Cacti collapsing in extreme Arizona heat

From Reuters

Arizona's saguaro cacti, a symbol of the U.S. West, are leaning, losing arms and in some cases falling over during the state's record streak of extreme heat, a scientist said on Tuesday.

Summer monsoon rains the cacti rely on have failed to arrive, testing the desert giants' ability to survive in the wild as well as in cities after temperatures above 110 degrees Fahrenheit (43 Celsius) for 25 days in Phoenix, said Tania Hernandez.

"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 (57-hectare) Desert Botanical Garden, which has over 2/3 of all cactus species, including saguaros which can grow to over 40 feet (12 meters).

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.

Cacti need to cool down at night or through rain and mist. If that does not happen they sustain internal damage. Plants now suffering from prolonged, excessive heat may take months or years to die, Hernandez said.

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 said.

View of a Saguaro, a resilient desert cactus affected by Arizona's extreme heat and prolonged drought, in Phoenix, Arizona, U.S., July 25, 2023. REUTERS/Liliana Salgado

Out of thin air

From The Guardian

Researchers have created a solar-powered device that produces hydrogen fuel directly from moisture in the air.

According to its inventors, the prototype produces hydrogen with greater than 99% purity and can work in air that is as dry as 4% relative humidity. The device would allow hydrogen to be produced without carbon emissions even in regions where water on land is scarce, they say.

Hydrogen is a zero-carbon fuel that yields only water as a byproduct when used in fuel cells. However, pure hydrogen is not abundant in nature [on Earth: it is the most plentiful element in the universe] and producing it requires energy input. Large-scale production commonly involves fossil fuels that generate carbon emissions.

The study’s lead author and a senior lecturer in chemical engineering at the University of Melbourne, Dr Gang Kevin Li, said the hydrogen-producing device could be powered by solar or wind energy.

A prototype produced hydrogen for more than 12 consecutive days in a monitored trial. “[For] one of them, we left it to run by itself for eight months,” Li said.

The device is comprised of spongy material with a hygroscopic liquid – fluid that absorbs moisture from the air, similar in function to silica gel sachets. The absorbed water molecules are then split at electrodes into hydrogen and oxygen gasses, a process known as electrolysis.

“Hydrogen is the ultimate clean energy … as long as you have renewable sources of energy to electrolyse the water,” Li said.

The device is estimated to produce up to 93 litres of hydrogen a square metre an hour. “If you have 10 sq metres of this unit, you can power a whole house … to replace your consumption of natural gas at home for cooking and heating,” Li said.

The prototypes are still only small in size, and the team has plans to create 1 sq metre and 10 sq metres units in the coming year.

The researchers envisage the device could be a useful tool in regions where liquid water is not readily available for producing hydrogen. “Large parts of the world have water scarcity problems,” Li said. “When you have lots of renewable energy – wind or solar – you [often] don’t have much fresh water for this type of hydrogen production.”

Dr Kim Beasy of Swinburne University’s Victorian Hydrogen Hub, who was not involved in the research, said hydrogen fuel, while important, was not a silver bullet for reaching net zero. “We’re coming to understand that hydrogen is going to be one piece of the puzzle,” she said.

“It’s going to provide us with direction out of some pretty hard-to-mitigate industries such as transport. We have no alternative to diesel at the moment … hydrogen is a really good option.”

The required economies of scale were “probably not going to be reached with clean hydrogen straight away”, Beasy said, citing the expensive price of conventional hydrogen electrolysers. “What we really need is more government support and subsidies in bringing down the cost of getting this technology on the ground.”

The study was published in the journal Nature Communications.

This article was amended on 14 September 2022 to make clear that hydrogen produces only water as a byproduct when used in fuel cells. When burned in air it also produces nitrogen oxides.

Hydrogen is a difficult green fuel.  Its atoms are so small it escapes easily through the atomic lattices of metals, and it makes pipelines brittle.  Converting hydrogen to methane via the Sabatier process makes it much easier to transport and store.  An additional use for this technology is to produce water in deserts.  

a water risk and solar energy potential; b water risk and wind energy potential (excluding coast areas).
Source: Nature

Extreme hotspot: what 60 C means for the Middle East

 From Al Jazeera

Food production is expected to be severely affected as a result of climate change with about one-third of arable land in MENA hit by extreme heat [Saudi Desert  Photo by Ahmed Jadallah/Reuters]

The Middle East and North Africa is already the hottest and driest region on the planet but climate change could make some areas uninhabitable in the coming decades with temperatures potentially reaching 60 degrees Celsius or higher.

The repercussions throughout the Middle East and North Africa (MENA) region would be devastating including chronic water shortages, the inability to grow food because of extreme weather and resulting drought, and a surge in heat-related deaths and health problems.

By 2100 about 600 million inhabitants, or 50 percent of the population of the region, may be exposed to “super-extreme” weather events if current greenhouse gas projections hold, one recent study in the journal Nature noted.

Lasting weeks or even months, the scorching heat would be “potentially life-threatening for humans”, it said.

“We anticipate that the maximum temperature during … heatwaves in some urban centres and megacities in the MENA could reach or even exceed 60 °C, which would be tremendously disruptive for society,” the scientists wrote.

George Zittis, lead author of the study, told Al Jazeera higher humidity from increased evaporation of the surrounding seas will increase the danger.

“Heat stress during summers will reach or exceed the thresholds of human survivability, at least in some parts of the region and for the warmest months,” said Zittis.

Major urban centres around the Gulf, Arabian Sea, and Red Sea – such as Dubai, Abu Dhabi, Doha, Dhahran, and Bandar Abbas – would all see severe temperatures on a more frequent basis.

“Cities will feel an increasing heat island effect and most capital cities in the Middle East could face four months of exceedingly hot days every year,” according to the World Bank.

About 70 percent of the world’s most water-stressed countries are in MENA. As the climate warms further, the social and economic fallout will be intense.

More than 12 million people in Syria and Iraq are losing access to water, food and electricity because of rising temperatures, record low levels of rainfall, and drought, which are depriving people across the region of drinking and agricultural water.

Syria is currently facing its worst drought in 70 years. Aid groups described the situation as an “unprecedented catastrophe”.

“The potential intensification of heatwaves in the already harsh, hot and arid MENA environment is expected to have direct negative impacts on human health, agriculture, the water and energy nexus, and many other socioeconomic sectors,” said Paola Mercogliano, CMCC Foundation’s director of hydrogeological impacts.

Increasing water shortages have already been blamed for igniting regional conflicts, and some researchers fear that fighting over scarce resources will intensify throughout the Middle East and North Africa as the world heats up further.

“Societal impacts may be relatively large …  Moreover, the human population of the MENA region is projected to peak around the year 2065,” Mercogliano told Al Jazeera. “Therefore, the threat to water supplies in the region with temperatures rising is very much serious.”

Water scarcity will also be a financial burden with estimates suggesting MENA will suffer the most of any region around the world, costing governments 7-14 percent of their gross domestic product by 2050.

The agricultural sector, which provides the most jobs in the Middle East and North Africa, could be devastated with water availability declining by as much as 45 percent.

Food production is expected to suffer severely as a result with about one-third of the arable land scorched by extreme heat.

With the warming of Earth already well under way, costly adaption measures will be necessary.

“Adaptation is essential for the survival of future generations under changing climate,” Mercogliano said.

Lebanon is developing hill lakes to conserve and store water for irrigation. In Egypt, efforts are under way to build wave breakers to preserve wetlands and coastal installations from seawater intrusion. In Jordan, treated wastewater is now used to irrigate agricultural areas, she noted.

“A project in Morocco is empowering women to harvest water from fog, while in Jordan another aims to empower rural women to help tackle agriculture in the context of climate change,” said Mercogliano.