The escalating global climate crisis is leaving its indelible mark on urban centres worldwide, and Tehran, the bustling political and commercial heart of Iran, is no exception.  

Home to over 9.1mn people and a floating population of 13.5mn people during the day, the city's vulnerability to the changing climate presents a significant national challenge, even if its initial impact has been less dramatic than in other regions. 

One of the most palpable effects for Tehran residents is the stark shift in seasonal patterns. Summers are now characterised by increasingly oppressive heatwaves, with temperatures regularly hitting record highs. Conversely, the cold season has noticeably shrunk, starting later and bringing less intense cold. 

"When I was young, sometimes it still snowed this season," recalled Mahin, a 70-year-old Tehran resident.  

Sara, 44, echoed this sentiment, stating: "I have warm clothes that I haven't worn in several years, because it doesn't get that cold at all."  

While air conditioning in almost all Iranian homes offers some respite, the country's recent electricity shortages, leading to government-imposed two-hour power cuts in Tehran neighbourhoods during peak summer, have exacerbated the discomfort.  

Authorities have even shifted government and bank working hours to 6 am to 1 pm, with Thursdays becoming full closures, to manage energy demand during the hot season (Friday is the weekend in Iran and Thursday is a half day). All government entities are also instructed to turn off their air conditioning systems after 2 pm.  

However, the most pressing environmental concern facing Tehran is the intensifying lack of rainfall and prolonged drought. This has pushed the city's water supply to a critical juncture.  

The CEO of the Tehran Province Water and Wastewater Company stated recently that the drought of the last five years, particularly the last two, constitutes the "most severe drought of the last 50 years”. 

Back in March, Deputy Energy Minister Mohammad Javanbakht confirmed the alarming state of Tehran's key drinking water dams – Lar, Latian, Mamloo and Karaj – all experiencing record-low reservoir levels.  

Tehran province has witnessed a stark 25% reduction in rainfall compared to last year, leaving these vital dams at a mere 6% average capacity.  

Despite assurances made by Mohsen Ardakani, CEO of Tehran Province Water and Wastewater Company in May, that formal rationing is not yet going to be implemented, he has urgently appealed to residents to slash their water consumption by 20% to avert a challenging summer.  

Rama Habibi, director of conservation at Tehran Regional Water Company, stressed in an interview with IRIB in January the critical need to explore alternative water sources, as the current supply relies on 55% surface water and 45% groundwater, both severely strained.  

Worryingly, authorities have issued serious warnings, with some not ruling out the possibility of water rationing if conservation efforts fall short.  

Climate scientist Professor Mehdi Zare warned in an article in Etemad newspaper in March of dire consequences if urgent action isn't taken. "Warming temperatures will reduce the lifespan of snow and increase evaporation," he explained, stressing that a single wet season cannot replenish deeply depleted reservoirs. He cautioned that without measures like artificial aquifer recharge, altered cultivation, and reduced consumption, the region faces "ecological drought" and ecosystem destruction, potentially turning the southern Alborz region and the area around Tehran into a "semi-arid region" within the next decade, requiring decades of recovery efforts.  

The inefficiency of Tehran's water system, where treated drinking water is used for all domestic purposes and only 10% of wastewater is recycled, further compounds the issue.  

President Massoud Pezeshkian has even revived the long-debated idea of relocating the capital, citing the water crisis as a primary driver, suggesting southern coastal cities as alternatives, though the feasibility remains questionable due to Tehran's entrenched population and commercial dominance. 

Water scarcity has also aggravated land subsidence, a dangerous phenomenon already affecting other Iranian cities and now engulfing the capital.  

Soudeh Najafi, head of the Tehran City Council's health committee, revealed in an interview with state news agency IRNA in May that subsidence rates in Tehran are estimated at a concerning 24 to 25 centimetres annually, particularly prevalent in southern areas but spreading elsewhere. She attributed this crisis to the "excessive extraction of groundwater resources and the reduction of water inflow into underground aquifers”, with illegal well usage exacerbating the problem. Land subsidence poses a severe threat to urban infrastructure, including roads, subway tunnels and homes. 

Finally, climate change is contributing to the increasing frequency of dust storms in Tehran, driven by the drying up of both internal and external water bodies.  

While western, southwestern and southeastern Iran have long battled dust storms, Tehran, located centrally, has been increasingly plagued by this phenomenon in the last decade. This past spring saw a particularly severe and unprecedented storm with winds reaching 100 kilometres per hour, widespread dust, and intermittent rain, causing significant damage, injuring over 50 people, and resulting in two deaths. 

“It feels like Tehran's destined to always have a hazy sky. It's those mucky particles in the colder months, and now we're getting hammered with dust storms when it's warm,” said Saeedeh, mother of a 10-year-old girl who is worried about her daughter’s health. 

During such storms, the sky turns a menacing brown, with objects flying through the air, creating truly apocalyptic scenes. Photos and videos, particularly those captured from elevated positions, convey the phenomenon's intensity, showing the city utterly enveloped in a swirling cloud of dust. 

“It's like the curse of Khuzestan has finally reached people in Tehran. Now they actually understand what we've been going through," grumbled Morteza, a 29-year-old motorcycle courier, speaking of Iran's southern province where he came from. 

Professor Bohloul Alijani, a leading climatologist, told Ettelaat newspaper in May that while a direct link to climate change in individual storms is complex, altered rainfall patterns due to climate change can influence their occurrence.  

Sheena Ansari, head of Iran’s Department of Environment, highlighted at an event on waste management in May the alarming statistic that 43% of Iran's wetlands have become dust hotspots due to environmental neglect. 

The increasing prevalence of these storms, often stemming from foreign hotspots in Iraq, Syria and Saudi Arabia, underscores the wider regional dissemination of this environmental issue. 

The confluence of extreme heat, severe drought, land subsidence, and increasing dust storms paints a concerning picture of how climate change is actively reshaping life in Iran's capital, demanding urgent and comprehensive action to mitigate its growing impact. 

This article is part of a series on how the climate crisis is affecting major cities around the world.

The other articles in the series are: 

Cities confront the rising tide of climate change

Taipei’s climate countdown

Accra under water

Jakarta’s sinking villages