris, London and New York are more often associated with culture, finance and history than with dangerous heat. Yet each summer all three are increasingly exposed to extreme temperatures they were never designed to withstand.

Like many dense urban areas, they amplify heat through what is known as the “urban heat island effect”. This reflects the way that warmth is trapped in concrete, asphalt and glass, turning hot days into hazardous ones.

With skyscrapers made of glass and steel, roadways encased in cement and blocks of residential apartments, New York traps heat like few other metropolitan centres. In fact, the city has one of the highest urban heat island effects in the United States, a measurement of thermal difference between urban and rural areas.

Heat kills more than 500 New Yorkers every year, a grim statistic that exacerbates inequalities along the lines of race and class. While many people escape to the seaside or countryside to find relief, others remain in cities where the heat can be harder to avoid and more difficult to endure. Yet these uneven experiences of urban heat are not new. In cities such as London, Paris and New York, coping with hot summers has long been shaped by inequality.

Across the 19th and 20th centuries, urban residents developed a range of strategies to manage extreme heat in densely built environments. Our research for the Melting Metropolis project examines everyday experiences of heat. Here are some of the ways people have coped with these conditions in the past and what they reveal about living with heat in the city.

London

For most historic urbanites, escaping the confines of their home provided the greatest relief from the heat. In the mid-20th century, some Londoners escaped to the roof of their apartment building to catch the cooling breezes that swirled above the city’s streets.

For many others, since the 19th century, public spaces have provided the greatest respite from heat in their homes. Londoners turned to the shade provided by trees in nearby parks, paddled in water fountains or went for cooling dips in lidos and ponds.

Historic urbanites have also tried to cope with the heat at home. In contrast to those who sought relief from the heat in public spaces, wealthier Londoners used money and technology to keep cool. In the 19th century they purchased imported ice from Norway or employed servants to operate fans.

Paris

In the heatwaves of the 19th century, Parisians also headed out in search of relief. Like Londoners, they made extensive use of the parks that urban planners embedded into the fabric of the city during the late 19th-century Haussmann-era redesign. But it was not only dense greenery that provided respite from the heat: the trees planted along the avenues of the city offered shelter from the rays of the sun on hot summer days.

Although the Seine held great potential for cooling down, bathing in its waters was banned in the middle of the 19th century. Despite the official ban, photographic records show that some Parisians in search of freshness broke the law and took the plunge.

To keep cool indoors, the more privileged 19th-century Parisians used ice imported from northern regions or collected locally during the winter and stored in ice houses until temperatures rose. Ice remained a luxury item until the late 1870s, when technological developments allowing ice to be made artificially lowered its cost and widened its accessibility.

Daily life in Paris – including in the summer – had undergone thorough transformations by the middle of the 20th century. Air conditioning began to gain momentum but some traditional ways to cool down have remained at the core of summer life: crowds continue to swarm café terraces, the banks of the Seine stay packed with people, 19th-century water fountains are still used to refill water bottles.

New York

In the 19th century, the tenements of New York City were filled with people sleeping on roofs, sweating on fire escapes, and avoiding the sweltering indoors. The wealthy simply fled the city for countryside estates. Newspapers called these seasonal migrants “heat refugees”.

When seeking outdoor relief, most 19th-century New Yorkers headed to the beach – the city is an island, after all. But by the 20th century, they were also planing block parties with plenty of ice from corner store bodegas. On occasion, they also cracked open fire hydrants – a relief strategy that has become a classic trope of New York City summers.

Future heat waves

For as long as episodes of extreme heat in cities have affected urban life, urbanites have developed ways to cope. Today, cities are taking heat more seriously when they look to the future and working towards adaptation strategies. The disastrous heatwave of 2003 served as a wake-up call in Paris, which implemented a heat plan the following year and continues to work on ways to make the city more liveable in the summer.

Central to New York’s climate resilience plans, air conditioning has become a political battleground in activists’ fight for a “right to cooling” (a bundle of legislation championed by local environmental justice organisations).

Though it can compound the problem of climate change, technologically aided cooling keeps people alive as we all find ways to weather the intensifying heat. In May 2026, the UK’s Climate Change Committee declared that the British way of life is under threat from heat.

In June, London will launch its heat plan for the capital, a first step in supporting the city and its residents to live better with extreme heat.

About the author: Chloe Dutell is a Postdoctoral Research Associate, School of Histories, Languages and Cultures Faculty of Humanities and Social Sciences, University of Liverpool.

The article is reproduced from The Conversation thanks to a Creative Commons licence

Protest and military action raised the prospect of regime change in Iran and Venezuela, and the voices of both countries’ diasporas were heard loud and clear through the media of their host nations.

Venezuelan exiles in the U.S. were, according to the popular narrative, broadly behind President Donald Trump and his plan to “run Venezuela,” as the nickname “MAGAzuelans” suggests. Meanwhile, the Iranian diaspora rallied behind Prince Reza Pahlavi as he positioned himself as a leader-in-waiting, projecting an image of unified exile support.

Diasporas are often treated by media and policymakers as monolithic blocs — politically unified, ideologically coherent and ready to be mobilized for regime change. But as a scholar of migration and security in Latin America, I know this assumption misunderstands how diaspora communities form, evolve and engage politically.

Iranian and Venezuelan émigrés might broadly oppose their current governments — having left them, this is unsurprising. But they are far from unified on what should replace those governments, who should lead or how change should come about.

Migration waves shape politics

Diasporas are not uniform because their constituent populations did not arrive all at once, from the same places or for the same reasons. Each migration wave carries distinct political orientations shaped by the circumstances of departure.

The tendency of diasporas to become politically frozen at the moment of departure appears across contexts. El Salvador’s diaspora in the United States, which first left during the 1980s civil war, developed a reputation for being “stuck in the ’80s” — mentally still fighting battles that had long since ended at home.

This temporal displacement has consequences. Iranian-American sociologist Asef Bayat, writing about the Iranian diaspora, argues that exile opposition to the ruling government back home “suffers from a political disease, positioning itself against the movement it claims to support.”

In other words, diaspora activists may advocate positions that resonate with Western audiences but find little support among those actually living under authoritarian rule. This lack of accountability to political consequences back home can rankle the constituencies on whose behalf they seek to advocate.

Research on the Venezuelan diaspora reflects similar dynamics. A 2022 study found that Venezuelan exiles hold more extreme anti-government views than those who remained.

Despite this presumed disconnection, homeland politicians often devote disproportionate attention to those who have left. The logic is simple: emigrants send money home — accounting for as much as 25% of gross domestic product in some Central American and Caribbean countries. Politicians assume that this financial power translates into political influence over remittance-receiving relatives.

One party official in El Salvador told me: “If we get one Salvadoran in Washington to support us, that gives us five votes in El Salvador — and it doesn’t even matter if the one in Washington votes.”

My own research tested this assumption using polling and voting data across Latin America and found it to be exaggerated. Remittances and family communication mostly reinforce existing partisan sympathies rather than swing votes.

But the belief in diaspora influence matters politically — and diaspora voters can be weaponized by authoritarian leaders. El Salvadoran President Nayib Bukele, in his successful and plainly unconstitutional 2024 reelection bid, expanded external voting through online balloting, increasing diaspora votes by 87-fold over the previous election.

Diasporas can influence home-country politics through several channels: direct voting, financial support for opposition movements, lobbying host governments and transmitting democratic values through what sociologist Peggy Levitt calls “social remittances.” Other research has found that remittances can undermine dictatorships by helping fund opposition activities.

Yet authoritarian governments have developed sophisticated countermeasures. Freedom House recorded more than 1,200 incidents of physical transnational repression against dissidents — including assassinations, abductions and unlawful deportation — between 2014 and 2024 involving 48 governments.

The limits of exile politics

For Venezuela and Iran, these lessons counsel caution. Nearly 8 million Venezuelans have fled their homeland — the largest displacement crisis in the Western Hemisphere. Iranian emigration accelerated after the 2022 protests.

Both diasporas contain passionate activists, wealthy donors and would-be leaders positioning themselves for future rule. But passion does not equal unity, and visibility does not equal representation.

The loudest voices on social media — or those amplified by U.S. officials and media — may represent narrow slices of diverse communities. There may be consensus on opposing the government back home, but far less agreement on what should be done or how change should occur.

Nor does diaspora opposition necessarily translate into regime vulnerability. Authoritarian states have learned to insulate themselves from diaspora pressure while simultaneously using emigration as a safety valve, turning potential dissidents into remittance-senders.

Diasporas can contribute to democratic change through funding, advocacy and the transmission of democratic values. But ultimately, the path to democratic change in Venezuela, Iran and elsewhere will be determined by those who remain, not those who left. Diasporas can support that struggle; they cannot substitute for it.

About the author: Michael Paarlberg is Associate Professor of Political Science at Virginia Commonwealth University.

This article is reproduced from The Conversation under a Creative Commons licence.