How the unbearable heat in US state of Phoenix is killing even cactus plants

Across the world, many countries are battling extreme weather thanks to climate change. European countries including Italy, Spain and Greece are suffering through record-breaking temperatures, while parts of India have been inundated with floods. Parts of the United States, meanwhile, are battling a record heatwave. In the state of Arizona, the saguaro cacti – a classic symbol of the American West – is in peril from the extreme temperature. Let’s take a closer look: What happened? Arizona is facing a heatwave unlike any other in its history. On Sunday, the high temperature in the desert city of Phoenix – which has more than 1.6 million residents – climbed past 43 degrees Celsius for the 31st straight day.

The previous record stretch of that temperature or above was for 18 days in 1974.

The agricultural desert community of Yuma is expecting highs ranging from 40 C to 44.4 C and Tucson is looking at highs ranging from 99 to 111 37.2 C to 43.9 C. The heat has left the saguaro cacti losing arms and in some cases even falling over, scientist Tania Hernandez said on Tuesday. This, as the summer monsoon rains the cacti rely on have failed to arrive – all of which is testing the desert giants’ ability to survive in the wild as well as in cities. “These plants are adapted to this heat, but at some point the heat needs to cool down and the water needs to come,” said Hernandez, a research scientist at Phoenix’s 140-acre Desert Botanical Garden. The garden has over 2/3 of all cactus species, including saguaros which can grow to over 40 feet. Plant physiologists at the Phoenix garden are studying how much heat cacti can take. Until recently many thought the plants were perfectly adapted to high temperatures and drought. Arizona’s heat wave is testing those assumptions. Why is this happening? Cacti need to cool down at night or through rain and mist. If that does not happen they sustain internal damage. As per Mirror UK, this happens as cacti open their pores and absorb carbon dioxide. But the heat is interrupting this natural process and putting the catci under strain. Plants now suffering from prolonged, excessive heat may take months or years to die, Hernandez said. [caption id=“attachment_12940342” align=“alignnone” width=“640”] Phoenix ’s record-breaking temperatures are killing off cacti. AP[/caption] CNN quoted Desert Botanical Garden Chief Science Officer Kimberlie McCue as saying the combination of the extreme temperatures and lack of rains have left the cacti “highly stressed.” McCue added that a saguaro can appear “fairly normal” or feel somewhat squishy before it quickly collapses

Only then does it reveal that it has been rotting from the inside due to extreme heat.

USA Today quoted the National Park Service (NPS) as saying that the average life span of a saguaro is 150–175 years – however some plants can live for over 200 years. But McCue told CNN she and her team have been witnessing more and more of the cacti die since 2020 when record temperatures caused stress in many of the saguaros. “Everyone looks at cactus and says ‘oh, these are desert plants, so they should be just fine.’ But cactus are living things,” McCue was quoted as saying by The Independent. “They literally can’t function, and the way I describe it is they start to suffocate.” McCue said once the plants start dying, little can be done to save them. “If that plant is really starting to shut down, doesn’t matter how much water you pour on them, they won’t be able to take it up and do anything with it,” she added. Cacti in Phoenix are being studied as the city is a heat island, mimicking higher temperatures plants in the wild are expected to face with future climate change, Hernandez warned. ‘Anyone at risk’ Scientists warn that July will prove to be the hottest globally on record and perhaps the warmest human civilization has seen. The extreme heat is now hitting the eastern part of the US, as soaring temperatures moved from the Midwest into the Northeast and Mid-Atlantic, where some places are seeing their warmest days so far this year. The new heat records being set this summer are just some of the extreme weather being seen around the US this month, such as flash floods in Pennsylvania and parts of the Northeast. “Anyone can be at risk outside in this record heat,” the fire department in Goodyear, a Phoenix suburb, warned residents on social media while offering ideas to stay safe. For many people such as older adults, those with health issues and those without access to air conditioning, the heat can be dangerous or even deadly. Maricopa County, the most populous in Arizona and home to Phoenix, reported this week that its public health department had confirmed 25 heat-associated deaths this year as of 21 July with 249 more under investigation. Results from toxicological tests that can takes weeks or months after an autopsy is conducted could eventually result in many deaths listed as under investigation as heat associated being changed to confirmed. With inputs from agencies